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Carbon fork: carbon steer. Should tighten the stem hard?(4 posts)

Carbon fork: carbon steer. Should tighten the stem hard?VictorChan
Aug 8, 2001 5:23 PM
I just got my Weyless carbon fork (410gram) today from SuperGo. Cut the extra steer tube and mounted on the bike. It fitted well but I have several questions. Should I really want to tighten the stem (threadless) real, real hard? Would that crack the carbon steer tube? The whole fork is carbon. Second, I am using the Ahead headset. I can use the top cap of the headset to fine tune and tighten the headset so that the fork won't be any freeplay. Unfortunately, the part that allows me to do that (a metal claw thing inside the steer tube of the old fork) couldn't be removed. It is jammed inside the old fork steer tube. So, there isn't any way I can fine tune and tighten the headset and newer carbon fork. Right now, the carbon fork and the headset have some free play or rattle. Is the metal claw thing replaceable? I will visit my LBS tomorrow morning to see what they can do about it.

re: Carbon fork: carbon steer. Should tighten the stem hard?peloton
Aug 8, 2001 5:49 PM
Okay. With a carbon steerer you are going to want to do a few things. The 'metal claw thing' you are referring to is the star fangled nut. A star fangled nut should NEVER be used with a carbon steerer, even if you could get it out of your old fork. You will need to get an expander nut meant for usage with a carbon fork. A star fangled nut can scar the inside of a carbon steerer and predispose it to early failure. The new exander nut that you will get will allow you to put the stem, spacers, and top cap on like you would with any threadless system in place of the star fangled nut in your old system. You will then take the play out of the headset by tightening the 5mm bolt on the top cap like usual. The tightness of the bolts on the stem should be done to the recommendations of the manufacturers of the stem and the fork. Check with the companies who made them for this. The values they give you will be represented in foot lbs. You need a torque wrench to measure this. A torque wrench is a good idea today with the light steerers and stems we have to prevent over tightening and possible failure. Don't just tighten the stem on tight to make up for not having a top cap on there right now. You could overtorque the bolts and do damage to the steerer or the stem bolts. This could cause failure. So, in short- Go to the shop and get an expander nut to take the place of the star fangled nut. Adjust everything as you usually would with a threadless system. Tighten all the bolts to the manufacturers recommendations. Also, leave a spacer above the stem with a little steerer sticking above the stem. This will prevent the stem from pinching the carbon of the steerer in when the stem is tightened and causing damage.

If you don't feel comforable with all this, let the shop do it the first time. Then you will just have to make the usual adjustments of a threadless system. Good luck.
re: Carbon fork: carbon steer. Should tighten the stem hard?VictorChan
Aug 8, 2001 6:35 PM
Thanks. :-)
re: Carbon fork: carbon steer. Should tighten the stem hard?B1
Aug 9, 2001 8:00 AM
I have a Cannondale Cadd 6 witha full carbon fork. It has a pretty cool stem cap that has a 1 1/2" long sleeve that fits inside of the steerer tube to prevent the stem from collapsing the carbon steerer.
Check out a Cannondale dealer and see if you can get one of these, the only thing, they come in 1 1/8" only.