datlas 

I am slowly trying to put together a new build as my winter project.

I have a clamp-on FD that has a 34.9 diameter and the bike needs a 31.8.

I think I need a shim like this:

https://www.jensonusa.com/store/produ...m.aspx?sc=FRGL

However I am wondering if anyone has tried using a home-made shim from aluminum foil, folded over...and if that works or not. It's only 2mm...

Thoughts??

RT

Buy the shim. The pressure needed to secure the FD to the seat tube will smush the foil significantly and there will be much trial and error in finding the right thickness uncompressed before you get it. Jenson ships quickly too.

datlas 

OK I was kinda hoping to MacGyver it but I suppose I can bite the bullet and get the shim.

wjclint

I built up my son's bike and had the same issue. I took a slice of some PVC pipe I had in the garage and cut it into two segments and used that as a shim. It wasn't a perfect fit, but when I tightened it down it wrapped the PVC down tight to the tube. It hasn't moved or shifted since and works just fine. Added benefit was the frame was white and matched the PVC. It was an aluminum frame so I wasn't worried about putting to much uneven clamping pressure on it.

DScott

Buy the shim, or make a similar one of solid material. Making a foil shim that is 1.5mm thick by layering .02mm thick foil is tedious, if not ultimately unworkable.

datlas 

Maybe. Then again .02 x 2^6 = 1.28 so 6 folds should probably do it!

DScott

Isn't it the 7th fold that gets you to ~1.5mm?

I hate math. Buy the shim.

datlas 

Let's count....from 1st fold: .04, .08, .16, .32. .64. 1.28....I think that's 6, right?

I will probably still get the shim. I need to buy a headset too and Jenson has a decent price on the Cane Creek S-3 which is what I am inclined to get.

Math rules, btw.

Commodus

I made one for my bike. I had to go from 34.9 to 28.6 and I couldn't seem to find one.



Quick bit of turning and a band saw cut later...

Lathes are really handy when working on bikes, I recommend getting one.

DScott

OK, yeah, I like math. It just doesn't always like me.

jan nikolajsen 

Definitely tinker. Lots of fun.

Here's my PVC shim. Haven't moved 1000+ miles later:

Stratman351

I must say, I admire you guys that are willing to go so far as to invest in a lathe to avoid paying $4 for a built-to-fit shim. And I kinda hate to ask the OP what he paid for his frame such that he's willing to forego a $4 shim in favor of folded aluminum foil.

Disclaimer: I'm not really very handy, so maybe that's why I'm sort of amazed by some of the recommendations in this thread. OTOH, I do most of my own bike work, which often drives my wife to ask, "how come you can work on that bike but plead ignorance when I ask you to change a light bulb or hang a picture?"

datlas 

I do appreciate all the comments.

But I am still not going to buy a lathe instead of a $4 shim...