Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

Shimming 25mm handlebars to a 26mm stem

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

Shimming 25mm handlebars to a 26mm stem

Old 07-13-20, 10:16 AM
  #1  
jonwvara 
Senior Member
Thread Starter
 
jonwvara's Avatar
 
Join Date: Apr 2006
Location: Washington County, Vermont, USA
Posts: 3,290

Bikes: 1966 Dawes Double Blue, 1976 Raleigh Gran Sport, 1975 Raleigh Sprite 27, 1980 Univega Viva Sport, 1971 Gitane Tour de France, 1984 Lotus Classique, 1976 Motobecane Grand Record

Mentioned: 57 Post(s)
Tagged: 0 Thread(s)
Quoted: 499 Post(s)
Liked 218 Times in 119 Posts
Shimming 25mm handlebars to a 26mm stem

This may or may not be of interest to anyone, but I recently had to shim a set of older 25mm French handlebars to fit a modern 26mm Nitto stem (part of a LeJeune project that's about done; I will post a few photos by and by). The standard 25.4-to-26 shims were obviously too thin, and I didn't want to go the beer-can route. So I obtained a 25.4 to 26.4 seatpost shim. It fit very nicely into the stem handlebar clamp, allowing me to neatly trace the shape of the clamp area with a fine-point Sharpie.

At only a half-millimeter thick, the material was pretty flimsy, so to cut it neatly I slid it onto a piece of one-inch dowel, taped it in place, and cut along the lines with a jeweler's saw. Cleaned up the cut lines with some fine emery paper, and put it in place in the stem clamp, with the slot in the one-piece shim aligned with the slot in the handbar clamp. Inserted the bars, tightened bolt. It's about perfect--even on minute examination it's hard to see that the bar has been shimmed.

Okay, that's it. I doubt that I'm the first one to do this. It's not rocket surgery, but I thought it was kind of neat.
__________________
www.redclovercomponents.com

"Progress might have been all right once, but it has gone on too long."
--Ogden Nash
jonwvara is offline  
Old 07-13-20, 02:41 PM
  #2  
T-Mar
Senior Member
 
Join Date: Nov 2004
Posts: 20,672
Mentioned: 557 Post(s)
Tagged: 1 Thread(s)
Quoted: 3678 Post(s)
Likes: 0
Liked 1,099 Times in 819 Posts
Always nice to hear about successful project completion, regardless of how small, Enjoy.
T-Mar is offline  
Old 07-13-20, 03:50 PM
  #3  
Salamandrine 
Senior Member
 
Join Date: Oct 2015
Location: Los Angeles
Posts: 6,287

Bikes: 78 Masi Criterium, 68 PX10, 2016 Mercian King of Mercia, Rivendell Clem Smith Jr

Mentioned: 120 Post(s)
Tagged: 0 Thread(s)
Quoted: 2310 Post(s)
Liked 556 Times in 400 Posts
That's a small but useful tip for somebody in the future. Sounds simpler, faster and easier than finding correctly dimensioned sheet stock, and then having to roll your own.
Salamandrine is offline  
Old 07-13-20, 04:17 PM
  #4  
malcala622 
Senior Member
 
malcala622's Avatar
 
Join Date: Oct 2014
Location: Pico Rivera, CA
Posts: 3,423

Bikes: 88' Bianchi Giro. 88' Bianchi Krono. 92' Tommasini Prestige. 80' Gios Torino. 83' Basso Gap

Mentioned: 78 Post(s)
Tagged: 0 Thread(s)
Quoted: 985 Post(s)
Liked 605 Times in 395 Posts
I may need this in the future if I should build another funny bike. The Scott aero bars have a 25.0 clamp and itd be nice to pair it with a 26.0 stem.
__________________
88' Bianchi Giro. 88' Bianchi Krono. 92' Tommasini Prestige. 80' Gios Torino. 83' Basso Gap




Last edited by malcala622; 07-13-20 at 04:51 PM.
malcala622 is offline  
Old 07-13-20, 04:45 PM
  #5  
agnewton
Senior Member
 
Join Date: Jun 2010
Location: Cerca De Troit
Posts: 96

Bikes: Peugeot UO-10, '78; Fuji Sp.RR, '73, mixte '75

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked 17 Times in 13 Posts
Originally Posted by jonwvara View Post
This may or may not be of interest to anyone, but I recently had to shim a set of older 25mm French handlebars to fit a modern 26mm Nitto stem (part of a LeJeune project that's about done; I will post a few photos by and by). The standard 25.4-to-26 shims were obviously too thin, and I didn't want to go the beer-can route. So I obtained a 25.4 to 26.4 seatpost shim. It fit very nicely into the stem handlebar clamp, allowing me to neatly trace the shape of the clamp area with a fine-point Sharpie.

At only a half-millimeter thick, the material was pretty flimsy, so to cut it neatly I slid it onto a piece of one-inch dowel, taped it in place, and cut along the lines with a jeweler's saw. Cleaned up the cut lines with some fine emery paper, and put it in place in the stem clamp, with the slot in the one-piece shim aligned with the slot in the handbar clamp. Inserted the bars, tightened bolt. It's about perfect--even on minute examination it's hard to see that the bar has been shimmed.

Okay, that's it. I doubt that I'm the first one to do this. It's not rocket surgery, but I thought it was kind of neat.
Useful and neat. The kind of solution that I am going to need someday and glad to find it shared on the forums.

Now, if only there were a similar trick to fit 26.0 mm bars into 25.0 mm stems.
agnewton is offline  
Likes For agnewton:
Old 07-13-20, 05:19 PM
  #6  
oneclick 
Senior Member
 
Join Date: Feb 2020
Posts: 867
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Likes: 0
Liked 295 Times in 186 Posts
I'm sure I saw negative thickness shims on Sheldon's site.

All the reviews were positive.
oneclick is offline  
Likes For oneclick:
Old 07-13-20, 06:16 PM
  #7  
Last ride 76 
1/2 as far in 2x the time
 
Last ride 76's Avatar
 
Join Date: Nov 2013
Location: Northern Bergen County, NJ
Posts: 1,935

Bikes: Yes, Please.

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 498 Post(s)
Liked 278 Times in 219 Posts
A true craftsman, Jon.
I am too impatient, and go the beer can/utility knife route sometimes even skipping the sharpie step... (This may belong in the confessions thread.)
But now that I know a better way, moving forward, I may have to buy a few shims.

Drat you jonwvara. You've ruined beer can shims (except in emergencies) for me, for ever...

"Drat" was another Dix "ism" I had forgotten - till just now. Cheers, Eric
__________________
I seem to have lost what little mind I had left before this all started.

Last edited by Last ride 76; 07-13-20 at 06:18 PM. Reason: Correcting the auto-correct...
Last ride 76 is offline  
Old 07-13-20, 10:11 PM
  #8  
bulgie
blahblahblah chrome moly
 
bulgie's Avatar
 
Join Date: Apr 2009
Location: Seattle
Posts: 522
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 294 Post(s)
Liked 386 Times in 207 Posts
Originally Posted by malcala622 View Post
I may need this in the future if I should build another funny bike. The Scott aero bars have a 25.0 clamp and itd be nice to pair it with a 26.0 stem.
Remember when Lemond used Coke-can shims to hold his aero bars in the TdF? I think it was 1989.

That may have been back when Coca-Cola was an official sponsor, so he may have been required to use Coke cans -- no beercan shims allowed!

To Jon V: thanks for the tip, hope I remember it next time I need it!

Mark B in Seattle
bulgie is offline  
Likes For bulgie:
Old 07-13-20, 10:18 PM
  #9  
malcala622 
Senior Member
 
malcala622's Avatar
 
Join Date: Oct 2014
Location: Pico Rivera, CA
Posts: 3,423

Bikes: 88' Bianchi Giro. 88' Bianchi Krono. 92' Tommasini Prestige. 80' Gios Torino. 83' Basso Gap

Mentioned: 78 Post(s)
Tagged: 0 Thread(s)
Quoted: 985 Post(s)
Liked 605 Times in 395 Posts
Originally Posted by bulgie View Post
Remember when Lemond used Coke-can shims to hold his aero bars in the TdF? I think it was 1989.

That may have been back when Coca-Cola was an official sponsor, so he may have been required to use Coke cans -- no beercan shims allowed!

To Jon V: thanks for the tip, hope I remember it next time I need it!

Mark B in Seattle
Do I remember?!?!....No not at all I was barely past my first birthday.
__________________
88' Bianchi Giro. 88' Bianchi Krono. 92' Tommasini Prestige. 80' Gios Torino. 83' Basso Gap



malcala622 is offline  
Old 07-14-20, 01:34 AM
  #10  
bulgie
blahblahblah chrome moly
 
bulgie's Avatar
 
Join Date: Apr 2009
Location: Seattle
Posts: 522
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 294 Post(s)
Liked 386 Times in 207 Posts
Originally Posted by malcala622 View Post
Do I remember?!?!....No not at all I was barely past my first birthday.
Well, I "remember" the 1913 TdF, when Eugène Christophe broke his fork and had to forge it at the local blacksmith shop himself, because outside assistance was not allowed back then. Remember reading about it anyway. Believe it or not, 1913 is a few years before I was born, practically no time at all in the cosmic scheme of things.

-mb
bulgie is offline  
Likes For bulgie:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.