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Discussion Starter · #1 ·
First, my apologies if this is posted in the wrong forum.

I've just been handed a 20+ year old mtb for an overhaul. After a little elbow-grease and acetone on the frame (somebody painted parts of it with a brush and oil paint), I can see it's a Maruishi (?) never heard of that. At least it's a chromoly frame :). I'll do the usual bearing re-packing, cable replacement, drive-train scrub down and so on. The wheels are reasonably straight, although the back one has a nasty flat spot.

A troubling thing about this bike is that somebody has trimmed the handlebars (or they used to be super narrow). They're too short, making for an uncomfortable riding position. My son's junior-mtb (24" wheels/13.5" frame) has wider handlebars than this bike. The bars are welded to the stem with two smaller tubes (looks like a triangle between the stem and bars). I'm thinking the whole stem/bar assembly should be replaced.

The part that's causing brain cramps is the quill diameter is around 21mm. I've been told that this was done briefly in the early days of mountain bikes, and that it's actually 21.1mm. Sheldon Brown's site claims it's really 21.15mm. I measured the stem itself at 21mm right on the money. Regardless, this size seems to correspond to old-school BMX bikes, which means that's all I've been able to find for a stem that will fit this bike.

Does anybody know of a simple adapter to take the 21.1mm up to a standard 1-1/8" diameter so a threadless stem can be used?

Better yet, is there such a thing as a reasonably light-weight 21.1mm quill stem that has a standard 25.4mm bar clamp? To keep the geometry the same, the existing stem length is about 130mm on a roughly 30 degree angle.

Bicycle frame Bicycle tire Bicycle wheel rim Bicycle part Bicycle accessory
 

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yes, thats called .833 and measures out to 21.1 as you found out. Finding something nowadays might be tough although I might have a bullmoose bar (thats what those are called) with a .833 quill. I will check.

Besides that, it might be "easier" to have the bar width extended by a frame builder. Otherwise, it might take some patience on ebay to find something to fit. I have actually seen some 22.2/ 7/8" bullmoose sanded down to fit, but I wouldnt recommend that.
 

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I have an extra BMX-sized bullmoose bar too - although I'm not sure of the width. If you're interested, let me know and I can measure it tonight.
 

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Discussion Starter · #4 ·
Thanks for the offers gentlemen, but what I was really hunting/praying/begging for was a stem that would allow the use of a more conventional set of bars. This might improve the fit options a little.

I phoned around to multiple LBSs (skipping long version of story here) and found a stem with a 21.1mm quill (not a bmx stem), but it's definitely going to bring the bars closer to the head tube. Since the bike is being set up for a shorter person than the previous rider, this may not be a bad thing. The bullmoose bars put the bars around 130mm away from the head tube, and the new stem will bring them in by about 50-60mm. Could anybody guess how much quicker this is going to make the handling of the bike?

At this point, I'm looking at a 30-50mm riser bar. This is really for the mother-in-law, street use only, so a more upright relaxed riding position is probably better.
 

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I'm in the process of restoring a '92 Trek Multitrack 720. Check out universalcycles.com. So far, they have had everything I've been looking for. It looks like they have some options for you as well.
 
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