Victor Campenaerts Hour Record Attempt

[Look585]

Anyone know what tire format was used? Tubulars (126 years of tradition) or clinchers (supposedly faster)?

[ultraman6970]

The only ones that could try to use clinchers in a track are the guys from specialized :P

Dude sure used tubbies and probably really light ones, not like 32 mm ones that they say are faster

[nooneline]

Originally Posted by Look585

Anyone know what tire format was used? Tubulars (126 years of tradition) or clinchers (supposedly faster)?

Vittoria Pista tubulars on Campagnolo Ghibli discs. All in all a pretty conventional setup.

[Lionel]

22mm pista at 200psi.

[oldpotatoe]

Vittoria Pista tubulars on Campagnolo Ghibli discs. All in all a pretty conventional setup.

Campagnolo disc wheels..of course a new WR..duh...

[ultraman6970]

Sure 160 grams... 21mm or 19 mm those had been around for a while.

200 psi? I doubt it...imo like 130 or 140, no more than that. And even if you go back 40 years you can speculate they used helium gas Which I doubt ;D

[Lionel]

Yes 200psi

[ultraman6970]

Darn... cant imagine that...

[Mark McM]

Originally Posted by Look585

Anyone know what tire format was used? Tubulars (126 years of tradition) or clinchers (supposedly faster)?

According to CyclingNews, he used special Vittoria tubulars.

It is true that all else being equal, clinchers are usually faster. But all things aren't always equal. It is well accepted that on very smooth surfaces, increasing pressure decreases rolling resistance. Tubulars can be used at higher pressures than clinchers, so on very smooth surfaces (such as an indoor velodrome), tubulars may be faster if used at higher pressures than clinchers can tolerate.

(Another factor to consider: The main cause of tubulars having more rolling resistance than clinchers is hysteresis in the glue. Road tubulars have to be able to be removed and replaced easily, so a soft tacky glue is used, which results in hysteresis losses. However, if tubulars are mounted with a hard glue, the losses are much less, and may even be less than clinchers - but hard glues prevent easy replacement of tires. The article doesn't say, but if I were preparing the tires for an hour record attempt, I'd use a hard glue.)

[nooneline]

Originally Posted by ultraman6970

Sure 160 grams... 21mm or 19 mm those had been around for a while.

200 psi? I doubt it...imo like 130 or 140, no more than that. And even if you go back 40 years you can speculate they used helium gas Which I doubt ;D

For those tires? Definitely more than that. Harder isn't always faster, and on track bikes there's definitely a spot when you stop seeing gains and start seeing losses, but that spot is much, much higher than 140, especially with those tires on that track.

Maybe not 200psi, but not far below I'd wager.

[Look585]

Originally Posted by nooneline

For those tires? Definitely more than that. Harder isn't always faster, and on track bikes there's definitely a spot when you stop seeing gains and start seeing losses, but that spot is much, much higher than 140, especially with those tires on that track.

Maybe not 200psi, but not far below I'd wager.

My guess is they were pretty close to 200psi at the start and measurably less by the end. Those Vittoria Pistas lose pressure quite quickly.

[nooneline]

Originally Posted by Look585

My guess is they were pretty close to 200psi at the start and measurably less by the end. Those Vittoria Pistas lose pressure quite quickly.

Reminds me of Josh/Silca's essay about Zipp's development of the 303, and how work around tire pressure involved setting Roubaix pressures above the target for the last 1/3rd of the race, based on loss rate.

I also recall that Colby Pearce did some pretty rigorous testing of CRRs of different tire pressures, and found a pressure after which high-pressure track tires got slower - IIRC it was around 180psi, but i don't recall the important specifics.

[ultraman6970]

Ex track racer here, and I have used clinchers in a rental bike at a track. Let me tell you this... CLINCHERS SUCKS in the track!

[Mark McM]

Originally Posted by ultraman6970

Ex track racer here, and I have used clinchers in a rental bike at a track. Let me tell you this... CLINCHERS SUCKS in the track!

Can you expand on that?

[m_sasso]

What I find astounding is Campenaerts didn't use a face shield, could be talking nonsense however seems like he could have improved his aerodynamic efficiency markedly by utilizing one?

Use clinchers ever other day on the Burnaby boards for training and they roll just fine.