Front derailer shims
#1
Senior Member
Thread Starter
Join Date: Jul 2005
Location: Norfolk, VA
Posts: 52
Bikes: '06 Trek 4500, 2004 Trek 4500, 1998 Diamondback Topanga
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Front derailer shims
OK I'm putting together a comutter bike and one of the new parts is the front derailer. I got a pretty good deal on it and didn't even think to check the clamp size. Well it's a 31.8 clamp and the bike is 28.6. So I was thinking of making my own spacers either out of rubber hose or lathing out some plastic. But I saw a derailer advertised with a shim for just this, but I can't seem to find just the shim. Does anyone know where I could buy one or should I just stay with plan A and make my own?
#2
Senior Member
Join Date: Jul 2005
Posts: 259
Bikes: Trek SU200, Trek 7300 FX (Spouse's)
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
First try calling your LBS to see if they have them. If not, or if they want a ridiculous amount of money, then make your own, except make it out of metal, not rubber. Head to down to Lowe's, Menard's, or Home Depot, and a good wander around ought to find you what you're looking for. Looks like you'll need something roughly 31.8 - 28.6 = 3.2 mm thick. My first guess would be to look at hose clamps (hack saw off the part which bulges out that you won't need).
#3
use your best eye
Join Date: Mar 2006
Location: Olympia, Washington
Posts: 3,050
Bikes: '75 Bertin, '93 Parkpre Team 925, '04 Kona King Kikapu, '05 Bianchi Vigorelli
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
I think that a lot of Shimano front deraillers now come as a 31.8mm with 2 shim sets to make up the two smaller sizes. Like the othber poster said, go to your LBS. If it is a shop of a reasonable size, they likely will have tons of leftover shim sets and won't need to charge much (hopefully). Bring your deraillerr to check the fit.
Ditto- don't use rubber. The deraiiler mount must be rigid or the shifting quality will suffer considerably. Poss. use hard, flexible plastic, say cut from a five gal. bucket or such. You need to find the right thickness, so that the deraiiler's band clamp does not completely close up when fully tightened.
Ditto- don't use rubber. The deraiiler mount must be rigid or the shifting quality will suffer considerably. Poss. use hard, flexible plastic, say cut from a five gal. bucket or such. You need to find the right thickness, so that the deraiiler's band clamp does not completely close up when fully tightened.
#5
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2025 Post(s)
Likes: 0
Liked 1,095 Times
in
741 Posts
Originally Posted by tgarcia2
Looks like you'll need something roughly 31.8 - 28.6 = 3.2 mm thick.
#6
Senior Member
Join Date: Jul 2005
Posts: 259
Bikes: Trek SU200, Trek 7300 FX (Spouse's)
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by HillRider
No, you need a shim (31.8-28.6)/2 = 1.6 mm thick. The shim needs to correct for the difference in radius, not the difference in diameter. BTW, 1.6 mm is almost exactly 1/16".
#7
cab horn
Join Date: Jun 2004
Location: Toronto
Posts: 28,353
Bikes: 1987 Bianchi Campione
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 42 Post(s)
Likes: 0
Liked 25 Times
in
18 Posts
Well if your LBS does not have shims from old school shimano FDs (they come with them standard). Take a Heineken or your favourite beer can and make one yourself. Cut strips out and layer it and hold them together with some thin tape. Sandwich it and tighten the bolt. and done.
Been using it like that for the last 6000 km and not a problem.
Been using it like that for the last 6000 km and not a problem.
#8
Senior Member
Join Date: May 2005
Location: Queanbeyan, Australia.
Posts: 4,135
Mentioned: 85 Post(s)
Tagged: 0 Thread(s)
Quoted: 3450 Post(s)
Liked 420 Times
in
289 Posts
I was in exactly the same situation as you. I have a 31.8mm band front derailer on a 28.6 mm seat tube. I'm using the Shimano shims that my LBS had from new derailers they had but didn't need the shims for. Something important that I found is that you need 2 shims as they are only half size even though you may be told that you only need 1. With 1 fitted initialy it just didn't align properly or hold tight enough.
The Shimano shims are plastic but once mounted properly with 2 shims I have had no further problems.
Regards, Anthony
The Shimano shims are plastic but once mounted properly with 2 shims I have had no further problems.
Regards, Anthony