Carbon wheel testing

[bigbill]

Wheels for purposes. I've got a set of rim brake Boyd 60mm on the way. I didn't buy them to ride the mountains, I got them for flat to rolling terrain. My mountain wheels (and I'm not a good climber, therefore good descender) are alloy. But even heat buildup, it depends on the rider and how good of a descender they are. Scrub some speed, hit the turn, accelerate out. If a person is braking that long at a time on a descent, then they've chosen poorly with regards to wheels.

[adrien]

This reminds me of the kids in the hall skit where the guy's mom tells him not to put salt in his eye. He forgets and puts salt in his eye, and it hurts.

I have some Enve 4.5s. I've never dragged the brake more than, oh, a hard squeeze for 5-6 seconds, then ease off. Don't drag brakes for 5 minutes.

I'm not sure I'd want a wheel designed for that.

[mcteague]

The other brands strike back!

https://www.bikerumor.com/2017/12/14...im-brake-test/

Tim

[bigbill]

Originally Posted by mcteague

The other brands strike back!

https://www.bikerumor.com/2017/12/14...im-brake-test/

Tim

That is a better article than the Alto test results. Good response. It makes me feel better about the Boyds that I unwrapped last night. I've got a set of carbon tubulars from around 1999 that are Ambrosio rims with Record hubs. They essentially don't have a braking surface and I never expected to actually stop quickly, just to scrub some speed before the crash.

[zap]

.

Originally Posted by zap

Boy, this write up will ruffle some feathers.

[54ny77]

interesting tests.

the takeaway: all carbon clinchers fail at some point. got it.

[ergott]

Originally Posted by 54ny77

interesting tests.

the takeaway: all carbon clinchers fail at some point. got it.

It would be interesting to see an alloy wheel with butyl tubes and another with latex tubes as a control. There have been reports of tires blowing off alloy rims in extreme circumstances too.

[54ny77]

all rims will suck under the right circumstances. learning how to brake properly under all conditions helps. feathering, front vs. rear, scrubbing speed, scrubbing water/grit, getting yer ass as far back as possible (weighting the rear), yadda yadda.

although, if you're bombing down a hill doing 40+ with full carbon hoops (and have the right pads, of course) and have to do a full tilt panic stop, good luck with that one.

think: "george, george, george of the jungle, watch out for that......buuuuuuuuush!"

[ergott]

Great technique doesn't make up for riding on public roads where you are subject to traffic. On a closed course I'd have no problem bringing any wheel down just about any descent. When you factor in something like a Fondo where you are stuck behind people it's hard to descend safely.

If I were looking into testing conditions, I'd take the gps files from some people doing rides like the Levi Fondo which are known to melt rims. See what kind of speed is being scrubbed, the %grade, figure on being forced to drag brakes due to congestion and top it off with a 250lb rider.

If your wheels survive that, (disc, alloy or carbon), then I think you can sleep well. If not, put some major warning labels on your rims.

[coachboyd]

That is what my guy who does CFD work did. He simulated the descent of White Oak in the Hincapie Gran Fondo and was able to calculate brake forces, heat levels and such.

There's lots more really fun stuff in his blog.
http://rockets2sprockets.com/carbon-...r-destruction/