tranimal

How safe is it? Anyone with experience? Should I just cough up the money for a real shim? Thanks.

Thetank

if you're mounting them on a 26.0 stem you probably don't even need it. I switch between risers and drops all the time without the need for a shim. if you need one, just buy one they're really cheap.

iloveboston

ive been using beer can shims for years with no problems. i say go for it and dont worry.

JackD

It is obvious that you should only use aircraft grade aluminum for shims. If you insist on using soda cans, flatten the material between two granite surfacing plates and use #1000 grit to make sure it is consistant across both directions (the cold drawing process of constructing cans can lead to irregularity in thickness). Following that an anneal and quench cycle will relieve any latent stress. Once you have that done make sure to round the edges to remove any possible stress risers. And finally, prepare a steel mandrel 0.008" in diameter less than the bars to bend the shim around. If you bend around the bar, the material will naturally spring open a bit larger. DO NOT bend with your fingers.

Powder coating the shim while attractive is a BAD idea as it changes the coefficient of friction and totally f's up the hard work you have done dimensioning the shim.

jdms mvp

^ lol ridiculous' technical description of how to create a shim from a soda can

caloso

I use diet soda cans for the weight savings.

tranimal

Thanks for the responses. I'll see if it'll fit in the stem without a shim. If not, I'll try try the soda can method.

MIN 

I find that i have best luck at this whole shimming thing when i use the foil off the belgian beer bottle. Chimay guarantees success.

iloveboston

schlitz can has never done me wrong and is always handy

darksiderising

The most important question we all should ask is: "What type of stem do you have?" With a traditional single bolt stem, you are in much more dangerous territory than a multiple-bolt with a removable pinch plate.

Brvn

I dont but my friends that I know have in the past. One time while testing out someone elses bike the handlebars slipped forward pretty drastically. Luckily I wasnt going very fast. I assume it was just his shoddy job. I personally am currently riding a jammed 26.0mm bar into a 25.4 stem, so what do I know.

fivehoursfree

I just did this. My stem has a cutout on the mounting plate, so a little bit of BudLight logo shines through.
There is nothing dangerous about it. At the worse, your bars come lose and spin a little, then you tighten them back up, or put more shim. Or you minutely bend your bars, or stem.. whichever is weaker.

powerband

Funny. I just asked the same question about shimming on another forum. The recommendation was shims made from a soda/beer can.

https://www.bikeforums.net/classic-vintage/467283-rigging-shim-cinelli-bar-stem.html

I did it tonight and then cranked down on the bars with gorilla strength. It's pretty solid. Hopefully I won't lose my denture.

na975

beer can shims can slice your fingers up in a blink of an eye!

JackD

I forgot to add "don't blink" to my instructions...

Yeah, blinking will lead to severe digital damage.

alheim

JackD, you know you have too much time on your hands. But I'm impressed regardless .. how did you come up with this?

powerband

It is not too hard to see that he is a Handlebar Shim Specialist (HSS).

JackD

An old guy named Giuseppe taught it to me. He of course grew up in the days when aluminum was like gold and started with steel cans until one day a recon plane over Napoli developed engine trouble and crash landed in his fathers semolina field and ended up rolling straight into the barn. The pilot was dead so they just closed the barn doors and salvaged the metals. Some of it was perfect for handlebar shims. One of the other things he built out of the parts was a desmodromic crank set, but that never really took off due to arguments with his fascist brother-in-law over who actually owned the intellectual property. Fabio took the concept to Ducati in the early 50's.

Anyway, he is the one who put most of the effort into developing the shimming process. When the 70's came along and aluminum cans were everywhere, everyone else jumped on the bandwagon and did it themselves. Some just cut the shims with no prep and were horribly disfigured. Some blinked and you know all about not blinking. It crushed him and he complained bitterly about the loss of the craft to anyone who would listen. As long as he was buying the cinzano I listened. There are a lot more of his secrets which died with him because they took too long to explain and he was already incoherent by the time he got to the critical point - elliptical bearings was one of them which still cause my thorax to constrict when I think about the loss.

powerband

Liar.

Seriously?

powerband

So I want to know: How has this craft survived all these years? Who is your teacher?

erichsia

Tell us more about the elliptical bearings! More!

JackD

The elliptical bearing saga is a long one. I mentioned the desmodromic cranks, well, elliptical bearings were Giuseppe's follow-up. The thinking was that with a synchronized set of elliptical bearings the effective crank length could be varied through out the powerstroke and thus could provide a way of adjusting the gear ratio, or at least that seems like what he was trying to get to. The trouble was that he wouldn't let this secret go until he was deep into the bottle. I tried different ways to pry it out of him which did not involve intoxication, but my spy just reported that he cried out "mamma" at the critical moment - a far cry from the free-body diagram I was expecting. She was rather expensive too, so I just kept pouring and hoping that our discussion of eggs, pears and other oblong objects (of which my spy possessed two excellent examples) would stimulate discussion. It rarely did. And he died before I had a complete understanding.

powerband

I do recall Dr. Giuseppe's departure when the Desmodromic engineering process and units were sold to Caviga in 1985. It was a sad day, with industry prophets crying that the new company would kill the Ducati name, replacing it with something like "Trumph" or "Triumph," or some ridiculous badge like that, a made-in-the-Phillipines product mostly comprised of cheap Chromoly and plastic. If my memory serves me well, I remember reading that Giuseppe disappeared for a 28 months and many at that time theorized that he suffered progressive Alzheimer's for sucking on too much aluminum, and had one day walked aimlessly to Afghanistan and started a club called the Talibo or Taloban, so something like that. But, thank goodness that this was just a misinformation because it was his brother Alfonso.

I believe that it was soon after that Giuseppe introduced elliptical bearings. Which was later purchased by an actual company called Triumph and shipped to their factories in the Phillipines.

erichsia

Now that just sounds like horse****.

JackD

Indeed. Giuseppe died in '81