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Video & Interview: Aaron Gwin on the Tire Testing Process

Jun 7, 2021 at 15:45
by Sarah Moore  

What does your tire testing process look like? How long do you spend on each tire?

I guess it kind of depends on the specific tire, but generally the tire takes at least a year to go from a rough design on paper to something you can ride. We usually dial things in on the computer first to get all the dimensions and shapes as close as we can and then we make a few 3D mold samples to confirm that everything looks right. Once those samples look good, they start the actual tire mold and we wait for tires from there. Ideally, you nail that first rideable sample pretty close because those molds are costly to change once they're done. Assuming the size and dimensions of the tire are good, on the rideable samples we can then start playing with tire compounds, casings, etc. to find what works best with that specific tire.

How do you work with engineers to develop a new tire? What are some examples of feedback you might give them that they would then work with?

I like to work as close as possible and thankfully with Kenda, they're stoked to have me as involved as I want to be. Usually, there's a gap in the tire line that we feel needs filled or improved and we start from there. With our most recent prototype tire, I actually drew the knob design on paper and then sent it to one of our engineers, Tony. He then put my drawing into a 3D computer program to get exact specs, dimensions etc. Once we had that we just slowly dial things in.

My feedback is usually just trying to relate what I feel on the track to what I think needs improved. For example, I might want the tire to brake better so we'll work on potentially making the rear edge of the center knobs wider or open up the gap between the knobs so that the tire will dig in better.

Gwin's Leogang World Champs race bike.

When testing tires, what tire pressure do you go with? Do you test the prototype tires and competitor tires multiple times with different air pressures?

I usually try to keep pressures as consistent as possible just to compare thing's on an even scale. It can be tricky when testing competitor tires because everyone usually has a slightly different casing and compound lay-up which requires some air pressure tweaking. I really like to test the best of what other brands have to offer compared with what we have back to back. I learn a lot when doing that and ultimately if we can make a tire that we like better than everything else that's available, we've accomplished the mission.

How many prototypes do you generally ride for any given new tire?

Every tire is different, but with this latest tire, we probably tested 5 or so versions of it to find the exact design, compound, casing, layup, etc. that we liked best.

What are the most important things to look for in a tire?

For me, I just want a tire that's very consistent and predictable in a wide variety of terrains. I think knob spacing and design is very important. I can look at a tire and pretty much know exactly how it's going to ride before we ever mount them up. The casing layup and size is also really important to get right when it comes to the overall comfort and performance of the tire. For example, if you go a little too wide, narrow, stiff, or soft on the casing, you can really mess up a tire that has a great tread pattern.

Do you think there is a perfect tire or is there always a compromise?

I think you're always compromising a little bit if you're looking for one tire to "do it all". Fortunately, we have multiple tires for different tracks and terrains so I do feel like with the options, you should be able to get pretty close to having a perfect tire for certain tracks.

How many different models of tires do you have at every World Cup DH event?

Right now we're using 3 different models (Dry, Intermediate and Mud).

How many runs will you typically do on a set of tires before changing them on a World Cup weekend?

Every track is different, but I'd say on average we will use 2-3 sets per weekend. That keeps the tires very fresh and always feeling exactly the same. For practice days at home, I ride the tires a lot longer between changes.

Can you think of a race where you totally blew it on tire choice and it ruined your race?

I can't thankfully. I maybe haven't nailed it every time, but I can't think of a race where I felt I completely blew it.

What about a time when you think your tires were the difference maker for a win?

I think MSA 2017 in the rain when I ran dry tires. Not to say that I don't think I could of won on a different tire, but running those was a risk that ended up paying off.

What are your go-to tires?

Right now I'm really loving the Pinner model and new proto model we've been developing with Kenda. I'm pretty much always running those tires either front and rear or a combo of the two. They both work really well for me.

Author Info:
sarahmoore avatar

Member since Mar 30, 2011
1,452 articles

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flag DoubleCrownAddict (Jun 9, 2021 at 1:00) (Below Threshold)
 Gwintire, as in close to retirement.
  • 8 2
 Gwintinental, Aarontrager, Michelgwin
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 "I tell them their tires suck, they give me big $$ to make them better" "I get them to make a minion"
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 Which works best - Sharpie, Jiffy, or shoe polish?
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 Plastidip latex paint.
  • 4 0
 Clearly you haven't tried the new Kenda tire lineup, there's really no reason anybody would want to go back to Maxxis after trying it...
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 @ungod: what Kenda tires do you like for intermediate terrain on enduro bike, Hellkat F / Pinner R? AGC F&R?
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 @RadBartTaylor: HellKat is grippier but a little slower rolling, like a fast rolling Magic Mary. It's good for pretty much every condition I've tried it in. Pinner is faster rolling but doesn't do as well in loose/blown-out conditions.

So it really just comes down to what you're willing to tolerate. For an all-around combo, I think the HK (f) / Pinner (r) is pretty unbeatable. If you want to roll faster, go Pinner/Pinner. I find that even though the Pinner slides a bit in blown-out conditions it's still totally predictable and easy to reign back in.

If you're unsure you could always just buy a single Pinner, put it on the front of your bike, see how you like it. If you don't like it in the front it's still guaranteed to be a kickass rear tire, and then you can pick up a HK for the front instead.

I've run all of the above combos and I'm now trying a Pinner (f) / Regolith (r). The Regolith is a great tire too, but a little on the lighter side (850) so I paired it up with a Tannus tubeless insert. So far so good!
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 Serious question: where do tires go when they die? When I used to live in Canada, MEC would take spent tires and tubes for free and recycle them. I tried to find somewhere in SoCal but nobody would take them and it made me almost sick to think how many bike tires go straight into the landfill. Just the number of tires in my garage is ridiculous.
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 You could try taking them to Les Schwab. They usually have a pile and will let you throw them in (at least where I live).
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 The volume of disposed bike tires must be minuscule compared to car tires. But you're right, would be nice to see all tires get recycled correctly.
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 I keep the tubes and tires for doing "things".
Tubes are great to swee into bags,making a strong, water proof moto carrier. It looks nice also, if you are not into "new" stuff.

Old tyres (fold), are great to place them into chainstays, or other areas that need protection (ex: downtube on uplifts).

I also use on some walls/pillars in the garage, and have helped saving car paint when wife parks or take the car out Smile
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 I thought it was common knowledge that recycled rubber is turned into athletics tracks and rubber fall areas at children's playgrounds. But yeah, obviously they have to go through a recycling process.
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 Many towns in the US take All tires to recycle. Mine does - check out where you live.
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 @tsn73 "where do tires go when they die?" -- isn't "lying around in a corner of your garage" the proper way to go?
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 @Waldon83: now think about the amount of tires thrown out, and the amount of childrens playground and atheltics tracks built.
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 @Waldon83: also footing for indoor horse back riding arenas.
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 @Waldon83: there are all sorts of regulations about being a certified waste tire hauler in California that resulted from tire fires. I have tried auto shops and tire shops and they won’t take them. Bike shops are just throwing them in the trash too as there doesn’t seem to be any other option.

California talks a lot about being green but it’s just talk. It’s still so difficult to dispose of a lot of things properly that they just go in the bin.
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 You can always cut them up and make sandals like this guy:

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 @tsn73: So, true. California has banned disposal of so many things and haven't created any solutions to dispose of the stuff which creates even more problems. People are forced to resort to worse solutions.

The latest ban is pressure treated lumber at the beginning of 2021 where they only have one certified landfill to take pressure treated lumber in the middle of nowhere for all of California. It has created such a big problem for construction industry. I'm sure contractors have resorted to creative ways to dispose it because they can't store it.
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 You can send them to Green Guru in CO for upcycling. I know several shops and bike businesses that do this. www.greengurugear.com/pages/recycling-to-upcycle-program
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 @FloImSchnee: For sure until the dreaded day when you try to clean out that garage.
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 @TDMAN: do you have a picture of your tube bag? Or bag of tubes?
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 “2-3 sets per weekend”

Should there be a tire limit like in Formula 1 where riders have to use their tires more?
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 Yeah one set for practice and another for the race. Maybe another set if it's super muddy or rainy. That's crazy...
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 Limit 1 set per rider. Unless they donate them to Pinkbike commenters after race weekend, then unlimited.
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 1 set for the season like the rest of us mortals.
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 @davemays: that would be interesting
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 @hatton: you.....you said exactly what he said. 3 sets. ¯\_(ツ)_/¯
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 Please do not give the UCI more regulation ideas.
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 Rider give out tires at races after they're done quite often.
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 @schofell84: its true. Bernard Kerr gave me some swamp things at windham in like 2015 or so.
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 They didn't ask him about how he felt about there not being a fantasy DH league...
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 Kenda has been crushing it IMO. The Hellkats and Pinner Chicken Gwiner's are awesome. As an added bonus, they come Maxxis wobble free from the factory.
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 Hellkat is an extremely underrated tire.
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 I still have a Tomac signature model Nevegal from the 90s. Can't bear to toss it like I did a Maxxis Mobster DH (but that was hard - what with the little mobster guy on it)...
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 Unfortunately we're a marketing based world, and Maxxis is on their Marketing game.
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 @suspended-flesh: i have one as well, though probably not from the 90s.. tried running it for a while and almost died too many times.. now it sits in the corner awaiting its final resting place..
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 @laxguy: Hmmm maybe it was the early 00s. I think I 'won' it at a race (consolation prize) - never rode on it - I was a Maxxis guy back then.
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 I've been running the pinner front and rear this season, and last year used the pinner as a front with an aggressor rear. no flats, no wobbly carcass, they hold air, have good durability and have a ton of grip and drift predictably when they do break free . i can't imagine switching back to maxxis at this point. i know everyone loves them, but wobbly weepy carcasses, bead tears, etc I could hardly ever wear out a tire before something ruined it.
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 My Pinner is straight, so is my Mary but my Hellkat wobbles.....
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 Would be interesting to know if the development is done using inserts or not, and if one or the other, why? Generally tire, (tire insert) and rim manufacturers should come together and figure this out, probably a lot of room for improvement.
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 Picked up a pinner pro on a deal. Running it as a rear and it feels good, however, the fooking thing just won't keep air. I have 3 times the amount of sealant that I normally would and it's still flat in hours. Had a Schwalbe on before it and was holding air fine so not the rim, rim tape, valve etc.
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 That is weird. I have had the exact opposite experience. My Schwalbe MM / HD combo would loose 0.5 bar between two weekends, the Hellkat / Nevegal holds air for ages on the exact same bike/wheel setup.
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 Clean it well inside and spread rubber cement. works wonders.
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 How many layers of rim tape do you have inside and are you running inserts? Unless rim tape is applied methodically and sometimes heat-shrunk to the rim, a single layer is not enough, even if perfectly sized - despite the imagery in those many dream bike internet build videos for MTB and road. Inserts also tend to compress the tape away from the rim sidewalls, toward the center channel, creating a point of egress for air at the crucial bead seat/rim wall area. So in both cases, more tape and the right type of tubeless tape is needed for airtightness (the more compliant the better; Muc-off makes awesome stuff, as does DT Swiss and Peaty's). Furthermore, with rims like Spank (which are great overall, in my experience), the "Oobah" ridged design in the middle tends to make taping more difficult - because it eliminates a uniformly flat surface for the tape to adhere to. This makes methodical taping even more critical with Spank rims. Obviously, I have no idea what you're running rim wise or how much tape you've applied, but those are just some important points to double check as you address this issue, which is certainly frustrating to deal with.

My experience with Schwalbe is that no TR tire holds air better, to the point where you can end up getting away with less-than-perfect taping or rim combinations for sealing purposes in a way that you couldn't with almost any other tubeless tire brand. A lot of this comes down to how burly the new Super Gravity and even Super Trail casings are (let alone the full DH iteration). Just something to think about. Cheers and good luck!
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 Na it's rim tape check it
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 Air it up, and then spray the wheel and rim with a soapy water mix. If the bubbles come from the spoke holes, your tape is bad.
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 Probably bumped your tape when you swapped tires. You might check out the Specialized 2bliss strips (like $7 each), they replace tape with a more permanent strip. You'll never have to tape again!
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 @HogtownWheelsmith: Double tape. Haven't had issues with any other brand that I run...Maxxis, WTB, Spesh and Schwalbe.
Put the Kenda on and I'm having issues.
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 @Noeserd: Nope. It's not.
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 @takeiteasyridehard: Yes, yes. I know. Not the tape.
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 @Dustfarter: you said " it's still flat in hours" if the cut is very small you can't find it with soapy water, just give it a look. also try the soapy water with the tire, if it doesn't bubble and if you are sure it's not the valve its %100 tape
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 @Dustfarter: Based on your comment, I am assuming it loses air fast while parked. If that's the case, soapy water all over it will show you where. If it's out the spokes or valve, probably is tape. If its between the tire and rim, then the diameter of that tire isn't precise enough to seal tightly down on the ring's bead shelves and a couple laps of gorilla tape will fix it. Or, maybe you have a cut, and will find bubbles on your tire. We are all just trying to help, but I understand how leaks are annoying. If it only happens when riding, run more pressure or get cushcore. There are a lot of possibilities, but one easy troubleshooting method: lots of soapy water. If you dont want to do that, don't blame the tire....
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 @Dustfarter: Fair enough. At this point, I would take the tire off - even though ideally you shouldn't have to do this! - and remove the usable pools of sealant with a syringe. Also remove any clumped particulate that will end up rattling inside your tire if left inside there. But leave in the thin sealant film that will have covered the inside of the tire. Don't wipe all of that off. Let the air hit this film overnight and codify the sealant into a hardened thin layer inside the tire. The hardened latex will effectively become another layer of airtightness, and it's not likely to become re-liquified once you re-add the sealant again after mounting the tire once more. If you're sure that it's not the tape at this point, try what I've suggested and you will find that you hopefully seal off any remaining micro-pores inside the tire. The issue right now, despite having so much sealant inside, is that it would almost all be liquid - no doubt superior to having nothing in there or not enough sealant, but perhaps not fully effective to address the leaking. This is a hack, but it has worked for me in the past with the odd fussy tire.
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 aynone notice the Pinner in the trail casing to be way to flimsy? Im 195lbs and im running Pinner ATC 2.4 in the back with 30 psi and tannus tubeless insert and im getting the tire to roll in high speed berms which isnt very confidence inspiring,
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 I'm 205 with the same setup, 2.4 Pinner ATC with tannus. Dt Swiss xm1501 wheels I'm running 24psi and haven't had the same issue.
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 190 lbs and no rolling with a 30id wheel and i only run 25 psi in the rear. i've taken some gnarly hits with the atc casing right to the sidewall - sharp rocks - and have yet to tear or flat one. for the weight i've been really impressed
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 Tone back the gnarly shralping brah...also, how wide is the rim?
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 Hey what do you know. Not a Maxxis tire in sight.
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 Wait till you see the tread patterns...
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 the newest prototype tire is a assegai clone...
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 time to give kenda another shot? Last time i rode kenda, it was some 26x2.5 nevegals that were just stuff, terrible grip and overall very meh tires. The downhillers budget tires when he couldn't afford some new 3c maxxis tires every couple months.
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 DEFINITELY worth giving them a shot.
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 Pinner Pro is such a great tire for what it’s designed for. Just wish they offered the stick-e compound in the lighter ATC casing.
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 Pinner is great for CO front range. My favorite tire.
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 @jwdenver: SoCal here, so I like to tell myself it’s basically a custom tire made for where I live!
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 Kenda is doing some BRILLIANT which somehow slips under the radar.
Their Dual Tread/Dual Compound approach makes so much sense.
the TLBig Grin R -
dual tread - different rubber compounds placed side to side. Lighter, optimized side grip, ideal for front tires.
dual layer - rubber compounds placed one on top of the other, in 2 layers. provides structural rigidity, support and durability at the cost of weight. Ideal for rear tires.
I dont know of any other brands who optimize front/rear tires to such a level (i may be wrong), but the sport is truly at a level now where we should expect this from manufacturers!
i'm sick of putting DH casing 1300gram tires up front because i want maximum grip, or putting uber-slothy soul sucking knobby sticky rubber in the back because i want a reasonably durable casing. start optimizing! There's so much more to F/R tire design than knobs!

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 Pretty much every brand does what you described....whether they market it clearly or at all is another story...that may be the win for kenda...
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 @takeiteasyridehard: how so? Can you give an example nof another tire that applies this? (Im talking about tread rubber placing, not protection casing).
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Copied from maxxis webpage:
"Maxxis 3C Triple Compound mountain technology uses a harder, longer lasting base layer and two progressively softer top layers in order to optimize traction and stability. Maxxis offers three different configurations of our 3C Triple Compound mountain technology: MaxxSpeed, MaxxTerra and MaxxGrip."

Copied from the Michelin page:
(though not as clearly defined, it is the same as maxxis 3c)
A combination of three different rubber compounds providing different performances. Available in the Competition Line."

Copied from the Schwalbe page:
"Triple Compound Technology. Special rubber compounds are used in various areas of the tread – substructure, bead seat, center – which exploit their respective strengths."

I could go on...but I think you get the point....everyone does it. On high end tires of pretty much any manufacturer the base layer is always harder for support, and then the surface layers of the sides and middle are different and softer. They all use different mixes of rubber for specific regions and layers. If you're paying for MSRP $70-100 tires, they all have it.
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 @foxinsocks: sorry I re-read your comment and noticed it was focused on front versus rear...


Series of rubbers specifically designed for Enduro use on the front tire, which offer outstanding grip.

I at least know Michelin markets this way. Maxxis basically makes the same thing but you have to select it...maxxgrip for front, and maxxterra for rear....as far as others, idk. You're right as far as marketing goes. Practically speaking, you just choose the soft 3c for front, and faster rolling 3c for rear from the brands mentioned before...
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 If we were to take the theory that racers set their suspension up in a manner very different to how an average rider needs it, it makes me wonder if racers developing tyres might have the same effect. What Gwin prefers at the speed he rides might not be best suited to the average riders needs? I just wonder how much truth there is in that as an assumption or whether it doesnt apply to tyres?
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 IMO, a tyre specific for the rear should have half the profile of front tyres with extra stiff reinforced sidewalls. Lower pressures could be run to give the tyre added contact area, without the tyre burping in corners. It would also give a proxy Mullet set up.
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 Sounds like the Michelin Wild Enduro Rear. Lower profile than the Wild Enduro Front, reinforced casing.
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 Msa 2017 , What a race (raining) , Gwin was always off race line , in grass !! Maybe he was on grass tire ?!? Kenda golf cart tire?!?
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 He was on Onza then in 2017!
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 MSA victory in pouring rain on dry tires?? Someone please explain.

Just Gwin being Gwin? wtf...
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 @Altron5000: an Onza which he designed! Pretty epic run TBH
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 Oh great one please draw tread profiles on a napkin for us, our engineers aren't worthy
  • 1 2
 Pinkbike - “How do you go about starting the design process with a new themes?”

Tyre Company - “Well basically we start with a Maxxis Minion or whatever else they have out that works, scan it into our computer and then do our best to duplicate it without invoking a patent/copyright infringement.”

Pinkbike - “And how do your pro-riders feel about that?”

Tyre company - “Who cares? They just Sharpie out a their Maxxis tyre of choice anyway. The main part of their sponsorship contract is that they have to swap them back after each race run in case Pinkbike users are wandering around with camera phones.”
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 Brought to you by Kenda.
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 Is every world cup racer using inserts? If so I wonder if we will ever see a return of tubular's with a built in insert?
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 Next interview: Chains Testing Process
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 Think I’d like nothing more than for Gwin to come out and dominate the season again
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 Probably the most interesting Gwin's interview for a while. Thanks Pinkbike... and thanks Aaron.
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 Come back to Gwinning!
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 Black a logo out and bang them on the rim is my guess?
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 Haven’t read that much about rubber since I was 16 years old.
  • 1 0
 From the video, looks like a Magic Mary. Not a bad thing.
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 Looks like a V 10?
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 Isn't the Nevegal still the best all-around tire from anyone in the industry?
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 Maybe 20 years ago haha!
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 The Nevegal was never great, but it was good. Everyone new about it and bought it because it was OEM on almost every MTB bike on the planet.
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 We called them Nevergrips in NZ...
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 Back in the day, it was available in enough different casings and compounds that you could easily have a "bad" tire...or a pretty decent one. Kind of how most brands roll nowadays, meanwhile Kenda seem to have simplified their lineup. I'd give the new version a chance if it came in my preferred size.
  • 2 0
 Tioga Comp III.
  • 1 0
 @speedingant: Always been curious about that name. Nevegal is indeed a very small ski resort in northern Italy.
  • 1 0
 @Tasso75: it was once a stop on the WC
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 @SterlingArcher: got it, Thanks!

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