masi61

I'm building up my new old Cannondale CAAD3 R1000 into my new road bike and I now have all the parts stockpiled. I need to build this baby up! . I have an older blackburn workstand that works fine for my steel road bikes but I would be afraid to try to clamp a tube of the aluminum frame and risk damaging it. I'm also reluctant to use the seatpost because I spec'd a nice clean old Syncros aluminum seatpost with intact decals on it. Am I going to need to purchase one of those Park seatpost clamping devices I've seen, or should I use a sacrificial seatpost ? What have you tried ?

HillRider

The sacrificial seat post is the easiest low cost solution. Buy the cheapest MTB-length post you can find in the correct diameter. It can even be steel and have one of those necked down tops intended for a department store bike saddle clamp.

I bought a Kaloy MTB seatpost off of the remainder table at an LBS a few years ago and I recall it was $5.

masi61

Thanks, I think I may even already have a 27.2 straight steel post sitting around that I could use.

toomyus

dude, you couldnt dent alumium even if you wanted to, the bike will be tight in the vice wayyyy before you can put a crushing load on the tube. there is very little difference between steel and alumiun in terms of strength. i throw all my bikes on the stand , even my carbon one. as long as you are careful and dont crank anything down, you will never have an issue. Oh yea, i use a fluffy hat to line the tube that i clamp down ,so that way there is no direct contact on the frame, stops scratches , etc

iluvfreebeer

+1 on the seatpost, I've seen an old Klein and a Cannondale wrecked by overzealously tightening the stand clamp.

toomyus

key word, "by overzealously tightening ". you will wreck anything cranking down on a hollow tube. it just needs to be snug, i hope you guys are not as rough in the bedroom, hahah

Retro Grouch 

I don't care much what you do with your own bike, but I sure hope that you don't work on anybody else's bike. I've read your reply pretty carefully and I can't find one single thing that I agree with.

Proximo

I've clamped my carbon and aluminum bikes in both an old Blackburn and now a new Ultimate stand with no ill effects. Look, if you can tighten a front derailleur band clamp up to 60 inch/lbs on a carbon tube (as Felt specifies for their carbon frames) with a torque wrench and not damage it, you are *not* going to damage that tube in a repair stand tightening it by hand unless you get terminally stupid.

Jed19

+1 on the cheap seatpost. I use a cheap Kalloy seatpost as my "repair clamp-in seatpost" on my bikes.

Better safe than sorry.

Regards,

vw addict

if you are worried about your brand new aluminum seatpost why not just wrap it with an old piece of inner tube? Or just buy a carbon post like you should have.

toomyus

thank you proximo, i totally agree, its all about the torque specs and knowing the crushing loads of all the parts. you must be an engineer like myself

Grand Bois

You don't have to be an engineer to figure it out.

mechBgon

Some of the things you might do to a bike clamped into a repair stand exert torque. Such as installing a bottom bracket, for example. It's not always just a matter of the bike hanging there from the stand with nothing happening. +1 for using a seatpost for this task. I might clamp to the frame of an X-Mart 10-speed, but if I were the guy you entrusted your Cannondale to, you can bet I'd put a seatpost into your bike to clamp onto.

Proximo

When I install bottom brackets, no stand seems to hold the frame steady enough. I always use my non-wrench hand to hold the frame above the bottom bracket. This allows me to steady the frame and oppose the wrench force thereby avoiding excessive forces on the stand clamp, or anywhere else.

No, I'm not an engineer (I write software, but that doesn't count here) but like dirtdrop says you don't have to be one to figure this stuff out. It's just common sense. Carbon and, particularly, aluminum road bike frames are not eggshells nor are they cast iron. Use common sense and follow the manufacturers specs for torque ratings.

It's instructional to torque the various screws on a bike down to specification then try to undo them with hand tools just to see how tight a given torque setting is. It might surprise you.

Dustin07

Seems to me like just clamping directly to the bike would be fine, but like mentioned:

the sacrificial seat post = cheap insurance. I rarely need a full face helmet but often wear one when racing bmx.... cheap insurance.

mechBgon

After 10+ years as a bicycle mechanic, it might not surprise me This is my professional position: don't clamp repair stands onto nice frames if it can possibly be avoided. I've seen even steel frames crimped in routine work before. I've read enough high-end frame owners' manuals to know what they say NOT TO DO. Even if I'm not worried about the tubing, the frame's finish is another consideration. Keep the customers happy, don't put wear on their finish.

My repair stand is a Park Tool PRS-2 (dual-arm professional shop stand) with a customized 100-8C clamp made for me by Park Tool, if anyone's curious what I use (no ring on the donut on mine, so as to jive with my PRS-2 properly... thanks Calvin!).