Sunday, November 18, 2012

Pulleys That Work With a Nuovo Record Derailleur?

No pictures right now but I wanted to throw this out as I am dealing with this issue again.First I found a thread that talks about this issue

I have two pairs of the Soma pulleys on two different bikes and am finding they seem to have a weak point. I have one set on a bike with a NR derailleur and another with a GS derailleur; the GS I ride most the time. Recently I noticed the shifting of the GS had gotten sloppy and there was a lot of friction in the drivetrain. I removed the pulleys and found both had bushings so worn that the steel sleeve was rattling around; I probably had 4000 miles on them. I checked the bike with the NR derailleur and found the jockey pulley was worn but the tension pulley was not. I'm not sure what the problem is and it may be my fault for not servicing them enough (I've never had this problem with Campy pulleys). I do have one theory however. When I first installed the Soma pulleys on the GS derailleur I was surprised to see some green corrosion inside the bushing and outside the sleeve. I'm thinking the manufacturer may has used a grade of brass with too much copper or too soft (or something like that).
I do have a fix however that is still in the experimental stage . I have a number of worn Campy pulleys where I pounded out the bushing (these bushing seem to never wear out of spec) and did the same for the worn Soma pulleys. The GS/NR/SR bushings are 12mm outside diameter, where the Soma pulleys are 10.1mm (the difference is the thickness of the brass; I first tried to drill out a Soma pulley which crack it). So I ground down the OD of tht Campy bushing to fit the Soma body using a simple tool; I slid the bushing onto a 1/4"x 6" drive extension some black tape underneath  so it would say put. I then attached the extension to a drill motor and clamped the drill motor in a vice.   I then took a file and ground the Campy bushing to about 10.1+; slightly narrowing on one side so it could be easily inserted into Soma bodies; the bushings were then pounded  into the Soma bodies with no problem. In regards to which sleeve to use, the Campy sleeve OD is 9.3 mm while the Soma are 9mm. The Campy sleeve is also about .2-.3 longer, so you either need to grind down the Campy bushing or use the Campy sleeve (I used the Campy sleeve). I have installed the Campy bushings in two Soma pulleys and road tested them for about 6 month and they show no sign of wear.

 As of April 28, the combination pulleys have worked flawlessly with no sign of excessive bushing wear.