Cycling News tire test

[XXtwindad]

Originally Posted by fa63

There was a good discussion on the forum recently on the Wind Tunnel Aero testing that Cycling News did. It seems like they have now tested a bunch of tires for their rolling resistance using "a simulated tarmac surface based on a scan of a Paris street" and at speeds that most mortals can achieve (9 m/s or 20 mph and 11 m/s or 25 mph, roughly). All were 28 mm (printed) width tires, except a couple that weren't available in that size (Specialized Turbo Cotton, Challenge Criterium RS, Conti Aero 111), and in that case they used the closest available size. The test pressure was 73 psi (except the Specialized Turbo Cotton which is 26 mm so they inflated that to a slightly higher pressure). Below is a summary of the results, with rolling resistance given in terms of Watts (per tire).

It would have been interesting to test something like the Conti Gatorskin to see perhaps what the "worst-case" scenario might look like But alas, the difference at ~20 mph between the worst performing tire (Pirelli P Zero Race 4 Season) and best performing tire that many use for daily riding (Continental GP5000 S TR) is about 11 Watts per tire, or roughly 22 Watts for the pair (I know weight distribution on a road bike isn't perfectly 50/50 front/rear, but close enough).

I was also surprised the Vittoria Corsa Pro Control did relatively poorly.

And of course, it doesn't matter how fast your tire is if a) you don't care and b) it is so fragile that it flats constantly :) In this case though, something like the Continental GP5000 comes out looking pretty good as it is a good balance between performance and durability -- I have been riding them for years and while not as supple as Vittorias, I can't remember the last time I flatted on them (I use TPU inner tubes).

Kind of renders everything else moot, no?

[fa63]

Sure, but as I stated in my original post, I ride Continental GP5000 tires on crappy Atlanta roads and can't remember the last time I flatted. To me, it makes no sense to ride slow-rolling "all-season" or "protection" type tires for the relatively low probability of flatting.

Having said that, I probably just jinxed myself and will flat on my next ride

Originally Posted by XXtwindad

Kind of renders everything else moot, no?

[Spdntrxi]

supple is underrated..

Give me :

Enve RaceDays and PowerCup TLRs all day.. Hell even the Aero111 feels better then a Conti5000 STR.. and all 3 of these have gobs more grip then 5000 too, Maybe 6000 will be better if they use the same compound at aero111.

[XXtwindad]

Originally Posted by fa63

Sure, but as I stated in my original post, I ride Continental GP5000 tires on crappy Atlanta roads and can't remember the last time I flatted. To me, it makes no sense to ride slow-rolling "all-season" or "protection" type tires for the relatively low probability of flatting.

Having said that, I probably just jinxed myself and will flat on my next ride

First few rides in, I like those as well. Incredibly smooth and fast-rolling. 🍻

[ojingoh]

GP5k is a great tire.
Veloflex, fresh, is a nice tire. I found that durability was poor though, but I'm a rolling tire destroyer, apparently.

To answer Mark Mc's question: It's complicated.
I'm going to quote the 4th Ed of Bicycling Science, Wison/Schmidt 2020. On page 305 the authors state:
Summary The theory and correlations discussed (in the preceding chapter) show that there is more to the rolling-resistance coefficient than the speed- and load-independent constant usually assumed. The effects of diameter, width, and tire pressure are well-researched, and temperature effects are at least acknowledged. The proportion of losses from sliding friction and hysteresis seems to be unknown. The single empirical formula for the coefficient of rolling resistance as a function of all of the described variables remains to be developed.

[C40_guy]

This article caught my attention. I'm looking for the follow on study...

What is the effect (mitigation) of dirt, mud, pebbles, etc. packed in between the knobs on my gravel tire? Does the increased aero smoothing outweigh the additional rotational weight? Are there other factors involved?

Inquiring minds don't really want to know...we'd rather be riding.

[RoosterCogset]

What system weight was put on the tires? 73psi for 28mm, the Silca calculator tells me is about right for a 120lb Rider+Bike+Gear total weight. Seems like an odd choice of tire pressure.

[Wunder]

Originally Posted by RoosterCogset

What system weight was put on the tires? 73psi for 28mm, the Silca calculator tells me is about right for a 120lb Rider+Bike+Gear total weight. Seems like an odd choice of tire pressure.

I believe 73 PSI is the ERTRO limit for tubeless on hookless rims. I also find it’s close to right for me at 165 even using tubes.

[Wakatel_Luum]

And Veloflex are no more I see.

[gravelreformist]

Originally Posted by RoosterCogset

What system weight was put on the tires? 73psi for 28mm, the Silca calculator tells me is about right for a 120lb Rider+Bike+Gear total weight. Seems like an odd choice of tire pressure.

A 28mm tire on a 21mm ID rim is likely to inflate to 29-31mm real-world. You have to use the real-world number in the calculation.

For 170lb combined system weight, 29mm tire, worn pavement, high performance tire/fast group ride/road bike I get almost exactly 73psi, and that's what I've been running on these size tires in the real world, so seems like a reasonable choice to me.

[El Chaba]

Originally Posted by Wakatel_Luum

And Veloflex are no more I see.

Yes…This is devastating news.

[jamesdak]

Originally Posted by Wakatel_Luum

And Veloflex are no more I see.

What??!!!!!! Tell me that's not true!!

[meyatt]

Originally Posted by RoosterCogset

What system weight was put on the tires? 73psi for 28mm, the Silca calculator tells me is about right for a 120lb Rider+Bike+Gear total weight. Seems like an odd choice of tire pressure.

I don't think the Silca calculator is very good. I ride 28mm tubeless and do 67/69 front and rear at 168 pounds on hooked rims. For hookless when it mounts a bit wider I'll drop into the 58/60 range.

[gravelreformist]

Originally Posted by meyatt

I don't think the Silca calculator is very good. I ride 28mm tubeless and do 67/69 front and rear at 168 pounds on hooked rims. For hookless when it mounts a bit wider I'll drop into the 58/60 range.

Silca is pretty transparent that their calculator is optimized for what is fastest, not what is most comfortable.

[meyatt]

Originally Posted by gravelreformist

Silca is pretty transparent that their calculator is optimized for what is fastest, not what is most comfortable.

maybe, in my experience it's slower and harsher on gravel and road (I'd say this is purely anecdotal but based on the frequency of particular roads I ride on, I feel like I've some quantitative backup).

The SRAM pressure calculator tends to be more on the money for me.

Plus, increase the pressure, increase risk of punctures — the thing that really slows you down.