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Currently I'm using standard butyl inner tubes on my clincher carbon wheels. My bike uses rim brakes, and searching on internet I have found that carbon rims are not great for dissipating heat:

During sustained and hard braking both the rim brake track surface and the pad surfaces can reach +200°C (+392°F). If the rim brake track is not 100% flat and smooth, wide spots in the brake track can concentrate heat up to 250°C (+482°F) in the area between the rim hooks, which also heats the inner tube which is getting into the realm of the resin failing/melting.

Full Carbon Fiber rims should be used in racing situations ONLY, as well as configured as a tubular. (OMG!)

source

I also have found some info in regards to heating on latex inner tubes:

However, being thinner, Heasman explained, “latex tubes are more prone to heat fluctuations and will likely blow out sooner than a butyl tube on heated rims through prolonged braking”.

Bear in mind that if you are faced with a long, wet or particularly technical descent, you may have no choice but to drag the brakes.

Heasman points out that this is a potential advantage “with disc brakes, where rim heat is irrelevant”.

source

A latex tube is also known to be somewhat delicate and susceptible to greasers and degreasers, ammonia and solvents, direct prolonged sunshine and high heat, all which may contribute to damaging its properties. These agents, light and heat must be avoided as much as possible.

source

So I was thinking on giving an opportunity to latex inner tubes, but I'm really worried about how safe that would be when combined with rim brake carbon wheels. How safe would that be on flat rides or short descents (e.g 1000m at -7%)? and on a long descent (e.g 11km at -10%)?

(To add some more fear to the mixture, I also found this heat test by Alto)

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    I've never tried latex tubes sorry so can't answer - the sheer cost of latex tubes combined with the inability to reliable patch them make it infeasible.
    – Criggie
    Jan 22 at 22:19
  • 1
    Can you go tubeless?
    – Michael
    Jan 23 at 7:21
  • Yes, tubeless is also a possibility. Is it better for rim brake carbon wheels? Jan 23 at 14:20

1 Answer 1

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If your riding style generates little to no braking heat and/or you enjoy taking risks latex tubes are fine.
If your riding style generates heat - or you think you could get into a situation where you will generate heat then don't use latex.

Here are some quotes.

Also be careful using latex tubes in rim braked carbon clincher wheels. Because carbon rims don’t transmit heat as quickly as alloy ones, prolonged braking on descents can lead to hot spots on the rim, which in turn can damage the tube leading to failure.

If you don’t drag your brakes on a descent this is unlikely to be a problem, but if you’re an inexperienced descender it’s something to be aware of.

Cycling Weekly - Cycling inner tubes: tube sizes valve types and materials explained

That said, we strongly recommend against using latex tubes with carbon clincher wheels—a sentiment shared by most major wheel, tube, and tire manufacturers. Since the carbon braking surface heats up more than alloy, it can cause latex tubes to burst and fail. If you're running carbon clinchers, go with butyl tubes.

Competitive Cyclist - Challenge S.C. Latex Tubes

t is correct to say that latex tubes should not be used in carbon clincher wheels. It is correct to say that latex does not handle heat well compared to butyl.

Butyl rubber can support much higher temperatures for longer periods of time.

The reason why latex works on carbon clincher wheels (this is my personal opinion), is due to the ability of the rider. Expert riders are able to do descents with limited use of brakes and [thus] give the possibility to the equipment to cool down. Never reach extreme heating. The heat is generated on the external part of the rim and will take time to transfer inside the rim. Generally between tire and rim strip, the tube has no direct contact to the carbon rim and if there is no rim strip it is on the cool part of the rim.

Heat in carbon [rims] does not dissipate fast and generally seems to be concentrated in the braking area.

Criterium and other types of riding do not have [the] problem of wheels heating, so latex can be used with no problem. As manufacturers, we do not know how consumers will use the product, and, to be on the safe side, we prefer to give warning not to use it.
— Alex Brauns
President, Challenge Tech

VeloNews - Technical FAQ - Latex tubes with carbon clinchers

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    This is true for only full-carbon rims, right? Rims with an aluminum braking surface (or aluminum rims with carbon aero shell) should be fine I'd suppose.
    – MaplePanda
    Jan 23 at 4:16
  • Why do the tubes fail in the first place? It’s the tyre which has to take up all the force.
    – Michael
    Jan 23 at 7:21
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    @Michael You are correct the tire takes the force of pressure. Since Latex is thinner and can't handle as much heat - in a high heat situation the tube deflates without the tire blowing off.
    – David D
    Jan 23 at 21:52
  • @MaplePanda It is within the realm of possibility to heat up aluminum rims enough to get latex to fail - but less likely.
    – David D
    Jan 23 at 21:59
  • When "experts" (in the last blockquote) are riding in terrain with sustained descents, they're doing so on closed roads, or training when they could use butyl. For the rest of us that's not an option (OK, there's the etape du tour, but with so many bikes around all doing their own pace you could still end up on the brakes quite a bit). No amount of expertise will significantly reduce brake use if you keep catching up with cars on the way down, but there are too many coming the other way to allow overtaking
    – Chris H
    Jan 25 at 16:45

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