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paris-roubaix [SPOILER]
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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/9/23 10:28 AM

paris-roubaix [SPOILER]

WvA seemed a bit spent at the end. He still had some kick left but could not get away from Philipsen when he tried. Still, you have to wonder how different things would have been if Wout didn't have that puncture at ~15k to go. Then it was just him and Van der Poel and being in contention for the win is surely worth some watts that might not appear when you're fighting for second.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

4/9/23 1:41 PM

Jumbo Visma seemed to have more than their share of tire issues, which brings to mind a couple of questions:

- Are the Vittoria tires they're using just crap?
- Why don't they use sealant in their tires for a race like Paris-Roubaix?

From the video it appeared that Wout's flat was a pretty slow leak, likely something that sealant could handle easily.

It was a bit alarming to see the footage of riders on tubeless tires having them come off the rim and others with carbon rims that completely shattered and collapsed. I suspect - and hope - there's going to be some serious reevaluation of equipment choices after this race.

I wonder how the riders using the on-the-fly pressure adjustment systems fared. There were some on Jumbo-Visma, but Wout wasn't one of them.

Van Der Poel is pretty obviously the best bike handler in the modern peloton. He could have (should have?) crashed numerous times, but always managed to keep the rubber side down. Simply amazing!

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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven

4/9/23 4:13 PM

Bob Roll commented that given a choice, with disc brakes, the teams prefer to change the bike if there is a flat tire.

Rim brakes would clearly make more sense at P-R.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/9/23 5:25 PM

Can't add much, other than I expected this race to break record for short dueation, and was right.

Bike handling skills best of the best. I was sure on that right hander a feeler ga. would be required to see how close his foot/pedal got.

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/9/23 11:18 PM

I watched appx the last 100k but definitely saw some tire-off flats and at least one wheel break. Didn't always know who it was happening to as it was Dutch TV and I know exactly three words in Dutch but agree that it seemed like there were some bad equipment choices. Try to save a few seconds but risk losing the race.

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Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

4/10/23 1:33 AM


quote:
Why don't they use sealant in their tires for a race like Paris-Roubaix?

Did you see Derek Gee's front tubeless tyre blow off on the Arenburg cobbles, when he was at the front of the race in the break? Sealant clearly visible.

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/10/23 3:54 AM

I thought his whole wheel was coming apart for a second.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/10/23 8:59 AM

I am sure that last few feet of carbon on cobble totaled the rim...

I was surprised to not see a green Vitoria air liner in use..

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LeeW
Joined: 13 Jan 2004
Posts: 453
Location: near Baltimore, MD

4/10/23 9:00 AM

Curious how the variable tire pressure system might work? I can easily envision lowering the tire pressure on the fly, but what type of source are they using to raise the pressure on the fly? Someone please enlighten me.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/10/23 9:35 AM

Only thing I could imagine is a co2 cartrige in a pocket in the carbon rim, 180 from the valve/control valve. Carbon fiber cartriges?

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/10/23 10:16 AM

Letting air out, as mentioned, seems pretty easy. But some form of co2 cartridge would cause balance issues with the wheel, I would guess. Maybe it's only variable in one direction?

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

4/10/23 10:44 AM

Nick, I did see Derek Gee's flat and commented on the sealant when it happened. I'm pretty sure that Jumbo-Visma was using tubulars.

UPDATE: J-V was apparently using Vittoria Corsa Pro tubeless tires. At least they had been testing them. I didn't see any evidence of sealant when Wout flatted.

As for the pressure adjustment system, it's done with a pump built into the hub. Here's a link to an article about he Gravaa system:

https://www.cyclingtips.com/2021/09/want-on-the-fly-tyre-pressure-adjustment-gravaas-kaps-wheels-can-do-that/


Last edited by Brian Nystrom on 4/10/23 10:54 AM; edited 1 time in total

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LeeW
Joined: 13 Jan 2004
Posts: 453
Location: near Baltimore, MD

4/10/23 10:54 AM

Thanks for the link Brian.

Cannot tell from the photo, but I'm guessing there must be a significant diameter tube or pipe to run the high-pressure air from the hub up toward the rim/tire?

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

4/10/23 10:55 AM

The article shows pics of it. The tube is surprisingly thin.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/10/23 12:07 PM

Interesting..

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LeeW
Joined: 13 Jan 2004
Posts: 453
Location: near Baltimore, MD

4/10/23 1:26 PM

I was viewing on a mid-sized phone screen. Guess I missed seeing it in the pics.

Doubtful that I would ever want the system, but interesting (to a former engineer🤣).

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/11/23 3:53 AM

That's pure wizardry.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

4/11/23 7:40 AM

Combine that with a Classified 2-speed hub and SRAM's new Transmission drivetrain and you'd have the ultimate bike!

Of course, none of this stuff is compatible - yet - and it would cost five grand, but still... ;-)

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/14/23 11:49 AM

https://www.cyclingnews.com/news/paris-roubaix-crashes-spark-debate-about-tubeless-tyre-safety-on-the-cobbles/

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/19/23 12:44 PM


quote:
https://www.cyclingnews.com/news/paris-roubaix-crashes-spark-debate-about-tubeless-tyre-safety-on-the-cobbles/


So tubeless is better?

Yeah.

Why?

No tubes!

But what about total loss of pressure on rough surfaces?

Put an insert in!

Isn't that just a tube?

[crickets]

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/19/23 1:24 PM


quote:
Isn't that just a tube?

[crickets]


ROTFLMAO!

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

4/19/23 3:35 PM

Well...

...not unless you consider a piece of foam a tube. Inserts don't contain pressurized air and their purpose is to:

a) prevent a flat tire from bottoming out on the rim

b) keep the tire on the rim

In normal use, they only contact the tire at the bead.

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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven

4/20/23 6:06 AM

It seems to me that P-R would be the perfect application for tubeless tubular. Or do they have more rolling resistance than tubelless clinchers?

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

4/20/23 11:53 AM

If it were me I wouldn't care, tbh. I'd rather deal with rolling resistance on an inflated tire vs what we saw in this race. WvA's puncture surely changed the last 12k of that race significantly.

Or maybe I have no idea what I'm talking about because I don't really know just how much of a difference the rr makes between the two choices

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

4/20/23 1:55 PM

I'll say this. 2 rides same bike. 1st 30mm tubeless tubulars with small dot tread, Schwalbe g-zero speed.

2nd, 36mm Gravel King slicks that run small @34mm on wide-ish rims, but with latex tubes.

GKs felt amazing, gotta try sans tubes. G-Zero Speeds lived up to 'speed' designation. Felt like go fast bike, even with my fat ars abord..

Bike canti Tomii CX team stampede race machine..

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