What's the consensus on carbon clinchers, seriously?

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weightLight
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by weightLight

Fantazmagoically carbon clinchers are the shanitzz pop!

chaffordred
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by chaffordred

shoopdawoop wrote:Wmv I'm not entirely sure; however my recent experiences with my carbon clinchers supports what I've read that cc+latex is no good. With two different brands (Vittoria and challenge) of latex tubes I had 4 tubes blow with both veloflex 25mm and 27mm paves after rather short periods. I always check that the tube is fully inside the tire and not pinched and I use velox cloth rim strips. Two tubes blew within minutes of initial inflation and the others happened within 50miles of riding and racing (once under my girlfriend in a crit which is when I finally gave up!).

On regular butyl tubes I have around 1200miles with no problems again using both brands of tires. So perhaps I'm just very unlucky but from my end they seem like a bad match.


I have had the exact same issues you describe.

I bought a set of Far Sports 38mm carbon clinchers, fitted a pair of Michelin latex tubes. The front tube exploded about 5 minutes AFTER inflation, the rear tube exploded during a crit. This could be down to bad luck or poor fitting, but I have now put around 1k miles on these rims with butyl tubes (Michelin ultralight) and had no such issues. I have also fitted hundreds of butyl tubes again with no such issues.

Both times the latex tubes literally exploded and ripped a 3 inch gash in the tube. The explosion during the crit was as I went into a sharp hairpin bend, as I got out the saddle to accelerate out BOOM, the bike went sideways and I hit the deck. The Schwable Ultremo tyre was destroyed and the road rash was'nt pleasant either!

Before using carbon clinchers I had been using Mavic Cosmic Carbones (alloy brake track) with latex tubes and had no issues.

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WMW
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by WMW

tharmor wrote:the inner tubes were heating to considerable figures causing the "blow up" mentioned above.


Tubes do not "blow up" due to heat! Something else is happening.

Do you have a link to Hed's findings?
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WMW
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by WMW

chaffordred wrote:Both times the latex tubes literally exploded and ripped a 3 inch gash in the tube.


Not a chance.

Seriously guys, this is sounding like Bikeforums. Think about it a second. If the tube is properly installed there is hardly any stress on it at all, regardless of how high you inflate it.

Latex is less forgiving of small holes and sharp edges in the rim bed, and poor installation technique. It is much easier to get a latex tube stuck under the tire bead. *That* is why you are having better success with butyl.

Or maybe the rims are defective.
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shoopdawoop
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by shoopdawoop

I had similarly large blowouts however WMW you are likely right; latex tubes are much harder to install and I certainly am less apt to really muscle around the tube and tire with a tire iron/lever on the CC. Its just I so rarely have problems with flats (less than 5 instances in the last 20,000 miles), even whilst frequently switching to latex or different tires (from race to training), that the quick string that occurred only with the CC+latex gave me apprehension. Im going to go grab a few more latex tubes and really try and get them perfect.

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WMW
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by WMW

Powder the tire and tube, inflate the tube enough to give it shape, and make sure the tube isn't pinched or distorted. Add a little air and check around the bead again.

Better check the rim's bead hook also.

And probably best to use something besides the 45g Vred tubes. The Vittorias seem fairly robust.
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tharmor
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by tharmor

WMW wrote:Tubes do not "blow up" due to heat! Something else is happening.


From Lennard Zinn @velonews April 30, 2013 ::

Late vs. gradual braking to prevent blowouts

Dear Lennard,
There has been much talk recently about the potential for heat-related blowouts with carbon clincher rims. While I have never had this problem myself, and have never heard a first-hand report of such an occurrence, I remain concerned. With the advent of SRAM’s hydraulic rim brakes, the potential for heat buildup seems even worse. My question is whether a very late and powerful braking action or an earlier, more gradual braking action will control heat buildup better. I will be doing a seven-day race through the Alps this summer and I’d like to be as prepared as possible for the notoriously steep (upwards of 22 percent), twisting descents. Also, are latex tubes any more or less susceptible to heat?
— John

Dear John,
My experience with doing a lot of testing of carbon clinchers on Flagstaff Mountain above Boulder is that shorter, more powerful braking produces less heat buildup than does prolonged braking. I’ll ask around more about this, because it’s a very good question.

The inner tube type is irrelevant; the tire only explodes because the tire bead blows off the rim when it gets hot enough, and no tube could hold the pressure once it’s no longer constrained within the tire.
― Lennard


Read more at http://velonews.competitor.com/2013/04/ ... op3jQQs.99

eric
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by eric

Full CCs can be made much lighter than carbon/aluminium hybrids. Farsports 38mm rims are 390g. I have a set of their older narrow basalt brake track 50mm rims which are 410g each. Farsports 38mm wheels are in the 1230g range, the wheels I built on the 50mm rims are 1320g using White H1 hubs which are not the lightest.
I use the 50mm wheels in big climbing races that also have descents and some flat because they're light and aero (and tubulars are not an option for me due to lack of support). I've had no problem on 6000' 55 mph descents. The aero wheels are an advantage for this- with them I've attacked and ridden away on these descents in the past. I used to have guys I'd dropped on a climb pass me on the next descent.

Farsports uses their own molds as do all the reputable chinese carbon rim manufacturers. They do their own testing. I've seen pictures of their rig in action. With my 38mm wheels I got some sort of test report to some EU standard. While I don't understand it and therefore it's sort of worthless, I've never gotten that from a name brand carbon manufacturer. Of course they do their own testing too, they just dont' report the results.

Having been involved in standard processes I don't see them as a panacea. It quickly becomes political- the various representatives are trying to steer the standard to where it's more advantageous to whoever they represent. Big players will want to create a barrier to entry that they can meet but others can't, while other players will be trying to water it down or make it require technology they own. The actual technical merits can be lost in the process. And it takes freaking forever.

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FIJIGabe
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by FIJIGabe

Eric, don't fool yourself. One of the big problems with carbon clinchers is that there is no standard that they must meet (either in the US or in the EU) for safety. There's nothing to say that those numbers are legit, and even if they are, whether they would meet or exceed any standard

For me, I'll run my CC's on tubeless tires, I can safely run them 15psi below what I run my standard clinchers, and I have the benefit of a firm grip of the tires on the lip of the rim. That's not to say it's a cure-all, because it won't prevent overheating of the laminate material, leading to deformation, but at least I've got some protection against "blow out".

weightLight
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by weightLight

Tubes blow up due to rapid air loss.

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FIJIGabe
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by FIJIGabe

Tubes explode before they lose air? Please explain.

weightLight
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by weightLight

Yeah people pump air in them to quite a pressure, it is insane man!

chaffordred
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by chaffordred

WMW wrote:
chaffordred wrote:Both times the latex tubes literally exploded and ripped a 3 inch gash in the tube.


Not a chance.

Seriously guys, this is sounding like Bikeforums. Think about it a second. If the tube is properly installed there is hardly any stress on it at all, regardless of how high you inflate it.

Latex is less forgiving of small holes and sharp edges in the rim bed, and poor installation technique. It is much easier to get a latex tube stuck under the tire bead. *That* is why you are having better success with butyl.

Or maybe the rims are defective.


Not a chance?

Previous to using carbon clinchers I was for many years using wheels with alloy brake tracks/latex tube combos and never had a problem. My local Decathlon store has always done good deals on Michelin Latex tubes, so they were my tubes of choice. I have always been aware of potential installation problems, particularly regarding seating the tube under the tyre bead. I had just spent 3 months over the winter building this particular bike up, scrutinising every single detail/component, so when it came to installing these pair of latex tubes on this pair of brand new carbon clinchers I again painstakingly checked and double checked the tubes were seated properly. These last thing I ever wanted was to spend the whole of winter building a £7k bike up, only to crash it and find it was due to poor installation of an inner tube.

As I said in my previous post the front tube exploded around 5 minutes after installation. The rear exploded during a crit. Prior to the the race I had put about 200 miles on the tyre/tube/wheel combo including a 6 mile warm up on the day. If the tube had been installed incorrectly it would have exploded prior to this race. On inspection of the latex tube it had a three inch gash where it had exploded and ripped the tube open. It also destroyed the tyre.

Since this I have put it in 150+ miles a week on the same rim/tyre combo and they have not skipped a beat. The only change being butyl tubes (Michelin Ultralights).

BTW In case you think I'm trying to stir up some kind of panic (your reference to Bike Forums). This is not the case. I think the Far Sports 2014 38mm CC's are fantastic. I also think Latex tubes are fantastic. They seem to roll better and almost add a 'shock absorber' effect to your ride. The point I'm trying to make is it is of my opinion that the combination of the two do not seem to work (for me) and when I noticed another poster had the same issues I felt compelled to register and post as I wouldn't want to see anyone else experience what I did.

Zoro
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by Zoro

My son has been bugging me for carbon clinchers. As he races, on great wheels I said no - train on your alloy ones. Wed he had a blow out and messed up his pretty alloy clinchers - looks only, they work fine. Carbons would have been ruined.

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WMW
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by WMW

chaffordred wrote:As I said in my previous post the front tube exploded around 5 minutes after installation. The rear exploded during a crit. Prior to the the race I had put about 200 miles on the tyre/tube/wheel combo including a 6 mile warm up on the day. If the tube had been installed incorrectly it would have exploded prior to this race. On inspection of the latex tube it had a three inch gash where it had exploded and ripped the tube open. It also destroyed the tyre.


I'm not claiming that you are making anything up... but that you are misinterpreting the cause of the problem.

Do you understand that a tube cannot possible "explode" unless its container fails? When the tube is properly installed, it expanded a small amount (even at high pressure) and pressed up tight against the tire and rim bed. If the tire or rim bed fails (suddenly) to contain the tube, then it can explode. You keep saying that the tube is the issue... but it couldn't be. It is either poor installation, or something wrong with the tire or rim.

Also, latex can in fact survive in a pinched state for a long time, and the explosion occur while riding when extra heat or forces are invloved.
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