steer tube cutting questions

[blondie]

when you are cutting the steer tube what is the length you mark it below the stem to cut. 3 mm sound good

[BikeAnon]

If you cut the steerer below the stem, you'll have nothing to attach the stem too.



Seriously, though, what's the steerer made of, and what does the mfg require? For carbon fiber, make sure you have enough poking above the stem to let you fit a 5mm spacer. http://www.velocipedesalon.com/forum/f2 ... post697495


But, don't pay attention to me, these guys actually know what they are talking about:
http://www.parktool.com/blog/repair-hel ... and-sizing

http://www.artscyclery.com/learningcent ... tubes.html


It's cool looking to have your stem cap sit flush on the stem.... but with. CF tube, make sure it extends beyond the top of the stem for safety. Or replace your fork more often. Whichever suits your wallet or safety-comfort level.

[kkibbler]

For carbon fiber, make sure you have enough poking above the stem to let you fit a 5mm spacer.

It's cool looking to have your stem cap sit flush on the stem.... but with. CF tube, make sure it extends beyond the top of the stem for safety. Or replace your fork more often. Whichever suits your wallet or safety-comfort level.

This is not a universal recommendation. Different manufacturers recommend differently, at risk of voiding your warranty. Some say spacer above, some say no spacer above, some say no spacer below. Personally I don't see how a spacer above could hurt, but I'm not in charge of your warranty. Best to check with whoever made your frame or fork.

[rpenmanparker]

For carbon fiber, make sure you have enough poking above the stem to let you fit a 5mm spacer.

It's cool looking to have your stem cap sit flush on the stem.... but with. CF tube, make sure it extends beyond the top of the stem for safety. Or replace your fork more often. Whichever suits your wallet or safety-comfort level.

This is not a universal recommendation. Different manufacturers recommend differently, at risk of voiding your warranty. Some say spacer above, some say no spacer above, some say no spacer below. Personally I don't see how a spacer above could hurt, but I'm not in charge of your warranty. Best to check with whoever made your frame or fork.

This. But to answer OP's question 3 mm ought to be about right. You need just enough depth below the top of the stem or added spacer for the top cap to sit completely above the steerer edge and not foul it. Even after exerting preload. Otherwise you won't be tightening your headset by raising the fork in the assembly, you will just be exerting pressure on the top edge of the steerer tube.

EDITED:
So it really depends upon the design of the top cap and how much it protrudes into the well. Some are deeper than others. Here is how to find out how exactly much you need. Just fasten the stem very LOOSELY to the top of the UNCUT steerer tube with about 5 mm clearance inside. Just tight enough that it doesn't move by itself. The top cap should sit above the steerer leaving a space inside. Now tighten it, and it should push the stem down as the space closes up. When the cap is flush with the stem and tight against the top edge of the steerer, tighten the stem so it won't move from that position. Disassemble and remove the cap and measure the depth of the steerer tube in the stem. Then add about two mm more to that depth. Check that the top cap rides freely in the well. Then you can use that value for the depth to cut the steerer when you have everything assembled with the head set tight and the right number of spacers below the stem. Mark a line at the top of the top of the stem or stem plus extra spacer above it and cut the required number of mm below that line.

[blondie]

thanks, i will be keeping 3 spacers just for, prob one below and two above.