Bicycle Mechanics - can i put 25.4mm bars in a 25mm clamp?

I have a Peugeot stem with a 25mm clamp and I would prefer not replacing it if possible. Given the difficulty of finding 25mm handlebars, it is tempting to consider 25.4 mm bars. Has anyone had any luck with this sort of thing? Is it a situation where some patient sanding can make the difference?

If not, any advice on how best to obtain 25mm handlebars would be greatly appreciated. I have some saved searches for this on eBay but nothing's come up yet.

Thanks,
Noah

0.4mm isn't very much. I rather suspect that the "25mm" bars are actually 25.4 (i.e. one inch) but are so named because of French revulsion for anything English.

No, they are really 25.0mm, and if you try to put a 25.4 in there you will regret it. I stupidly tried some french "Philippe" without calipering them first and scratched the he** out of 25.4 bars, as well as never getting them fully in the clamp.

Sanding the clamp area would weaken the bar in its most highly stressed area, that's a Darwin experiment.

Sanding the clamp area would weaken the bar in its most highly stressed area, that's a Darwin experiment.

Maybe he was referring to sanding within the clamp area of the stem.

While I'd agree sanding is probably not the best idea, taking 0.2mm off the inside of the clamp (0.4mm off the diameter) is probably not going to weaken it much, if at all. That's the sort of thing you do when you just can't bear to part with the stem, and you don't mind a wreck at the least opportune time to pay for it. Note: you'd still have to replace the stem once it breaks.

It's not hard to find 1" British/American (hence 25.4mm) threaded stems. They're practically giving them away everywhere you look. On the other hand, 25.0mm french handlebars are becoming hens' teeth. So, unless you're restoring a classic and don't mind the time and effort (and probably expense) you're better off just getting a new stem.

I've mismatched way worse than that without a problem during actual use, but as was said, you'll probably get lots of scratches on the bars.

I have a Peugeot stem with a 25mm clamp and I would prefer not replacing it if possible. Given the difficulty of finding 25mm handlebars, it is tempting to consider 25.4 mm bars. Has anyone had any luck with this sort of thing? Is it a situation where some patient sanding can make the difference?

If not, any advice on how best to obtain 25mm handlebars would be greatly appreciated. I have some saved searches for this on eBay but nothing's come up yet.

RUN AWAY! RUN AWAY!! RUN AWAY!!!

Old French stems are dodgy even used with the correct handlebars. This could cost you some teeth!

See: http://sheldonbrown.com/velos

Sheldon "French Frames, Yes; French Stems, NO!" Brown

]

RUN AWAY! RUN AWAY!! RUN AWAY!!!

Old French stems are dodgy even used with the correct handlebars. This could cost you some teeth!

See: http://sheldonbrown.com/velos

Sheldon "French Frames, Yes; French Stems, NO!" Brown


LMAO!

Hah.

]

RUN AWAY! RUN AWAY!! RUN AWAY!!!

Old French stems are dodgy even used with the correct handlebars. This could cost you some teeth!

See: http://sheldonbrown.com/velos

Sheldon "French Frames, Yes; French Stems, NO!" Brown

Hmmmm... I am pretty fond of my teeth. Does the brand of old French stem make much of a difference? I see where you especially warn against AVA in the "velos" section of sheldonbrown.com. My stem is an "Atax," I believe, with the Peugeot logo on it. If I'm really better off not using an old french stem I can certainly plunk down a few more dollars for a new one with a 25.4 clamp, I just liked matching up a Peugeot stem with a Peugeot frame.

Thanks to everyone for suggestions and help :)

Not sure how the clamp is on your stem. Is it one of the older steel ones with a single bolt clamping it down? Can you use a screw driver to pry it open just a little larger?

Sorry to bring back a three year old thread, but I was wondering if anyone had further input on this. I'm trying to fit a pair of Nitto Randonneur bars @ 25.4mm into a 1982 Peugeot UO-14 stem which is 25.0mm and can't really see how sanding .2mm would be consequential to the safety of the stem, but thought it best to consult the knowledgebase here. Thank you!

Personally, I would spend $10 and replace the stem. If your headset is french sized, then your stem is slightly smaller diameter as well (I am not sure when Peugeot made that change). But taking .1mm off the body of the stem is a lot less risky IMHO than taking .2mm off the stem's clamp. The choice is yours.

Not sure if the OP ever did end up trying this, but I tried to do that once and I ended up with a handlebar clamp section that was egg shaped (the excess squeezed itself into the gap where the bolt was). Considering the possible dental work after a handlebar or stem failure, I tossed the bar and got compatible parts.

Part of the problem is that the stem is pretty much never going to come out of the frame without an epic fight. Plus I like the original look of the Peugeot branded stem, I just don't want to wind up in the hospital, or worse the morgue, if anyone has good reason to think sanding .4mm total out of the inside of the stem clamp is a horridly bad idea.

I'd say use a shim to use French bars in an English stem and get a new stem rather than put English bars in a French stem. It may fit out of the box; stuff is a little undersized sometimes. If not, it is easy to sand down.

I don't have nor can I find French bars and just spent a good bit of money on the Nitto bars. I love the bike but, as with all things French, it is such a pain with all the tiny quirks. So I either need to figure out the safety factor of sanding the clamp area or a way to free the stem from frame and fit (if anyone has some good suggestions) a new stem into place.

More Data:
I weigh 146lbs.
Plan on using the bicycle, after some more work, for touring, probably staying away from anything on the bars (no decaleur) if the original stem is used.
Here's a picture of the stem. I don't know if having a vertical bolt makes a difference.
http://img824.imageshack.us/img824/6315/0407101426.jpg (http://img824.imageshack.us/i/0407101426.jpg/)

DEJA VU! :D

I just finished restoring an old Peugeot mixte frame that used the same stem as that one! Same shifters as well. Sand away with no concern other than maintaining a nice round shape. There's more than enough material that it won't miss a lousy .2mm off the inner diameter. If it's going to fail for any reason it will NOT be because you sanded out a smidgeon of metal from the clamp. In fact it would be more prone to crack and fail if you pry it apart to stuff the bigger bar into the hole.

Use a sanding drum so you tend to maintain the concentricity of the overall hole. If you can hopefully it'll accept a 1 inch drum even if you have to wedge it open JUST a little.

Part of the problem is that the stem is pretty much never going to come out of the frame without an epic fight. Plus I like the original look of the Peugeot branded stem, I just don't want to wind up in the hospital, or worse the morgue, if anyone has good reason to think sanding .4mm total out of the inside of the stem clamp is a horridly bad idea.
I wouldn't sand it, but if your bar is beefy, it will probably take the pinching just fine and probably won't fail on you.

You can use an allen key to hold the clamp open for the bars. Stick it in the gap and turn it 30°. If it doesn't open far enough, go to the next size up.

Whether or not you expand the clamp in the stem to 25.4, gently file down the corners where the notch of the bar clamp meets the bore for the handlebar. Just take them down a little until they are no longer sharp points. Those can gouge up a bar.

I carefully sanded the clamp with a round wooden dowel and 80 grit sandpaper for a good 45 minutes checking against the bar fit every minute or so. The bars got scratched up a bit (slight gouges which I polished out with 3-400 grit sandpaper) on the curved parts (bar tape will cover this anyway) and everything is as snug as possible to fit through the clamp without resorting to brute force or grease.

I found out that the depth of a paint stirring stick is the same as the gap in the clamp area with the bolt removed prior to sanding. Using that as a reference point, with the new bars inserted the distance is exactly the same in the clamp with no bars inserted, so I'm confident that the bars themselves aren't putting any stress on the clamp having been sanded to the right diameter.

I was very careful not to over tighten bolt. There's more of a gap with the bolt tight against these bars than the crummy straight one, someone had replaced the original drop bars with, but I think this is a function of the sanding and the bar itself is locked in solid with the bolt tightened as much as it is.

With all my weight as a standstill and hopping around a bit there isn't any movement, creaks, no visible stress cracks, or otherwise noticeable indication of failure. So hopefully nothing bad will happen with use.

When I have time, probably within two days, I'll take some better pictures with a proper camera.

If it's for a 25.0 bar it may also be a 22.0 quill, which means you're boxed in a corner fork ID is not 22,2mm either .
a small adjustable hand reamer is the right tool, I'd get a section of 1.0 inch tube to test fit, as the reamer is slowly expanded , then the cut will be smooth, and uniform , as soon as the 1" tube fits in you're done
then you will be assured the bar will fit in . when you slide it thru the stem..

So far I am still alive. Here's how everything turned out.
http://img812.imageshack.us/img812/5412/img0404y.th.jpg (http://img812.imageshack.us/i/img0404y.jpg/)
http://img213.imageshack.us/img213/9566/img0402m.th.jpg (http://img213.imageshack.us/i/img0402m.jpg/)
http://img403.imageshack.us/img403/629/img0403f.th.jpg (http://img403.imageshack.us/i/img0403f.jpg/)

Good job, except since you plan to use the bike for any serious riding, you will need to address this problem:

"Part of the problem is that the stem is pretty much never going to come out of the frame without an epic fight...... Plan on using the bicycle, after some more work, for touring,"

I would not want to embark on a tour without the ability to maintain part of the bike.

You need to be able to pull the stem to do any meaningful headset maintenance or replacement. Avoiding/delaying removal could make eventual removal more difficult. I would do a search of the forum on stuck stems. I have had about a dozen bikes in the last two years with stuck stems, where I was able to eventually remove them, following the steps outlined in Sheldon Brown site and elsewhere.

It's great seeing a resurrected thread with Sheldon's input :)

A very old French stem and Nitto Albatross bars. I didn't want to give up the stem because I like its style.

http://inlinethumb14.webshots.com/44045/2887774920068014369S600x600Q85.jpg (http://sports.webshots.com/photo/2887774920068014369uJZKFK)

Good job, except since you plan to use the bike for any serious riding, you will need to address this problem:

"Part of the problem is that the stem is pretty much never going to come out of the frame without an epic fight...... Plan on using the bicycle, after some more work, for touring,"

I would not want to embark on a tour without the ability to maintain part of the bike.


You need to be able to pull the stem to do any meaningful headset maintenance or replacement. Avoiding/delaying removal could make eventual removal more difficult. I would do a search of the forum on stuck stems. I have had about a dozen bikes in the last two years with stuck stems, where I was able to eventually remove them, following the steps outlined in Sheldon Brown site and elsewhere.

I can't figure out what you are talking about or whom you are quoting.

He's quoting me from earlier. Per advice from Cambridge Bicycle I'm going to try using CLR to unstick the stem,

maybe just tour in France, where the problems came from.. :innocent: :roflmao:

He's quoting me from earlier. Per advice from Cambridge Bicycle I'm going to try using CLR to unstick the stem,

Now I get it. I missed that part.

Good luck with the CLR. It certainly works for unclogging my shower heads. In case it doesn't work, check this out:

http://www.bikeforums.net/showthread.php?601711-Freeze-Off-to-the-rescue-AGAIN!!-(stuck-BB-this-time)&highlight=freeze