Technical FAQ: More on Paris-Roubaix tire rolling resistance
More analysis of tire pressure and rolling resistance at the ‘Hell of the North,’ and tubeless tires removal and installation.
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Dear Readers,
An update on last week’s column about Paris-Roubaix tire rolling resistance test. Since then, I found out that, “Florian Vermeersch rode 4 bar at the front and 3.8 bar at the back,” according to his Lotto-Soudal team.
On our Paris-Roubaix rolling-resistance test, we did steps in pressure every half bar. We found the minimum rolling resistance with Vermeersch’s 28mm Vittoria Corsa Control 2.0 TLR tubeless tires to be at 4 bar on the simulated cobblestone surface with a 40kg load on the wheel. So, Vermeersch’s pressures hit the sweet spot at which his tires required about 20.8 watts each to roll them on the simulated cobblestones at 35kph.
― Lennard
Dear Lennard,
What is the tire jack in the photo at the top of the October 26,2201 column?
A friend and I have been having serious trouble breaking the bead on a tubeless tire to take it off the rim. One friend even had shop mechanics squeeze his tire in a bench vice to get it off. I personally have had to cut tires off.
The photo of the jack with the long crossbar on the bead looks like it might work in these extreme situations. Could you address why some tubeless tires just won’t come off? It seems to be related to a bead shelf with a lip, sealant, and a long time on the rim.
Also, I have used bead wax instead of soapy water and it is easy to use and seems to work well. I don’t know if there would be a problem contaminating sealant, but there is very little wax on the tire, but it sure makes the bead slippery.
— Dave
Dear Dave,
It’s a Vittoria tool. It’s a must for installing a tubeless tire that has the Vittoria Air-Liner tubeless inserts Florian Vermeersch was using when he got second place in Paris-Roubaix.
The tool compresses the foam insert to get the tire bead into the rim valley. We have been discussing how important having the bead in the valley is for easy tire installation. The tool comes with some clips to disperse around the rim to hold the bead into the rim valley all of the way around when you’re trying to get the last bit of it pushed over the top of the rim. I use Bead Biter Tire Levers clamped around the rim to do the same thing.
As for why some tubeless tires won’t dislodge from the bead shelf, I think it has to do with a combination of a tight fit and dried sealant gluing it on. That same Vittoria tool could help pop the beads off.
― Lennard
Dear Lennard,
I enjoyed your tire article. I’m, a longtime fan, and I used to help manage Team SpiderTech with my cousin Steve Bauer back in the day, so Guillaume Boivin still stays with us off-season to train (he was just here and then coming back in December).
ISN released details on their setup and what shocked me was they put 55cl of sealant in each tire! That’s roughly double what I’ve been running in my 30mm Pro1 road tires and would seemingly add weight and rotational mass.
I’ve never seen you address the issue of sealant volume in terms of performance or am I off base?
— Ian McLagan
Dear Ian,
Thanks for that! That answers the question I had in my column last week, namely, what tires and pressures the eighth and ninth placed riders, Tom Van Asbroeck and Guillaume Boivin from Israel Start-Up Nation, were riding. I said they “probably were on the 30mm Maxxis Velocita tubulars that came in seventh in our test (the second-fastest tubular after the Specialized Turbo Cotton tubular),” and indeed you have confirmed that. That tire performed best in our test at 4.5 bar (65 PSI), which is within the 3.5-4.5 bar (51-65 PSI) that they rode.
I have not tested rolling resistance as a function of sealant volume. I had better put that on the list for the future!
― Lennard
Dear Lennard,
It’s finally happened. The content of your column is now only accessible by becoming a member of Outside/VeloNews.
— Steve
Dear Steve,
Indeed, my column last week about Paris-Roubaix tire rolling resistance couldn’t be read in its entirety without having paid for an Outside+ or VeloNews subscription. What is — and is not — available to non-subscribers is constantly being evaluated within the company, I expect that my Tech FAQ column will generally continue to be available as free content, while my scientific test articles may require a subscription.
Although I played no part in the choice by VeloNews to put last week’s Tech FAQ behind the paywall, I understand the reasoning: The company paid $4,000 for the testing by Wheel Energy Oy, in addition to other expenses directly related to it. That’s 100 paid Outside+ subscriptions or 200 VeloNews ones. And I don’t work for free; the money to pay me and the salaries of everyone at Outside as well as the company overhead has to come from somewhere. The Internet has killed print advertising, which used to fund magazines like VeloNews; online advertising revenues are much lower. Add to that the consolidation in the bike industry that puts a bunch of smaller brands that all used to advertise separately under the umbrella of a few big companies, and there is a huge revenue shortfall to bring you the kind of content VeloNews readers have come to expect.
The Outside+ subscription comes to $4.16/month ($2.17/month for VeloNews only), which seems like a pretty good deal for the great content here. I pay a lot more than that for my online newspaper subscriptions, and much more yet for a print one. By subscribing, you’ll get the satisfaction of knowing you’re making it possible for me and the rest of the people who bring you great stories, photos, and videos on this site and in the print magazine to continue doing so. An Outside+ subscription will also get you two free copies of any of my books, which together retail for the same amount as the annual subscription, as well as lots of other benefits from Outside’s vast array of magazines, events, and other services.
I want to know how much of a Paris-Roubaix rider’s power is consumed by his or her tires, and I think lots of other readers do, too. That’s why I did the test. For something more applicable to your own riding, look for upcoming articles I wrote on testing the rolling resistance of popular gravel tires and of the rolling resistance difference between butyl, latex, and polyurethane inner tubes. Yes, they’ll require subscribing to VeloNews or Outside+.
― Lennard
Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.” He holds a bachelor’s in physics from Colorado College.
Follow @lennardzinn on Twitter.
