Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-07-05, 11:18 PM   #1
JimJim
Member
Thread Starter
 
Join Date: Mar 2005
Bikes:
Posts: 25
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
spreading FD cage for compact crank

Anyone have experience with spreading the front deraileur cage of Shimano Ultra-9 triple to get some additional width to work over the entire gear range without cage rubbing on a 50-34 FSA Energy compact crankset driving a wide 11-32 rear sprocket with Shimano XTR rear derailleur?

I have no problem shifting over the full range, but the front derailleur cage rubs the chain despite carreful adjustment. I purchased the Ultra-9 triple front derailleur hoping that it would better handle the compact crankset and the wide rear gear range. Spreading the front deraileur cage seems like the logical next step. Anyone Been there...Done that?
JimJim is offline   Reply With Quote
Old 05-08-05, 07:06 AM   #2
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Posts: 26,903
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 206 Post(s)
Doesn't sound to me like the right thing to do.

Where exactly does it rub? If your front derailleur is set up right you should have two shift positions for each chainring. That should take care of any rubbing on the sides of the deailleur cage. Check out the Park Tool website and follow their instructions beginning at the very beginning if you don't know how to get your derailleur adjusted that precisely.

My Energy crank with 109 octalink BB rubs on the big chainring when I'm in the little chainring and the two smallest cogs. I just use that feature as an audible indicator that it's time to change chainrings.
Retro Grouch is offline   Reply With Quote
Old 05-08-05, 07:20 AM   #3
sydney
Senior Member
 
sydney's Avatar
 
Join Date: Jan 2004
Bikes:
Posts: 9,428
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Retro Grouch
Doesn't sound to me like the right thing to do.

Where exactly does it rub? If your front derailleur is set up right you should have two shift positions for each chainring. That should take care of any rubbing on the sides of the deailleur cage.
There is a trim position in the shifter for each chainring.
sydney is offline   Reply With Quote
Old 05-08-05, 07:22 AM   #4
sydney
Senior Member
 
sydney's Avatar
 
Join Date: Jan 2004
Bikes:
Posts: 9,428
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by JimJim
Spreading the front deraileur cage seems like the logical next step. Anyone Been there...Done that?
That's not the answr, and I wouldn't.
sydney is offline   Reply With Quote
Old 05-08-05, 08:51 AM   #5
Moose
mousse de chocolat
 
Moose's Avatar
 
Join Date: Jul 2001
Location: Northeast Ohio, USA
Bikes: Masi Speciale Fixed, Fuji America Fixed, "Modernized" Gitane
Posts: 1,141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have done it and it worked fine, just don't go hog wild. Front dr's are cheap anyway so it's worth a try before you buy a new one that'd work without modification.
__________________
I feel more like I do now than when I first got here.
Moose is offline   Reply With Quote
Old 05-08-05, 04:35 PM   #6
Al1943
Senior Member
 
Join Date: Feb 2005
Location: Oklahoma
Bikes: Trek 5500, Colnago C-50
Posts: 9,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Are you sure that the chain rub is on the derailleur and not the inside of the big ring? With the chain on the 34 and the smaller cogs it's fairly common for the chain to rub the inside of the big ring due to the big difference in the 34 and 50.

Al
Al1943 is offline   Reply With Quote
Old 05-11-05, 09:42 PM   #7
JimJim
Member
Thread Starter
 
Join Date: Mar 2005
Bikes:
Posts: 25
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Progress report:

I took the screw out of the back of my Shimano Ultegra triple front deraileur and evenly spread just the rear portion of the inner and outer cage about 1/4 of an inch total. I inserted a 1/4 inch nylon spacer and a longer screw. In my first trial ride today, the chain rubbing is almost gone over the full 50/34 front to 11/32 rear. I'll test it over 100 miles this weekend to see if the chain jumps or jams.
JimJim is offline   Reply With Quote
Old 05-12-05, 08:02 AM   #8
slagjumper
Senior Member
 
slagjumper's Avatar
 
Join Date: Apr 2005
Location: Down on East End Avenue.
Bikes: Salsa Las Cruces, Burley R&R and a boat load of others.
Posts: 1,816
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I would avoid bending. It allways seems to take longer than it should to set up my fr d. Sheldon Brown's web site has some great tips on setting them up. His site is a huge resource for bike mechanics.

http://sheldonbrown.com/derailer-adjustment.html#front

If the derailer is designed to work with your cw range and has the correct curve and stuff. I would try to
1) put the adjusting screws in the middle position.
2) get the outer cage to come as close to the big ring as you can (1mm-1.5mm) w/o hitting.
3) remove slack from cable in low ring.
4) Adjust trim
slagjumper is offline   Reply With Quote
Old 05-12-05, 08:18 AM   #9
sydney
Senior Member
 
sydney's Avatar
 
Join Date: Jan 2004
Bikes:
Posts: 9,428
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by slagjumper
I would avoid bending. It allways seems to take longer than it should to set up my fr d. Sheldon Brown's web site has some great tips on setting them up. His site is a huge resource for bike mechanics.

http://sheldonbrown.com/derailer-adjustment.html#front

If the derailer is designed to work with your cw range and has the correct curve and stuff. I would try to
1) put the adjusting screws in the middle position.
2) get the outer cage to come as close to the big ring as you can (1mm-1.5mm) w/o hitting.
3) remove slack from cable in low ring.
4) Adjust trim
1) WHAT??... 4) Trim is in the shifters and doesn't 'adjust'. Aome don't even have trim and if the front is friction, it's essentially infinitely variable. He didn't mention what the shifters are,but many that have shifters with trim to cure the problem,don't have a clue.... WWW.parktool.com repair section has good instructions too.
sydney is offline   Reply With Quote
Old 05-13-05, 10:04 PM   #10
JimJim
Member
Thread Starter
 
Join Date: Mar 2005
Bikes:
Posts: 25
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
100 mile update:

I ended up making two modifications that allow me to shift all gears between 50/34 front and 32/11 rear. I have experience adjusting FD with 53/39 with 11/23, but the wide range compact gearing did require bending the rear of the FD cage for a slightly wider exit for silent running.

1) This was a new bike build with a nice and shiny braze-on deraileur. The new "D" metal block and lock washer that came with the front deraileur, even when tightened down, slipped after many shifts. The FD cage would end up skewed after many shifts and bumps. I did not want to bend the hanger to match the saddle point, so I roughed up the "D" block with sandpaper which stopped the slipping.


2) I kept the widened rear cage but removed the spacer and longer screw and just bent the screw bracket on the front cage. This kept a low, flat bottom rear cage.
JimJim is offline   Reply With Quote
Old 05-14-05, 06:26 AM   #11
sydney
Senior Member
 
sydney's Avatar
 
Join Date: Jan 2004
Bikes:
Posts: 9,428
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by JimJim
100 mile update:

I ended up making two modifications that allow me to shift all gears between 50/34 front and 32/11 rear.
I duno what the point is to that anyway,but whatever....
sydney is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 03:36 PM.