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!