Outer chainring - OK to use double on triple?
I'm replacing some worn-out drivetrain components on my Jamis Aurora, specifically the chainrings (52/42/30), chain and cassette (11-32). So I go to the LBS to get 52t and 42t chainrings (I rarely use the 30t so I'm leaving it alone). They have the chainrings but the outer is a Shimano Ultegra 52t/130mm and the packaging says it is for a double. The LBS guys say it should work fine but I thought I'd double-check with the collective.
So, does anybody know if outer chainrings for doubles are different from outer chainrings for triples? Are the ramps and pins different? Will I have any problems with installation or shifting if I use the double?
I bought the 52t so I'll try it this weekend unless anybody says this won't work. Any comments or experiences are appreciated.
Shimano makes two different 52T rings, one intended to mate with a 42T middle ring (triple) and the other with a 39T inner ring (double). Theoretically they are specific. However, everything I've read and seen says the difference is so minor as to be insignificant.
A type vs. B type. It will work fine, though Shimano claims they need to be different for proper shifting.
Yup. I swapped an an A and a B, and the shift is a little crunchier, but it works.
Originally Posted by capwater
At the same time, though - if you're paying full retail, you should get what you pay for. I got a new mismatched ring for $15 that Harris ends up with a ton of them from doing singlespeed conversions, but with a good deal I didn't mind. I'm also running Tiagra, so the FD shift was never silky smooth in the first place. If I was paying full price for a higher end group (like Ultegra), though, I'd expect it to work as designed.
Mr. Underbridge, I understand the sentiment about expectations for higher-end components but this chainring was a pretty good deal (I'm a regular at this LBS) so I don't mind experimenting a bit. I'm running a Tiagra FD right now so I don't expect things to be buttery smooth, just as long there's an improvement over the current shifting with a worn chainring.
Thanks for the comments and info everybody, much appreciated!