Road Bike, Cycling Forums banner
1 - 5 of 5 Posts

·
Registered
Joined
·
8,116 Posts
Discussion Starter · #1 ·
Let me preface this: I unconverted one of my fixed gears for commuter duty. I wanted to go cheap-- so I only used spare parts. I took an old steel frame, added an old 600 downtube friction shifter- run a single 42t front, and an assortment of anything that fits in the rear.

I am using a 9 speed Ultegra rear deraileur-- that a friend gave me (nice friend!). I am using a cheap SRAM chain-- a PC58. I was using a 7-speed twist tooth rear freewheel until I broke too many teeth (the climate here is brutal for commuting). I switched to an old 6-speed rear- I think it is about 105 level. Anyway, this is definitely a frankenbike. The trouble is that I am experiencing derailer noise... or some sort of noise. It is not fixable by adjusting the shifting. My question is whether the chain could have anything to do with this. My thinking is that theoretically, this should all work-- and it is functional. It gets me to work and back-- in style with bullhorns and panniers. It is just getting to the point that I am becoming annoyed. The twist tooth cassette was really no better... for whatever that is worth. It was missing so many teeth near the end that it was only good as a single speed. And lest you think I am insane- yes, I am using a completely different wheel.

Would I benefit from switching to a 9-speed chain? Or am I insane for piecing together such parts. It doesn't seem to me that this chain should be incompatible with the modern Ultegra deraileur... but i could be wrong.
 

·
"Cypress Gardens" Fl.
Joined
·
686 Posts
I re-read your post several times, and to be honest with you I believe the derailleur wheels are too narrow for that PC-58 chain. The chain is made for 6,7,8-speed which would be a 3/32" chain. You need 8-speed Shimano jockey wheels because your chain is made for it. 9-speed chains are narrower than 8-speed chains.

btw ~ whats cheap about a PC58 chain?
 

·
Registered
Joined
·
777 Posts
All derailleur chains are the same inside width - 3/32". It's the outer width that gets narrower as the number of gears goes up. So that's unlikely to be the problem. FWIW, I'm using a PC58 with two different "9-speed" rear derailleurs... No problems.

Is the drivetrain noisy in all gears, or just in one? If it's just one, suspect the cog. Get two chain whips, pull the cogs off the freewheel, and flip the offending one over. If it's all gears, check the derailleur, chain, and chainring. If the chain was run for a significant time on a badly worn freewheel, it may have worn into the longer pitch of the worn freewheel teeth, and now won't sit down nicely on the new one. New freewheels should get new chains, and 8 speed chains are cheap. Make sure that the B-screw on your derailleur is properly set. Clean the pulleys (heck, clean the whole thing.) Check the goodness of your chainring's teeth.

If all else fails, throw the bike up in the stand and watch the drivetrain very carefully while you turn the cranks. Drivetrain noise sources are usually visible as well, the chain won't run right where the noise is coming from. A stiff link, for example, will cause the derailleur cage to move as it goes through.

--Shannon
 

·
Registered
Joined
·
8,116 Posts
Discussion Starter · #4 ·
In friction mode, how is the B screw relevent?

tube_ee said:
All derailleur chains are the same inside width - 3/32". It's the outer width that gets narrower as the number of gears goes up. So that's unlikely to be the problem. FWIW, I'm using a PC58 with two different "9-speed" rear derailleurs... No problems.

Is the drivetrain noisy in all gears, or just in one? If it's just one, suspect the cog. Get two chain whips, pull the cogs off the freewheel, and flip the offending one over. If it's all gears, check the derailleur, chain, and chainring. If the chain was run for a significant time on a badly worn freewheel, it may have worn into the longer pitch of the worn freewheel teeth, and now won't sit down nicely on the new one. New freewheels should get new chains, and 8 speed chains are cheap. Make sure that the B-screw on your derailleur is properly set. Clean the pulleys (heck, clean the whole thing.) Check the goodness of your chainring's teeth.

If all else fails, throw the bike up in the stand and watch the drivetrain very carefully while you turn the cranks. Drivetrain noise sources are usually visible as well, the chain won't run right where the noise is coming from. A stiff link, for example, will cause the derailleur cage to move as it goes through.

--Shannon
 

·
Registered
Joined
·
21,832 Posts
B screwed?

filtersweep said:
In friction mode, how is the B screw relevent?
The B screw effectively adjusts the distance of the upper pulley from the cogs. This is relevent whether you are shifting in friction mode or with an indexed system. Believe it or not, you can have a smooth shifting or poor shifting friction system, just like with an indexed system, depending on how well you adjust things.
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top