carbon steerer / stem setup



OHsingltrakr

New Member
Sep 29, 2003
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I just picked up a demo frame and fork online which came with Columbus integrated headset and carbon steerer. I feel pretty good setting preload but I'm not sure how much to tighten clamp against steerer tube. I haven't been able to find any specs online. I may just haul it down to the shop and pay a shop fee for a little setup and education, again. Any feedback from you fellow riders appreciated. I always feel like a schmuck hauling bikes into shop they know I bought online, but second hand is the only way to buy anything half decent on my puny budget. Thanks for looking!
 
Check the stem manufacturer's website for torque specs. You can also check out http://www.parktool.com for torque specs based on the size and number of bolts. Be sure to lube the threads and don't tighten until you hear cracking and popping sounds. That's bad.
 
Carbon steerers are made to be run with as little stack as possible. It must be absolutely no more than equal to the steerer diameter. (better to have none at all)
 
Originally posted by tafi
Carbon steerers are made to be run with as little stack as possible. It must be absolutely no more than equal to the steerer diameter. (better to have none at all)
DOH??
 
Originally posted by Aztec
Wow, first I've EVER heard of that one. Jeez, most built bikes come from the FACTORY with 2 or 3 cm.
I finally figured out what he was trying to say,but it still has nothing to do with the question as originally asked and answered by Dorian.
 
Thanks for the heads up tafi, the stack and diameter are currently equal at 1.125" It was setup up factory with four spacers under the stem as you can see the marks from stem and spacers. I guess it'll be alright for now. I'll ride it a bit then disassemble and reinspect. There's plenty of tube to recut it lower and reinstall the star nut if necessary. Thank you to Dorain, I emailed the maker of my stem and hopefully they'll respond before the rest of my build up parts get here.
 
Originally posted by OHsingltrakr
Thanks for the heads up tafi, the stack and diameter are currently equal at 1.125" It was setup up factory with four spacers under the stem as you can see the marks from stem and spacers. I guess it'll be alright for now. I'll ride it a bit then disassemble and reinspect. There's plenty of tube to recut it lower and reinstall the star nut if necessary. Thank you to Dorain, I emailed the maker of my stem and hopefully they'll respond before the rest of my build up parts get here.

I wouldn't go with a star nut, better to get a compression plug. If the stem sits at the top of the carbon steerer tube (all the spacers below the stem and none on top) over time it can deform the carbon at the top. If you use a compression plug, the plug fills the end of the tube by about a half inch so the tube can't be deformed. You can also solve this by putting spacers on top of the stem so the stem is compressing in the middle of the steerer tube and not at the very end.

Compression plugs are not expensive and well worth it for a full carbon fork.
 
There may be one in it, I spoke generically when I said star nut. The fitting inside is installed about the same depth as star nut but it looks solid unlike a star nut. The top cap has a long bolt with a spring and various spacers, I setup up spacers to get an appropriate compression of the little spring using feel and common sense. This unit comes within about .5" from the top of the steerer on the inside but my stem comes to the top on the outside, should I swap spacers and lower it a bit, davidbod?
 
Pulling it apart again davidbod pointing out what I believe is a compression plug makes sense. The fitting appears to be a little less than an inch high. I pulled out 2 spacers lowereing the stack and centered stem on the fitting up and down then re-setup top cap and spring. This all goes together feeling solid and looking right now. Thanks for the help!
 
Originally posted by tafi
Carbon steerers are made to be run with as little stack as possible. It must be absolutely no more than equal to the steerer diameter. (better to have none at all)
That's not absolute,but an industry recommendation, and some manufacturers allow more. And not necessarily better to have none,as that part is just hooey.