"Hack" for oversize headset?
 

OK, so I have this old Gary Fisher MTB ($5 CL find!), with a small frame that I'm putting my son on. The problem is that the stem is too far of a stretch for him, so I was looking around for a shorter stem, but couldn't find one that fit.

Now that I'm looking more deeply into various sizing issues, I'm worried that, according to Sheldon Brown's threaded headset cribsheet, I'm beyond the "oversize", and into the "mainly tandem" department. I can't find my calipers to be absolutely sure, but with a tape measure, I could swear that the INNER dimension of my headset/steerer tube hole is a lot nearer 1 1/8" than 1".

Now obviously, I don't want to go to some tandem specialty place and pay >$100 for a quill-to-threadless adapter and also a 60mm stem -- not for a $5 bike! But I got this crazy idea and I wonder if you geniuses could give me any feedback how this would work:

I get a "regular oversized" quill stem, meant to fit in a headset/steerer tube with ID 1" (and OD 1 1/8").

I take the over-over-size stem that I have, totally unscrew the long bolt and remove the diagonal/expansion thingy from the bottom.

I take a hacksaw or a dremel cutting wheel and cut me a 1"-2" section of that pipe, which I already know perfectly fits inside my headset.

I insert that into the headset as a sleeve to take up space between a "regular oversized" quill stem (OD 1"?) and my over-over-sized steerer tube. Given that these sizes seem to have exactly 1/8" increments, it seems that we are working with 1/16" thickness metal here, so hopefully the regular-over-size stem would fit into this "sleeve" just right.

Make sure the new stem's expansion bolt is fully below the sleeve so when it expands it will be pressed only against the headset

Tighten that sucker up; the expansion bolt would expand more than usual, but hold the bottom of the quill stem securely against the inside of the headset, and hopefully the sleeve would keep the top end from rattling around.

Any ideas how well this would work, or would I be signing up my son for a deathtrap where his stem may suddenly and catostrophically break free from the headset at any time?

OR, what if I get a regular-over-size stem and just use it as-is (no makeshift sleeve)? If I tighten it up, I'm thinking it would make the stem come out of the steerer at a little bit of an angle, but would that make any difference in terms of security? I mean, this kid's only 8, it's not like he's going to put a lot of stress on this thing...

OR, what if I make a long sleeve from my over-over-size stem and put a regular-oversize stem inside and keep the expansion-bolt inside the sleeve, would that be able to tighten?

OR, what if I make a long sleeve, and cut a slit all the way down one end -- THEN would I be able to take full advantage of the gripping-properties of the expansion bolt of a regular-over-size quill stem?

OR... (you guys are the experts, what would you do?)

OR, maybe I should find somebody that can weld, and ask them to slice a few inches out of the forward-arm of the stem and weld it back together?

1) find your calipers
2) measure exactly
3) post pics

And you write things like "INNER dimension of my headset/steerer tube hole is a lot nearer 1 1/8" than 1" -
If your headset - the bearings - has an 1 1/8" I.D - can take an 1 1/8" O.D steerer tube - then it's really a quite common size. An 1" quill stem would fit.

It might be simpler (and reversible for when he grows) to put on a handlebar which sweeps back more than what he's got.

I would try to stay away from that - even if it was a steel stem. Sure, a stem is thick walled enough to be welded w/o too much concern for burn-through. But stems are rarely nicely cylindrical, so getting the cuts to line up is likely to be quite time consuming.
And if it was me, I'd like a sleeve inside for reinforcement. also tricky with non cylindrical pieces.

Alloy - I wouldn't even try.

But mainly I don't think it'd need to come to that - unless you prove me wrong with measurements and pics.

Well I looked high and low last night. I remember leaving them on the piano bench, and my son said he saw them there and put them on the computer chair... and there the trail goes cold. But you don't want to hear all that drama.

So you say "your headset - the bearings"; when I say 1 1/8" ID I mean the hole that the quill stem fits into, seems to me bearings are somewhere else, and I'm not sure how their diameter would relate (Sheldon Brown has separate columns in his cribsheet for crown race and frame cup)

But are you saying that quill stems have at least 1/8" of slop, so if a quill stem is 1/8" too small (1/16" gap all around), that's fine, the expansion bolt will still do its job?

You're right, that is probably a much simpler answer; I will be going back to Ye Olde Bike Shoppe (I recommend highly for anyone in San Diego!) Wed night when they get some hot pink bar tape in (for my wife's bike, not my son's bike!!), and I will look around.

As you can't find your calipers, I'd suggest getting a strip of paper, wrapping it around the stem that fits, marking where it overlaps, lay it out straight, measure the distance and divide by Pi. It seems very unlikely an MTB of that vintage would have anything but a 1 1/8" steerer which would mean a quill stem diameter of 1" (typically called a 1 1/8" stem because they go by steerer dimensions).

That's the one. A 1 1/8" quill stem will actually measure 25.4mm, or 1". These are not hard to find. Cheap and cheerful with no hacking required.

CAC, good idea. Quill stem diameter of 7/8" vs 1" should yield circumferences of 69.8mm vs 79.8mm, a whole cm difference, which should be well within the resolution of a makeshift paper measuring tape. While I'm at it, I might as well measure my steerer tube ID/OD. I will report back tonight.

Fisher did do 1-1/4" action up front for a couple of years. He called it the Evolution headset. Unfortunately those were also the days of 140-150mm stems.

If it is an Evolution equipped bike, I'd just shine the bike up, put it on CL for $100 + (highend depends on what model it is)

Then find a bike that fits.

There are several on eBay, if the bike has a 150, there are some 130s available, if that's enough reach reduction.

LesterPup: Thx for letting me know I might not be crazy! I tape-measured the reach (quill-bolt to center of handlebars) at about 4.5". I don't know if that's meant to be 110 or 120 (would they ever make a 115?), but that's already too long, so I was hoping for a 60.

Maybe like this? (including a cannibalized sleeve?)

Steerer tube INTERNAL diameter 1 1/8" (and thus size=OD=1 1/4"):
http://farm9.staticflickr.com/8181/7...b185a48563.jpg

Quill circumference 89mm (--> OD=1 1/8")
http://farm9.staticflickr.com/8311/7...cddbaa4385.jpg

I found the model, it was hidden behind a sticker, it is a Gary Fisher Advance:


http://farm9.staticflickr.com/8029/7...8af92f868c.jpg

and looking very carefully at the headset, you can just make out "Fisher Evolution"
http://farm9.staticflickr.com/8038/7...cf0b9bf91b.jpg



Bikepedia.com skips from 1993 to 2003 for the Gary Fisher Advance, and the 1993 doesn't list headset info. But mine's not a 93, because that lists an Altus group, and this has Exage. For other models I can see 1 1/4" headsets up to 1995, then suddenly in 1996 everything seems to drop back down to 1 1/8.

Also FYI the too-long reach which caused this whole investigation is 110mm. But given the rarity of 1 1/4" headsets, I don't expect to find a replacement stem (for a price I'd be willing to pay for a $5 bike). My plan is to maybe look for some moustache bars or lean back some bmx riser bars or something.

Thanks all for your help (especially LesterPup, the only one who believed in me!)

BTW, I still don't think I've heard any answers to my original question, would it work if I chopped up the existing quill to use as an adaptor sleeve for an easy-to-find 1 1/8" stem?

It's really more like a $75-100 bike that you got for $5.00. If it was really clean you could probably pull $125 within a month of posting.

I don't think I'd hack up a perfectly good stem for a franken-rig. You might be able to make it work as a shim if you split the stem where the expander from the inner stem is inserted but...

I'd just clean it up and sell it, then get another bike.

If that saddle height is offering proper pedal stroke then that bike is too big for your youngster. Probably needs a 13-14" frame.

But I reckon you could get a Trekking bar and allow him to grow into the bike. This one cuts reach by almost 4" I think, but there may be milder ones.

http://media.nashbar.com/images/nash...-NCL-FRONT.jpg

I'm not familier with that bar, what is the real purpose for them?
It almost looks like a Scott AT4 but in reverse.
Scotts have a bridge of course, is this bar stiff enough to use as shown?
It might solve my own retrofit of a 1 1/4 long reach stem problem, since I'm going to be swapping bars anyways.

Their purpose is multiple hand positions in a non-drop bar format, I reckon. Sometimes also called butterfly bars.

I doubt they're stiff enough for dirt jumping when grabbing near the ends, but fine for mellow trail riding.

Thanks, I'll have to check them out.

Nitto makes a 1 1/4" threadless adapter: http://www.amazon.com/Nitto-Column-3...uckduckgo-d-20

Yeah, it's not all that clean. Fair number of rust spots.

As for size, I'll admit I probably pushed him up to 26" a little too soon, but his little brother now owns the 24". He's a big boy for 8, and he does enjoy riding it (except for his arms), and a year from now it'll be great. Just gotta swap handlebars for a while. It's a good solid bike, he'll get maybe 3-4 years out of it, and then his little brother after him, after which it will be in no worse condition than it is now, and I'll be happy to CL it for $50, or hey, why not sell it to a kid for a token $5, make him as glad of a good deal as I was!

I just received mine from Amazon this past Saturday and installed it on my tandem.
It works perfect, and Amazon's price was significantly lower than the other on-line sellers for the identicle product.....$36 vs $60 everywhere else.
One click ordering, low shipping charges, and then only a couple of days for it to arrive.
Very pleased!
Now I'm just looking for a solution for my triple tandem's 1 1/4" threadless that is not only short reach but tall with a short (35-40mm) clamp.
Probably have to go custom.

well seems tape measure is all the accuracy you felt you needed ..
If it is in fact a 1.1250'' ID
then somewhere near you you can seek someone , modest machine shop
to hack a threadless from a threaded conversion quill
to make a tube that size , into a wedge quill at the bottom, have it stick up a ways
and being a 1.125 tube , there the currently common stems to grip around it.

How about this:
http://www.amazon.com/ACTION-BUSHING-STEM-QUILL-ALLOY/dp/B001D1BAOU/ref=pd_sbs_sg_23?tag=5336714512-20-2147483553-20

1.25" steerer makes sense in a head tube that short.

Nice! Now I won't have to shy away from olde Fishers.