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  1. #1
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    "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. #2
    Senior Member cnnrmccloskey's Avatar
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    Quote Originally Posted by jonnycomelately View Post
    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?
    Try to make it fail, it you fail before it you've done it properly

    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.
    Quote Originally Posted by Braden1550 View Post
    Monocoque unicycles with internal gear hubs, ridden by extortionists with an excellent sense of balance.

    You'll see. Unless you drilled out your eyes because they were too heavy.

  3. #3
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    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. #4
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    Quote Originally Posted by fixiekid505 View 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.
    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. #5
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    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.
    Last edited by fixiekid505; 04-26-10 at 08:21 PM. Reason: hostility apology

  6. #6
    chickenosaurus j3ffr3y's Avatar
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    coke can, or better yet get the goya cans for mango nectar or the cans for coconut water, they are a little thicker.
    2010 Motobecane Team Track
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  7. #7
    Senior Member cnnrmccloskey's Avatar
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    Quote Originally Posted by fixiekid505 View 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.
    for some people the difference between a couple bucks and the left over from a can can actualy make a difference, and why did you quote me?
    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.
    Quote Originally Posted by Braden1550 View Post
    Monocoque unicycles with internal gear hubs, ridden by extortionists with an excellent sense of balance.

    You'll see. Unless you drilled out your eyes because they were too heavy.

  8. #8
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    Quote Originally Posted by fixiekid505 View 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.
    jeez, i really pissed you off didn't i?

    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?

  9. #9
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    See edit.

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    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.

  11. #11
    old and fixed... clubman's Avatar
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    Zen and the Art of Motorcycle Maintenance answers all shim questions and much much more. Seriously, read it.

  12. #12
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    Quote Originally Posted by fixiekid505 View Post
    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.
    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.

  13. #13
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    Quote Originally Posted by clubman View Post
    Zen and the Art of Motorcycle Maintenance answers all shim questions and much much more. Seriously, read it.
    probably my favorite book ever.

    to summarize: if/when that $2 shim fails, your bike will be worth exactly that.

  14. #14
    Senior Member cnnrmccloskey's Avatar
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    Quote Originally Posted by fixiekid505 View Post
    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.
    *EDIT* wrong venue to talk ****.
    Last edited by cnnrmccloskey; 04-26-10 at 08:38 PM.
    Quote Originally Posted by Braden1550 View Post
    Monocoque unicycles with internal gear hubs, ridden by extortionists with an excellent sense of balance.

    You'll see. Unless you drilled out your eyes because they were too heavy.

  15. #15
    Senior Member Brian's Avatar
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    Quote Originally Posted by dookie View 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.
    Wait, you need math to work on bikes now?

  16. #16
    Veteran Bastard Scrodzilla's Avatar
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  17. #17
    headtube. zzyzx_xyzzy's Avatar
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    Quote Originally Posted by dookie View 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.
    0.3mm is about four times thicker than most aluminum beverage cans these days.

  18. #18
    Senior Member cnnrmccloskey's Avatar
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    Quote Originally Posted by Scrodzilla View Post

    What Nitto really needs to do, is to start packaging beer in their shim material, best of both worlds
    Quote Originally Posted by Braden1550 View Post
    Monocoque unicycles with internal gear hubs, ridden by extortionists with an excellent sense of balance.

    You'll see. Unless you drilled out your eyes because they were too heavy.

  19. #19
    Elitist carleton's Avatar
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    Quote Originally Posted by cnnrmccloskey View Post
    What Nitto really needs to do, is to start packaging beer in their shim material, best of both worlds
    Hahahaha!

  20. #20
    %#&*#%>?% Build your own's Avatar
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    I guess there will always be DIY for the mechanically inclined and the "proper" way for double left handed ,anal retentive shop-a-holics

  21. #21
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    Quote Originally Posted by zzyzx_xyzzy View Post
    0.3mm is about four times thicker than most aluminum beverage cans these days.
    0.08mm seems awfully hard to believe? data please?

  22. #22
    Comanche Racing PedallingATX's Avatar
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    Quote Originally Posted by clubman View Post
    Zen and the Art of Motorcycle Maintenance answers all shim questions and much much more. Seriously, read it.
    that book sucks.
    skinnytire

  23. #23
    Veteran Bastard Scrodzilla's Avatar
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    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.
    Last edited by Scrodzilla; 04-27-10 at 08:13 PM.

  24. #24
    Senior Member NateRod's Avatar
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    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?

  25. #25
    Senior Member gobby1095's Avatar
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    Quote Originally Posted by jonnycomelately View Post
    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.
    Hm, I wouldnt listen to them, theres a reason these shims are manufactured, soda can shims DO slip semi easily, even when sanded or whatever. Better to spend $10 or however much it is and have peace of mind. And its a small price to pay versus getting in a colossal and startling crash in the middle of the road.

    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.

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