trek4ever

I'm talking C-Dale, CAAD8/9, Trek SLR, Giant TCR, etc. Is it okay to use one of those trunk racks where it has rubber clamps around the top tube? How easy is it to dent the top tube (the thinnest of all the tubes)? Can a dented frame still be ridden?

Snuffleupagus

I've never dented, nor seen dented a top tube from a trunk rack. The only time I've ever put a dent in an aluminum frame was a head on crash at 30+ mph in a crit. The frame had a bend in the TT, and at the advice of my LBS, I won't be riding on it. I've also got a 24lb Giant full suspension MTB that has been crashed in the most inventive ways possible, and has yet to dent. We're talking like 6ft falls to rock...stackups at godknowshowfast on singletrack, etc.

I wouldn't worry about it. If you smack a modern frame hard enough to dent it, you'll KNOW about it

curiouskid55

When I crashed head-on into a car my aluminum Specialized folded up like a cheap suit. So dont do that and it should be fine.

SDRider

I've yet to dent or break a frame of any material...damn, I probably shouldn't have said that.

scuzzo

humm, a friend of mine at a afternoon club ride had some one tap him at no more then 10mph in the back stays on a caad8. totaled the framec omplete loss, seat stays folded on left and right. while on one ride i went to sprint with a 853 steel bike back wheel came out and ramed into the seat tube and twisted up the der hanger really ugly. was able to bend that back the schwinn rides on.... perhaps they have crossed the line in how thin you can drawl out a tube.. but thats just mho.

Grasschopper

That was just the bike's crumple zones at work.

merlinextraligh

My wife's brand new Caad7 fell over in the garage, landing on a christmas tree stand, and dented the top tube to the point that the frame had to be replaced. Admittedly it was the perfect storm, hitting a hard sharp edge at exactly the thinnest portion of the top tube. However, if the force of falling over sideways was enough to do that, I think it's entirely possible that overzealus clamping in the wrong place could cause damage.

Note that Bike shops always clamp to the seatpost in the workstand, precisely to avoid this problem.

This doesn't mean that a thin walled Al frame isn't strong, or will fail riding. They're designed to deal with the forces encountered riding, and at the same time be very light. They're not designed to take much of a wack sideways on the thin points of the tubing, however.

DocRay

You should never clamp a top tube, any material. Especially today's double-butted tubes or CF.
You should not ride a bike with a dented top tube.
Try this demonstration:

1. drink a beer
2. Stand on the empty can
3. now, dent the side of the can
4. Stand again on the can, it will collapse
5. Drink two more beers.

Mariner Fan

Good point DocRay. Those thin wall bikes are a bit scary for a clydesdale like me. Very strong but easily dented.

H1449-6

Thin-walled Al works well for beer cans.

DocRay

6. drink another beer.

DocRay

Most good steel frames are so thin at the centre you can squeeze them with your fingers. Dent them, and they are junk. Regardless, the Al frames are still stiffer at the BB, and a good AL frame with out-test any steel frame at EFBe.

TheKillerPenguin

It took a 40+mph crash to do this, and then I was able to ride it up a mountain. I'm 170lbs, btw.



Last year I dented the top tube of my caad7 (not too bad) in a crit and was able to continue using it as normal after my LBS inspected it, until I crashed it 2 more times and killed it.

Anyway, response to the original question- those rubber straps aren't going to hurt anything. They're flexy and don't put enough pressure on the top tube to hurt it.

H1449-6

I assume you mean that you can deform them (permanently or temporarily) by squeezing?

I haven't owned any such bike in 15+ years of riding steel (about a dozen bikes). Guess none of my steel bikes are stupid light.

Snuffleupagus

Holy Freakin Crap Dude!

I thought I had a crash heavy year (ate it in a crit, and went down when the chain came off my SS). You may well take the cake for crashes...in fact...I think I'll start a poll in the racing forum. I imagine you're the winnar

TheKillerPenguin

heh, that's what you get when you start racing 2 months after you start riding. Those 3 crashes on the caad7 were last year, not this year. What I put up a picture of was the Caad8 I crashed this year.

DocRay

you can deform them.

"Stupid light" is a typical term used by luddites and Rivendell owners. Tried indexed shifters yet?

Ally bikes are not just lighter, they are stiffer where it matters. This is why no one races steel frames in UCI.

trek4ever

Are they also less durable? Also, how good are "name-brand" manufacturers at warranty-ing thin alu frames that are fatigue-failed?