lupo68288

Hello everyone,
I had a bikefitting some weeks ago and the bikefitter recommended to shorten my fork shaft from 35mm Spacers to 0mm Spacers. But because I have internal Cable routing I need to shorten my stem by 15mm then ride it some weeks an if it feels good, I should shorten it again in about 5mm heigt and then again the last 10mm. Because of that I asked my local bike shop for a mechanic appointment so they can shorten my fork shaft for 15mm. They did it and after 1 week riding I called the shop again for another appointment, but they said the next appointment they can give me is at the end of May. So I'm thinking about to do it myself. The problem is that I don't know how easy it is and if I need to disconnect my hydraulic breaks for this.

I do a lot of the mechanics things myself, like changing tires or rewaxing my chain, adjust the breaks/derailleur, centering the rim and such stuff. But I never shortened something. The bike costs like 8gran and I don't want to break something or take the risk that I do something wrong, so I can't ride it until the appointment.

It would really help me, if somebody can say, how easy the process is and what I need to disconnect for it to work (I will search a youtube tutorial for the cutting process myself, but if you have some godd tutorials/advices don't hesitate the send them in).

Thank you in advance for the answers

Mr. 66

You lower the stem and not cut the ‘steertube’ just restack the spacers from under to over. This way if you don’t like the lower you can put it back.

lupo68288

As I Said I have fully internal cable Routing so IT isn't possible to restack the spacers on top. (I have the FSA NS ARC stem)

Jeff Wills

A hacksaw and a cutting guide are what you need.


However, since you’re concerned about how much you have invested in this bike, I’d suggest you hand it over to a professional mechanic to do this. Expensive bikes can lead to expensive mistakes.

Kontact

The problem is that every 10mm of stack you remove creates 10mm of extra length of hydraulic brake line. Sometimes a fat tubed carbon frame has plenty of room to take up the slack in the downtube, head tube and fork leg. Sometimes not.

You might consider taking a plastic or alloy round spacer and grinding it to roughly match the FSA stem contour so you can continue to play with stem height without the factory top cap, substituting a round cap. When you have established where you like it, then take it in to be cut. The top cap is just there to compress the stem down for your headset bearing adjustment, so anything that gets you there will work in the short term.

70sSanO

The shop just didn’t cut steerer, they also reposition the star nut or compression plug. Not difficult to do. Cutting a carbon steerer does take some care.

There is always an “if” to consider when making a permanent modification. As in if it doesn’t feel good. Although the fitter wants you to get used to lower bars, it is a bit of a catch-22 to even pose the “if” because if it doesn’t work out, you’re sol.

Fashioning an angled cap and being able to move spacers on top to get a proper pre-load is a good suggestion.

John

lupo68288

ok yea I saw the video and I think I will wait the month until the appointment so the mechanics can cut the spacer

veganbikes

I would recommend having a professional do it with all the integration I would not faff about with it and create a very expensive problem for yourself. I love the look of an integrated bike but working on one can be quite the nightmare. Maybe if I get a custom frame built designed around internal routing and my desired geometry I might consider it but at that point it would probably be a fixed gear or if it had to be geared it would be wireless.

Dan Burkhart 

I have worked on hoses and cables routed through the headset, and believe me, that’s not where you want to start learning about steer tube shortening. I would leave this to the shop.

Kai Winters

Suuuuuuuuuuuuure, it's easy...you can do it and you only need a hack saw...just start cutting...
Really???
Wait for the appointment and get it done by someone who...hopefully...knows what they are doing because based on your post you have no idea.
Or go ahead and do it and make sure to video the process...it will be very instructional for many

Kontact

Yeah, really. You might not be able to do much for yourself, but it is utterly unnecessary to keep bashing every home mechanic that even considers accomplishing something on their own.

This type of FSA stem is relatively easy to take apart for cutting access.

grumpus

For any future searches you may make, this is called a steerer tube, or just steerer.

oldbobcat

Good idea. This is hardly the carbon steerer for a first-timer to practice on.

Camilo

I've cut several carbon fiber steer tubes without any sort of saw guide.'

When I'm absolutely sure where to cut the tube (check, double check, triple check), I put a wrap of masking tape around the tube and mark it in complete circumerence at the correct cutting point. I then score around the tube at the mark with a nice sharp, fine hack saw. I then just carefully cut the tube, making it as square as possible. It doesn't have to be perfect, but if it is visibly off square, I square it up a bit with a file. I then dress the outer and inner edges with sandpaper or a file, just to smooth the edges.

I've used a hose clamp as a cutting guide and it's a good option, if you have one, and if you don't feel comfortable doing it this way.

A cutting guide will certainly make it quicker and easier, but it's not necessary if you don't have one.

cyccommute 

I would certainly suggest some kind of test before taking a fitter’s ideas as gospel before cutting the steer tube. Cutting a steer tube is forever. There is no going back if you don’t like it. Look into a stem with a negative rise or just flip the current stem.

Additionally, ff you can’t just reposition the spacers, you won’t be able to just saw off the steer tube either. You’ll have to shorten any cables or hoses that go through the headset as well. Cutting the steer tube off 3 times will require 3 adjustments to the cable/hoses as well.