Video: Tire Pressure is Way More Important Than You Might Think - The Explainer

Feb 21, 2021
by Mike Levy  


THE EXPLAINER

What's The Deal With Tire Pressure?





While tire pressure isn't anywhere near as interesting as the latest downhill bike, impossibly light carbon wheels, or some battery-powered drivetrain, the boring truth is that's far more important. None of the latest and greatest gear will save your ass if you're way out to lunch when it comes to tire pressure. And if that describes you, the best-case scenario is that you're not getting the most from your expensive bike. Maybe you'll need to buy a new tire or rim. Worst case? You end up on the ground, possibly even injured, and all because you didn't check your tire pressure.

Today's Explainer covers the basics of tire pressure, and we'll talk about why you should care, what you should look for, and I'll try to convince you to finally buy (and use) a pressure gauge.

Previous Explainer episodes:
Episode 1 - What's the Deal with Linkage Forks?
Episode 2 - Carbon Fiber Leaf Springs
Episode 3 - What's the Deal with Chains?
Episode 4 - What's the Deal with Cross-Country Racing?
Episode 5 - The Basics of Modern Mountain Bike Geometry
Episode 6 - Why Are We Using 12-Speed Drivetrains?
Episode 7 - Decoding Mountain Bike Tire Hot Patches


280 Comments

  • 200 11
 30 psi in my minions
  • 100 4
 I do care about levy's opinion
  • 46 123
flag IntoTheEverflow (Feb 21, 2021 at 7:30) (Below Threshold)
 I don't care about your opinion.
  • 13 6
 @Forest-Gnome: ride so fast cus I run 300 dollar carbon pedals
  • 34 1
 28.99 (too soon?)
  • 10 0
 yes!!!!!! and 32 in my rear when I am doing Jamaican tours so we can keep on riding with all the tyre ripping and thorny lava and corral..... even fresh cut grass is like nails in the Westend. besides the Godfather agrees.
  • 7 3
 30 psi my Assegai.
  • 31 1
 @IntoTheEverflow: whoever downvoted this lived in a cave untill now or does not ride park exclusively...
  • 21 41
flag Dornbox (3 days ago) (Below Threshold)
 30 psi sounds insanely high to me. Granted I don’t know what it is but Minons always feel super squirmy unless I run them around 25psi But every other tire I run, 21 in front and 19-20 in the rear. Anything more then 21 psi in new England has me sliding or bouncing off our always damp roots. The only time I find rim or torch a tire is when I have a bad landing on a rock or an extremely bad line choice while doing “Mach Enduro”. Maybe it’s my hard tail or ridged MTB upbringing that’s blessed me with the gift of proper line choice but 30psi sounds like a day at Rampage or Crankworks to me... or a road ride.
  • 22 3
 @Dornbox: you must weigh like 100 pounds
  • 11 1
 @jackheat: I run 22 rear, 20 front. 155lbs, still on my original rim. A lot depends on rider weight, but also sag preferance, tires, and riding style.
  • 2 4
 @jackheat: I’m typically 175-190 fully kitted with a pack depending on the time of year. Pre tubeless days I did flat a lot... lot... lot. But since going tubeless 12 or more years ago, the worst I’ve done is blown a tire off the rim on an off camber landing or something equally stupid. Although in my old age I’m now riding more Park and DH / Enduro than ever so knock on wood.
  • 6 0
 @Dornbox: that casing do you ride, that's also important.
do you have inserts?.
it is also strange that you ride less pressure on the rear than the front tire
  • 3 1
 @tiagomano: typically mid / trail casings. Never DH. Your right about the pressures, I flipped them in my post. *Front is 19-20 and rear is 21.
  • 1 0
 @Dornbox: I find with the excellent traction of the Assegai running a slight higher pressure in the front is better for jumps as the bike feels a little more balanced with rear slightly draggin (slowing the bike on upramp) more than the front.
  • 25 0
 www.youtube.com/watch?v=QyTyjQbvylg

1:36, since no one seems to get the reference.
  • 1 0
 Tire pressure is just like an opinion, to each it's own!
  • 1 0
 @dwee 30 front 35 rear on my Mary's.
  • 95 1
 to be accurate, higher volume tires do not allow you to run lower pressure because there is more distance between the carcass and the rim in his balloon analogy. higher volume tires allow you to run lower pressure because they have more surface area...er, you know, the square inches part of PSI. the greater the surface area, the more the load...er, you know, the pounds part of PSI, is distributed throughout the carcass of the tire.
  • 26 4
 To be fair, its both. Ultimately it's down to energy absorption, so its force times distance. Force (as you say) is going to be down to the area being pushed in, which increases as you push deeper and have to deform more tyre. But the distance part is, as Mike says, down to that distance to the rim; and that distance to the rim will increase the area being pushed too. So wider tyres are win win win.
  • 13 1
 Came here to say this. For those of you that want to get even nerdier - Pressure = Force/Area, or Force=Pressure x Area. That force is effectively the one that keep the tyre from smushing (I know it's not that simple, with change of pressure with volume when the tyre deforms, but its a pretty good approximation). The area is the contact area with the ground. If you increase the area you need to decrease the pressure to retain the same force. You're welcome fellow bike nerds.
  • 4 7
 Correct! Bigger contact patch from a large tyre means you’ve got more force on the ground for a given amount of tyre sag and air pressure.

This is also why you can run more pressure for spiky rocky trails vs smoother dirt and root trails - the spiky rocks press on less of the contact patch, in effect shrinking it.

On my hardtail I can drop the pressure by over a quarter when going from dry sharp rock to wet slippery mud and roots, running the same tyres.
  • 4 4
 @threehats: It's exactly opposite. Bigger contact patch means there is less force per square inch and thus you can get away with lower pressure, which means less counter acting force.
Which also means that tire pressure depends on wheel size, since 29er has naturally more contact patch for the same tire width.
  • 10 4
 I disagree. The total tire carcass toroidal surface area (which is what you seem to be referencing) is largely irrelevant. Contact patch surface area, of course, is critical. And for a given bike/rider effective mass, the contact patch surface area is determined *solely* by the PSI, and has nothing to do with carcass size. If the PSI is the same, a lower volume tire and a higher volume tire will have identical contact patch surface area. That is a simple byproduct of equal & opposite forces. The shape of the contact patch at the same PSI may differ somewhat between tire/rim examples (ie, longer/skinner vs shorter/wider), but the actual surface area will be identical.
A larger tire doesn't enable lower PSI because it has more total carcass surface. It allows lower pressure, in part, due to the balloon analogy (larger cylindrical cross section in region adjacent to ground = greater distance from trail to rim to absorb cumulative force before bottom out) and, importantly, the wider rims that typically come along with larger tires. Wider rims support a sidewall "geometry" that is less vulnerable to collapse under cornering pressure, so we can run lower pressures before negative consequences creep in.
Wide rims, stiffer sidewalls and larger tires geometrically suited to those rims have all combined to make lower pressures viable for riding compared to 10+ years ago.
  • 8 8
 @threehats: "bigger contact patch from a large tyre" . . .
A large tyre does not equate to a bigger contact patch. Only a lower pressure will result in larger contact patch. (assuming the same bike/rider mass).
  • 9 8
 @lkubica: "29er has naturally more contact patch for the same tire width"
Not exactly. At same PSI, a 29er may have a different shape contact patch compared to a 26er (probably longer/skinnier if same tire width), but the surface area of the contact patch will be identical.
  • 4 6
 @Barrold: "I know it's not that simple, with change of pressure with volume when the tyre deforms"
Meaningful changes of tire pressure when MTB tyres deform is essentially a myth. The rise in pressure as a tyre conforms, over even a large-ish obstacle, is insignificant.
It comes down to PV/T = PV/T. The rise in pressure when the tire is deformed is directly proportional to the reduction in volume caused by the deformation. Even in the case of a bottom-out event, the reduction in internal tire volume is on the order of 1-2% (I won't bother you with the toroidal volume math to reach that; its fairly intuitive if you just imagine the size of the deformation compared to the other 100 inches of circumference). So tire pressure would only rise 1-2% during the deformation event. Insignificant.
  • 44 2
 I also came here to tell people I'm an engineer!
  • 7 3
 @Inertiaman: This is false. All you need to do to test your theory is to take your example to the extremes. We'll use a 26" 2.4 tire, and say like a 200" 2.4 tire--imagine a monster truck sized tire in a 2.4 width. Because of the angle of attack of the larger wheel, *much* more of the tread will be in contact with the ground at a given tire pressure. Especially in the real world where surfaces like dirt/mud have give or ground surfaces are uneven.

Now a person can have the debate that between a 27.5 and a 29" wheel the difference in contact is minuscule and thus negligible, but larger wheels do, in fact, have a larger contact patch.
  • 17 3
 @mikealive: Sorry, you're wrong, not because I say so, but because Newton says so.
Assuming your two examples have the same bike/rider mass, then a very direct application of Newton's Third Law dictates that a 26x2.4 at 30psi and a 200x2.4 at 30 psi will have an identical contact patch surface area. The dramatically different angle of attack in these two examples will absolutely yield a different *shape* of contact patch, but the actual surface area will be identical in both cases.
The contact patch surface area is solely determined by the force and the PSI. Say 90 pounds of force (150 lb rider + 30 lb bike equally distributed across two wheels) at 30psi: 90p/30psi = 3 sq inches.
As a contrary example to help you imagine this, take your monster truck that weighs 6400 pounds, distributed equally on 4 tires, so 1600 pounds per tire. If those tires are 40 psi, the contact patch must be 40 square inches per tire (40 x 40 = 1600). There is no other possible answer. The tire size is not even part of the equation.
This, of course, ignores corner cases which would not actually represent a pneumatic tire system. For example, a 700c x 23 road tire at 5 psi will completely bottom out, at which point its not a pneumatic tire system, but essentially just a strip of rubber on the rim.
  • 3 1
 @Inertiaman:

I’d say the truth is somewhere in-between —— static contact patch being one thing, but active/dynamic contact patch is effected by tire width, in my opinion & experience——-

2.0 tire at 30 psi deflects (verticals travel) a certain amount on a certain bump/impact. 3.0 tire at 30 psi deflects much less on the same impact. Not 100% sure of theory, but this is borne out in tons of miles on different tires, and general sense of comfort/ traction when switching sizes
  • 4 16
flag mikealive (3 days ago) (Below Threshold)
 @Inertiaman: You need less 'hoiven' and more 'broski' in your approach. This is not lab work dude, not that hard to grasp honestly, lol. You're not working with mathematically perfect spheres and planes.. as noted by the part where I stated (and you ignored) "real world where surfaces like dirt/mud have give or ground surfaces are uneven." Stay in the lab though, I'm sure you have some pencils that need sharpening.
  • 6 3
 @AckshunW: Absolutely the contact patch surface area will increase when dynamic factors increase the effective force on the wheel/tire. But that *area* increase must, by definition, be identical regardless of tire size.
Cornering, bumps, etc will perpetually change the shape of the contact patch.
I'm NOT stating that different tire sizes *behave* identically if at the same pressure. There are many variables at play that will influence the ride characteristics (sidewall stiffness, contact patch shape, etc) and no doubt these will manifest themselves in ways that riders will notice.
If you accept the fact that the contact patch surface area is the same at given PSI regardless of the tire size -- and it is a fact, not a theory -- then it may actually HELP you conceptualize what parameters really are driving your real world observations.
  • 18 3
 @mikealive: This is hardly lab work. Its basic high school physics. Real world dirt and mud do not exempt things from the law of equal and opposite forces. This isn't even remotely a controversial concept, except in MTB forums. You can literally download a spreadsheet that computes tire patch shape based on tire dimensions and pressures . . . you can visually see how the patch changes shape, but not size, as tire dimensions are manipulated while pressure is held constant.
Even things like uneven ground surfaces can be modeled, by using an intersection of a torus with shapes other than a plane. It will absolutely influence the shape, but not the the size, of the patch
As I noted to @AckshunW, please consider that I am not challenging your real world perceptions of how different tires behave. I am simply illustrating that these behaviors are not due to tire-size-driven impacts on contact patch surface area. Rather than mock me (incorrectly, fwiw) as a lab nerd, you could perhaps accept these centuries old concepts as the physical facts they are, and assign your real world observations, more accurately, to other variables.
  • 2 1
 @lkubica: And anyone else who disagreed with me - read what I actually wrote. I started that as the contact patch enlarges whilst the tyre sag stays the same and the tyre pressure stays the same, the ground force has to increase. This is physics.

What you have all failed to consider that this statement means that the load on the tyre has to increase - ie the mass of the rider+bike. Therefore as this load does not increase in a static situation, either the tyre sag or tyre psi (or some of each) must decrease.

Optimum handling comes from having the right amount of tyre sag for the conditions and your riding style - this is what it’s really all about. Air pressure is how we measure it but it’s the sag that really matters, just like with our suspension.
  • 4 1
 @Inertiaman: Basic high school physics is a massive oversimplification when we’re looking at the behaviour of pneumatic tyres in the real world.

Again, it’s all about tyre sag. There is an optimum amount of carcass deflection for a given situation. You cannot achieve that optimum amount of tyre sag and identical contact patch sizes when using two tyres of very different volume and diameter - the smaller tyre will either have too much sag or a smaller contact patch.

Simplifying vehicle dynamics to school level Newtonian physics is a fool’s errand.
  • 5 4
 @threehats: I carefully read what you wrote. Its wrong on multiple levels.
"as the contact patch enlarges whilst the tyre sag stays the same and the tyre pressure stays the same, the ground force has to increase. This is physics."
How could the contact patch possibly enlarge while the tyre sag stays the same? Aren't these just different measurements of the same parameter (tire compression/conformance)?? ie more sag = more patch.
Secondly, you seem to be saying that one can increase contact patch, keep the same tire pressure the same, and as a result the "ground force" must increase. This is true, but the "ground force" cannot increase unless the equal and opposite "rider force" is increased. A larger tire cannot magically create a larger contact area and therefore a larger "ground force" independently of the rider force. The "rider force" is defined by the mass of the rider/bike and any dynamic/accelerating forces (g-outs, or pumping through trail undulations). You can assume whatever you'd like for that force, but by definition the ground force must match it. And contact patch surface area at the intersection of that ground force and rider force will be determined by those forces and the PSI . . . period . . . the tire size has nothing to do with it.

I agree its all about the tire sag . . . sufficient to get great traction, but not so much that bottom-outs and rollovers are likely. But sag in a MTB tire is almost exclusively determined by air pressure, and to a lesser extent, sidewall stiffness.

In good faith, I really think your observations can be explained by the different *shapes* of contact patches. All else being equal, wider tires = wider/shorter patch, and larger diameter tires = longer/skinnier patch. Adding to that, its intuitive to me (could be wrong) that wider/shorter patches may aid more in cornering, while longer/skinnier patches may aid more in climbing. So undoubtedly a rider's preferences could lead them to a particular tire dimension favorite which cannot be duplicated by a different size tire at the same PSI (despite that tire having the same surface area of contact patch).
  • 11 0
 @eldsvada: allways alot of rocket surgeons here!!!
  • 7 1
 @kawin20: and brain scientists.
  • 13 1
 At age 74 I'm always so appreciative of those who have the time to "count the number of angels on a pinhead" and debate it ad infinitum, or use their quasi-scientific knowledge to explain their wisdom. Especially if they don't bill by the hour!! (Apologies to those who do).
I'd suggest picking some tire pressures you find useful and seeing if they work for you. Then adjust accordingly.
Unless you're racing at the highly competitive level and/or chasing personal bests, the trail conditions that day, your personal mental/physical/emotional state, and risk tolerance are probably more important.
Apologies for digressing from the infinitesimal to the big picture; but a long-term 95% solution has always been my credo! :-)
:-)
  • 5 0
 @Inertiaman: “ "as the contact patch enlarges whilst the tyre sag stays the same and the tyre pressure stays the same, the ground force has to increase. This is physics."
How could the contact patch possibly enlarge while the tyre sag stays the same? Aren't these just different measurements of the same parameter (tire compression/conformance)?? ie more sag = more patch.”

Because I’m comparing tyres of different volume.

“ Secondly, you seem to be saying that one can increase contact patch, keep the same tire pressure the same, and as a result the "ground force" must increase. This is true, but the "ground force" cannot increase unless the equal and opposite "rider force" is increased.”

Yes, that is what I said. Read it again. I fixed the other variables so the applied load, either static system weight or static weight +/- dynamic loading has to increase to maintain sag with increasing contact patch at fixed psi. Therefore a larger volume tyre needs lower psi to maintain sag due to the increasing contact patch for the ideal sag.
  • 2 1
 @jddallager: Well said, Can't help but think that all these over thinkers even know what it's like to actually ride a bike and actually enjoy it for being exactly that. Ride your bike
  • 2 3
 Contact patch is proportional to pressure and nothing else. The contact patch multiplied by the pressure equals the upwards force that supports the rider.

A 24" x 1.25" BMX tyre with 20psi has same contact patch has 29" x 3.0" tyre.

All other effects are incorrect. There difference in contact patch shape, but not area. Knobs complicated the issue slightly, but not carcass flexibility, or any other such nonsense.

This is such simple physics, it drives me mad that no-one understands!!!
  • 1 0
 It's true.
But, this means that a wider tyre uses less "travel" than smaller tire given the same pressure. Since the contact patch has the same area, it has to be "shorter" for a wider tyre, which means that the wider tyre uses less travel.
The same with wheel size - it requires a greater force to load a 29inch tire by 1cm than for a 26 inch tyre, because for each 1cm of "travel" contact patch grows quicker for tire with more diameter or wider tire.
So, you can have less pressure in a 29inch tyre then in 26 inch tyre even if they have same width and "height".
And this is something we all experience every day. That's why 29ers are said to have more grip - you can get away with less pressure/larger contact patch with the same bottom-out resistance as smaller tire.
  • 4 0
 As with most mechanical systems, it's all "a little more complicated than that"... Tyres are complicated because the carcass has stiffness as well as the air pressure behind it. If you let a car tyre go completely flat, the rim probably won't touch the ground, for example. You could roll around on a bike on a few psi on tarmac and not have rim to ground contact, and the contact patch won't follow pressure = force/area. But no need for physics - just find the pressure you're comfortable with and tell everyone else they're wrong!
  • 2 0
 @Inertiaman: Are you not conflating the pressure inside the tire with force exerted by bike and rider on the ground, or are they the same thing?

If I put my bike on the work stand and inflate my tires to 30psi there is 30 pounds of force applied to every square inch of the tire, it has noting to do with the force between the tire and ground.
  • 3 0
 @Inertiaman: Slow day at the Jet Propulsion lab?
  • 5 1
 @Inertiaman: "This is hardly lab work. Its basic high school physics."

You're right, if tires followed an ideal balloon model you'd use in high school physics, contact patch wouldn't change with tire size. However real tires don't work like that. You have to account for the structure of the tire adding load support. For example, non-pneumatic tires exist. Their contact patch size isn't influenced by pressure at all. Normal tires fall somewhere between your high school physics model and the non-pneumatic tire model.
  • 2 2
 @jeremy3220: I recognize that the tire structure can play a role in the force transfer equation. A car tire can support hundreds of pounds on the sidewall structure alone. Your airless tire example is another extreme case. However, its not the case we're discussing here. The force supported by the sidewall structure in a typical MTB tire is so very low that it is insignificant in our context (ie, comparing tire patch size on two tires at typical operating pressures with only modest difference in diameter or width). I have a front wheel with an EXO sidewall Minion sitting in front of me with zero PSI. It can't even support the trivial weight of the wheel; the rim is resting on the floor. So the sidewall element supporting rider load is less than ~3 pounds compared to a minimum of 80-120 pounds of force being transferred. An extremely stiff downhill carcass would raise that 3 pound value, no doubt. But it will still amount to a largely insignificant factor in determining the contact patch size under operating loads, and even if one argues the small factor is "significant" it will cancel out when comparing two differently sized tires of similar carcass construction.
  • 2 2
 @ChiefSilverback: It may help to proactively distinguish pressure (the psi in the tire) from force (the pounds supported). In your work stand example, the force between tire and ground is zero and the contact patch is zero. Think of the pressure in the tire as the baseline state of a pneumatic system. The tire carcass structure, bead, rim, etc serves as a structure to support that system. So you can have 30 psi in the tire even if its not supporting a load. But when it does support loads, it does so at 30 pounds for every square inch that is in contact with the ground.
  • 2 2
 @mountainsofsussex: The system is complicated, but the determinants of contact patch are relatively simple. While sidewall stiffness can support some force independent of tire pressure, it is an insignificant amount in our typical MTB tire case. One can see this directly if you let all the air out of your tires: the bike weight alone is more than enough to leave the rims resting on the ground. With stiff downhill tires, the factor will be greater, and I might consider its role significant in extreme low PSI examples, but at riding pressures it will diminish greatly.
Whatever support *is* provided by the sidewall, the factor will essentially cancel when comparing two tires of similar construction which differ only in size (the fundamental "argument" here is the false claim that, all else being equal, a larger tire will have a larger contact patch than a smaller tire).
  • 3 0
 @Inertiaman:

But what I was trying to say (and I think everyone else), is that tire “travel” matters much more than static contact patch, it terms of how a tire feels / traction produced.

So that’s why different width tires need different pressure to feel similar.
  • 3 0
 @Inertiaman: Not really, that's why casing design makes such a big difference in handling characteristics in mtb tires.
  • 4 0
 @Inertiaman: You’re looking at a static system to analyse a dynamic system. Take that completely flat tyre and roll it down a hill - it will then usually support itself. This stuff is deeply complex and oversimplifying it to basic school physics just creates more confusion.
  • 2 2
 @AckshunW: Different tires need different pressure to feel similar. Tire "sag" or "travel" matters more than static contact patch size when trying to reach optimal tire performance. I have absolutely no problem with those statements.
My arguments here have been very specific: to refute the notion that all else being equal (carcass construction and PSI) a larger tire will have a larger contact patch than a smaller tire.
In practice, a larger tire may i>correspond/i> to a larger contact patch, but that is because it is typically run at a lower pressure and can still provide good ride characteristics at lower pressures.
  • 2 2
 @threehats: I didn't initiate the static case. An assertion was made that a static comparison of two tires of different size and same PSI would show a larger contact patch on the larger tire. It is that notion, and only that notion, that I am trying to debunk.
Illustrating the relationship between PSI and contact patch in a static context is highly relevant, even to the dynamic case. The fact that dynamic factors complicate the system behavior does not negate the static baseline parameters.
  • 1 2
 Overthinkers are the folks that build cool shit for us mooks. And just because youre too simple to understand the engineering doesnt make you a real life coach.
  • 3 1
 @Inertiaman: The assertion I made did not state constant load, it stated constant sag. Either you don’t understand that or you don’t want to understand that because it means admitting you’re not very good at reading.
  • 2 0
 @Inertiaman: This whole conversation is awesome! It seems like it’s really a function of the tire stiffness and the fluid pressure and viscosity of the air which mean these components could be analyzed separately using computation fluid dynamics and see how it responds to different wave functions inputs. Could we get someone actually create this model? Maybe we could mathematically optimize tire pressure.
  • 2 1
 @Joegrant: it's not a mountain bike tyre, but here's a thesis on the subject. At lower pressures, it's extremely non linear, presumably as the carcass stiffness becomes more difficult. That's probably more similar to the regime is mountain bikers operate in. www.google.com/url?sa=t&source=web&rct=j&url=pure.ulster.ac.uk/files/11388459/Measuring_grip_and_the_contact_patch_9780784413005.278.pdf&ved=2ahUKEwj7n-TE0f_uAhUJAcAKHS1MBrwQFjAVegQIGBAC&usg=AOvVaw1I_kxP_XjPL700tW7ljZtM
  • 1 0
 i found the engineers thread
  • 96 1
 Just pick a tire pressure, and be a dick about it.
  • 18 1
 Wow buddy running 29psi over here. Sir we only accept 30psi in our group rides /s
  • 6 0
 @lehott: run 29psi front 27.5psi back - only acceptable pressures for 2021. Best of both tire presures.
  • 72 3
 Where are the 15 psi bros that wonder why they crack or dent rims? "but but I need traction......"
  • 9 1
 That is what lifetime warranties are for. Running stupid low tire pressures, so you don't have to worry about destroying wheels. ;P #sarcasm.
  • 18 3
 It works great when your a 130# rider
  • 7 7
 @5piggies: Not really, my experience is that I cannot go lower than 23psi at the back and 20psi in the front. And even then I add a few for the trails that demand more. It all depends on your speed, riding style and the trail.
  • 3 0
 @tonit91: I should add I don’t get big air either
  • 49 5
 @tonit91: to be fair mate everyone was wondering what pressure u run
  • 6 1
 Ever since I started using inserts I now have sick traction and I don't change rims every season ;P
  • 6 70
flag conoat (Feb 21, 2021 at 9:58) (Below Threshold)
 @5piggies: it's the only bonus to being a 130# weakling though, so you there's that. Oh.....I guess all the extra time you have to ride since you aren't getting laid!
  • 6 2
 @mackay66: Just sharing my experience, that's all.
  • 2 2
 @tonit91: Yep. If you’re smooth enough and can pick good lines you can run less pressure and corner faster.
  • 18 0
 @conoat: wtf are you compensating for? Got a tiny pecker or something?
  • 3 1
 @jclnv: corner faster until the tyre tears off the rim, then you faceplant. Its a fine line working out low can pressures go.
  • 4 2
 @smuggly: Yep, rider skill is key. Voulioz ran 21psi front.
  • 2 0
 @5piggies: I'm 135lbs and not running anything near 15psi. Running 25+ psi/rear/ 22+ psi/front even with DH casings. I think you have to be a 75lb rider. Lol.
  • 6 3
 @tacklingdummy: I ride lots of roots and wet terrain in the PNW If i were down in so Cal, I would probably run more pressure for the rocky terrain. I’m also 60yo, so not the biggest thrasher on the mountain.. I just like riding with friends and cleaning some tough climbs, then going home and making passionate love to my wife Wink
  • 2 0
 @labrinsky: 3 inches at 90mph will still do some damage... (for my metric friends thats 7.62cm and 144.841kmh)
  • 1 2
 @tacklingdummy: I'm 132lb and am running 14-17psi on the front with cushcore and tube. In the rear I'm running cushcore and tube with 17-20psi. EXO casing. No flats, tons of grip and no more broken/dented rims.
  • 2 0
 @SintraFreeride: Nice. Interesting setup with the tubes. Cushcore is a different setup for sure. Can run lower pressures. I just don't want the extra weight.
  • 2 0
 @tacklingdummy: I have found that running cushcore with tubolite tubes and exo tires comes out to about the same as dh tires setup tubeless so no weight gain.
  • 1 0
 @SintraFreeride: Tubes with Cushcore?!?!?
  • 1 1
 @G-Sport: It avoids the mess of sealant, hehe. The tube only weighs 44g.
  • 1 0
 Why so high? I run 13-13.5psi...though that is on my hardtail with 3" tires and I weight 150lbs.
  • 1 0
 @SintraFreeride: Interesting, just never heard of anyone doing this. So you've cut holes in the Cush core for the valves to poke through presumably... Isnt it super hard to mount everything?
  • 3 0
 Avoids the mess of sealant but now you can get a flat from a thorn and have to deal with removing cushcore to change a tube. To each his own but I avoid tubes like the plague.
  • 1 0
 @G-Sport: I just poked a hole for the valve to pass through. It doesn't effect the performance of the insert. I run narrower tubes so the installation is about the same.
  • 1 0
 @labrinsky: Yes it is prone to thorns but where I live that is highly unlikely.
  • 65 1
 Always start high.
  • 12 0
 nice.
  • 2 0
 It’s a must
  • 47 2
 In all seriousness Levy is dead on in this one. I'll not touch a knob, dial, doo-hickey on my suspension for years... but I will check my tire pressure before each ride. And if I have it off by a couple PSI... I'll feel it. Low(er) pressures and cushcore are a godsend.
  • 6 1
 Yep, me too. Also, you should check out Tannus Tubeless for your next round of inserts. I used to use CC pro, but recently went Tannus and I get all the benefits of CC pro at almost half the weight, lower cost and they don’t cut up... so far anyway, don’t seem to be a wear item like Cush Core.
  • 3 0
 @islandforlife: I've heard Tannus inserts were really good, I think I might try those out next time. I did however put cushcore to the test - and it did the job. I sliced rear sidewall @ top of Racerocks in Cumberland.. rode that sucker all the way down to the Rec lot (mostly fire roads). I figured.. 'well I got these damn things for this reason.. lets see what happens!'
  • 45 1
 You mean I'm not supposed to fill it up to the recommended PSI printed on the sidewall?
  • 9 0
 Actually yes. Yes you are.
  • 22 1
 Trust us. Levy was wrong, he's just trying to create buzz to drive clicks and engagement. Yes, you want to start with the recommended PSI on the sidewall.
  • 6 1
 This whole site is funded by Big-Air sheeple!
  • 4 1
 @TEAM-ROBOT: hey! Back to your vital home!
  • 1 0
 That's the right pressure if you fill the whole tire with sealant - don't get yourself confused here
  • 3 0
 The tire some manufacturers recommend doing exactly that for 24 hours to allow the carcass to stretch. I have heard this mentioned by Maxxis and Schwalbe reps on different podcasts.
  • 3 0
 @Avanwin: wow, never heard that. I'll try next set of new tires I have, thanks.
  • 2 0
 @TheLoamDeranger: they recommend using a tube for this stretching period, then continue with your regular tubeless setup. I'm sure tires eventually stretch to their intended size with normal riding but this maybe a good way to get them broken in a little faster.
  • 43 8
 I was pretty pumped to see this video, hopefully it blows up and gets some serious traction, not too inflate your ego too much.
  • 15 2
 The naysayers will tell you that your puns fell a little flat, but I still think you're riding high my friend!
  • 2 0
 I just got a puncture in my tyre, it's depressing
  • 26 1
 I dont trust my gauge so I count how many pumps until my tire looks right. Usually I run 112 pumps in the front and 136 pumps in the back. Also I found watered down stucco works better than sealant in my tires.
  • 8 0
 We need a YouTube video from you on this method.
  • 3 0
 magicthumb^TM does away with full deflation for pressure regulation.
  • 22 1
 I just put a picture of Sam Pilgrim on my pump and pump to the max PSI. I try to keep my tires off the ground as much as possible.
  • 23 3
 still runnin' 32-35 in my DH casing minions with cush core. maybe i should lose some weight
  • 14 4
 Unrideable. I think my teeth would rattle out of my face at those pressures, and I weigh 190 pounds.
  • 6 1
 @TEAM-ROBOT: I've been struggling with it for years. I'm 200lbs - it's probably a combo of riding style which i've tried to clean up, stiff suspension set up, and maybe super short chain stays which make me plant a ton of my weight on my rear wheel. high PSI seems to have the best results because I just like dirty cheeseburgers too much. miss yer website.
  • 4 0
 Finally someone who understands. I started running DH casing tires with inserts after destroying every brand and tire casings up to DD from Maxxis in short order. When I tell people my setup they of course assume its overkill I am overstating the issue, hahaha. Like you, 200lbs, short chainstays, and I don't ride carefully...at all.
  • 3 1
 @Maestroman87: similar weight and I've always ran like 30-32psi in my DH bike and 29er and I break EVERYTHING. I've never had a cracked rim though similarly, where as a dude in my group at Retallack obliterated his ENVE in front of me, and psi in the lower 20's makes me feel like I'm folding over the sidewall. I can do mid-high 20's without much fanfare but I prefer it a little more. "Unrideable" at 32psi means you need to have somebody help you tune the suspension more. Using the tires as a low speed compression bandaid ain't the way. Let the tires do their job, let the suspension do its job. Also though... maybe I should lose some weight haha
  • 4 1
 I get you guys are bigger but something is up with how you ride if you’re destroying that many wheels and need those kind of pressures especially with cushcore.
  • 9 0
 @MikeyMT: I remember a conversation with the Fox suspension techs at Whistler as I was getting ready for the Air DH race on A-Line. That year there were a million bomb holes in the berms on A-Line, and if you hit them they were crazy rough. I asked the suspension techs how they would recommend tuning my suspension for those big hits. More air pressure? More tokens? More high speed? Slower rebound? There advice was to avoid the holes. I said "You're kidding" and they said no, we can't do anything to your suspension for those holes that won't make your suspension feel like doodoo everywhere else in your run. Avoid the holes.
  • 5 1
 @MikeyMT: I think if I were running EXO tires, I could see running 32 psi in a front tire in certain situations. But 32 psi in a 29" downhill casing front tire with cushcore on a trail bike? Sounds insane. Anything over 25 psi for me and the bike starts to feel ROUGH.
  • 2 0
 @MikeyMT: Fair enough. I also don't use cushcores though. I literally can't recall the last time I got a flat though (to be fair there's not much shale out this way but you do get root/rock sidewall tiny punctures over the course of a season), and I've had a custom set of wheels rocking on both my bikes for 5 years without touching the spoke tension a single time. I've broken frames, pedals, cranks, shocks, hubs... I'd like to not add rims to that list. EX571's, DT Comp spokes, Hope Pro2 Evo hubs, brass nipples... and keeping pressures around 30 seem to have done me right so far.
  • 1 0
 Similar weight. Lots of rocky trails and some local race laps. Also running Cushcore front and rear and run Assegai front and Dissector rear, both DH casing, and run them at 26F and 28R for pressure. Stans Flow rims. Minimal issues with punctures (none last year...). Two seasons ago I ran a similar pressure but with E13 rims and had a bunch of issues with flats. I've had rims in the past that felt easier to puncture on also so believe that rims can be a factor. You do what works for you... but don't be afraid to mess around and try other things also. I have tried running lower and like the velcro traction feel but don't love the squishy/unpredictable feel at higher speeds trying to corner or the increased risk of punctures. For me, 26/28 feels like a good compromise. I ran 28/30 for years but have been trying to soften up my tires and suspension (which I usually ran quite stiff) over the past few years.
  • 1 0
 @TEAM-ROBOT: that must of been 2017 lol. It was bad that year with all the smoke too. No Cushcore 24-28 seems about right. Cushcore...try lower or change your riding style. I’m typically running 18F 20R with carbon hoops and Cushcore. 20/22 in the desert. No flats or broken wheels for years. I’m no Gwin or anything but above average for general population.
  • 1 0
 @TEAM-ROBOT: just no need for more than 25 with Cushcore. Even at the gnarliest bike park.
  • 1 0
 @TEAM-ROBOT: Yup. As much as they'd like you to believe otherwise, there is no "ideal" suspension setup that works for every terrain.
  • 1 0
 @MikeyMT: My problem going under 26 is that I will get too much tire roll on jump faces and berms, Charlie probably has the same issue. With inserts it's not that the tire is rolling off the bead letting air out, it's just enough squirm when pushing hard to throw you off balance/line. Robot man rides faster than the average weekend warrior/racer and has to run fairly more aggressive settings than the average guy.
  • 1 0
 @adamdigby: How wide of rim...I found I had the same issue with a 25mm rim...30mm rim no issues with roll.
  • 18 0
 Bad rim tape jobs are the worst.
  • 8 0
 The tire is the most important part of any vehicle. It is your link between earth and machine.

Can we have more on tire inserts? You mentioned about the balloon, and the air volume inside... but can you hit on the different types of insert and how they affect inflated performance ie: Hucknorris vs Airliner vs Cushcore?

Airliner envelopes the whole tire, where Cushcore only 1/4 to 1/2, and Hucknorris is just a small strip. This changes the air volume and the way the tire not only responds or rebounds, but also how it conforms to the ground. One point I'm curious about - does each style change the rolling resistance at given pressure?
  • 1 0
 Second
  • 12 0
 I always start high.
  • 7 0
 Check tire pressures and fork/shock pressures before every ride religiously. It’s a major key to making every ride good and KNOWING ,not guessing on setup. And everybody else’s tire pressures are just that,theirs, unless you are both using the same pressure gauge, tires,inserts,etc...Also, digi shock pumps are the only way to go. You can be off 2-3 psi either way every time with a standard pump and then can’t understand why your bike feels different every ride. Doesn’t mean a thing if you spend 7-10k on a bike but don’t set it up right.
  • 1 0
 What makes a digi more reliable than an analogue pump?
  • 11 0
 Your mouth says 24psi but your eyes say 420
  • 11 2
 After a helmet, the next best mtb kit is a topeak digital tyre gauge.
  • 7 0
 It must have taken a long time to get so many clips of @mikelevy crashing like that. Kudos also for making it look so realistic.
  • 5 0
 I find tire pressure very seasonal.

In the summer in the PNW, I can run 28-30psi and that feels great.

In the wet roots and rocks of wintertime, I feel like I’m riding a ping pong ball at those pressures.

The problem was that if I lowered pressure enough to feel like I had “any” traction on the roots, it would feel squirmy in any berms when I had any pace.

Tannus tubeless inserts seem to have let me have my cake, and eat it too, so to speak. I can drop pressure and track through root gardens without bouncing and sliding off line like I did at 30psi, and I can not squirm in the berms. Good stuff.
  • 2 0
 You like them better than cushcore?
  • 3 1
 @diegosk:

Haven’t tried cushcore, sorry.

But Tannus tubeless was cheaper, lighter, and easier to install (did my second wheel 100% by hand).

So far it’s been great for me. It lets me run about 4-6psi less and retain about the same cornering support and feel. Which means that I’m running 18-20psi in the rear right now, whereas before if I dropped below 24psi it felt like I was using a marshmallow as a rear tire in the berms.

I’m 190-200lbs geared up, and using a DD equivalent-ish casing Michelin Wild Enduro rear tire, if that helps you at all.
  • 7 3
 Hey Levy....that was a great video! Now completely off of that topic, can you tell me why nobody makes a waterproof flat pedal shoe? There are quite a few options for clipless, but nothing for flats. Not even one with lace covers. I live in the PNW and I would like to keep my feet dry and on flat pedals! If anyone knows of an option out there, please let me know!
  • 28 1
 spray that waterproofing stuff on your shoes. I spray it on everything. It makes towels kind of useless, but oh man are they smooth.
  • 10 0
 Shimano's flat pedal shoe has lace covers and it's also fairly good at keeping water out, so i'm told.
  • 17 0
 Because brands seem to think people who wear flat pedals want them to look like skate shoes, so they can wear them to the pub after riding.
  • 2 4
 @melonhead1145: yeah , awefull taste..
  • 4 0
 @DAN-ROCKS: The Franks Red Hot sauce of mtb.
  • 4 0
 Running 5-10's with the lace cover and the Bontrager waterproof oversock over light merino socks.. Absolute mint for PNW riding. Those oversocks are one of the best apparel pieces I own. No cold or wet feet.
  • 4 0
 I've ziptied innertube over my laces (to the eyelets) and then glue-gunned the ziptie holes. Works pretty well as kludges go.
  • 3 0
 Waterproof socks are where the smart money is. They really work.
  • 5 0
 Not totally waterproof but the 5/10 Eps model is awesome! They have a one poece leather upper and lots of insulation in the tongue. I live on Van Island and they work great year round.
  • 1 0
 @wowbagger: Not that good if you ask me. I've also tried Mavic XA Thermo and they're not that good either. Neither are waterproof, not even close.
  • 3 0
 @rrolly:

PNW guy here too.

lightweight wool socks, with waterproof socks on over them is a great combo. I added the waterproof socks this season, and it’s absolutely been worth the money.

Shoes still get sopping wet, but at least my feet don’t feel it.
  • 2 0
 Yeah, that's really a pain in the ass... The only one I know (and wear) is the Vaude Moab STX (kind of Goretext).

adidas/5-10 have the Terrex Trail Cross Mid Pro, but they are too stupid to put Goretex on these (like they do on their hiking boots).
  • 1 0
 @wtroost: I love my Five Ten Freerider EPS High tops, but when I went looking for a backup pair, they seem to be discontinued. Tragic!
  • 1 0
 @yoobee: FWIW, Adidas did announce a GTX version of the Mid Pro, way back in 2019. It was supposed to ship in August 2020. Supposedly it is still in the pipeline, but delayed.
  • 1 0
 @Inertiaman: Yes, I know. Don't know where the problem is. Too little demand maybe?

Did someone try the Fizik Terra ARTICA X2 on a flatpedal?
  • 2 0
 Adidas GTX model is due this fall after having been postponed 1 year.
  • 2 0
 Thanks for all of the feedback!! I have some ideas on how to keep my feet dry and warm until someone has an option for us “flat pedalers”!!
  • 7 2
 However, if you aren't running some super light XC tires, a proper tubeless setup should hold air similar to a tube. In my experience, Schwalbe Super Gravity holds air really well without sealant, almost like a car tire.
  • 3 4
 Also, if you inflate with a CO2 canister, that will seep out your tire quite quickly. Those are temporary fixes only and the gas in the tires needs to replaced with an air pump later on.
  • 2 0
 @rrolly: Hmm, a CO2 molecule is larger than either an O2 molecule or an N2 molecule (and those are the two main components of atmospheric air). So I don't think that's correct. However, the CO2 will acidify your tire sealant, which is probably not a good thing in the long term.
  • 3 0
 @barp: Empirically, CO2 does leak out faster though. I believe it dissolves into the rubber or something.
  • 2 0
 @MaplePanda: Good point, I hadn't thought about solubility.
  • 4 1
 Brilliant video. Such an important message but so hard to get across. Hopefully this is passionate enough that people pay attention. Also important to say always use the same gauge.
I used to find that 1psi either way was a huge margin. At 22psi in the back I was definitely going to pinch puncture sometime in the next couple of rides. 23psi was golden for several months. And 24psi was noticeably giving up grip. Now running prototype inserts and I can come down to under 15psi no problem, at that level I can feel the squirm of the tyre starting to get a bit unpleasant but don't need to worry about pinching or burping and 16psi feels perfect.
At these pressures 1psi is 7% and if the gauge has a slight error then you could easily be 10 - 20% off. Maybe time for gauge manufacturers to start resolving more precisely?
  • 3 0
 I have a 0 - 15 PSI gauge for my fatbike, and a 0 - 30 PSI gauge for my trail bike. Gauges are supposed to be most accurate in the middle of their ranges, so it's horses for courses.
  • 6 0
 Important note: always use the same gauge

Your $30 floor pump and $4 gauge from Harbor Freight are likely a little off.
  • 2 0
 Even my $60 Crankbrothers floor pump has a gauge that’s 10psi off and it seems to vary. I haven’t used a floor pump with a gauge that’s even close. Like 1 or 3, ok I can work with that, but anymore why even put a gauge on there.
  • 3 0
 Using a consistent gauge to inflate your tires is super important. I got to the trailhead and noticed my front tire lost some air since I pumped it up at home. I borrowed my buddies pump and pumped it up to the usual pressure. Except the gauge on that pump wasn't calibrated the same as mine and I ended up putting way too much air in. I did the squeeze test and it felt too hard, but the gauge said otherwise, so off we went. I ended up washing out my front tire on an easy jump and sprained my ankle really bad. I was off the bike for 3 months because my pressure was off.
  • 4 0
 Levy we love you don’t change. Quick question does your morning routine include a Jade egg?...
  • 4 0
 Didn’t pinkbike hire Seb Stott? He’s the one to explain things like this.
  • 2 1
 I appreciate the tire pressure content being one of the most debated metrics in MTB'ing, but there is a lot of misinformation in this video....but to fair, it leads to the same conclusion as the right information would so...... I guess a net gain?
  • 3 0
 But bro, gear range is totally the small one x the big one. Broken clocks... twice a day etc.
  • 5 0
 Why can't the pressure gauge on pumps be more accurate?
  • 1 0
 Very little air actually passes through the sidewalls. If it did cars would need air in their tires a lot more often than annually. In my case the air escapes around the valve stem and a dab of silicone around the stem before installing it results in an incredibly stable tire air pressure. I still check it of course before every ride.
  • 1 0
 But car tire sidewalls are a hell of a lot thicker than bike tire sidewalls. I've seen sealant weep through the sidewalls of a tubeless-ready tire, and if the sealant can find its way through there I'd assume the air can too.
  • 1 0
 In my experience, one factor that contributes to folks running higher pressures is that they actually have a shitty pressure gauge. So they think they are running 35psi in their Minions but are actually running 28. My old floor pump was terribly inaccurate and I have seen many others like it.
  • 1 0
 This was a really long video that, IMO, didn't really say a lot. You spent a lot of time covering unnecessary information while simultaneously not covering the most important aspect: how to actually know what to look for or feel for when shooting for a good target.
  • 1 0
 The solution to that balloon, leaking sidewall tubeless thing... tubes Smile

My magic numbers:
Dh casing tyres (Uk in tracks)
21/23 in the dry
19/21 in the wet.

Recently the 2 FR youtubers who are riding a lot together just now indicated that they are the magic numbers for them too.

Glenlivet.... 35-50psi and some lightweight tyres, there is something fun about easy red trail centres and light tyres at high pressures, the bike fair shifts down the hill.
  • 1 0
 Noticed in one of the videos of Metailler and Vanderhoek doing steep lines on the North Shore that when Remy used his digital gauge it was way off compared to what Vanderhoek thought it read off his pump gauge before he left for the ride. What is the trusted reading? How do you know 28psi or 23 psi is indeed that?
  • 1 0
 220lbs Rider
27.5x 2.4 WTB TrailBoss on 35mm rims (fits beautifully) - I have ran down to 23 psi with this setup and I haven't pinched it yet.
On the front I run a WTB Vigilante 27.5x2.5 on 35mm rims and I've run that down as low as 22psi without issue.
If I am going to ride rocks or roots I'll bump that up 2psi or so.

On my last set of tires (Onza Aquila and Ibex both 2.4 on the 35mm rims) I had to run 25-27 psi to get them to feel right.
My point: Tire casing and shape are super important.

the WTB tires use a shorter sidewall, sort of like a low profile sports car tire. The Onza tires featured a more traditional lightbulb shape, even on the wide 35mm rims.
  • 1 0
 Wow this is really eye opening guys. Not just the engineering debate and douchebaggery (LOL) but the pressures people are running. When Stans came out I called Stan and asked for the best pressure for a 26x2.3 tire as a 185lb rider. He gave me 26PSI. It seemed like magic right out of the gate. Game changer. Since then I've gone to 27.5 F&R and now to a mixer over the past 5 years. I always assumed that with the larger volumes meant the pressures should come down. I now run my Maxxis 29x2.6 Assguy and 27.5x 2.5 DHR at 20 and 22PSI. I run 29mmID carbon wheels and have yet to crack one or even damage it. I guess I tend to ride over things as much as I can. Not sure if that's what's saved me but looking at all the comments I see 30PSI avg across the board. We ride the sandy, dusty hills of Southern California and my biggest concern is washing out. Seems like when I go up in pressure it makes it so sketchy with steering. Anyone else have this? I don't feel my sidewall giving out. Maybe I don't have enough weight on my front end while cornering but it's been the cause of many of my crashes and it's hard to commit to corners now. I'm going to give higher pressures another try especially since we some racing coming up in Temecula where it's sandy dirt and sharp rock. Does anyone else out there run in the low 20s for this sort of terrain? Shouldn't we all be listing tire size along with pressures?
  • 1 0
 Step 1: Search the internet for the lowest PSI people use on your brand/size of tires and rims.
Step 2: Cross-reference those people's usernames with posts complaining about the manufacturer not covering their damaged rims under warranty. Add 5 lbs. pressure to the PSI they were using.

Works every time. *GRIN*
  • 3 0
 Consider yourself a hot mess if you don't notice the difference a couple PSI can make on your rig.
  • 4 0
 “A bad rim tape job”....... nobody wants that. Great video Mike.
  • 3 0
 First step is getting a good 0-30 tire gauge. What. you think is 25psi might actually. be 32... or 20.
  • 1 0
 Yep, gauge on my floor pump reads 2-4psi higher than my digital gauge every time. If I were inflating my kids BMX tires for him to go ride with his buddies, no big deal. If I think I put 23 in my trail bike but only got 19, there's a good chance I'll be having a rough day.
  • 1 1
 I wouldn’t mind ntirogen in my tires, especially for those 4000-vertical-foot Whistler Peak to Village morning runs in late September =) www.aaa.com/autorepair/articles/top-4-myths-vs-facts-about-using-nitrogen-to-inflate-car-tires
  • 2 1
 FYI, that article AAA incorrectly states that compressed atmospheric air is “oxygen”, which is incorrect — “air” is only about 21% oxygen (and 78% nitrogen). But the rest is worth reading if you’ve never considered nitrogen for your bike(s), road car(s) or race car(s)...even though AAA omit certain nuanced details.
  • 1 1
 How could this have missed, and how could no one have mentioned the TYRE WIZ.
A great tool that provides interesting data capture. Check every morning? Just look at your cell phone. Changes in elevation? Temps? Check the app.
  • 3 0
 How did we even ride bikes in 2008 when you couldn't inflate your rock hard minions below 30psi?
  • 3 1
 I run what Norco suggests for my weight - around 21/23psi front/back. Although that seemed a bit high on front for yesterday's slick ride on BC's west coast.
  • 3 0
 I find the "Ride Aligned" system has us setting up suspension relatively stiff, and tires relatively soft. 21/24psi suggested for me too.

First year on a Norco - interested to try out and also tweak their suggested setups. I mean if they've put that much time, resources and energy into Ride Aligned, I'm going to at least give it a shot.
  • 1 1
 27,5 wheels ——front dhf 2,5 wt exo+ Maxterra 21/22;rear dhr2 2,4 wt exo+ maxterra 24,5/25,5 and I weigh 80kg geared up ,for me is perfect,more pressure only if I was a pro (even so I probably only increase slightly more the pressure like f-23,r-27)or I went for some big drops ,and that’s it ,I could never ride pressures like 30 or more psi in the tires
  • 4 3
 Religious tire-pressure-checker here. I'm super sensitive to it now. Just a couple PSI makes a big difference. 26 rear and 23 front for me
  • 3 0
 Another great video mike.
  • 2 0
 Different pressures for trail, park, and jumps. Make sure you air up for hitting jumps, tire squirm will ruin your day.
  • 1 0
 Hell yeah, I run 23-25 on the trail and over 40 at the jump park.
  • 2 0
 The guys I see running around on flat tires because they read on the internet that lower psi is the bestest....
  • 3 0
 Too much effort. I'll stick with my estimated 30 ish psi.
  • 2 0
 I see you rode the new Troy LTD @mikelevy. Did I miss an article or is it forthcoming?
  • 3 0
 6-8" of snow. 4 psi rear, 3 psi front yesterday. YMMV.
  • 3 0
 if u wanna vrrrp the berms run 8 psi and watch out for the pressure police
  • 2 1
 Jared graves posted up about tires pressures . Check it out

But 30psi +\~ for fast and aggressive riders is where you wanna be .
  • 4 1
 What about Sam Hill who is arguably faster than him both downhill and EWS and is running 23F 27R?
  • 2 0
 @stormracing: that’s just his opinion on the subject . Was just saying he did a little thing on it .
  • 3 0
 wiseman once said, "Start high, end low"
  • 1 0
 How about a video on how to quickly and easily swap a saddle. I am sure that PB has a few tricks, and this jigsaw puzzle of seat post clamp/saddle rail is a real nemesis.
  • 2 1
 tannus inserts, 2.3 -2.6 Maxxis whatevers, 18-24 psi, no matter your weight, where you live, your "pace", or your skills.. good to go. all you need to know.
  • 2 0
 Blah Blah Blah tech mumbo jumbo .... What is really important is that the "Guru" look is a good look for you Levy
  • 1 0
 Best cold open Levy! This is how I talk normally.... with dire consequences !!
  • 3 2
 20psi front and rear for me on dh casing tires. I'm only a light fella but charge hard. Never have a problem.
  • 2 0
 25 psi in front and 28 psi in the rear. im 85 kg ride a Bronson V3.
  • 1 0
 25psi front and 28psi rear. Tubeless stans. Not worth it going into lower 20s due to chance of punctures or breaking bead.
  • 2 0
 I run 69 psi I don’t care what people say!
  • 1 0
 @mikelevy

youtu.be/Oht9AEq1798

your professionalism is outstanding
  • 1 0
 A bad rimjob can cause leaks of air and sealant. Be aware guys. Could be a pretty uncomfortable ride
  • 2 4
 I've got to call BS on the tire insert part. Inserts obviously reduce tire volume and it is 100% not true that reducing the volume is a reason you can safely run a lower pressure. Yes, I know that's not the only thing he said about inserts and why they may be good for some riders, but it's definitely something he said and it's wrong. Sure the rim will be protected and you probably won't roll the tire off, but the tire will collapse through the remaining air volume more easily at the same PSI until it hits the insert. That may (or may not) be completely fine. You may still be able to run a lower pressure while improving performance, however you define that. Certainly your rims will be better protected at lower pressures. But any potential improvement has nothing to do with the reduced air volume. That aspect is made worse by inserts, not better. It's like taking 2.5" tires and giving them the interior volume of a 2.0" tire. That's clearly not something you'd want absent other mitigating benefits (which, I acknowledge, inserts have.) Maybe they just thought it'd be too confusing trying to explain the "one step backwards, two steps forward" nature of inserts.
  • 3 1
 The tire doesn’t “collapse through the remaining air volume more easily.” You’re not understanding the physics of how a dual-medium / dual-rate / position-dependent spring (pressurized air and a cushioning foam) of that nature works, especially as a Cush Core insert is a closed-cell EVA foam that does compress in response to the tire (and internal air) compressing before the tire directly contacts the foam. Your 2.5” acting like a 2.0” diameter volume statement is likewise not correct, but the spring rate of a 2.5-inserted-tire might increase at a rate between a non-insert 2.5 and a 2.0” when comparing the first maybe 1” of tire displacement (to put it simply without getting into the differences). I just wanted to let you know that you’re misunderstanding how the system works. No hard feelings — particularly as it’s a complex and highly-dynamic dual-rate position-sensitive spring system consisting of interactions between compressible gas / compressible solid (with gas-filled highly-elastic polymer cell walls), physical friction interactions between the tire sidewall and closed-cell foam insert, the ground, the rate of impact (and the ability of the polymer-based foam to convert some of that energy into heat via polymer chain internal molecular friction), the air pressure, the tire durometer and sidewall construction, the temperature and resultant modulus of the rubber and foam, how fresh the tire sealant is and its resultant lubricity (or adhesion) between the insert and the tire sidewall, etc, etc.
  • 2 0
 @WRCDH: Good observations on a complex system. I would add that the progressivity of initial (air-only, before touching insert) tire deformation is essentially nil. The reason is that the volume of the deformation event is SO small in proportion to the tire air volume (even when reduced by an insert). A 29x2.5 tire has roughly 900 cubic inches of volume. When deforming over obstacles or cornering pressure, we are talking about reductions in volume of 10-20 cubic inches or 2-3% scale, often MUCH less, which would cause a brief increase in tire pressure of equivalent %. In other words, a 20psi tire briefly ramping to 20.4psi without inserts or 20.5psi or 20.6 psi with large inserts. Hard to fathom that such trivial "progressivity" contributes much to the ride characteristics when so many other far greater variables are at play.
I've seen inserts described as "air tokens for tires", an analogy to progressivity in forks and rear shocks. I think its an invalid analogy. Fork or shock deformation events (aka, travel) can be 75% or more of total volume, and tokens can displace ~ 10% of volume. PSI changes can be 800%. No comparison to tires.
  • 2 0
 @Inertiaman: Additional to that, 1” tire compression (on a flat-ground landing) equates to about an 8” length of tire deformation along the circumference of the tire, so about 8.8% of the 91” circumference is affected. But it’s only about 15% of the volume in that area — so about 1.3% decrease in volume. The ramp-up is a function of the increase in tire/ground surface area as the tire compresses (and maybe 10% additional adjacent deformed tire area not in contact with the ground) along with the pressure increase — so yeah, the spring rate doesn’t change a whole lot. But if the volume is decreased by say 40% by a compressible insert of relatively high spring rate, then that 1.3% becomes 1.82% — acting across that say 8” long section, about 16 square inches of which are engaging with that 1.82% increased tire pressures. Figure maybe 3% for a big impact / landing.

But a big part of the “ramp up” feeling is the sidewall stretching in response to the impact deformation as well as the differential increase in pressure (of say 2% or so) — with its rubber and high-elongation elastic fiber reinforcement. Those fibers and their orientation and plying and adjacent rubber “matrix” are optimized (in numerous ways) for maybe 5% strain in normal riding conditions around 25psi (and which is why the sidewall will fail at about say 80psi when the fiber reaches its maximum strain of about 15%). That elastic rubber strain and elastic fiber strain in a thinner sidewall with less rubber gives the tire a lively bouncy feeling (and the extra rubber and decreased proportional contribution of fiber strain, is part of what gives Maxxis Maxx Grip DH casing tires a “dead” or “well damped” feeling). That’s one reason why sidewalls with less rubber are more “bouncy” than thin sidewall tires — extra rubber usually damps the compression and rebound of the tire during impact (again, friction / heat related to internal polymer chain movement), as well as damps the return of the strain energy stored in the fibers. But when reducing the tire air volume maybe 40% with a compressible high-spring-rate Cush Core when used with a thinner sidewall like EXO or thinner, you can get more fiber strain for a given pressure, or similar fiber strain (compared to no insert) at lower pressure — maintaining similar tire liveliness and somewhat similar response at a slightly lower pressure (in concert with the actual friction-based physical interaction of the foam and sidewall). And that contribution of reduced air volume is discernible in terms of “feeling” as well as traction and dynamic tire response characteristics.
  • 2 0
 @Inertiaman: *correction* in my last comment:
“That’s one reason why sidewalls with less rubber are more “bouncy” than *thick* sidewall tires — extra rubber usually damps the compression and rebound of the tire during impact...”
  • 2 1
 depends on volume and carcass pliability. let's push a monolithic number like we we do with seat tube angle tho
  • 1 0
 120 lb rider running 17 front 21 rear. Exo casing on 2.5 and 2.4. Runs great
  • 1 0
 BTW, use soapy water to check leaks around beads, sidewalls and valve stems.
  • 1 0
 I got lazy one day and just used water in a spray bottle. It still worked perfectly +less mess.
  • 1 0
 How about checking the pressure after some km of riding ,you will be surprise
  • 1 0
 Pressures??? Squashy as an orange in summer, easy peel tangerine for winter
  • 1 0
 I feel a bit tired after watching this video. Bad rim tape job thing got me awake though.
  • 1 0
 Thanks for the video. Now there will be a worldwide shortage of pressure gauges.
  • 2 0
 These comments are tiring
  • 1 0
 Mike Levy, don't look so deflated! Tire pressure are each owns airOppinion!
  • 1 0
 A video about tire pressure with no mention of speed and rolling resistance? Did I miss something?
  • 1 0
 cushcores and 20 psi all the way
  • 1 0
 Very entertaining; enjoyed the video. Good info too
  • 3 2
 run 30+ and quit your worrying.
  • 1 0
 Rider skills are way more important that you might think !
  • 1 0
 When is it better to run a stiffer casing instead of higher pressure?
  • 2 1
 If i dont run 45 psi I get pinch flats
  • 2 1
 20/23 psi for a 90kg rider here... Say a prayer for my inserts!
  • 2 2
 rear 2.4 : DH 24psi dry -1-2psi in wet
front 2.4 : Exo 22psi dry -1-2psi in wet
170lbs fully geared
  • 2 0
 Mach enduro! Haha
  • 1 0
 Thanks for the levity Mike!! I needed that!!
  • 1 0
 23 and 24. with XC Cush. feels fine to me
  • 1 0
 Toga yoga was epic... lmao.
  • 1 0
 Takeaway: Tires get Tired.
  • 1 0
 What the heck is a rim tape job?
  • 1 0
 I’m fat so uh. 32psi front. 38psi rear. #noproblems
  • 1 0
 Note to self, don't ask to borrow Levy's pressure gauge, smells like feet.
  • 6 6
 30+ all the time No matter what terrain.
  • 3 0
 Ditto, but then again I'm a clyde so my opinion may be too specific...
  • 1 1
 You’re doing something wrong for sure.
  • 3 3
 Unpopular opinion. Minions suck. Yeah I said it.
  • 1 1
 27 front and 28 rear ..... 230 lbs geared up ........ BC rider.
  • 1 0
 What is this MBUK?
  • 2 3
 TYRE!!!!
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