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Some Recent Crr Tests
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TOPIC: Some Recent Crr Tests

Some Recent Crr Tests 6 years, 8 months ago #26565

  • AFM
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I tested a few tires about a month ago. All were clinchers and included was a production R4 Aero tire, VF Record, and a Conti Grand Prix SuperSonic 23. I ran a few days worth of tests on the tires as I got some “unexpected” results. My control tire with latex tube (Michelin Pro 2 Light with Michelin Latex 22/23) was repeatable and within typical range so everything appears to be working OK.

Here are the results:

Tire/tube, weight (g), width (mm), Crr, Notes

Bontrager R4 Aero 22/Vred Latex tube, 173, 25.6, 0.00250, New Tire

Velo Flex Record 20/Vred Latex tube, 141, 22.8, 0.00219, Used Tire

Continental Grand Prix Super Sonic 23/Vred Latex tube, 164, 23.5, 0.00226, New Tire


The R4 Aero tested out slightly higher than the 3 I tested previous to production release. One thing I noticed is that the production tire weighed 173 grams while the 3 that I tested weighed ~ 164 grams. As I saw with the Aero Wing TT tires weight does matter with Crr. The new R4 tested at Crr of 0.00250 compared to the previous 0.00245 so very close. I didn’t run any tests after putting any miles on the tire.

The VF Record rolls very well. I compared it to some that I have and the one from you is very flexible – feels like a wet noodle. The tire has been used in the wind tunnel and may have many trainer miles on it ?? The tread doesn’t show any wear. The measured Crr of 0.00219 is very low compared to 0.00245 from slightly used tires I’ve tested before.

The Continental Grand Prix Super Sonic 23 is also a fast rolling tire. It tested at a Crr of 0.00226 which is actually the fastest clincher tire and tied for the fastest overall (with the new Vittoria Crono 22 tubular). The size 20 version came in at 0.00251 so it’s not surprising that the 23 is faster.

All of these tires were tested on a wide rim wheel. The measured outside (between brake tracks) and inside the tire hook dimensions of the wheel as ~ 23.7 mm and ~ 17.8 mm. The Record measured higher than nominal (20), the SS 23 measured close to nominal (23), but the R4 22 was much higher than nominal size of 22. I did not test these tires on my Velocity AeroHead test/control wheel but past testing showed very little effect of rim width on Crr.

Re: Some Recent Crr Tests 6 years, 8 months ago #26566

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That's very cool.

I have an old SuperSonic from way back... I used to use it for hillclimbs before I switched to tubulars. It has very poor durability: I had another but it didn't last long. It's good to hear it has good Crr.

Re: Some Recent Crr Tests 6 years, 8 months ago #26567

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The GP SS 23 is new this year and I am assuming has the "black chili" rubber compound so it may roll better than the older versions ?? It is very low weight for a 23 and so the durability would be suspect. Ron has been using the GP SS 20 for TT's with good success IIRC.

Re: Some Recent Crr Tests 6 years, 8 months ago #26568

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Hello AFM and All,

Once again - Thanks!

Where do I contribute to the your coffee fund? I feel I am freeloading and would like to make a contribution. (seriously)

Can you accept PayPal?

I use the Bonty R4's and like them - did use Michelins.

Bontrager R4 Aero 22/Vred Latex tube, 173, 25.6, 0.00250, New Tire

The above new data is similar to old test at 0.00245 but is the width at 25.6 a typo?

The old data was 22 width.

Cheers,

Neal

Re: Some Recent Crr Tests 6 years, 8 months ago #26570

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Neal wrote:
Hello AFM and All,

Once again - Thanks!

Where do I contribute to the your coffee fund? I feel I am freeloading and would like to make a contribution. (seriously)

Can you accept PayPal?

I use the Bonty R4's and like them - did use Michelins.

Bontrager R4 Aero 22/Vred Latex tube, 173, 25.6, 0.00250, New Tire

The above new data is similar to old test at 0.00245 but is the width at 25.6 a typo?

The old data was 22 width.

Cheers,

Neal


No problem - but my favorite charity is Wounded Warriors. Besides you have contributed your fair share and more !!

The tests were done using a wide body rim - you can see that all the widths are larger than on the Velocity Aerohead that I usually use. For some reason the R4 bulges out - it may have something to do with the aero wings ?? The GP SS 23 measured 22.0 mm width on the Aerohead rim.

Have you had good durabilty with the R4's. The pre production ones that I had seemed to cut easily but they may not have had all the puncture resistant layers installed ??

Re: Some Recent Crr Tests 6 years, 8 months ago #26573

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AFM wrote:
I tested a few tires about a month ago.

<snip>

I did not test these tires on my Velocity AeroHead test/control wheel but past testing showed very little effect of rim width on Crr.


cool! Glad to hear from you, Al!

Just so I understand what was done...you tested your control tire on the newer wide rim and it was within the expected range that you've seen on your AeroHead rim...then proceeded with the testing of the other tires on the new wider rim?
-kraig

Re: Some Recent Crr Tests 6 years, 8 months ago #26574

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Hello AFM and All,

Tried to PM you for eMail address - no joy.

Opps - did not read your posting carefully enough about the test on the wider rim.

Measured my tires: Rear Zipp 1080 Bonty R4 22.2, Front Zipp 404 Firecrest Bonty R4 23.8.

Should have been more aware after I had to redo my brake pads to fit the new front setup.

My eMail This e-mail address is being protected from spambots. You need JavaScript enabled to view it so I can send PayPal to you for keeping or donation as you wish.

My tires are about 1 year old and holding up well (knock on wood) - no flats.

Cheers,

Neal
Last Edit: 6 years, 8 months ago by Neal.

Re: Some Recent Crr Tests 6 years, 8 months ago #26575

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kraig wrote:
AFM wrote:
I tested a few tires about a month ago.

<snip>

I did not test these tires on my Velocity AeroHead test/control wheel but past testing showed very little effect of rim width on Crr.


cool! Glad to hear from you, Al!

Just so I understand what was done...you tested your control tire on the newer wide rim and it was within the expected range that you've seen on your AeroHead rim...then proceeded with the testing of the other tires on the new wider rim?


I tested the control tire as usual on the Velocity AeroHead rimmed wheel - Crr was typical. Then tested the three tires on the wide rim. I ran addtional tests again using the wide rimmed wheel but did not test the same tires on the Velocity AeroHead rimmed wheel. Time is a little harder to come by these days.
Last Edit: 6 years, 8 months ago by AFM. Reason: Missend

Re: Some Recent Crr Tests 6 years, 8 months ago #26587

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I'm currently riding MIchelin Pro Race 3's with regular butyl tubes.

What Crr should I expect?

What would be the Crr if I switched to Vred latex tubes?

Re: Some Recent Crr Tests 6 years, 8 months ago #26588

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Dreadnought wrote:
I'm currently riding MIchelin Pro Race 3's with regular butyl tubes.

What Crr should I expect?

What would be the Crr if I switched to Vred latex tubes?


www.biketechreview.com/tires_old/images/...ire_testing_rev9.pdf

Re: Some Recent Crr Tests 6 years, 7 months ago #26589

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I was just out at my LBS and picked up a couple of tubes...and scored an old AeroWing TT 23mm for $30 since the R4 is replacing it. I should have known that you'd already tested them weeks ago! It looks like if the durability is as good as the Aerowing TT then I may switch to R4s when my current stock wears out. I've had good luck (knock on wood) so far with the "2nd generation" of the Aerowing TT, no flats and only a few small slices. Similar in durability to the EVO CXs that I was using before the Bontys came out.

Your chart also reminded me why I was going so slow this spring, since I switched to old Axial Pros to wear them out before tossing them. At least I'll blame the slowness on the horrible Crr...

Re: Some Recent Crr Tests 6 years, 7 months ago #26592

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triguy42 wrote:
I was just out at my LBS and picked up a couple of tubes...and scored an old AeroWing TT 23mm for $30 since the R4 is replacing it. I should have known that you'd already tested them weeks ago! It looks like if the durability is as good as the Aerowing TT then I may switch to R4s when my current stock wears out. I've had good luck (knock on wood) so far with the "2nd generation" of the Aerowing TT, no flats and only a few small slices. Similar in durability to the EVO CXs that I was using before the Bontys came out.

Your chart also reminded me why I was going so slow this spring, since I switched to old Axial Pros to wear them out before tossing them. At least I'll blame the slowness on the horrible Crr...


The Aero Wing 23 weighing under 200 grams is a fast tire. It might get down close to the R4 Aero with some minutes on the trainer based on what I've seen with the AW 19. Not sure about the drag ?? The R4 tires I tested seemed a bit fragile - 2 of them were badly cut but arguably that could have happened to any racing tire.

Yeah I was disappointed in the Axial Pro Crr. I had a few left over and hoped they would roll better.

Re: Some Recent Crr Tests 6 years, 6 months ago #26652

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I am considering the Veloflex Record since it appears to have the best roller data, but it is only available in the 20c width. Too much compression on a 20c tire can actually increase the contact area to make the rolling resistance greater. Is that a problem for heavier cyclists? Is there a weight limit for those riding the 20c width?

Re: Some Recent Crr Tests 6 years, 6 months ago #26653

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Dreadnought wrote:
I am considering the Veloflex Record since it appears to have the best roller data, but it is only available in the 20c width. Too much compression on a 20c tire can actually increase the contact area to make the rolling resistance greater. Is that a problem for heavier cyclists? Is there a weight limit for those riding the 20c width?


My thought on that particular VF Record shown above is that it is an outlier - not sure why but other VF Records I've tested are ~ 0.00245 (2 used tires - not a large sample) although another one from Jens was higher at 0.00279 ?? Are these VF Records like a box of chocolates ?? Possibly as they are hand made ??

You might consider using the Conti GP Super Sonic - 20 on the front and 23 on the rear. There is less load on the front wheel so less rolling resistance plus a narrow tire should be more aero which is more important on the front wheel.

In general the heavier the rider the higher the tire pressure. There are some tables from Zipp and Michelin IIRC which list recommended tire pressure vs. rider weight. I think these tables are based on some recommended range of tire sinkage (casing deformation) determined by the manufacturer - not sure what the basis for the tables is but I suspect comfort and resistance to pinch flats ??

Re: Some Recent Crr Tests 6 years, 6 months ago #26661

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Dreadnought wrote:
I am considering the Veloflex Record since it appears to have the best roller data, but it is only available in the 20c width. Too much compression on a 20c tire can actually increase the contact area to make the rolling resistance greater. Is that a problem for heavier cyclists? Is there a weight limit for those riding the 20c width?


There is certainly a tradeoff. I recall seeing some charts awhile back where the aero advantage of the narrower tires tended to offset the Crr increase above 20mph for most rims. Of course there are other considerations.

I've been using the Conti Supersonics in 20mm for a couple of years and have been very pleased. They don't last long because the tread is very thin (<500miles on the rear), but they aren't fragile. They also look like they'd be more aero (ie smoother) than the Records.

Re: Some Recent Crr Tests 6 years, 6 months ago #26662

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AFM wrote:

My thought on that particular VF Record shown above is that it is an outlier - not sure why but other VF Records I've tested are ~ 0.00245 (2 used tires - not a large sample) although another one from Jens was higher at 0.00279 ?? Are these VF Records like a box of chocolates ?? Possibly as they are hand made ??


FWIW, the VF Record I've tested on my rollers is my reference tire, primarily because it is the lowest Crr tire (IIRC) that I've tested.

This could be relevant data, especially if one carries a lot of weight on the front wheel (whether by nature or nurture).
-kraig

Re: Some Recent Crr Tests 6 years, 6 months ago #26665

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kraig wrote:
AFM wrote:

My thought on that particular VF Record shown above is that it is an outlier - not sure why but other VF Records I've tested are ~ 0.00245 (2 used tires - not a large sample) although another one from Jens was higher at 0.00279 ?? Are these VF Records like a box of chocolates ?? Possibly as they are hand made ??


FWIW, the VF Record I've tested on my rollers is my reference tire, primarily because it is the lowest Crr tire (IIRC) that I've tested.

This could be relevant data, especially if one carries a lot of weight on the front wheel (whether by nature or nurture).


It could be that each individual VF Record has to be tested ?? The range I've gotten testing 4 used tires is from 0.00219 to 0.00279. Big spread. The weights have been ~ 140 grams although I didn't weigh Jens' used tire.

Re: Some Recent Crr Tests 6 years, 5 months ago #26669

AFM,

It could be that there is some variance in each model but more then likely what we are seeing is an upgrade in the casing. The 350 Tpi casing seems like a dream - fwiw I just order 3 clincher tires and when the USPS lady handed me the package I thought for sure it was a mix up as there was no way 3 clinchers tires could fit in the box she handed me. I pulled them out and all I have to say is wow - they made my new 2011 Conti Supersonics feel like a steel rod. I think what would be interesting to note is what version each of the tires is that you tested. It is probably tough to tell, but the newer 350 tpi ones have the new updated Veloflex logo and the older ones should have the older Veloflex logo.

I had used the Velo Record 20+ tubular for a long time on the front, and then I switched to the Velo Record 22+ tubular, and now I am on clinchers and intend to start racing these front and rear. The tubulars seem to be more aero in tread to casing, but without a doubt in my mind these roll well. Unfortunately the Velo Record 20 Ccincher is out of stock in the US - literally you won't be able to track one down from a retailer. My suspicion beyond normal Veloflex supply issues is that they are upgrading this to a 22 inch version. Time will tell.

Re: Some Recent Crr Tests 6 years, 5 months ago #26670

Kraig,

Why not run this tire on the back? Sure the tread is super think and you won't get a lot of miles out of it, but according to the German Tour puncture test it performed pretty good IMO. It lasted 57 seconds versus only 15 for the new PRB 2.0 Vittoria Corsa Evo. No doubt it didn't last the full 180 seconds from the likes of the Conti GP4000 or Michelin Pro Race 3, but 57 seconds is not bad compared to the Vittoria Corsa Evo and that tire is probably the most used race tire out there.

Re: Some Recent Crr Tests 6 years, 5 months ago #26671

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__ wrote:


Why not run this tire on the back?


I personally don't trust it as a rear tire.


It lasted 57 seconds versus only 15 for the new PRB 2.0 Vittoria Corsa Evo. No doubt it didn't last the full 180 seconds from the likes of the Conti GP4000 or Michelin Pro Race 3, but 57 seconds is not bad compared to the Vittoria Corsa Evo and that tire is probably the most used race tire out there.


Sounds like an interesting test. How many samples did they test and what was the spread of those samples for each tire brand/model?
-kraig

Re: Some Recent Crr Tests 6 years, 5 months ago #26672

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AFM wrote:
kraig wrote:
AFM wrote:

My thought on that particular VF Record shown above is that it is an outlier - not sure why but other VF Records I've tested are ~ 0.00245 (2 used tires - not a large sample) although another one from Jens was higher at 0.00279 ?? Are these VF Records like a box of chocolates ?? Possibly as they are hand made ??


FWIW, the VF Record I've tested on my rollers is my reference tire, primarily because it is the lowest Crr tire (IIRC) that I've tested.

This could be relevant data, especially if one carries a lot of weight on the front wheel (whether by nature or nurture).


It could be that each individual VF Record has to be tested ?? The range I've gotten testing 4 used tires is from 0.00219 to 0.00279. Big spread. The weights have been ~ 140 grams although I didn't weigh Jens' used tire.


Yeah, that is my thought - one needs to comparatively evaluate each tire - there are no guarantees it seems.

My particular veloflex record 20mm was purchased in 2008 (who knows when it was manufactured) and has a mass of 137g. It's Crr is sub 0.0020 on my rollers.
-kraig

Re: Some Recent Crr Tests 6 years, 5 months ago #26677

I don't have specifics on how many tires were tested but the mag has tested the Vittoria a few different times in different issues and seems to have a similar poor performing result each time. It gives me confidence to run the tire but now I probably have jinxed myself. I think the best thing to do is ride the tire in training to give you the confidence to be able to depend on it in a race situation.

Re: Some Recent Crr Tests 6 years, 4 months ago #26741

AFM - so I have been trying to use the Veloflex Record clincher as my racing tire - from a puncture perspective it has been rock solid - but from a wide-rim compatibility perspective well not so much.

It had been going well until a race a few weekends ago when I had a tire blow off in the hot sun after it had been sitting around in transition for a few hours on a 100 degree and almost windless day. I always thought this was kind of a myth and was due to improper installation of tubes but my mindset has since changed. During the race I could not change the tube for the life of me - it kept blowing off time and time again - it was extremely hot and extremely mailable. After the race I sat down with the tire and decided to do some experimentation. Fwiw on race morning I pumped this 20mm tire to 112-115 psi with a latex tube.

So what I have found out after testing this tire on both a Zipp 404 Full Carbon Clincher and a HED C2 rim is that the tire does not want to stay put. This is regardless of butyl or latex however, butyl does seem to last a little longer. For testing I picked some warm midwest days and with an arsenal of about 20 butyl tubes and 10 latex tubes I managed to come to the conclusion that eventually when the tire warms up and the pressure gets high enough that the tire will slip off the bead exposing the tube and then bam.

For testing to accelerate the test I moved up to 125 psi - the limit of the Zipp carbon clinchers. After the Veloflex I moved on to a similar construction open tubular - the Vittoria Evo Corsa. I too had problems with this tire on both rims and although it seemed like time to explosion was a little longer than the Veloflex in both butyl and latex explosions. I then moved on to thicker bead tires with less flexible casing. These tires hold the pressure fine even when I got risky and bumped up to 160 before baking in the sun and heat. Successful tires included Bontrager R4, Conti Supersonic 22, and Conti Gatorskin 25. I then went back and test a Vittoria SC Corsa and blew it off a Zipp 808 Full Carbon Clincher with both Butyl and Latex. And then back to further tests of the more define Bonty and Conti tires.

I am 100% confident these Open Tubular tires with very flexible casing have problems on both HED C2 Rims and Zipp Carbon Clincher Rims. Anyone that has worked with these rims knows how easy it is for tires to mount and dismount without tools. I wonder if this is partially what is causing the tires to blow off. I no longer feel confident running the Open clinchers type tires and will avoid these. I put in calls to both HED and Zipp. Vince @ HED instructed me that I should never put more than 90 PSI in a tire on a C2. Zipp denied any previous issues. They said they were going to dig into it some more but they never got back to me. I would be curious to know if you have ever had any problems. I also didn't know if you would be willing to test any of the wide-riims with Open Clincher products with higher PSI and letting them bake in the sun for a period as is common at triathlon venues.

Re: Some Recent Crr Tests 6 years, 4 months ago #26742

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usedzipp.com wrote:
AFM - so I have been trying to use the Veloflex Record clincher as my racing tire - from a puncture perspective it has been rock solid - but from a wide-rim compatibility perspective well not so much.

It had been going well until a race a few weekends ago when I had a tire blow off in the hot sun after it had been sitting around in transition for a few hours on a 100 degree and almost windless day. I always thought this was kind of a myth and was due to improper installation of tubes but my mindset has since changed. During the race I could not change the tube for the life of me - it kept blowing off time and time again - it was extremely hot and extremely mailable. After the race I sat down with the tire and decided to do some experimentation. Fwiw on race morning I pumped this 20mm tire to 112-115 psi with a latex tube.

So what I have found out after testing this tire on both a Zipp 404 Full Carbon Clincher and a HED C2 rim is that the tire does not want to stay put. This is regardless of butyl or latex however, butyl does seem to last a little longer. For testing I picked some warm midwest days and with an arsenal of about 20 butyl tubes and 10 latex tubes I managed to come to the conclusion that eventually when the tire warms up and the pressure gets high enough that the tire will slip off the bead exposing the tube and then bam.

For testing to accelerate the test I moved up to 125 psi - the limit of the Zipp carbon clinchers. After the Veloflex I moved on to a similar construction open tubular - the Vittoria Evo Corsa. I too had problems with this tire on both rims and although it seemed like time to explosion was a little longer than the Veloflex in both butyl and latex explosions. I then moved on to thicker bead tires with less flexible casing. These tires hold the pressure fine even when I got risky and bumped up to 160 before baking in the sun and heat. Successful tires included Bontrager R4, Conti Supersonic 22, and Conti Gatorskin 25. I then went back and test a Vittoria SC Corsa and blew it off a Zipp 808 Full Carbon Clincher with both Butyl and Latex. And then back to further tests of the more define Bonty and Conti tires.

I am 100% confident these Open Tubular tires with very flexible casing have problems on both HED C2 Rims and Zipp Carbon Clincher Rims. Anyone that has worked with these rims knows how easy it is for tires to mount and dismount without tools. I wonder if this is partially what is causing the tires to blow off. I no longer feel confident running the Open clinchers type tires and will avoid these. I put in calls to both HED and Zipp. Vince @ HED instructed me that I should never put more than 90 PSI in a tire on a C2. Zipp denied any previous issues. They said they were going to dig into it some more but they never got back to me. I would be curious to know if you have ever had any problems. I also didn't know if you would be willing to test any of the wide-riims with Open Clincher products with higher PSI and letting them bake in the sun for a period as is common at triathlon venues.


Sorry to hear of your troubles. I don't have any C2 wheels (previous testing was done using a C2 Jet 9 rim and an unlabeled wide rime from Trek) so I have no direct experience other than the garage testing done at ~ 70F but with 120 psig in the tires (I had not heard of the 90 psig limit from HED). Possibly using narrow tires on the wide rims contributes to the problem ?? Possibly you may have already done this but posting your experience over on Slow Twitch would result in more exposure to the Tri racer population and any adverse experience such as you describe. I don't get over there as often as I did a few months ago but I don't recall any description of the problem.

Re: Some Recent Crr Tests 6 years, 3 months ago #26743

I would have liked to get the expert opinion of the ST crowd but unfortunately censorship at Slowtwitch by the moderators is a little out of control. Although explained to me in a much more conspicuous way, they apparently are not a big fan of usedzipp.com *surprise* *surprise* and chose to restrict my account because of it. But that is an entirely different topic.

So with that being said I did take a look at the 20mm Veloflex Record and oddly is just a little shorter from bead-to-bead than the 25mm Gatorskin, and it is roughly the same width as the Bontrager R4. On the other side the Vittoria Evo Corsa is wider from bead-to-bead than the 25mm Gatorskin even though it is marked as a 23. It would be nice if someone out there could confirm my results.

I may do some more testing and see if I can find a PSI/Heat safety margin I am comfortable with otherwise I might need to find a new rear tire. I tried a brand new R4 on the rear for a recent race and although it survived, I did notice that the casing was cut about 1 cm all the way thru threads. Luckily the latex didn't pop out of the crack and burst. It reiterates to me for whatever reason the Bontrager casing is not very durable. Surprising though because I thought the 220 TPI casing was inherently more durable than say a 350 TPI casing Veloflex, but personal experience would indicate otherwise.
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