Tech Tips

KNOW YOUR CARBON - IMPORTANT INFORMATION : 

With any full carbon clinchers from any brand - no matter how expensive, what the brands claim or the country of origin, the fact is that carbon and excessive heat do not mix. Particularly with clinchers.

Carbon Clinchers: The clincher bead hook and brake track is complicated. It is designed to absorb forces trying to collapse the walls (Braking force) and forces trying to explode the walls (Air pressure force). It is also designed, built and treated to operate at temperatures up to 200c. Even the most advanced carbon material and resin is only able to safely withstand temperatures up to 220-250c. So when a rider inflates their tyres to the max 120psi before riding in the hills, be aware that when hot air expands (the air in your tyres heating up from braking friction) the explosive forces trying to push the clincher rim walls apart accelerates, increasing the risk of failure in the rim structure.

Weight and carbon clinchers: Failure risk is increased the heavier the rider is, as heavier riders descend faster. Of course the heavier the rider is the harder the brakes work to slow that mass down and the more heat is generated. With the weight rating labelled on the rim, this is more closely related to heat rather than the material not actually being able to structurally hold more than that weight. A detailed explanation can be found in this article written by David P Swain from Sportsci.org.

Also in relation to heat generated from braking, is the subject of the use of lightweight latex tubes. Latex tubes are not as resilient to the effects of excessive heat and will fail at a much lower temperature than good quality rubber tubes that contain butyl. The use of latex tubes in carbon clinchers with a rim brake track is an absolute no-no.

Carbon Tubulars: The risk with carbon Tubulars is minimised as the air pressure is contained within the structure of the tyre, therefore extra explosive force isn't applied to the carbon structure.

Disk Brakes and Carbon: Disk brake bikes remove heat failure risk altogether, moving the braking heat to the disk rotor. 

We recommend the following;

  • Do not ride your brakes: On long descents be mindful to try and minimise heat transferred into the wheels. Although these rims feature a very durable high-temp resistant brake track, they will perform better if you brake only when needed, so long descents get in your drops, put your head down and enjoy the thrill.
  • Run less pressure: We have settled on wider rims (23mm & 25mm) so you can run less pressure, This is not only safer as the wheel heats up, it also helps improve the suppleness and handling of your bike. We find riders who used to run 100-120psi drop down to 80-95psi
  • Only use Carbon Brake Pads: Carbon brake pads are designed to run cooler. So make sure you run only pads designed for carbon rims. Use only Curve pads supplied, ENVE pads, Swiss Stop Black Prince. 
  • Do not install latex tubes!: Latex tubes are very thin and fragile. They cannot absorb any heat generated from braking friction. Use standard, high quality rubber tubes that contain butyl.
  • Correct pad installation: When installing your carbon specific brake pads, make sure the pads are as low on the braking surface as possible. The rim bed of Curve rims have strategically been placed high, with a low tyre bead wall to ensure the heat friction and braking force has sufficient reinforcement where needed. This also helps direct the heat generated from braking friction into the hollow section of the rim, rather than into the tyre. Toe the pads so the pads are at an angle where the front edge of the pads make contact first then caresses the rim as force is applied. Rather than the pads clapping against the rim. Same as you would with cantilever brakes and V-Brakes. This helps reduce and eliminate squeaky, noisy brakes.
  • Break 'em in: We recommend approximately 200km of undulating terrain. Terrain that does not have long steep descents but gentle ups and downs where periodic short controlled braking is performed. 
  • Take care: Carbon clinchers and tubulars are 'high performance' albeit, disposable pieces of equipment, that can give you a lot of riding pleasure... but it is our job to inform you of the facts around them.
  • 50% replacement warranty: If you do by chance happen cook your wheels, we will replace the rims at 50% of the retail cost (excluding labour)