lightweight tubeless rims

Everything about building wheels, glueing tubs, etc.

kulivontot
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Joined: Sun May 16, 2010 7:28 pm

by kulivontot

Does carbon tubeless work well? And does it have the same tension doing limitations of alloy? And will hard downhill braking literally explode tires off your rim?
Last edited by kulivontot on Thu May 25, 2017 6:51 pm, edited 1 time in total.

by Weenie


fporter
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Joined: Tue Oct 07, 2008 7:58 pm

by fporter

Carbon tubeless has worked extremely well on my mountain bike. I made a set of wheels using the 733 rims from Asian Cycle Express. They are hookless (the above road rims have hooked bead). No problems with tire retention even with large tires (high leverage) at low pressure. The key is the bead shelf that maintains the bead seal when the tire is deflated. The bead shelf also prevents radial movement of the tire.

I just started riding tubeless on the road with a set of Roval CLX 32 wheels and Schwalbe Pro One tires. So far so good. Over 10k feet of vert in the last 3 rides w/ no problems. The bead shelf of the CLX is not as good as the bead shelves look in the above suggested rims. If you look at the cross section of those rims they have a nice flat shelf and a small 'bead bump' to help with bead retention when deflated. The road tubeless rims also have bead hooks that along with the shelf will prevent blow off.

Prior to the CLX wheels I rode 2 different sets of Reynolds MV32 wheels (with inner tubes, both Verdestein latex and light butyl) for about 15 years (first set was stolen so got another set). Never had a problem with tires exploding off the rims or any other problems, heating or otherwise, for that matter. They were solid. Rode them in the Alps and in the mountains around Salt Lake City. One event of note, I was once descending east side of Teton pass. I came up on traffic and had to slow abruptly from nearly 60mph to 25mph. Full-on hard braking and didn't have a problem. But I like descending fast and don't ride my brakes. I think the fear that is common about carbon and rim brakes may have come from folks that don't like to go fast & ride their brakes without alternating front->rear->front, etc. causing problems. But that could cause problems with alloy rims too.

Braking of the Reynolds and CLX rims is nice: no lack of power & good modulation. The CLX are quieter than Reynolds but that could be pad difference too. Braking is Ok in the wet too. Rode the CLX down a mtn with intermittent light rain yesterday and it was fine, no anxiety. Approaching first switchback I pumped the brakes a few times to check braking and it was ok.

Those rims listed above also make mention of using 'high Tg' resin. This means high temperature resin specifically to resist brake heat problems. Check the sites for the spoke tension limits. Unrelated to tension, I've read where alloy nipples in carbon rims may have problems with galvanic corrosion after a while but good anodizing should help reduce or eliminate that.

bm0p700f
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by bm0p700f

depends on the rim really. The carbon rims I use work fine tubeless. Some rims however are more tubeless compatible than others as I have never had those rims I can;t really comment on how easy setup will be.

405g is quite light though for the light bicycle rims. You could just wait for the new mavic open pro @420g claimed.

kulivontot
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Joined: Sun May 16, 2010 7:28 pm

by kulivontot

Let me rephrase, how well do carbon road tubeless road rims work? Do carbon tubeless road rims have the same tension decrease as alloy tubeless road rims? Will running shitty off-brand carbon tubeless carbon rims blow the tire off the rim in the same way that shitty non-tubeless carbon clinchers with poor descending technique do?

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ergott
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by ergott

I had a pair of Enve 2.2 rims that I sent back because after I built them and put tires on the tension dropped about 20-25kgf. Carbon is just as susceptible to design issues as alloy with regards to tubeless. The problem is relying on a friction fit. Not all tire manufacturers have exactly the same bead circumference so that can potentially exacerbate the situation if you have a bad combination of tire/rim.

fporter
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Joined: Tue Oct 07, 2008 7:58 pm

by fporter

kulivontot wrote:Let me rephrase, how well do carbon road tubeless road rims work? Do carbon tubeless road rims have the same tension decrease as alloy tubeless road rims? Will running shitty off-brand carbon tubeless carbon rims blow the tire off the rim in the same way that shitty non-tubeless carbon clinchers with poor descending technique do?


Just thinking out loud here but a mid depth (~32mm) wide carbon tubeless rim will weigh about the same as a acceptable strength/durability/stiffness box section aluminum rim. But the wider & deeper carbon rim will likely have higher hoop stiffness and lateral stiffness. So for the same weight I think the carbon will in general perform better.

Regarding your other questions, i have no idea as I don't waste my time or risk my health testing shitty components using known problematic technique.

dtwolfen
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Joined: Wed Feb 15, 2017 9:05 pm

by dtwolfen

Having been hunting the Web for a mysterious set of rims I came across hunt wheels. Where do they get their rims from? 380 claimed weight for a 30mm carbon seems great. They don't seem to sell just the rims and I can't find anything saying they make their own. Does the manufacturer have their own website?
Thanks

bm0p700f
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by bm0p700f

Every tubeless compatible rims I have used sees a 200 - 250N tension drop with tubeless tyres. There may have been a few exceptions but I have forgotten now. Pacenti rims are the worst and the tension I see with these is huge, that does not howeverstop then V1 and V2 SL23's from cracking.

I have never had a problem with that tension drop. Never a spoke failure with a wheel fitted with a tubeless tyre's so in my book it is a non issue (although there is time I suppose for that to happen). Maybe some of the hookless rim designs can get around this, however then the rim is tubeless only which is quite limiting.

I just tend to prefer wheels with tubeless tyres to be very stiff so even though there is a tension drop (radial wheel stiffness does not seem to be a contributing factor as it happens on shallow rim and deep rims to a similar extent of the same spoke count) the wheel is stiff enough for it not to matter as the spokes dont go slack.

I dont know how this will play out with a 32mm deep carbon rim as all the carbon rims I have setup with tubeless tyres are wide 50mm deep affairs. They are showing no issues and the tension drop is around 200N DS.

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