cutting carbon steerer tube question

[IJWS]

Hey forum, I've been going down google rabbit-holes for 20 minutes already and I just wanted to ask if anyone can tell me what the deal is with cutting my steerer tube. Specifically, I'm wondering how much the steerer needs to clear the top of the stem by. As it is now, I have about 5mm above the top of the stem. It does not look PRO. It's not keeping me up at night but it's always bothered me. I think I'm going to swing by the LBS tomorrow and have them trim it but is there anything I should look out for? Thanks!

*btw, I'm already aware that a finer tooth blade should be used, possibly tape around the cut, don't inhale carbon dust etc... just wondering about the clearance issue.

[ultraman6970]

Well, to be honest with you is your call if you want that cut or not, personally I leave enough so is not a problem at the time to sell the frames. If you have 5 mm above the stem then sure you are using like a 6+mm spacer and then the top cap, based in what I said before and since I always leave like a cm of room to play with, then I would not cut your fork, but is your call.

If carbon just put some painting tape around the area and use a dremel, if aluminum I been using a pipe cutter, super clean cut. No idea if the pipe cutter could be a problem with carbon, never done that test.

[pdmtong]

some camps say 5mm, other camps say 10mm. the idea is to keep the stem clamping far from the edge of the cut tube, so the tube structure won't be crimped by the stem being tightened.

me, I leave 10mm.

also, consider the steerer length you may need if potentially swapping stem brands...stem stack height can easily vary as much as 10mm between mfgs.

[kramnnim]

Look at some of the photo galleries of various pro bikes and you'll see that the 5mm spacer above the stem is normal. :)

[IJWS]

ok, 5-10mm thanks a lot guys!

[buldogge]

That's the extra/top spacer height…the steerer length will need to be 3mm shorter so the top cap will function properly.

-Mark in St. Louis

ok, 5-10mm thanks a lot guys!

[zzy]

One thing to know, which MANY shops do not, is that you need to make the first cut about 3/4th of the way through. Then cut the rest of the way from the opposite side. If you go all the way with one cut you will damage the fibers at the opposite end of the cut.

I once had a shop hand me back a $400 fork like that and tell me it's normal. They even used the wrong blade. That was a fun discussion.

[Shoeman]

One thing to know, which MANY shops do not, is that you need to make the first cut about 3/4th of the way through. Then cut the rest of the way from the opposite side. If you go all the way with one cut you will damage the fibers at the opposite end of the cut.

I once had a shop hand me back a $400 fork like that and tell me it's normal. They even used the wrong blade. That was a fun discussion.

Same thing happened to me at a Big Pro Shop used a hacksaw blade. needless to say it wasn't pretty, ripped up some of the strands and luckily it still works ok.

[oldpotatoe]

Hey forum, I've been going down google rabbit-holes for 20 minutes already and I just wanted to ask if anyone can tell me what the deal is with cutting my steerer tube. Specifically, I'm wondering how much the steerer needs to clear the top of the stem by. As it is now, I have about 5mm above the top of the stem. It does not look PRO. It's not keeping me up at night but it's always bothered me. I think I'm going to swing by the LBS tomorrow and have them trim it but is there anything I should look out for? Thanks!

*btw, I'm already aware that a finer tooth blade should be used, possibly tape around the cut, don't inhale carbon dust etc... just wondering about the clearance issue.

3mm above stem for a 5mm spacer..to ensure the steerer is all the way thru the stem clamp area. If 5mm too much, smaller above, thinner spacer..just gotta be able to adjust HS w/o cap hitting top of steerer.

Use a guide, new-ish 32t hacksaw..won't hurt the steerer on the opposite side.

[fuzzalow]

Use a guide, new-ish 32t hacksaw..won't hurt the steerer on the opposite side.

Yep. The carbon weave, unless defective (see PRC knockoffs) is encapsulated in the epoxy binder matrix. How wive's tales like this get fermented is the stuff of LBS lore. All those carbon threads caught up in the teeth of a hacksaw, killed the tension in the carbon weave so the whole steerer went limp!

[lhuerta]

http://www.parktool.com/blog/repair-help/fork-steering-column-length-and-sizing

https://www.youtube.com/watch?v=fZ-HcRcp658

https://www.youtube.com/watch?v=RflE5p3OPgM

https://www.youtube.com/watch?v=KuWEBjCmo8U