"properly" shimming 25.4 bars in a 26 stem
#1
Senior Member
Thread Starter
Join Date: Mar 2010
Posts: 120
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
"properly" shimming 25.4 bars in a 26 stem
just before it got nasty and was closed, an op on an earlier thread mentioned that a shim on any bars but flats can fail unless it's done properly. what's the proper (and improper) way to do it? i've been using a piece i cut from a red bull can to fit just shy of all the way around, and as wide as the ribbed bit on the bar. sound ok?
#2
Senior Member
Join Date: May 2009
Location: Portland Oregon
Posts: 744
Bikes: '82 Giante super challange, 70 Gitane Tour de France, GT Gutterball
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
just before it got nasty and was closed, an op on an earlier thread mentioned that a shim on any bars but flats can fail unless it's done properly. what's the proper (and improper) way to do it? i've been using a piece i cut from a red bull can to fit just shy of all the way around, and as wide as the ribbed bit on the bar. sound ok?
any Time I'm shimming somthing I don't like to have to wrap the shim, one layer, if it survives a fail test then its good.
#3
Senior Member
Join Date: Nov 2009
Location: Albuquerque, NM
Posts: 59
Bikes: 1974 Urago Track
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Walk down to your LBS and ask for a proper shim like smart person would do. Now that the jack ass thread is dead and gone we have to take any opportunity we get to ridicule others.
#4
Senior Member
Thread Starter
Join Date: Mar 2010
Posts: 120
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
nice. 'cept when i went to the lbs they told me i'd be wasting my money and that i should just use a can. dude.
#5
Senior Member
Join Date: Nov 2009
Location: Albuquerque, NM
Posts: 59
Bikes: 1974 Urago Track
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
How much are shims?
On second thought you're right you might go bankrupt buying a shim.
Or better yet just get 26.0 bars, there's a thought.
woww...... things that are SUPPOSED to work together.
Edit: I apologize for the hostility, I thought this was cnnrmccloskey's thread. But shims work best when they're the proper thickness, but nothing beats a correct fit.
On second thought you're right you might go bankrupt buying a shim.
Or better yet just get 26.0 bars, there's a thought.
woww...... things that are SUPPOSED to work together.
Edit: I apologize for the hostility, I thought this was cnnrmccloskey's thread. But shims work best when they're the proper thickness, but nothing beats a correct fit.
Last edited by fixiekid505; 04-26-10 at 08:21 PM. Reason: hostility apology
#6
chickenosaurus
Join Date: Sep 2008
Location: Boston, MA
Posts: 1,189
Bikes: 2010 Motobecane Team Track, 1997 GT Edge, 2012 Kilo TT Stripper
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
coke can, or better yet get the goya cans for mango nectar or the cans for coconut water, they are a little thicker.
#7
Senior Member
Join Date: May 2009
Location: Portland Oregon
Posts: 744
Bikes: '82 Giante super challange, 70 Gitane Tour de France, GT Gutterball
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I said that mostly as a joke cause you just needed to chill, I didn't even make fun of anyone, you on the other hand seem to be itching to jump all over people for being 'hipsters'... or maybe I'm thinking of a different Fixiekid
This may be a topic better suited for the mechanics forum
Last edited by cnnrmccloskey; 04-26-10 at 08:25 PM.
#8
Senior Member
Thread Starter
Join Date: Mar 2010
Posts: 120
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
i don't know how much they cost because the mechanics at the shop all agreed it was stupid to buy one. and i don't want to have to buy new bars because i like the ones i've got. and because if i can shim them, what's the point? now if shimming is just a bad idea, say so. otherwise, maybe instead of picking a stupid fight you could answer my question or move along?
#10
Senior Member
Join Date: Jan 2005
Posts: 1,301
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 12 Times
in
1 Post
you're talking about a 0.6mm delta in the diameter, which for the math challenged is 0.3mm shim thickness. you know what a 'proper' shim is going to be? a paper thin sheet of aluminum, or brass if you're shopping at nordstroms.
a well shaped strip from the beverage can of your choice will be just fine. if you want something more techie than the next guy, go to a local hobby shop and get a sheet of brass. they should have many sizes and thicknesses, so you can dial it right in to 0.3mm.
i've been using a $2 piece of hobby shop brass to shim a high-zoot 26.8mm ti seatpost into my newer-than-the-post high-zoot ti mtb frame which takes 27.0mm. no worries after several years of serious off-road abuse.
a well shaped strip from the beverage can of your choice will be just fine. if you want something more techie than the next guy, go to a local hobby shop and get a sheet of brass. they should have many sizes and thicknesses, so you can dial it right in to 0.3mm.
i've been using a $2 piece of hobby shop brass to shim a high-zoot 26.8mm ti seatpost into my newer-than-the-post high-zoot ti mtb frame which takes 27.0mm. no worries after several years of serious off-road abuse.
#11
Phyllo-buster
Join Date: Jan 2010
Location: Nova Scotia
Posts: 8,844
Bikes: roadsters, club bikes, fixed and classic
Mentioned: 133 Post(s)
Tagged: 0 Thread(s)
Quoted: 2297 Post(s)
Liked 2,047 Times
in
1,253 Posts
Zen and the Art of Motorcycle Maintenance answers all shim questions and much much more. Seriously, read it.
#12
Senior Member
Thread Starter
Join Date: Mar 2010
Posts: 120
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
ahhhh... ok, that explains it. i mean, i've def asked some dumb questions since i joined, but this one? seemed pretty harmless to me.
#14
Senior Member
Join Date: May 2009
Location: Portland Oregon
Posts: 744
Bikes: '82 Giante super challange, 70 Gitane Tour de France, GT Gutterball
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#15
Senior Member
Join Date: Nov 2004
Location: Between the mountains and the lake.
Posts: 16,681
Bikes: 8 bikes - one for each day of the week!
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
you're talking about a 0.6mm delta in the diameter, which for the math challenged is 0.3mm shim thickness. you know what a 'proper' shim is going to be? a paper thin sheet of aluminum, or brass if you're shopping at nordstroms.
a well shaped strip from the beverage can of your choice will be just fine. if you want something more techie than the next guy, go to a local hobby shop and get a sheet of brass. they should have many sizes and thicknesses, so you can dial it right in to 0.3mm.
i've been using a $2 piece of hobby shop brass to shim a high-zoot 26.8mm ti seatpost into my newer-than-the-post high-zoot ti mtb frame which takes 27.0mm. no worries after several years of serious off-road abuse.
a well shaped strip from the beverage can of your choice will be just fine. if you want something more techie than the next guy, go to a local hobby shop and get a sheet of brass. they should have many sizes and thicknesses, so you can dial it right in to 0.3mm.
i've been using a $2 piece of hobby shop brass to shim a high-zoot 26.8mm ti seatpost into my newer-than-the-post high-zoot ti mtb frame which takes 27.0mm. no worries after several years of serious off-road abuse.
#17
headtube.
Join Date: Sep 2008
Posts: 803
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
you're talking about a 0.6mm delta in the diameter, which for the math challenged is 0.3mm shim thickness. you know what a 'proper' shim is going to be? a paper thin sheet of aluminum, or brass if you're shopping at nordstroms.
a well shaped strip from the beverage can of your choice will be just fine.
a well shaped strip from the beverage can of your choice will be just fine.
#18
Senior Member
Join Date: May 2009
Location: Portland Oregon
Posts: 744
Bikes: '82 Giante super challange, 70 Gitane Tour de France, GT Gutterball
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#20
%#&*#%>?%
Join Date: Feb 2008
Location: Mass
Posts: 845
Bikes: Pake,Shogun,Nishiki,Motobecane
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I guess there will always be DIY for the mechanically inclined and the "proper" way for double left handed ,anal retentive shop-a-holics
#22
Comanche Racing
Join Date: Feb 2009
Location: Deep in the heart of Texas
Posts: 2,820
Bikes: Presto NJS build, Specialized Allez Pro w/ full Dura Ace and Ksyrium SLs, 1990something Specialized Sirrus
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#23
Your cog is slipping.
If your 25.4mm bars are painted or powder coated, you may not need to bother shimming as they're most likely closer to 26mm (or more) anyway.
My powder coated risers (that are supposedly 25.4) measure in at 25.9 on my digital caliper.
My powder coated risers (that are supposedly 25.4) measure in at 25.9 on my digital caliper.
Last edited by Scrodzilla; 04-27-10 at 08:13 PM.
#24
Senior Member
Join Date: Aug 2009
Location: Brooklyn, NY
Posts: 1,666
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I've been riding my bars all this time on a 26 mm stem, under the impression that they were actually 26 mm bars.
I felt compelled to double check online right now and realized they're officially 25.4 mm. Interesting. Never had any issues so I failed to notice. Disaster waiting to happen?
I felt compelled to double check online right now and realized they're officially 25.4 mm. Interesting. Never had any issues so I failed to notice. Disaster waiting to happen?
#25
Senior Member
Join Date: Apr 2009
Location: Berlin DE/NYC USA
Posts: 173
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Nevertheless Im running 25.4 mm bars (nitto b123s) with a 26 mm stem, sans shim. I dont think its really a problem as long as you see some sort of gap between the tightening section of you stem (i.e. you can see a bit of the handlebars between the clamp area of the stem). Then you know that the bolts are exerting the proper pressure on the bars. The problem arises when the bars seem firm but the clamp area of the stem appear to be touching, then it probably hasn't achieved the 'proper pressure' and something bad could happen. Also it depends on what bars you are using. Im not too paranoid, not only because of the little gap, but because im using drops, which make it hard for me to exert too much vertical force. If I was running my bullhorns I might be a bit scared of some type of slippage.