Need to fit a 34.9 front derailleur on a 28.6 frame
#1
Newbie
Thread Starter
Need to fit a 34.9 front derailleur on a 28.6 frame
It's a m670 front derailleur. Shimano website says it fits a 28.6 frame with adaptor. Not sure if adapter was suppose to come with it as I bought it on ebay.
Can't find the adapter locally on Canada. Only a few US and UK sites have it. Any other ideas how I can get the derailleur on?
Can't find the adapter locally on Canada. Only a few US and UK sites have it. Any other ideas how I can get the derailleur on?
#2
Senior Member
Join Date: Dec 2005
Location: Sunny Tampa, Florida
Posts: 1,542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 101 Post(s)
Liked 49 Times
in
41 Posts
The thing you are looking for is a "Front Derailleur Clamp Shim." They do often ship with the FD.
Here's a example: https://www.nashbar.com/shimano-ulte...198030/p578001
Here's a example: https://www.nashbar.com/shimano-ulte...198030/p578001
#3
Senior Member
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 27,547
Mentioned: 217 Post(s)
Tagged: 0 Thread(s)
Quoted: 18372 Post(s)
Liked 4,507 Times
in
3,350 Posts
You will need a shim. If it is listed, it should come with the derailleur. Was it shipped to you new, used, new pull, no box, etc?
I'm seeing several from China.
https://www.ebay.com/itm/Bike-Bicycl...m/163664088013
That one even lists Canadian dollars, I think. The Chinese are pretty good at shipping at least something.
I'm seeing several from China.
https://www.ebay.com/itm/Bike-Bicycl...m/163664088013
That one even lists Canadian dollars, I think. The Chinese are pretty good at shipping at least something.
#4
Senior Member
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 27,547
Mentioned: 217 Post(s)
Tagged: 0 Thread(s)
Quoted: 18372 Post(s)
Liked 4,507 Times
in
3,350 Posts
The thing you are looking for is a "Front Derailleur Clamp Shim." They do often ship with the FD.
Here's a example: https://www.nashbar.com/shimano-ulte...198030/p578001
Here's a example: https://www.nashbar.com/shimano-ulte...198030/p578001
#5
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
The Shimano FDs I have gotten recently are sized for 34.9 and come with adapters for 31.8 and 28.6 so you will need a shim if they did not come with it.
#6
Junior Member
Join Date: Jul 2019
Location: far western MD
Posts: 98
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Likes: 0
Liked 39 Times
in
24 Posts
I just make a sleeve out of 6061 T6 in the lathe with the appropriate OD and ID then cut it in half to make 2 semicircular shims. Works fine. ( if you wanted to you could drill some small holes in it to covert it to drillium alloy)
#7
Sophomore Member
Join Date: Jan 2019
Posts: 2,531
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1628 Post(s)
Liked 1,057 Times
in
631 Posts
I tried a variety of shims recently, trying to get a 34.9 FD to fit a 28.6 seat tube. Maybe I'm an awful fabricator, but I had the worst time with trying to get the clamp secured with various shims made of inner tube, electrical tape, and finally sections of aluminum handlebar.
What would happen is the clamp would clamp down unevenly while tightening the clamp bolt. Which would cause the FD to "lean" a bit left, right, forward or back. This affected its operation badly, and performance was pathetic. It was also difficult to really clamp the FD down securely with a shim, there was always some movement if you grabbed the FD and moved it back and forth.
If I made a very wide shim, it looked awful, you could plainly see it sticking out. While narrow shims could be essentially invisible, I could not clamp the FD on straight to save my life. I finally stripped the allen bolt, and after much frustration, finally bought a FD with the right size clamp.
So anyway, I had a nightmare of a time with this, and if I had it to do over I would just buy the correct size FD from the start.
What would happen is the clamp would clamp down unevenly while tightening the clamp bolt. Which would cause the FD to "lean" a bit left, right, forward or back. This affected its operation badly, and performance was pathetic. It was also difficult to really clamp the FD down securely with a shim, there was always some movement if you grabbed the FD and moved it back and forth.
If I made a very wide shim, it looked awful, you could plainly see it sticking out. While narrow shims could be essentially invisible, I could not clamp the FD on straight to save my life. I finally stripped the allen bolt, and after much frustration, finally bought a FD with the right size clamp.
So anyway, I had a nightmare of a time with this, and if I had it to do over I would just buy the correct size FD from the start.
#8
Senior Member
Join Date: Jun 2019
Posts: 580
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 254 Post(s)
Likes: 0
Liked 182 Times
in
141 Posts
If there’s a bike shop near you, you might try asking them if they have one around. Since every FD they get comes with a set of shims, they often have a bunch of unused ones.
#9
Non omnino gravis
The specific part you're looking for is the:
Shimano FD band-clamp adapter, SM-AD17-S 34.9-28.6mm
I cannot find one on Amazon.ca or any sites that are specifically Canadian, but they are widely available online, and honestly, most any bike shop should have one.
Probably around 10 bucks.
Shimano FD band-clamp adapter, SM-AD17-S 34.9-28.6mm
I cannot find one on Amazon.ca or any sites that are specifically Canadian, but they are widely available online, and honestly, most any bike shop should have one.
Probably around 10 bucks.
#10
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
...What would happen is the clamp would clamp down unevenly while tightening the clamp bolt. Which would cause the FD to "lean" a bit left, right, forward or back. This affected its operation badly, and performance was pathetic. It was also difficult to really clamp the FD down securely with a shim, there was always some movement if you grabbed the FD and moved it back and forth...
#11
Insane Bicycle Mechanic
Join Date: Mar 2008
Location: other Vancouver
Posts: 9,835
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 802 Post(s)
Liked 703 Times
in
376 Posts
I made a front derailleur shim out of a 1 1/2" length of PVC pipe. It worked fine for years. I painted it black to match the frame and no one ever noticed it.
__________________
Jeff Wills
Comcast nuked my web page. It will return soon..
Jeff Wills
Comcast nuked my web page. It will return soon..
#12
Senior Member
Join Date: Mar 2015
Location: New Zealand
Posts: 1,053
Bikes: Gunnar, Shogun, Concorde, F Moser, Pete Tansley, Rocky Mtn, Diamant, Krapf, Marin, Avanti, Winora, Emmelle, Ken Evans
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 275 Post(s)
Liked 417 Times
in
218 Posts
a little bit of cheeky coke can poking out looks cool