Fastest tire - Vittoria Corsa Speed (open TLR)

Discuss light weight issues concerning road bikes & parts.
TobinHatesYou
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by TobinHatesYou

The Corsa Speed has a tread thickness of .8mm vs the Pro One’s 1.4mm. I would expect half the mileage.

CrankAddictsRich
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by CrankAddictsRich

alcatraz wrote:
Sat Jun 16, 2018 1:01 am
Have you tried turning the tire around? Is the dimple on the other side?

What about swapping rear/front.

Have you tried soap on the bead to try and get it evenly seated before putting in the sealant.
I'm assuming you were responding to me. I don't see how swapping the tire around would solve the issue? There wasn't a dimple in the tire, it was in the side of wheel and it was being caused by that specific tire. I swapped on the S-Works and everything was fine. I raced today. 20:39 for a 10 mile course. 29 mph.
zefs wrote:
Sat Jun 16, 2018 12:09 pm
Seems like a known issue with Yoeleo wheels: https://www.youtube.com/watch?v=EeBAQr-1ShM
There was another owner that pressed the side walls of the wheels and it was bulging but can't find the video.
Watched that video, the problem that guy is showing is not what my wheel was doing. That guy appears to have a bulge coming out in the brake track. The issue I had wasn't in the brake track, it was about mid way down the 88mm depth of the wheel, in the hollow section of the wheel and it was a gradual bowing in. The best was I can describe it... if you had an empty soda can sitting on the table and you put pressure on the top, pushing down, the can would be begin to deform along the sides. removed the tire and its gone. This issue was only evident with the Corsa Speed... and only did it with the 2nd Corsa Speed I mounted, not the original one. It is enirely possible that this particular tire had some defect or issue, but with just a 2 or 3 days to get it sroted before my next race, I wasn't gonna waste time figuring it out.
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by Weenie


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IrrelevantD
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by IrrelevantD

TobinHatesYou wrote:
Sat Jun 16, 2018 8:35 pm
The Corsa Speed has a tread thickness of .8mm vs the Pro One’s 1.4mm. I would expect half the mileage.
Right, with Vittoria claiming the graphene in the G+ compound making the tire more durable and longer lasting, I was wondering what people are seeing for real world longevity.
* There is a 70% chance that what you have just read has a peppering of cynicism or sarcasm and generally should not be taken seriously.
I'll leave it up to you to figure out the other 30%. If you are in any way offended, that's on you.

CrankAddictsRich
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by CrankAddictsRich

I can't speak specifically to the longevity of the Corsa Speeds because I've only raced on them in TT's, but I use the regular Corsa G+ tires on my road bikes and over the last two years doing approximately 8000 outside miles split between two bikes and have swapped tires, 2 times... the quick and dirty math says they're lasting 2000 miles, but I know that's not right because I've swapped on S-Works turbos for the winter months and also have a fair bit of MTB miles in the winter... maybe 1500 miles or so for a set.
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TheKaiser
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by TheKaiser

CrankAddictsRich wrote:
Fri Jun 15, 2018 9:35 pm
Finally, when I think its sealed, I take the bike out for a test ride... and I can hear a "knock, knock, knock" aound as I roll around. I realize that the sound I'm hearing is actually the sound of the carbon on the side of the 88mm wheel flexing... it almost has like a dimple in it that pops in and out as I roll (imagine squeezing a soda can). I get off the bike, worried that the wheel is being damaged. I immediately take the pressure out of the tire and end up dismounting the tire. The dimple goes away. I clean up the wheel from all of the sealant and throw on an old S-Works Cotton with tube... no dimple. With a race coming this weekend (tomorrow) I decided I dind't want to deal with this and swapped on a brand new set of S-Works cottons. The Corsa Speeds did feel great and were perhaps faster, but I can't say for sure by how much. I will not better tomorrow after I do a full race effort on the TT bike with the S-Works. They were extremely hard to munt though and I'm convinced that the 2nd tire that went on the front was SO tight that it was some how distorting the wheel.
Its a pretty well accepted fact that mounting tubless tires is likely to drop your spoke tension, due to the compressive force of the extra tight and robust tubeless bead squeezing the rim. There are a ton of threads out there discussing it, particularly in regard to light weight aluminum rims, like the Stans Alpha 340, and also many of the light aluminum mountain bike wheels. That is present to some some degree with all tubeless tires, but the tighter the fit, and the more flexible the rim, the larger the effect.

It sounds like that is what is going on with your wheels, but because the rims are so massive with so much exposed unsupported surface on the sidewalls, the outer rim structure with tire bed is compressing relative to to the inner rim structure with spoke bed, rather than them compressing together as a single unit, hence your dimpling rim sidewall. It sounds like its right at the threashold and then the extra force of your body weight is what pushes it over the edge once it hits bottom dead center.

I know you weren't asking for a diagnosis. I just wanted to mention all this because it sounded like you had people doubting your assessment and I think your assessment makes perfect sense given what we already know about tubeless tires/spoke tension.

zefs
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by zefs

CrankAddictsRich wrote:
Sat Jun 16, 2018 12:09 pm
Watched that video, the problem that guy is showing is not what my wheel was doing. That guy appears to have a bulge coming out in the brake track. The issue I had wasn't in the brake track, it was about mid way down the 88mm depth of the wheel, in the hollow section of the wheel and it was a gradual bowing in. The best was I can describe it... if you had an empty soda can sitting on the table and you put pressure on the top, pushing down, the can would be begin to deform along the sides. removed the tire and its gone. This issue was only evident with the Corsa Speed... and only did it with the 2nd Corsa Speed I mounted, not the original one. It is enirely possible that this particular tire had some defect or issue, but with just a 2 or 3 days to get it sroted before my next race, I wasn't gonna waste time figuring it out.
Found the video, is this what was happening on your wheels?
https://www.youtube.com/watch?v=Onb-HCIvcT0

alcatraz
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by alcatraz

Why don't the turbo cottons make the rim dimple?

I was thinking that maybe the bead didn't seat properly. Or you didn't run the turbo cottons to as high a pressure as the corsas.

/a

CrankAddictsRich
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by CrankAddictsRich

TheKaiser wrote:
Sun Jun 17, 2018 3:23 am

Its a pretty well accepted fact that mounting tubless tires is likely to drop your spoke tension, due to the compressive force of the extra tight and robust tubeless bead squeezing the rim. There are a ton of threads out there discussing it, particularly in regard to light weight aluminum rims, like the Stans Alpha 340, and also many of the light aluminum mountain bike wheels. That is present to some some degree with all tubeless tires, but the tighter the fit, and the more flexible the rim, the larger the effect.

It sounds like that is what is going on with your wheels, but because the rims are so massive with so much exposed unsupported surface on the sidewalls, the outer rim structure with tire bed is compressing relative to to the inner rim structure with spoke bed, rather than them compressing together as a single unit, hence your dimpling rim sidewall. It sounds like its right at the threashold and then the extra force of your body weight is what pushes it over the edge once it hits bottom dead center.

I know you weren't asking for a diagnosis. I just wanted to mention all this because it sounded like you had people doubting your assessment and I think your assessment makes perfect sense given what we already know about tubeless tires/spoke tension.
I think you've hit the nail on the head with your description of what is going on. No need to apologize.... I was not aware of this compressive force and spoke tension issue via tubeless and all of the people I've mentioned this problem to previously didn't mention it either. I'm guessing that it is perhaps more common knowldge in the MTB world than it is in the road scene because tubeless has been around longer. The roadie people I've mentioned it to all seemd to just look at me like i was crazy, "That can't be happening." or simply dismiss it as, "well that's what you get with chinese carbon." I'm guessing it is a combination of the super deep carbon section, plus an extremely tight tire... keep in mind, it only did it with the second tire I mounted, the first Corsa Speed did not exhibit this issue. I was runnign the first one with a tube tough, so I'm not sure if that makes a difference, or if perhaps, the second tire was just slightly out of spec and a little tighter.
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CrankAddictsRich
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by CrankAddictsRich

zefs wrote:
Sun Jun 17, 2018 7:52 am

Found the video, is this what was happening on your wheels?
https://www.youtube.com/watch?v=Onb-HCIvcT0
Yes... that is basically what was happening with my wheel, but that one is much worse than mine was. Mine was only doing it when I was on the bike, with my weight on it, as The Kaiser mentioned earlier.
alcatraz wrote:
Sun Jun 17, 2018 10:16 am
Why don't the turbo cottons make the rim dimple?

I was thinking that maybe the bead didn't seat properly. Or you didn't run the turbo cottons to as high a pressure as the corsas.

/a
See The Kaiser's post further up the thread... the Turbo Cottons don't have a bead that's anywhere near as tight as the Corsa Speed because they aren't a tubeless tire. They're a tubed clincher, so the pressure from the tube holds the tire in place, not the tire bead. As for pressures, I was running roughly the same... a little lighter on the tubeless set up for the one race I ran.
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alcatraz
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by alcatraz

Tube or not the bead holds the tire in place.

Corsa speeds don't currently mate well with your rims.

If the bead diameter varies slightly (which you've proven by testing different year corsa speeds) then it might vary from tire to tire or depending on which side of the tire you are using.

Perhaps it's your rim that is larger on one side than the other. Then you have to find the most relaxed bead among your corsas to make it fit that side.

Again it's worth testing turning the tire around or a second tire, if you are interested in getting the corsas working again.

CrankAddictsRich
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by CrankAddictsRich

I see what you're saying.... at this point, I'm not interested in spending the time to test to deal with all of the hassle and messiness of tubeless. I'm not convinced that the potential speed gain (if any) is worth the hassle.
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TheKaiser
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by TheKaiser

alcatraz wrote:
Mon Jun 18, 2018 3:47 am
Tube or not the bead holds the tire in place.
You are technically right that the bead holds the tire in place on either system (tube type tire, or tubeless type tire) but how the bead does so, and how it interfaces with the rim, are different.

With tube type tires, the bead is pressed against the outer walls of the rim as the tire is initially pressurized, and then as the tire pressure increases the hoop stress generated by the higher pressure will try to expand the tire's diameter further. All kevlar folding bead tires have some stretch to the bead, so as the hoop stress increases the diameter of the tire the bead will stretch and creep up the sidewall of the rim until the bead hits the "hook" at the top of the rim edge, but it should be unable to expand further because of the pressure of the tube holding the bead against the sidewall below the hook. That is why rims with that type of interface have traditionally been called "hook-bead" rims. Depending on just how stretchy the bead is, how loose a fit the tire is, and how much pressure you put in, the hook might do just a little work, or a lot of work, to retain the tire.

With at tubeless tire, the interface is more like a car tire, where the bead diameter is configured to be very tight, such that it sits on the flat surface at the bottom edge of the sidewall that some people have taken to calling the "bead shelf". Tubeless beads are typically made of carbon fiber rather than kevlar (the exception being the new Mavic system), so that they have far less stretch, and as a result the hoop stress is not able to expand them significantly and the bead very tightly squeezes this inner bead shelf on the rim. They are so tight, that it takes a ramp countour on the rim well to get them up onto the shelf when inflating, and even then it often also takes soapy water to lubricate the bead as it slides into place. That tightness is what keeps the bead from riding up the sidewall as pressure is increased, and it is also what allows for some of the new "hookless" rims, because the hook is no longer required (although most companies put a pressure limit on hookless rims, as the hook still acts as a failsafe).

So you are right that the bead is what is retaining the tire in both cases, but on a tube type tire the bead is pushing up and out on the sidewall of the rim, whereas on a tubeless tire the bead is squeezing inward.

TheKaiser
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by TheKaiser

alcatraz wrote:
Mon Jun 18, 2018 3:47 am
Corsa speeds don't currently mate well with your rims.

If the bead diameter varies slightly (which you've proven by testing different year corsa speeds) then it might vary from tire to tire or depending on which side of the tire you are using.

Perhaps it's your rim that is larger on one side than the other. Then you have to find the most relaxed bead among your corsas to make it fit that side.

Again it's worth testing turning the tire around or a second tire, if you are interested in getting the corsas working again.
As you point out, there is obviously some variance from tire to tire, and then as these articles explain nicely, there is also no current fixed standard for "Road Tubeless" which exacerbates things:
https://bikerumor.com/2015/01/14/why-is ... -get-here/
https://bikerumor.com/2015/01/29/why-is ... -the-road/

Since there isn't a hard and fast interface standard, in this case his 88mm rim may be on the big side of the bead seat diameter range by design, to ensure tire security, and the Vittoria may be on the tight side, for the same reason. Then, the individual example of the rim might be a on the bigger side of the manufacturers production variance, and then the Vittoria might be on the small side of the Vittoria variance, so you have the tolerances stacking up in a kind of worst case scenario. Actually, I suppose it's the 2nd worst case scenario, as the worst would be an opposite arrangement of tolerances resulting in a high speed blowoff!

alcatraz
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by alcatraz

Very intresting info. Thank you for a detailed reply.

I used my corsa speeds on tubed rims and didn't find them difficult or tight.

Maybe when mounting them on a tubeless rim it's a whole other story.

/a

ericoschmitt
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by ericoschmitt

TheKaiser wrote:
Sun Jun 17, 2018 3:23 am

Its a pretty well accepted fact that mounting tubless tires is likely to drop your spoke tension, due to the compressive force of the extra tight and robust tubeless bead squeezing the rim. There are a ton of threads out there discussing it, particularly in regard to light weight aluminum rims, like the Stans Alpha 340, and also many of the light aluminum mountain bike wheels. That is present to some some degree with all tubeless tires, but the tighter the fit, and the more flexible the rim, the larger the effect.
This answer and the thread made me even more worried. Got Stans 340 wheels waiting for the new frame, and a pair of Corsa open TLR in the drawer... Got GP4000's too, and first plan was using those with conti Supersonic tubes. When I saw rolling resistance test result and the claimed weight I got a pair. But they weight far more than 205g - 235~ actually. How I hate this. After adding sealant, valves, and tubeless tape (which are heavier than Rox Ultralites) they would save me 15g or less... And that's against 25mm GP4k. If using 23s, then difference is zero. So I thought "well, at least saves rolling watts, and maybe some confort". I knew the thread was thin already, but could save them for race only. Until I actually tried to fit them on the wheels, even before applying any tape, I couldn't. I will try to stretch them on a cheap and strong rim before.

And now this spoke tension thing. Maybe I should install them, pump, and then re-tension the wheels??

I also thought about those rolling watts. Because I've read about some wind tunnel test comparing tires, and the GP4000 thread pattern actually made it a bit more aero. Just can't remember how many watts that was. Corsa TLR save 8w from GP4k - but with standard butyl tubes. If using some Vredestein latex 49g tubes might save some 4 or 5w, and then those 3w left could be made from aero benefit... And GP4k last long, have good puncture protection, easy to fit.

Now I got a brand new pair and I'm wondering if I should even bother triyng to use them. I should decide it before I waste my Rox Ultralite tape. I could use some Kapton to test (cheap), but then I wouldn't be able to sell the tire pair as new if I give up...

by Weenie


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