Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take part in the July Giveaway for a brand new 26" Thruster® Street Style BMX Cruiser Bicycle


Re-gearing Problem
#1
For faster speeds, I changed the front and rear gearing on my road bike (new 7-sp freewheel and new triple crankset). After adjusting the front and rear derailleurs the bike shifts great in all gears with only one gearing exception....
with the chain riding on the middle chain ring and the rear at the outer most or smaller cog, the chain tries to shift up to the higher chainring, but can't complete the shift due to the front derailleur guide. This creates a jerking motion of the pedals. Since the chain is positioned in this gearing, at an angle to the front middle chainring, its what's causing the problem.
Since it's only in one gearing position, I can shift around this problem without to much trouble, but it would be nice to eliminate this.
I checked the front chain line dimension and it is correctly positioned at 45mm per the crankset installation manual.
Where should the rear freewheel cogs be located? I could adjust the rear freewheel position by removing one 2mm spacer that I installed to make the cogs line up with the old freewheel. Would a different chain help?
The bike is new, so the chain is new also. Thanks for the help.

  Reply
#2
I wouldn't worry too much about where any of these parts are "supposed" to be. Since you've changed everything, it's just a matter of getting them where they work. If you can remove a spacer on the freewheel to move it to the left, that should eliminate the chain rubbing on the largest chainring. Make sure to re-adjust the limit screws and cable tension on your rear derailleur. If you made extreme changes to the gearing ratios, you may have trouble getting the gears to run smoothly in all combinations. But taking out that spacer sounds like a good experiment.

  Reply
#3
I finally figured out what the problem was. Turns out when I swapped the crankset, I also had to change the bottom bracket. I used a 68x111 as per the Campy chain ring installation guide.
I just switched to a 68x115 bottom bracket and the problem went away. I had been riding around this shifting problem. So, by just moving the chain rings out further, I now have the full use of the gearing.

  Reply


Possibly Related Threads...
Thread
Author
Replies
Views
Last Post
 
6,210
11-07-2011, 07:55 PM
Last Post: Sparkie
 
6,646
04-12-2011, 07:25 PM
Last Post: Dvntie
 
10,460
10-27-2008, 07:42 PM
Last Post: DaveM
 
Guest
5,841
08-18-2008, 04:59 PM
Last Post: Alex Ramon

Forum Jump:

[-]
10 Latest Posts
Pinging noise fixed
Today 07:22 AM
60s Viner Repainted..?
Today 02:29 AM
Where are you from and What is your favo...
Today 01:22 AM
Need help finding a new rear derailleur
Yesterday 05:05 PM
FD cable pull on opposite side of frame
Yesterday 04:13 PM
26" Thruster® Street Style BMX | July 20...
Yesterday 03:34 PM
2020 road cycling season
07-04-2020 07:18 PM
COLSON TANDEM BIKE REAR STEERING
07-04-2020 08:44 AM
Work Table For Wheels
07-04-2020 08:29 AM
1980 Schwinn Suburban
07-03-2020 11:06 PM

[-]
Top 5 Posters This Month
no avatar 1. Jesper
62 posts
no avatar 2. CharleyFarley
17 posts
no avatar 3. Painkiller
15 posts
no avatar 4. Papa Dom
10 posts
no avatar 5. Joe_W
8 posts