Drop bar conversion on a mtb
 

I picked up a 1992 Trek 950; the bike is sweet with lugs, true temper tubing, and Deore LX parts (except for the few bits that the PO changed out). The paint job is in really excellent shape. It also has a super long wheelbase and so I want to do a drop bar conversion and turn it into a road/offroad touring bike.

Here is my problem. The bike has a 1 and 1/8 inch threaded fork which limits my ability to find tall stems. The stem needs to be around 8 and 1/2 above the top tube. That's a lot. The top tube though is the right length for me and the saddle height is of course a non-issue.

I think I have two options:

(1) I own a one inch nitto dirt drop stem that would do the job height wise but of course it is the wrong size. I could look around for a shim but I'm a little leery of this. Probably no good reason but I'm really conservative--for pretty obvious reasons I think--when it comes to stems and handlebars. Anyone have any experience in shimming a one inch quill stem so it fits into a 1 and 1/8 inch fork? I haven't had a lot of luck finding a shim like this; perhaps someone here could point me in the right direction?

(2) Alternatively I could get a threaded to threadless converter like this nitto, https://www.benscycle.com/p-2509-nit...-286254mm.aspx. I really, really like nitto products and trust them. It's not very long though. I should be able to find a threadless stem that angles upward sharply.

Am I missing something here? Is there another solution that I should be thinking about? I'd like to get this right the first time.

Go with the converter. Opens up the world of opportunities.

I rarely recommend converters, but this is one of those cases where it just works. Find a good LBS that lets you try out various stems.

There are really ugly MTB/hybrid quill stems available in that diameter with a lot of rise.

Nashbar ATB Comfort Quill Stem

I have at least two stems with a 1" (actual diameter) quill. I don't have any bikes that take this size quill, so consider them surplus, and am in fact a bit mystified how I ended up with them. I'll try to remember to take a photo for you.

I can't think of how you would safely shim a 1" quill stem to fit 1 1/8". I've never seen such a device.

So, I think the second option is your best (and safest) bet, paired with a +40 degree stem.

I've always admired those trek 9x0 lugged frames, but it's good to know that they have a weird headset. I avoid Fishers from the same era because of their 1 1/4" threadless headsets.

1" threadless isn't bad because it can be shimmed up. I did that with a drop bar conversion of a Univega Alpina for my girlfriend.

Would this work.

Sunlite Alloy 2 Bolt 1 1 8" Quill Stem 80mm 25 4mm 25 Degree Clamp Silver | eBay

The ID of a steel 1-1/8 fork like the OP's is exactly the same as the OD of a 1" fork. And, obviously, the ID of a 1" fork is exactly the same as the OD of a 1" stem quill. Therefore, you can make a very good shim by cutting a segment out of an old fork (I made mine from a damaged kids bike) and cutting slots in one end to allow it to expand. The only drawback to this compared to most commercially available shims is that the lack of a lip on the top will allow it to slip inside the 1-1/8" fork during assembly.

It is not really weird - it's exactly the same size as modern 1-1/8" threadless, just with the steerer cut too short to clamp a stem on. However, modern 1-1/8" headsets and replacement forks will drop right in if you ever need to upgrade.

This may help, or may add to your pain, but not long ago I found two (yes, two) of these at the co-op. Snatched 'em up like they were made of gold:

http://i79.photobucket.com/albums/j1...psg1cxcckm.jpg

Manufactured by Kalloy (if that's a manufacturer as opposed to an indication of potassium alloy construction). Beyond that all I can tell you is they exist, and they look like this:

http://i79.photobucket.com/albums/j1...psr72b5kmv.jpg

http://i79.photobucket.com/albums/j1...psohrwygnd.jpg

By way of contrast, here's what the same Trek looked like when the drop conversion was done but I was still on my stem quest:

http://i79.photobucket.com/albums/j1...psnvt9e3df.jpg

That's a threaded-to-threadless converter, plus a threadless rise extender, plus a threadless stem. It was somewhere between comedic and horrifying. 2/3 of that assembly are now in the BOC if it's headed your way (I may have just violated one of the crappy rules). Anyway, unless it's temporary I wouldn't recommend going that route. Ugly, clunky, and heavy.

EDIT: Yep. If you take the time to construct a long and only slightly informative post in response to some issue, complete with the taking/uploading of pictures, you can safely assume that someone around here will solve the problem in two minutes and forty keystrokes while you do it. :rolleyes: [MENTION=165276]brian3069[/MENTION]

FWIW, I used a piece of a steel can to shim a way too small quill stem into my 92 Paramount, and it worked just fine. I know there are few here who would approve. This situation always reminds me of 'Zen and the Art of Motorcycle Maintenance'.

That was likely a 21.1 stem (JIS 1"?) and a 22.2 steerer tube (ISO 1"?) - a total of 1.1mm diameter difference, so a 0.55mm shim is needed. For 1" to 1-1/8" the difference is 25.4-22.2 = 3.2mm, or 1.6mm shim, which would be a goddamn thick can.

To safely shim a 7/8" quill to fit in a 1" steerer, I would make a two-piece shim, each a piece of 1/16" aluminum curved into a half cylinder. The sliding wedge of the stem should push them apart, separately from one another, making a secure fit.

In bending 1/16" aluminum into a curve, its actual thickness may change a bit, so will need to be cleaned up with a flat file before it'll fit perfectly.

I just posted about this and bought this same stem in the 1" size for a conversion of my own. I was really impressed with the quality of it. I second it and recommend it. Plus, bonus for me was that I was able to use loop bars because the two bolt mount allowed me to mount them.

[QUOTE=Tim_Iowa;18131494]I can't think of how you would safely shim a 1" quill stem to fit 1 1/8". I've never seen such a device.

QUOTE]

I have put them on a couple of bikes, including my daughter's. They work great. I didn't have any trouble finding them online.

[QUOTE=Wilfred Laurier;18131534

It is not really weird - it's exactly the same size as modern 1-1/8" threadless, just with the steerer cut too short to clamp a stem on. However, modern 1-1/8" headsets and replacement forks will drop right in if you ever need to upgrade.[/QUOTE]

+1, I tend to prefer 1-1/8" vintage MTB frames and you can buy modern replacements from Surly, SOma or whatever if you pick up an old MTB with a suspension fork and 1-1/8" headtube... then you have modern, light and strong threadless set-up and can put a whack of spacers on it and it will look just like any other LHT out there.

[QUOTE=Grand Bois;18131780]link?

Fixed that for you. :) I don't know if a nested quote will notify the nested poster or not. [MENTION=27118]Grand Bois[/MENTION]

[QUOTE=Tim_Iowa;18131977]Okay, I'll find one for you. The ones I used are stainless steel, rolled over and not split at the top.

Alloy Shim to Fit 1 Inch 22.2 mm Insert Quill Stem - £13.27

It was a much smaller stem. It came off a '74 Free Spirit, whose seatpost size was 20mm IIRC. The point I was trying to make is that there are options, outside the box, which can function just fine.

I'd go for the Kalloy/Sunlite/whatever 1-1/8" quill stems posted. They're a little ugly, but not quite as ugly as the adjustable ones. And the price is right. :thumb: