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26.0 bar in 25.4 stem. Bad idea or no big deal?

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26.0 bar in 25.4 stem. Bad idea or no big deal?

Old 05-02-09, 02:14 PM
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genericbikedude
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26.0 bar in 25.4 stem. Bad idea or no big deal?

It sort of fits. Will this 86 my parts and lead to risks of catastrophic failure? Or is it fine?
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Old 05-02-09, 02:19 PM
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You'll need a little shim in there to make it tight. Otherwise your bars will head South when you hit a bump. A thickness or two of beer can will do.
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Old 05-02-09, 02:22 PM
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other way around. 26.0 bars in a 25.4 stem.
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Old 05-02-09, 02:34 PM
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Oops, sorry. I've run that set up plenty of times and still have my teeth. It's not ideal, but catastrophic failure seems unlikely.
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Old 05-02-09, 03:04 PM
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you can make it work, but is it worth it? if it's a budget project, give it a try. i have done it a few times and it's ok, but i don't like to tell other people to do it.
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Old 05-02-09, 07:49 PM
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If it's a 25.4 quill stem then start saving for a new face. If it's threadless. Make sure the faceplate isn't bottoming out with proper torque on the faceplate bolts. It probably will.
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Old 05-02-09, 08:05 PM
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How would squeezing the bars into the quill cause you to have a faceplant at speed? Maybe you are thinking of the steering tube? I wouldn't do that, but the handlebars themselves I don't see an issue. I'm no expert though.
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Old 05-02-09, 08:12 PM
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don't mix 25.4mm and 26mm stem/bar combinations.
that 0.4~0.6mm is enough to cause the bars to slip or the stem to crack from the concentrated stress.

you can use a shim for a 25.4mm bar to 26mm stem, but even that is not that great.
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Old 05-02-09, 08:15 PM
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I did just that with my Fuji Touring. I used 1" threaded stem with a 25.4mm clamp, front-loading two-bolt design with a detachable face plate. I had the face plate of the stem machined to better fit the 26.0mm clamp diameter of my handlebars.

I'm using a heavy steel stem, and it seems very solid to me. Machining a fraction of a millimeter off the walls of my 25.4 mm stem won't make much of a difference in strength. The LBS did the machining for $5 and are as confident as me that this will be solid.
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Old 05-02-09, 08:18 PM
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This is a big difference. If you did get the bar in, look at how theres no meshing at all of the radius of the stem.How could you want to ride that?
You will find 25.4mm Nitto bars out on ebay, or get an economical AND strong front clamping alloy welded stem made in Taiwan, by Profile or Pyramid thru most full service bike shops.
I would go this route if you like your handlebar, and it fits you just right, cause finding a nice fitting(fitting rider) handlebar can take years!
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Old 05-02-09, 08:22 PM
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https://sacramento.craigslist.org/forums/?ID=123541121

Hmmm...
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Old 05-02-09, 08:46 PM
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But why? The worst part is you know what you did. I once saw a guy with baggy pants shove a bunch of tools in his pants and walk out of Orchard Hardware. I pointed it out to the cashier who ran out to grab the guy. The guy turned and took a swing at him, his pants fell down and everything went everywhere. He knew things didn't fit when he started.
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Old 05-02-09, 08:51 PM
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I've put a 26mm bar in a 25.4mm open face stem plenty of times and there has been no failure.

You do have to be careful though. Creating a scratch that will become a stress riser is something you need to take seriously. What you need to do is position the bars carefully where you want them to be and then evenly tighten up the clamp bolts alternating as you go. If you need to reposition the bar then loosen it right off first and carefully move the bar. Don't just half loosen the clamp and twist which you can do safely if the bar and clamp are a matching size otherwise you will create a scratch that will become a stress riser.

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Old 05-02-09, 10:49 PM
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Originally Posted by operator View Post
If it's a 25.4 quill stem then start saving for a new face. If it's threadless. Make sure the faceplate isn't bottoming out with proper torque on the faceplate bolts. It probably will.
Why would it bottom out? The bar is bigger, so the issue would be if the narrow curvature of the faceplate pinches the hell out of 2 points of the bar.
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Old 05-03-09, 12:13 AM
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Originally Posted by curbtender View Post
But why? The worst part is you know what you did. I once saw a guy with baggy pants shove a bunch of tools in his pants and walk out of Orchard Hardware. I pointed it out to the cashier who ran out to grab the guy. The guy turned and took a swing at him, his pants fell down and everything went everywhere. He knew things didn't fit when he started.
That's really funnny.
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Old 05-03-09, 12:36 AM
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As a former machinist, hearing about people doing this makes me cringe.
Aluminum does not like to be deformed. With steel, it's not such a big deal, but aluminum tends to break catastrophically sooner or later after being stressed like that.
And if the bar does break, a lot of your body weight will suddenly shoot downward into the front wheel and you'll have marginal control (if any at all) over the bike.
It's not worth gambling with your life over. Don't be cheap and lazy, and respect the specs of the parts you have.
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Old 05-03-09, 02:07 AM
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Originally Posted by thenomad View Post
How would squeezing the bars into the quill cause you to have a faceplant at speed? Maybe you are thinking of the steering tube? I wouldn't do that, but the handlebars themselves I don't see an issue. I'm no expert though.
https://www.bikeforums.net/bicycle-mechanics/514817-26mm-peg-into-25-4mm-hole.html#13
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Old 05-03-09, 08:22 AM
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Originally Posted by thenomad View Post
How would squeezing the bars into the quill cause you to have a faceplant at speed?
Strain on the stem clamp from spreading the metal too far can lead to cracking and sudden clamp failure. Aluminum doesn't give much warning between initial cracking and complete failure.

Why not just use the proper size?
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Old 05-03-09, 05:05 PM
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Why not just use the proper size?

Because a steel 25.4mm stem that's as tall as I need it to be can be had for less than $10 locally. It has a split face that uses two 6mm class 10.9 (1/4" grade 8) bolts to attach to the rest of the stem. So, I'm trusting those two high-grade, quenched and tempered alloy steel bolts with my life. The tiny bit of material machined off the stem face is minor.

The perfect fit stem would be a Nitto Technomic that costs $45 plus $25 international shipping since it can't be found in Canada.

I already have one Technomic on one of my bikes, but when I needed a second extra-tall stem with a 26.0mm clamp I couldn't justify spending $60 extra when all I needed was to machine out a tiny amount of metal out of an overbuilt steel stem.

My road frames are 61cm and 64cm respectively. I suppose a taller frame would be nice, but I haven't been able to find larger frames without going custom - which I can't afford at this time.

Last edited by hernick; 05-03-09 at 05:24 PM.
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Old 05-03-09, 05:35 PM
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Originally Posted by hernick View Post
The perfect fit stem would be a Nitto Technomic that costs $45 plus $25 international shipping since it can't be found in Canada.
Nitto Technomic stems have been available in Canada for many many years. Norco is a distributor for them now, so their availability will become even more common. Suggested retail from your LBS is about C$70.
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Old 05-03-09, 05:40 PM
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Would you put your size 10 foot in a pair of size 8 shoes?
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Old 05-03-09, 07:34 PM
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Originally Posted by Torchy McFlux View Post
Nitto Technomic stems have been available in Canada for many many years. Norco is a distributor for them now, so their availability will become even more common. Suggested retail from your LBS is about C$70.
I think they're more like $80 since the last round of increases.

I'm cheap. I have no problem riding unconventional set ups or cobbling together a bike from disparate parts. I've shimmed, filed, respaced and cold-set beyond the bounds of good taste and judgment, but I don't take chances with handlebar/stem setups. Your 26.0 bar and 25.4 stem may well give you miles of good service, but if the bar kinks and fails, or one of the bolts shear, you wont be thinking about all the money you saved on the way down.

Like Torchy said, Nitto stems are available in both clamp diameters from any bike shop that orders from Norco. If you're more budget minded, they should also be able to get you a $20ish dollar "Zoom" stem with the proper dimensions.
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Old 05-03-09, 08:54 PM
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Well, I'm not gonna spend $80 on another Technomic. I didn't know they were available in Canada, as multiple LBS have told me they couldn't get the Technomic or anything comparable when I looked around last year.

I have looked through the catalogs of many bike parts distributors and haven't found any comparable stem with a 26.0mm clamp. Do you have any more information on that Zoom stem? I've seen many Zoom stems in various catalogs, but none that come close to a 120mm Technomic. I'd be interested in such a stem.

Oh, and if I can't trust a pair of class 10.9/grade 8 bolts as I've got on my current stem, what can I trust?
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Old 05-04-09, 08:44 PM
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I would get an 1 inch diameter (or slightly less) piece of round wood (or PCP-pipe), wrap some fine sandpaper around it and give the stem and the clamp a few buffs with it. If no wood (or PCP-pipe) available, I would just roll the sandpaper until it has roughly the diameter.
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Old 05-05-09, 01:37 AM
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What about using a threaded to threadless converter and an inexpensive threadless stem in 26.0? It might not be the classiest looking solution but it's cheaper and probably stiffer (if that matters to you) than the Nitto option.
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