Complete Guide to Downhill Rubber

[Percy]

@Percy: I specifically asked not to focus on rolling resistance. My question still stands.

Ok I'll answer another way.

When was the last time you saw a 60a (or equivalent) tyre on a World Cup DHers bike?
If harder rubber was faster, they'd know, and they'd use it.

Having said that, I used to run 60a tyres on the rear all the time to avoid replacing them every week! would just bung the sticky rubber on for races.

[StabprimoMonkee]

@Percy & @Kidwoo: WC racers are not completely immune to superstition. Take a look back over the last 10 years and observe some cargo cult **** we all did (including the Pros). Not every fast rider is an engineer like Barel and some others. And myself being an engineer I must admit that engineers sometimes rationalize really insane stuff - because it should work in theory (Biopace? OMG!).

And side knob squirm could be exactly the reason to use a harder (42a vs 40a OR 50 vs 42) compound tire in certain conditions.

Also AFAIK Peaty has been known to ride 50 compound tires at times - in races that is.

And I have absolutely no references to back my claims. But would like to hear some opinions.

So is the only reason for 3C tires better wear and rolling resistance compromise, thus ensuring a less variation in performance for longer intervals of time?

Also - I imagine that in certain conditions it would be better to run 70 spikes instead of 42.

p.s.: Kidwoo - calling me silly triggered a level 10 butthurt. I'm crying now, since I was certain that I am only curios.

[kidwoo]

When was the last time you saw a 60a (or equivalent) tyre on a World Cup DHers bike?

I can't turn my head fast enough to read the sidewalls. I get whiplash.

60d tires are immensely faster. Go put one on the rear of your bike and time yourself just rolling straight down anything.........literally anything.

So is the only reason for 3C tires better wear and rolling resistance compromise, thus ensuring a less variation in performance for longer intervals of time?

It's also so the knobs maintain some shape rather than just completely squish out and negate the fact that they have any shape designed into them. A knob is useless if it just always moves out of the way or presses flat.

The fact that you could start flicking whole knobs off a super tacky tire after 4 runs probably had a little to do with it as well.

I also called the question silly, not you.

[Percy]

I can't turn my head fast enough to read the sidewalls. I get whiplash.

60d tires are immensely faster. Go put one on the rear of your bike and time yourself just rolling straight down anything.........literally anything.

I was kinda hoping someone could answer definitively whether the WC pro's use them or not as well, cos Ive never been to a WC race, so havent had a chance to geek out on their bikes in the pits.
I might ask Hamroll or J-Lo next time I see them.
Plus my original (personal opinion based on I don't want to remember how many years riding) point still stands, I don't care how fast a tyre rolls in straight lines if I keep falling over in the corners cos the damn thing wont get a grip!!

It's also so the knobs maintain some shape rather than just completely squish out and negate the fact that they have any shape designed into them. A knob is useless if it just always moves out of the way or presses flat.

The fact that you could start flicking whole knobs off a super tacky tire after 4 runs probably had a little to do with it as well.

I also called the question silly, not you.

3C is teh rockzor!!

[kidwoo]

I was kinda hoping someone could answer definitively whether the WC pro's use them or not as well, cos Ive never been to a WC race, so havent had a chance to geek out on their bikes in the pits.

Who gives a fvck what color superman's panties are you aren't superman, just go put one on your bike and go time yourself like an adult who can make decisions for himself.

Besides, your answer is right here

Plus my original (personal opinion based on I don't want to remember how many years riding) point still stands, I don't care how fast a tyre rolls in straight lines if I keep falling over in the corners cos the damn thing wont get a grip!!

It's whiskey night can ya tell?

The above is what I would like to say but I'm not going to type all that out, plus it would be kind of rude. So the following is my real answer.

Here.

http://www.vitalmtb.com/photos/featu...8198/sspomer,2

Go to page 3 in the slideshow. See that HR semislick? That tire doesn't exist in anything BUT a 60d. So there's one example. At PMB I'd be surprised if half or more weren't running hard rear tires. Kind of a moot point anyway because who even makes hard dh tires anymore besides maxxis? Is one of those stupid schwalbe names a translation for '60d rubber?'

[S.K.C.]

Who gives a fvck what color superman's panties are ...

...(*giggles*) this intro is EPIC!!!

Commentary:Woo leads his response with the big guns. It's like kicking open the doors to a business meeting with no pants on, firing an empty of Stoli at the far wall, and then calling the whole room a bunch of pVssies.

It's whiskey night can ya tell?

...I want to party with YOU, cowboy.

Go to page 3 in the slideshow. See that HR semislick? That tire doesn't exist in anything BUT a 60d. So there's one example. At PMB I'd be surprised if half or more weren't running hard rear tires. Kind of a moot point anyway because who even makes hard dh tires anymore besides maxxis? Is one of those stupid schwalbe names a translation for '60d rubber?'

To be serious here and all craziness aside, as far as hard vs. soft compound race tires go, I have this observation:

About 4 or 5 years ago Maxxis introduced the 3C compound which without question is probably one of the grippiest, stickiest, most confidence inspiring compounds EVER to hit the market. A fresh set of these on most kinds of dirt will grip like hands to mammaries. Riders rejoiced at the improvement over the discontinued 40a Slow Reezay (SRY) and WC pros ripped holes in space time while defying the laws of physics. The Lord smiled, and it was good.

However in the past year or so I've noticed that the majority of Maxxis equipped WC pros are running the slightly harder Super Tacky 42a. This could be for a number of reasons. But considering the speeds most pros are carrying these days and taking into account how competitive it's getting out there, the main advantage that comes to my mind would be decreased rolling resistance.

So how much of a difference is there in traction between a 3C (40a shoulder knob/42a crown) and a 42a ST? When it comes to WC pros, probably not much considering how fast they are going while stuffing the bike into high speed corners with highly advanced handling skills. In other words, through their Jedi skills they can compensate for the decrease in grip and still rail corners like a cheetah mowing down a gazelle. Rarely, if every do WC guys or gals run 60a compound tires unless the circumstances are really, really unusual like what Woo was saying about PMB or other relatively "flat" tracks.

Woo - I *heart* you.

[kidwoo]

I assume you've ridden Super Tacky tires right? They friggin rule. The only problem is that they only friggin rule for about 4 runs if you're on something pretty rocky. I love the things but I just can't afford to buy them for what it takes to maintain a well working tire on my bikes. I think they grip better than the 3Cs but there are only so many days I could put up with loading my bike on the lift and watching knobs fall off a tire I'd just put on that morning.

[djjohnr]

I assume you've ridden Super Tacky tires right? They friggin rule. The only problem is that they only friggin rule for about 4 runs if you're on something pretty rocky. I love the things but I just can't afford to buy them for what it takes to maintain a well working tire on my bikes. I think they grip better than the 3Cs but there are only so many days I could put up with loading my bike on the lift and watching knobs fall off a tire I'd just put on that morning.

I've had OK longevity running them front only with a 3C in the rear.

[S.K.C.]

I assume you've ridden Super Tacky tires right? They friggin rule. The only problem is that they only friggin rule for about 4 runs if you're on something pretty rocky. I love the things but I just can't afford to buy them for what it takes to maintain a well working tire on my bikes. I think they grip better than the 3Cs but there are only so many days I could put up with loading my bike on the lift and watching knobs fall off a tire I'd just put on that morning.

Indeed sir I have! Yep - I've had the same experience with the 42a ST's. I ride quite a bit in Northeastern PA and Diablo and geographically speaking it's either dirt mixed with tons of loose aggregate or small/med./large rocks that don't move anywhere. The 42 ST's definitely shred fairly quickly and knobs get ripped off after a few days of riding on these surfaces. The 3C's wear MUCH better in this kind of rocky terrain. Personally, I can't tell any difference in rolling resistance but then again I'm not ripping at WC speeds (yet).

Also - caught this a few pages back:

The 2.6 is the same size as the old comp 32. It always measured 2.6.
And the compound is the same as the old one as well.
The only all new tire Michelin is offering is the wildrock'r DH which comes with same compound as the rest of the DH tires.
The one change I heard that they made is on the old comp 16's (which is now the wildgrip'r dh 2.5) is they stiffened up the outer knobs so they would not flex so much on hardpack.
I have the 2.5 wildrock'r tires on the way, and I will comment on them after I have some runs on 'em. That tread is great on my trail tires, so I can't wait to run them with the DH compound.

The compound Michy is using for the new line of DH rubber is the same compound they used on the old Comp/DH series which is a 55a Shore compound.


So here's something I was wondering the other day:

On VitalMTB, in the caption under the slide depicting Polish Pete airing up Gee's tires at PMB, the statement was that this tubeless setup (Conti DH tires -kevlar bead?-, Stan's rims -Flow?-, and Stans sealant) would be used as the main configuration for the rest of the season... on all of the tracks. Don't get me wrong, I think tubeless will be the next big breakthrough in pushing DH performance but ALL of the tracks? Tubeless? Really? I know Kovarik was running his DeeMax Ultimates with Schwalbes tubeless last year at some of the races, but I didn't think tubeless was quite there yet in terms of durability.

Anyone have any info confirming or refuting that the Athertons are running tubeless at all the races? If so - Issues? Are they using Flows or are they testing some new Stans proto rims?

[Percy]

Who gives a fvck what color superman's panties are you aren't superman, just go put one on your bike and go time yourself like an adult who can make decisions for himself.

But I am Superman.............arent I?
Anyway it was just a slightly geeky interest in what the pro's run question, I'm gonna run whatever works for me, not whatever the cool kids/ Sam Hill is running!
Which is why I rode 909's for ages, cos they work for me, its slightly......ahh.....un-kosher shall we say, for me to ride anything but Maxxis now though!

It's whiskey night can ya tell?

The above is what I would like to say but I'm not going to type all that out, plus it would be kind of rude. So the following is my real answer.

Here.

http://www.vitalmtb.com/photos/featu...8198/sspomer,2

Go to page 3 in the slideshow. See that HR semislick? That tire doesn't exist in anything BUT a 60d.

Yep, I can tell its whiskey night!!
No need to not be rude, its the interwebs remember!!

Ahem, we have a couple of 2.35 Highroller semi-slicks in 50a rubber sitting in the warehouse right now, they are quite old though.
Plus I'm 99.99% sure we cant get any moar!!

[marshalolson]

in the warehouse right now, they are quite old though.
Plus I'm 99.99% sure we cant get any moar!!

nope, but you can get 60 duro ones

[Pslide]

Just thought I'd add a video to this thread showing how bike tires are made (in Continental's factory), if anyone is interested:

YouTube - ‪How Are Bicycle Tyres Made‬‏

YouTube - ‪How Are Bicycle Tyres Made‬‏

Here is another from Schwalbe, a bit more in depth:

http://www.youtube.com/watch?v=V0P3oQWo22A&feature=player_embedded

http://www.youtube.com/watch?v=V0P3oQWo22A&feature=player_embedded

[Percy]

nope, but you can get 60 duro ones

Yep, and CRC have ST ones, apparently!

Not that they'd be any use round here at the moment, its a tad wet.........
And when its dry its way to dusty.

[kidwoo]

Yep, and CRC have ST ones, apparently!

Read the description at the bottom.

http://www.chainreactioncycles.com/M...x?ModelID=5846

Features:

• Super fast for Dual Slalom
• Lightweight single-ply casing
• Tire Size: 26x2.35
• TPI:60
• Max PSI:65
• Weight:720g
• Durometer:60a

Sounds like the same tire I just bought for a little bike. I don't know, maybe they are still available outside the US. If so, my bad. Hard to tell what you're buying from that page though. The link in the upper right to buy the thing definitely says 'dh' and 42a

[MarkDH]

Anyone got any comments on the compound used in the new Michelin tyres? I think Maxxis are taking the piss with pricing now so I'm looking for a High Roller alternative, and the WildGripr Descent 2.5 seems like an obvious choice. It looks like from comments above that they use 55 duro compound, but how does that translate when riding, especially in wet mixed terrain?