Video: Tech Talks - Data Under Pressure, Presented by Park Tool

Jul 26, 2018
by Pinkbike Staff  
Tech Talks Presented by Park Tool

In this episode, Calvin and Truman take a look at the Tyrewiz, and ask you how the data from the Tyrewiz could prove useful for your ride.

Tech Talks Presented by Park Tool is a monthly video series hosted by Park Tool's own wrench whisperer, Calvin Jones. The series covers the A to Zs of some of the most prevalent repair jobs, with the last highlighting how to bed in brakes.

Data Under Pressure

Views: 8,182    Faves: 7    Comments: 0

Need more Calvin in your life?

Episode #1 - Tubeless tire installation and conversion
Episode #2 - Saving that bent disc rotor
Episode #3 - Derailleur hanger alignment
Episode #4 - Shimano and Crankbrothers pedal service
Episode #5 - Trailside wheel repair
Episode #6 - Trailside chain repair
Episode #7 - Derailleur limits and cable tension
Episode #8 - Derailleur setup
Episode #9 - Fork wiper seal replacement
Episode #10 - Clipless pedal setup
Episode #11 - New cleat setup
Episode #12 - Top 5 next level shifting issues
Episode #13 - Fixing cassette play
Episode #14 - Gearing hacks
Episode #15 - Fixing sticky pistons
Episode #16 - Lubing fork seals
Episode #17 - A cleat's story
Episode #18 - Tricks of a mechanical mind
Episode #19 - Handlebar Trimming
Episode #20 - Chain Line
Episode #21 - Tools for a trip
Episode #22 - Bedding in brakes
Episode #23 - Direct Mount Chainring Install
Episode #24 - Wheel Balance 101

Stay tuned for more mechanical how-to videos with Calvin returning on the last Thursday of every month to show you the easiest way to get the job done. Want to know more? Park Tool's how-to section has you and your bike covered. / @ParkToolCompany

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  • 177 5
 Meanwhile, I'm running my tyre pressures precisely between 'F**k it, that'll do' and 'Rock f**kin solid'.
  • 44 2
 I've been experimenting with 'Heh, it's not leaked that much' recently.
  • 23 22
 I run my pressure like People on streets - ee da de da de
  • 16 1
 You must have the same gauge as me? Do you also have a torque elbow for getting your bolts right too, mine is so handy having it built in... :-)
  • 21 1
 Now if only we could adjust pressure on the fly I could have one more lever on my bars to crush my knee against.
  • 3 2
 @WAKIdesigns: that’s okay.
  • 22 2
 @RichardHulton: It's the terror of knowing what this world is about, watching some good friends screaming: LET ME OUT!
  • 3 1
*I* laughed.
  • 2 0
 @WAKIdesigns: Um bo bo
  • 1 0
 @chubbydentist: Scott bikes will have that at Interbike this year.....#AllTheCablesYouCanWant
  • 40 2
 Yeah, that's why I love biking. After a day of sitting in front of my PC screen, I can go out and ride my bike and watch another tiny screen with numbers! And when I come back home, I can sit down again and check all the numbers again on a PC. Great! I'l never get bored again in my life!
  • 6 1
 Hahah sooo true. Lots of people stuck in the data matrix, but not so grounded in reality...
  • 7 30
flag WAKIdesigns (Jul 26, 2018 at 5:32) (Below Threshold)
 yes my Stages gives U reading, ShockWiz says SU and now tyre wiz says CK and strava has put it together into yo cock so big my masta. Kudos to yo big long dong.
  • 6 0
 dont forget about the stupid kickstarter to have a sensor telling you how much airtime you had during your ride
  • 3 0
 @fercho25: shockwiz tells you that already.
  • 2 0
 Depends what your objective is. If I can go faster with more accurate data and understanding tyre pressures... I'll look at a screen.
  • 1 0
 @fercho25: REALLY?? Will this data upload to STRAVA???
  • 38 1
 30 PSI in my Minions, I don't care about your opinions!
  • 52 4
 How do you know it's 30? It might well be 28.99.
  • 6 0
 how many mm are 30 psi? got to be metric!
  • 7 0
 I fill my tires with vacuum to make them lighter
  • 2 0
 @Ben-P: 206.843 KPa, you're welcome
  • 1 0
 @Ben-P: 1551.45 mm Hg, yeah buddy
  • 2 0
 A true classic, refuses to get old.
  • 2 4
 You don't seem to care about grip either
  • 21 0
 Good idea but too much cash....I picked up this little beauty on ebay for £37

Modded it for Mountain bike use....

Low Pressure alarm
USB rechargeable LIPO
Even gives tyre temperature - everyone's favourite stat !!!

Its like a dropper post - you think why... but now I cant ride without it Smile
  • 7 0
 Great! But you can't check during pumping + it's not connected to Strava.
  • 1 0
 Btw. Garmin produces something similar. Also intended for moto, but it has ANT so you might be able to connect it to your garmin GPS.
  • 2 0
 But my pump has a pressure gauge..?:
You are right though - would be better if connected to Strava
  • 2 0
 Mate love it, I'm going to order one or similar. Does it work with presta valves though?
  • 3 0
 Can you explain in which way it is better than simply checking your pressure before your ride with either a precise gauge or a precise pump with inbuilt gauge ? (genuine question)
  • 1 0
 @sostokedaboutthat: It would with an adaptor
I drilled mine out for tubeless Schrader valves though
Would have done that anyway as I think they are superior in every way...and now with wide rims its really no reason to run presta
  • 4 1
 @Balgaroth: Its by no means an essential item but personally I find tyre pressures the number one thing I faff with during a ride. I am by no means a data monkey - I don't give a shit what my heart is doing etc. But where I ride In the UK we have a lot of steep, muddy, off-camber trails. You want to get your tyres as low as possible with out pinch flatting. A couple of PSI can mean the difference between making a turn, sliding off into the bushes or holing the tyre on the next rock garden. Also with expensive carbon rims I think its a good idea to get an early warning of a slow puncture - especially on long rocky descents...has the potential to save a lot of expensive rim replacements.

The one drawback is your friends will rip the piss - but secretly they are just jealous Wink
  • 1 0
 That’s pretty rad!
  • 4 7
 ndthornton - so you compare some gizmo for nerds to the invention of a dropper post? Ouch! As to tyre pressures for slippery conditions, just remove a bit of air since you are likely to ride slower anyways. I personally have an awesome solution to tyre pressure problems. A slightly leaky tube/tyre. Makes you readjust pressure at least once a day.
  • 1 0
Chicks dig nerds
Perhaps not at school - but definitely in later life Smile
  • 4 1
You know you want one really - stop kidding yourself and get it bought
  • 1 2
 @ndthornton: no, chicks do not dig nerds. They dig dudes with cash. Preferably hansom ones. 1 out of 1000 nerds get serious cash. If you are a nerd you need to get enough cash to compensate for your miserable social skills and looks, not to mention coming in 30 seconds.
  • 3 0
 @WAKIdesigns: I am sorry to hear of your experiences with prematurely ejaculating nerds...perhaps you were making them nervous? Who knows. Normal behaviour is to go for hours until accidentally thinking about Star Wars.
  • 1 0
 @ndthornton: if you lack cash you better be a self confident muscular dude that can make her laugh until her clit shakes a bit and then start trash talk that will convince her that she'll be coming time and time again tonight. Nerds tend to lack those skills and appearance so a car representing loads of cash is the only way. Then take her to a nice villa or a large apartment in a fancy district and you may ejaculate whenever you want. Just watch out for muscular dudes hanging around her.
  • 1 0
 @WAKIdesigns: The trouble with chicks that are interested only in money and muscles is there is always someone with more money and more muscles than you have...well not me personally...mine are outrageous...but people like you where only the ego is massive. My girl likes me for just being me - and I'm sure she will never meet another me as I've never seen one. So I can sleep easy and not worry about who is going to make my sandwiches in the morning.
  • 1 0
 @ndthornton: well, it is only a matter of who she can get. If you can make her feel that you have her back, she will stay. If you can make her come regularly she won’t look for another dude. If that matters for you that she is a ”fidelle”. Rverything is a matter of circumstances. Everything. As a male you have the privilege of having a partner who is eilling to stick together due to higher level of oxitocin.
  • 10 0
 The only thing I'd use this for is as an excuse. "Hey guys yes I'd normally hit this huge gap but look my pressure is 0.3 too low. I'll hit it next week honest."
  • 3 0
  • 7 1
 Best part of the video is how much pressure is lost during a valve tap, and how much average pressure gained during a full stroke of a standard floor pump. That’s actually useful data. Beyond that I think it’s useful for serious racers that are able to analyze data across multiple practice runs to determine what gives them an edge. But for just your regular shred out with your buds? Not very pertinent.
  • 5 0
 Why isn't anyone so far (neither in the comments nor in the video) talking about the one feature that actually would be helpful: getting recommendations on the right tyre pressure?
The product website says it does give recommendations, but I'm not sure if the recommendations come from the collected data (what I would expect), or if they are just based on rider weight and tire size (not that helpful and not worth buying the device).
  • 1 2
 I don't get what you mean. You can calculate the approximate corect pressures at home (you won't be changing that during the ride anyway). And the rest is your personal decission (say +-5 psi).
  • 1 0
More Rocks= harder
Soft forest ground = softer

Would be nice if it could calculate the pressure so you get minimal impacts on the rim
  • 6 0
 I have a "Calibrated Thumb." Simply squeeze the tire between fingers and Calibrated Thumb. Surprisingly accurate when check periodically with a tire gauge.
  • 2 0
 What is your periodic tyre guage the calibrated shoe?
  • 2 0
 Tire pressure to me is very important and I check it before every ride or race, but to check it while riding, I don't need the extra stress, plus isn't riding about getting out ripping around and enjoying your surroundings? How do you do that when all you're worried about is your tire dropping a tenth of a pound? LOL not to mention the most important fact, what about tire balance? Haha so many variables.

My thoughts..... just get out and ride, leave all the technology for the mechanics and racers who make a living from the sport.
  • 3 0
 Calvin/Truman - Would you check how various tire inserts affect impact compression and rebound on a course ride? Include the Huck Norris if you can. I think the graphs could provide a lot of good data.
  • 2 0
 Can you cross reference shockwiz data with tyrewiz? Within one app... say looking atbtraction then taking account deep impact events there would seem to be a cross over point to add psi to the tyre vs say a HSC/LSC change.
  • 1 0
 It would be interesting if it could identify when a particular pressure spike could be linked to a rim strike. Not sure how you would do that, but it seems like potentially some of the most useful data that the device could provide
  • 1 0
 I agree, but it's unfortunately impossible. unlike air shocks, air-filled tires do not change pressure significantly as they are loaded.
  • 1 0
 What a joke... TPMS sensors for your bicycle? ...and $200 for the pair?

These are so useful, the batteries died in the Garmin set I have on my motorcycle and I didn't notice for six months... I'm sure they'll be a huge addition to my cycling. Rolleyes
  • 1 0
 That would come in handy for cold weather fat bikes. You pump the tires up inside your warm home or garage and then once you hit the trailhead, your tire pressure drops to an unknown pressure because of the colder outside air.
  • 4 0
 Could be hacked into a shock wiz for a fork.
  • 1 0
 Id be interested to know how much the pressure rises from cold to having ridden and also at what point the pressure starts to rise i.e. how far do you have to ride before the temp/ pressure in the tyre starts to rise.
  • 1 0
 Changing ground temperature and of course the sun will heat or cool down the tire waaay more. I literally tried to warm up the tires of my van by driving these snake lines like f1 cars do but I did feel no difference. On a bike there even goes way less power through the wheels
  • 4 0
 General air temperature will have a much greater impact on tyre pressure. Pressure is directly proportional to temperature, but the temperature has to be first converted to Kelvin.

10 deg C = 283.15K
20 deg C = 293.15K

That's a 3.53% change. So 21 PSI would rise to 21.74 PSI. Not a huge difference, but enough to upset some people! Hoever, if you look at shock pressures the PSI difference is amplified somewhat.

Say you run 240 PSI in your rear shock and pump it up on a cold morning at 10 deg C. By the time the temperature reaches 20 deg C, your shock is at 248.47 PSI. If it reached 30 deg C, your shock would be at 256.95 PSI.
  • 1 0
Sorry yes I forgot that. But I think direct sun light can heat up the tires on hot days way more. Temperatures in the tire can easily go to over 50 degree Celsius when it'd only 30 degree putside
  • 1 0
 @terribleone1982: What about elevation? according to the Barometric formula (calculating the pressure as a function of the height above the sea level) around sea level, every 8m the pressure is reduced by 1 ‰ -->

if you go up 1000m your barometric pressure outside drops by 12% meaning the pressure will raise by about 12%
  • 1 1
 I liked the humor and nice presentation. But being serious for a second, and w/o considering the hefty price ($200?!), tire pressure is one of those set-it-and-forget-it things. I didn't buy into why you'd need it on the trail or off it. And unless there's a cut, whatever you last put in with the pump is what you have in there - so why wouldn't I just re-pump every week or two? I don't get the benefit of this.
  • 3 0
 199 bucks for that thingamajig!? Oh boy....
  • 2 0
 Guess I will have to rebalance my wheels if I install one of these... Death by data give it a squeeze hope for the best.
  • 1 0
 My thoughts exactly. Ever run a modern car with tyre monitors? They’re gash at the best of times, to have one as exposed to battery as on an MTB just seems pointless. Plus, you know within seconds if you’ve got a low tyre anyhow!
  • 2 0
 Might be interesting to look at how temperature and altitude changes effect the tyre pressure.
  • 1 0
 @emptybox: You won't get an answer in that book.
  • 2 0
Did you read it ?
  • 2 2
 @emptybox: No, and I know that I don't need to because the rise of tyre pressure by the change of temperature is affected by the tyre material properties. And you won't find that there. Actually you wont find it anywere and the only way to get precise data is to measure it.
  • 1 0
Be careful. Tire pressure is not rubber softness.
There is a mature tissue in nearly every mtb tire wich means the tire volume will stay nearly the same through different pressures.
There are many formulas in this book wich are exactly for that
  • 1 0
You better read that book if you make such a statement
  • 1 0
Here you can find what you said I won't find it anywhere besides it has nearly nothing to do wich tire pressure change in different altitudes. Enjoy!
  • 2 0
 @emptybox: 1) The volume is not constant. And you will get very only approximate results with this simplification. You can check this very simply by measuring the width of the tyre at two different pressures.

2) More importantly though, the elastic modulus of the fibres in the tyre changes with temperature ie. at 0°C and 50°C with the same pressures the tyre won't have the same volume (the tyre will be larger at 50°C). This is where it gets really complicated.
  • 1 0
 Ok engineers time to lower your pitchforks and ‘cool’ off
  • 1 0
1) I said the volume is NEARLY constant. Yes we only get an approximate result but are we doing rocket science or are we riding bikes?
Did try this once volume changed are minimal.

2) you are reffering to the coefficient of thermal expansion. There are databases for that information. Like the like I sent you. There will be a formula where you set yor temperature and you get the expansion. Easy as that. But steel to example as coefficient of 11,5*10^(-6) 1/K wich means steel will lengthen 0,0000115% when it gets 1 degree ( Celsius or kelvin) hotter. For steel it's a linear Funktion.
Read that book or a similar one or study that sh*t like I did.
  • 1 0
 would be very curious to know how much variation I get on my fat bike in the winter depending on how warm it is inside vs outside.
  • 2 0
 It changes a lot more than you would think...The one I use gives tyre temperature as well as pressure. From taking it out of a cool garage into a hot Summers day pressure can go up by 6 PSI easy. That's on a 2.5in tyre. Yet to try it on my fat bike
  • 2 1
 I got these yesterday and the novelty wore off after45 seconds
To be fair I didn’t pay for these, so even for free they’re kind of a waste of money
  • 2 0
 Never Tyrewiz on the electric fence
  • 1 0
 it would be cool to see like a spring rate of the tire on a hit verses it with cush core, along with rebound rate
  • 1 0
 @parktoolcompany: $199....seriously?
  • 2 0
 I feel so pressured
  • 1 0
 Bar-ing any issues I'd be pumped to try this out
  • 1 0
 I just want to ride my bike...
  • 1 0
 Love this vid guys Trueman you can rip!
  • 1 0
 so whats the point?

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