Originally Posted by Doge

Clinchers need a hooked brake track. Two things here - the brake track and the hook.

As alloy rims are extruded the thickness of the metal can be well controlled and makes a nice pronounced hook can be made to hold the tire well. Carbon is not extruded. The degree carbon takes bends or has differeent material thickness is based on the mold and hand layup. It is not unusual to have carbon rims with alloy brake tracks.


Then the brake track. This is more of an issue using rim brakes, but grit and rough pads are squeezing the outside of the carbon tracks while the air is pushing the walls out. Same is true of course for alloy, but this fatigue can cause side/brake tracks to splinter/blow out over time. So typically the carbon wall are thicker (or alloy) than the alloy ones to account for this. The clincher distance from inside the rim to the outside is further for carbon. The tire may be leaning on the edge of the rim more. Could you feel this? Don't know. It just doesn't mentally seem as right.

The net is in low profile clinchers - 25mm or so alloy rims are often lighter than the carbon ones, due to the brake track issues. Tubulars, not having the brake tracks are lighter in carbon.


Ride quality is based on the tire case material, tread, and width which affects the the cross section area, then the PSI. The width thing as another poster mentioned is having the same area of air in the cross section. Adjusting the PSI accordingly. Leaving the actual case material and where the air is is a mistake IMO. We also generally leave the PSI part out of many discussions. I think it is implied, wider gets lower PSI, but most the rolling resistance tests I have seen you have to be careful and see if the PSI was the same, or adjusted for cross sectional area. Also having air between rigid brake tracks vs floating on top of the rim can be felt.

Having air between rigid brake tracks vs floating on top of the rim can be felt.