Pick Your Poison – Tyre choice Val Di Sole
Dry, intermediate or mud tyres? It's a compromise at the Worlds.
Pick Your Poison – Tyre Choice Val Di Sole
By Steven Jones
The track here at Val Di Sole is steep, technical and when ridden hard for several days becomes blown out with dust concealing rock and root in some of the most horrible places. Tyre choice appears to be leaning towards intermediate tyres, considered by many to be muds (although in reality a mx style stud pattern dry tyre) that aids braking and cornering with their slightly more aggressive side knobs and lack of ramped front edges.
For some teams….in fact for several top teams tyre availability is limited hence they will be running unbranded rubber from other companies, the preferred choice being the Maxxis Shorty at present. For others such as Specialized the top racers Bruni and Brosnan have access to Butcher dry in 2.35 and 2.5, Hillbilly intermediate and Storm wet weather. Both Brosnan and Bruni are in fact trying cut down versions of both the Storm and Hillbilly.
Santa Cruz have an incredible amount of options both in tyres and also rim widths, this clearly has an effect on the tyre profile. For practice Greg seemed to be lined up with super wide rims opening out the Shorty considerably.
Danny Hart and the Mondraker team look set on Maxxis Shorty's at present but Danny has the Minion as a dry option.
Much of the talk evolves around traction in the dust however avoiding the dust (and the unknown that lies beneath) will factor into both line choice and therefore the rubber that ultimately gets chosen for race day. There's still a lot of thinking to be done as it shows from the talk (and actions) amongst the top riders.
To get a balanced view on the situation Bontrager Tyre Engineer Frank Stacy took time out to go through the reality of rubber choice here in Val Di Sole, and also discussed options with the top guns for the weekend, including their star racer Rachel Atherton, one of the few to race intermediate weather G5 rubber.
Here's the current status with tyre choices... if it rains then all hell brakes loose
Frank Stacy, Tyre Engineer, Bontrager
Dirt: We’ve looked at the different team approaches to tyres in the pits here at VDS and there seems to be a slight bias towards the Maxxis Shorty and Specialized Hillbilly style – but these are quite close to a dry tyres in reality?
Frank: Those tyres would often be considered mud tyres. You can throw in the Bontrager GMud tyre as well. They’re basically cut-down spikes but they do offer a larger surface area of the knob itself that does give a wider range than a true spike would.
And on this course, with this amount of powder, it makes sense to start the training on those types of tyres because you typically want something to bite down in it and those tyres do that really well.
Dirt: Is there a perfect tyre for this hill?
Frank: At Val Di Sole, the way the conditions are this weekend, you’re not going to get the prefect tyre, no way [laughing].
There’s too much variation top to bottom. You’ve got the roots that are everywhere, you’ve got rocks the whole way down and then the hardpack corners down the bottom are just so fast - crazy fast – and you’re carrying a lot of speed there. I don’t think there’s a perfect, single tyre that can get that done. It’s a compromise.
Dirt: So it’s a bit of a balancing act then?
Frank: Absolutely. You’re going to choose a tyre for what you’re most comfortable with.
If you’re really good on certain sections up top, for example, you might tyre up just for making your time there and live with it for the rest of the way down.
I don't think we’ll see 100% dry condition tyres here, I think it’s gonna be more of an intermediate type. Could be a cut spike-ish tyre – like the Shorty or GMud – or more of an intermediate tyre such as the Bontrager G5, which Rachel has been rocking hard all year.
Dirt: What about tyre pressures, they seem to be all over the place – I’ve seen it range from 22 to 35psi?
Frank: It’s rider dependent. It’s all about different riding styles and different bike setups - what about the suspension setup, hard or soft, stiff at the front, softer in the rear?
Typically our riders are in the range of about 25-29psi, depending on the setup and the course. But there are still some riders way up into the 30s and some in the low 20s too.
And the rim widths now have thrown a big curve into the mix. We’re spreading the footprints of these tyres out, we’re changing the stiffness points of the tyre sidewall. You’re able to adjust your tyre pressure way more now than you used to. You know, we’re splitting hairs!
Dirt: That’s an important point. Rim widths have been pretty varied…
Frank: That’s the move now, it’s big. Rim width has really opened up the entire tyre programme in fact. I think we’re going to see a lot more specific tyres designed around specific rims in future.
We do a lot of that now, but you kind of pick a standard rim and you design your profile of the tyre around it. I think where it’s going we are going to see a lot more of ‘this tyre goes on this rim and only that rim’ design.
It’s not uncommon to see a 30-32mm inner rim width – that’s a wide rim for a bicycle – but the most common is still around 28 or 29 inner rim width.
Dirt: Overall it’s going to be an interesting Sunday afternoon and a big challenge for the tyre experts?
Frank: I can’t wait, it’s going to be a great event. This course is a rider’s course and yeah, it’s tough on the tyre guys!