FarEastGang

My hardtail Mtb has got a good inch of spacers under the stem and I have been thinking about cutting the steerer tube down half an inch or so.

This is what I think needs to be done:

rubber mallet the fork to knock the star fangled nut down (if need be) mark it off, use a vise to steady it, apply cutting oil and have at it with a hack saw.

Is this is procedure more difficult than I think? Any advice?

Retro Grouch 

The first thing that I would do would be to take 1/2" of spacers from under the stem and put them between the stem and the top cap and ride around that way for awhile. That'll let you test for sure if this is something that you want to do because once you cut the steerer too short it can't be undone.

You will need to push your star nut farther down the steerer. Once it's been started that's fairly easy to do. A 1" piece of dowell would probably be best, but you can knock it down with a long bolt that's the right size. Be sure to measure to where you want it and don't push it down too far.

Once you know for sure where you want to cut it I'd recommend putting automobile hose clamp on the steerer to help you to get a nice square cut with your hacksaw. Don't forget to deburr the cut end for a professional job.

shane45

No, you'll need to hit the nut as mentioned above, not the fork.



Not necessary.

same time

Measure twice. Then, walk away, come back later, and measure twice again.

crankymtber

When I cut steerer tubes I use a pipe cutter. It makes a nice square cut. I've even made the cut without taking the fork off the bike, just position the bike so that any chips made during cutting won't fall into the headset area. I have leaned the bike over on the floor or suspended it on the wall of the garage in it's usual storage place.
A suggested, move your spacers around to get the stem in it's final position before cutting and try things out by riding before you make the cut.

DCCommuter

I've had good results with a pipe cutter, the kind meant for copper pipe, you can get one at Home Depot or any hardware store. It's designed to make a clean, square cut, which is hard to get with a hacksaw.

roadfix

been using a pipe cutter as well....

sydney

Hacksaw and hose clamp here.

Joony

after using a pipe cutter, do you guys file down the edges so it isn't as sharp?

sydney

Ya gotta dress up the inside and outside edge.

squeegy200

Pipecutter here as well. And yes, I use a file afterwards to clean up the edges.

aley

If you cut it with a pipe cutter you'll end up with a sharp burr on the inside that must be removed. You can use a round file to carefully remove most of the burr, then finish with sandpaper. If you don't have a round file you can do the whole job with sandpaper, but it'll take longer. If it's an aluminum steerer you can carefully trim away most of the burr with an X-acto knife, then finish with sandpaper. However you end up doing it, take your time and make sure you get a nice finish without removing too much metal from the steerer.

If you cut it with a hacksaw you'll want to knock off the burrs both on the inside and outside. A flat file works well for the outside edge and for removing the saw marks from the cut edge, and use the techniques above for the inside.

I wouldn't use cutting oil on the hacksaw, as it will just make a mess for no real benefit. Oil or stick wax are nice if you're using a bandsaw, but you'd better have a heck of an arm to run a hacksaw fast enough to really need oil. :-)

When you grab it in the vise, be sure to use a couple of blocks of wood to prevent damage to the steerer from the vise jaws. It's best if you can grab it by the part that will be cut off and discarded, but it sounds like that's probably not possible in this case.

The biggest thing is to take your time and do it carefully and neatly. It's not a race, and a few extra minutes now will be well worth it in the long run. Measure it carefully, tape everything up well to keep metal chips from getting where they don't belont, cut it slowly, and deburr it thoroughly.

FarEastGang

Thanks everyone for the advice, I'm going to take my mtb on a few rides with different spacer positions before I cut. When I do, I'll post on how it went.

Bike_13

15 years as a mechanic and that's the best advice I have ever heard - helps after a few beers too ....

shane45

As my Dad used to say: "I cut the damn thing twice, and it's still too short!!!"