Originally Posted by
Psimet2001
This one causes me to break out in hives.
Carbon rims, on average, are orders of magnitude straighter and more consistent out of the box than aluminum rims are.
The fact that you say you can "I can true up an alloy rim within .05mm." demonstrates that this is something you seemingly have to do often and I assure you that if you true all of your aluminum rims to under 0.05mm that your tension variance is so high that you're rims are going out of true often when being ridden or you're paying an immense ton of money on your rims. Quite simply the extrusion process for creating an aluminum rim is highly prone to small issues that the vast majority of extruders just can not control. These small variances in something as little extrusion pressure can greatly affect wall thickness variance. That variance can be in spec but will require a large tension variance in the spokes in order to maintain true. All looks good on the stand then you ride it...womp womp.
To top this off the process for forming the extrusions into a round rim and then connecting the two ends (pinning, sleeving, welding, etc) is by it's nature another natural point in which small variances are introduced into the rim's shape. Back long ago all the Kinlin XR300 rims of which we sold 1,000+ all had the same slight low spot about an inch from the rim joint. Turns out that's where they had a clamp holding it while joining. It was consistent, repeatable and introduced a tension variance that you had to handle a certain way.
Carbon rims deviate from this immensely. While they do have variances - like all manufactured items - the number of them that you can simply bring up to tension and have be almost at finish spec initially is astonishing. The rims are way more consistent. They don't change through use like aluminum rims do as well.
I have piles of aluminum rims that have been rejected due to variances being bad enough to prevent me from being able to build with them. Not so with carbon. Lucky for me I get to stretch tubulars on them.
Mr. Psimet, I know you are a true wheelsmith but I do not have to true my wheels often. Yes, having a true wheel is a pet peeve of mine, but I do not "over-true" my wheelsets. I use various high end and low end wheels. Carbon and alloy. And it seems to me that there is a better chance to get an alloy wheel more to my acceptance than a full carbon rim. All I know is what I know. And for me, the carbon brake track is not as smooth as a good alloy brake track. Perhaps I am using the wrong set point for truing a wheel. I use the brake track as a reference to true a wheel. JMHO I do not want to get into a "How to true a wheel" spat. It's an art, we all have our own special touch to create what we consider a well built wheel. The OP was asking if Carbon wheels are Generally Stronger than Alloy wheels. My answer is still no with respect to age. I believe that a carbon wheel will get brittle, and not with stand fatigue after time when an alloy wheel will last longer.