Tubeless & carbon clinchers safety

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twostroke
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Joined: Wed Jul 27, 2016 9:32 am

by twostroke

I've been following recently the evolution of carbon clinchers rims and I realised that tubeless options are becoming more and more available especially from well known chinese sellers. Thinking about the safety of carbon clinchers, one of the main concerns is the inner tube explosion caused by high temperatures during prolonged descents.
I'm wondering if by going tubeless there is an increased safety since the inner tube is no longer there... What's your opinion on that?

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dj97223
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by dj97223

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twostroke
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by twostroke

dj97223 wrote:Are you asking, Is it safe?

https://www.youtube.com/watch?v=kzw1_2b-I7A



I'm expecting it's safer, especially if you are riding low pressure.

Marin
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Location: Vienna Austria

by Marin

twostroke wrote:I've been following recently the evolution of carbon clinchers rims and I realised that tubeless options are becoming more and more available especially from well known chinese sellers. Thinking about the safety of carbon clinchers, one of the main concerns is the inner tube explosion caused by high temperatures during prolonged descents.
I'm wondering if by going tubeless there is an increased safety since the inner tube is no longer there... What's your opinion on that?


I don't think inner tubes getting damaged from heat is an issue with carbon since it conducts the heat much slower than aluminum - this is why the brake tracks stay warmer.

Tubeless comes with its own risks, I had a tubeless rear tire blow of a tubeless ready rim *after* a mild descent.

I don't really see an argument for tubeless in road applications - unless you get a lot of flats. I get about 1/year on tubes.

I used to flat every 2nd ride on my MTB, this is where tubeless was a killer application. But like suspension or disc brakes, many MTB technologies don't make a lot of sense on the road, no matter how hard they are being pushed.

TheKaiser
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by TheKaiser

twostroke wrote:Thinking about the safety of carbon clinchers, one of the main concerns is the inner tube explosion caused by high temperatures during prolonged descents.
I'm wondering if by going tubeless there is an increased safety since the inner tube is no longer there... What's your opinion on that?


High temps and tubes can be a problem, and that seems particularly so with the cautions around latex tubes in carbon clinchers, so I can see where you are coming from. Butthe other big issue with carbon clinchers is that the sidewall of the rim softens when subjected to high heat and will bow outward, allowing the bead of the tire to escape, and causing a blowout even if the tube is still at a safe temp (plus trashing your rim). From the anecdotal forum discussions I have seen, and a few magazine investigative tests like the one Velonews did that ran several wheels to failure down a steep hill, it seems that the rim sidewalls deforming is actually the more common failure mode than tube heating, so I don't think tubeless would really help that.

The only exception would be if the tighter fitting tubeless bead, which seats at the bottom of the rim well, were able to resist popping up and over a rim sidewall better than a normal clincher, which typically have a looser fit and ride higher up the sidewall closer to the bead hook. Not sure anyone has really tested that though, and based on some of the reports of tubeless blowouts, it seems that the lack of a tube can reduce the purchase of the bead so I wouldn't count on it...but if you had some rims made with a super hi temp resin, then it could be a good setup.

twostroke
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Joined: Wed Jul 27, 2016 9:32 am

by twostroke

TheKaiser wrote:
twostroke wrote:Thinking about the safety of carbon clinchers, one of the main concerns is the inner tube explosion caused by high temperatures during prolonged descents.
I'm wondering if by going tubeless there is an increased safety since the inner tube is no longer there... What's your opinion on that?


High temps and tubes can be a problem, and that seems particularly so with the cautions around latex tubes in carbon clinchers, so I can see where you are coming from. Butthe other big issue with carbon clinchers is that the sidewall of the rim softens when subjected to high heat and will bow outward, allowing the bead of the tire to escape, and causing a blowout even if the tube is still at a safe temp (plus trashing your rim). From the anecdotal forum discussions I have seen, and a few magazine investigative tests like the one Velonews did that ran several wheels to failure down a steep hill, it seems that the rim sidewalls deforming is actually the more common failure mode than tube heating, so I don't think tubeless would really help that.

The only exception would be if the tighter fitting tubeless bead, which seats at the bottom of the rim well, were able to resist popping up and over a rim sidewall better than a normal clincher, which typically have a looser fit and ride higher up the sidewall closer to the bead hook. Not sure anyone has really tested that though, and based on some of the reports of tubeless blowouts, it seems that the lack of a tube can reduce the purchase of the bead so I wouldn't count on it...but if you had some rims made with a super hi temp resin, then it could be a good setup.


Thanks for the reply! I will start riding with inner tubes and see how things will move on. It's my first time on full carbon wheels and I do have the feeling I need first to adapt checking how the brakes are behaving.

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Miller
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by Miller

Agree partially with the replies above. I had a pair of Gigantex carbon clincher wheels and one of those failed with a rim deformity that I attributed to getting hot om a descent of a local steep hill. The tyre didn't come off or anything, just developed a bump on the rim that made braking awful.

That was a few years ago. More recently I've been running tubeless on some deep section Farsports rims for time trials. I would be extremely surprised if a road tubeless tyre blew over the rim, the bead lock is very secure.

thelifeofapanca
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by thelifeofapanca

I don't think inner tubes getting damaged from heat is an issue with carbon since it conducts the heat much slower than aluminum - this is why the brake tracks stay warmer.


I agree, the inner tubes should not be affected of the heat!

TheKaiser
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by TheKaiser

thelifeofapanca wrote:
I don't think inner tubes getting damaged from heat is an issue with carbon since it conducts the heat much slower than aluminum - this is why the brake tracks stay warmer.


I agree, the inner tubes should not be affected of the heat!


I agree with both of you guys, in theory, however if you do a search for "carbon clincher latex tube" you will see that there are a lot of people reporting the rim's heat can cause unpredictable tube failure, including several rim companies (Zipp and/or Enve IIRC?). Then again, I have had many unpredictable latex tube failures in aluminum rims over the years, so maybe the rims are just being blamed unjustly for temperamental tubes.

Marin
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by Marin

Latex tubes fail if you pinch them under the bead. If you don't check after installation and before inflation, there's about a 1 in 3 chance from my experience that you will damage the tube.

Has nothing to do with carbon, but people love blaming the material before reviewing their technique.

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