nerobro

Howdy,

This winter I set upon the process of building my own bike. I picked up a bunch of parts I thought were reasonable. And short of messing up on the choice of three parts, I think I did pretty well. But first, to the meat of the issue.

I have an uncut bontranger carbon fork. It's got a 1-1/8" aluminum steerer. My initial plan was to cut my steerer tube two inches taller than the top of my installed stem. That would give me some room to adjust bar height. (at least for now... I can always cut it shorter later, as I get more flexible, and ideally narrower)

How do you cut your steerer. I was looking into using a pipe cutter. But it seems they won't make it through the 1/8" wall of the tube, and then I may run into issues installing the star nut due to flash left over from the cutting. So option number two, was to break out my calipers, and use them to scratch a line around the circumference of the tube, cut it off with a hacksaw and then level it with a file.

In my bike parts purchases, I managed to buy a seatpost that was a might bit to long. I'm not a tall guy, so even finding frames small enough for me can be a bit of a challenge. I'm much less concerned about cutting the seatpost, as nothing loads it axially.

Where can I get the barrel adjusters that screw into the shift cable guides on the downtube? I haven't seen those listed anywhere.

I built the bike almost completely from used parts. If anyone is curious, I'll happily post the parts I bought and put togother. My derailurs, rear sprockets, cables, and tires are all brand new items.

Just so you guys can see the progress...
The first batch of parts:

A little bit further:

And as of last night: I really just got the shifters shoved in there and the new tires installed and pumped up to pressure.


Mistake parts I bought:
31.8mm seatpost.
Powder blue stem spacers.
160mm 30 deg stem, that claimed to be 31.8mm, but wasn't.
Crankset with bad bottom bracket.

bluenote157

I dont think you need the screw type barrel adjusters that you are after. I think those are for bikes have braze-ons for downtube shifters. It appears that yours are the kinds that you slide into those guides and act as stops for the cables.

nerobro

The holes are threaded. And they have the detents to hold the adjusters in place on the face of them. :-/ maybe I should call fettish.

Now I know I'm running a 9 speed drivetrain, what is involved with putting a chain on the bike. The only chains I've used are motorcycle chains with rivet style, and clip type master links.

Peek the Geek

One thing you need to be aware of is the maximum recommended spacer height for that fork. Does Bontrager give this? On my Reynolds Ouzo Pro, Reynolds recommends not using more than 1" of spacers.

As for cutting, make sure you use a fine-toothed hacksaw blade (again, Reynolds gives a helpful recommendation, suggesting the use of a blade used for cutting ceramic tile). When cutting carbon, some people wrap masking tape around the steerer first, as further prevention against the carbon splintering.

jsharr

Get a metal hose clamp to use as a cutting guide on the steerer. Cut with hacksaw.

Peek the Geek

The following link will show you how to set the correct length for your chain.
https://sheldonbrown.com/derailer-adjustment.html#chain

Durward_Kirby

I have the same frame and am planning on building it up this spring. The cable stops do indeed take a special fitting or you can put down tube shifters on it. Look on ebay for the fittings in one of the vintage dealers there.

Joshua A.C. New

You can totally cut the steerer with a pipe cutter. That triangular thing on the back of the cutter is for scraping the inside bur.

AHemp

Yep, a pipe cutter should make quick, easy, and clean work of it. As for the downtube adjusters, they're probably just standard barrel adjusters. Any LBS should be able to help for free or very cheap.

Good work on the build... I'm thinking about going white with mine.

nerobro

Remember this is an aluminum steerer. ;-) No bontranger does not provide, or suggest a maximum stack height. I checked both the manual, and called my local bontranger dealer.

Really standard metal cutting stuff. :-) I can handle it, I'm just looking for the "best" method. if a tubing cutter will work, it will leave the best finish. And it will automagically make the cut perpendicular to the steerer tube.

I like the hose clamp idea as well. If I can't borrow a tubing cutter with sufficant capacity, I'll be doing that.

I ended up calling fettish today. They told me the easiest thing to do would be to contact the LBS. I have a very good one, so I should be in luck in that department.

Now if only my derailur, and bottom bracket would arrive. :-) I could be rolling in style by next weekend.

Camilo

I were in your position w/ uncut steerer, I'd flip the stem down rather than the way you have it flipped up in the photos before doing any cutting and base all cutting on handlebar position with the stem flipped down. With the stem flipped down, I would cut the steerer so that the handle bars are at least level (maybe even a tad higher - why not, just to see how it works?). You can then experiment with handlebar position by putting spacers above and below the stem until you figure it out. If it were me, I would prefer a final fit with the stem flipped down rather than up so it is more or less level with the ground rather than angled upwards like in your photo.

I just think the bike looks much better that way. Flipped up (like yours in the photo) doesn't really bother me that much because proper handlebar height trumps aesthetics big time. But given the option, IF handlebar height can be high enough with the stem flipped down, it just looks better. You still have that option!

Of course, the steerer will be longer with the stem flipped down rather than up. But to me, I'd rather have a taller stack of spacers under a flipped down stem, than a shorter stack of spacers under a flipped up stem.

Again, just my own opinion, others may disagree.

I wish I'd had that option with my bike. Good luck!

markjenn

Seems silly to me to add a bunch of spacers and make the steerer longer so that you turn around and have the stem go down to get rid of the height. The only reason I can see to reverse the stem and have it angled down is if you can't get the bars low enough, even with no spacers below the stem at all.

You're overthinking this. Build up the bike with a generous stack height that puts the bars as high as you ever think you might want them. Carefully mark the steerer even with the top surface of the stem. Now, measure 2-3 mm below this line (your headset mfg may spec exactly how much below) and mark a nice/straight cut line. Cut the steerer to this length. Anything that results in a reasonably straight cut is fine - hacksaw, fine-tooth metal cutting blade in a jig saw, etc. - but you want to make sure that no part of the cut is above the cut line. (I rigged a little jig/guide for my jig saw.) Put your star nut in, preload the bearing (not too much - again, the headset mfg will have a torque spec), tighten the stem, and finish your build.

Ride the bike awhile and swap spacers from below the stem to above the stem to find the optimal position. If the optimal position results in spacers above the stem and you want to get rid of them, then shorten the fork using the same process.

- Mark

HillRider

Don't use a pipe cutter. The "triangular thing" will remove the burr from the inside but the cutter wheel will raise a ridge on the outside of the steerer and make installing the headset difficult. As recommended by jsharr, tighten a metal hose clamp around the steerer with the upper edge at the cut line as a cutting guide and use a 32 tpi hacksaw blade. Or, have your LBS cut it at what will probably be a very modest charge.

Also, cut the steerer a bit long and use a spacer ABOVE the stem to give you some adjustment room until you know where you want the bars. You can shorten it to final length later when you are certain where that should be.

Ignore having the stem point down. If you need the bars up a bit, having the stem angled up is better than a lot of spacers.

The 1" spacer limitation applies only to 1" carbon steerer tubes. For Al or 1-1/8" anything you can use more. Easton allows 50 mm (2") of spacers below their 1-1/8" carbon steerers.

maddmaxx 

Pipe cutters make neat clean cuts. A light touch with a file will clean off the bur. Often the hardware store will be able to sell you a replacement cutting wheel for steel pipe which seems to do a better job than the original wheel on most cutters.

Peek the Geek

Oops. Sorry about that. I didn't realize the steerer was aluminum.

Deanster04

Take it to an LBS. They have a tool and can do the job in about 5 minutes. They will deburr the tube when they are finished. I wouldn't use a pipe cutter on an Al fork steerer tube. You want the top to be very straight so that the top cap will fit perfectly. It is a low cost job $10 to $20.

aesmith

Myself, I think I'd scribe a line right round, hacksaw just a smidge shy of the line, then file smooth and square. Then file a very slight chamfer on the inside and outside to take the burrs off. It wouldn't take too long.

For anyone not comfortable with that, the bike shop sounds a good option - but I'd be paranoid that they'd cut it at the wrong place. Make really, really, really sure it's clearly marked.

markjenn

Just to be clear on this, the top cap will fit "perfectly" as long as no part of the steerer is sticking up beyond a line a couple mm below the top of the stem. The critical thing is that when you tighten down the top cap, that it bears completely on the top of the stem and doesn't touch any part of the steerer whatsoever.

Beyond this, its mostly cosmetics. If you hack it off at an angle or roughly, it will still work fine unless you're a real gorilla and do it so badly that you actually cut it down far enough that you start reducing the area for the stem to clamp properly.

That being said, a nice/straight cut is the mark of a professional job.

- Mark

nerobro

The whole point of the pipe cutter is to ensure that the top is very straight. As mentioned earlier, the top cap does not fit against the steerer, instead it pushes down on the spacers and stem, and eventually on the headset. (at least untill you tighten the stem, in which case the top cap is then just ballast)

All that said, it looks like I'm going to do the hacksaw and file method. And I got my new bottom bracket in the mail last night.