Shimano Compact Chainrings

[Rpoole8537]

I purchased a Shimano FCC 6750 compact crank from Craigslist. I took my bike to local shop yesterday to have it installed, and the tech told me the big ring needed replacement. The crankset was sold to me as almost new, but i could see that some teeth had a saw blade look. After looking at some photos online, this appears to be the way they are designed. BTW, the crank arms look new, no scuffs at all. Can I get some opinions!

[rnhood]

Chain rings, especially Shimano, rarely wear out unless they are abused. You might want to take it to another shop for a second opinion, and perhaps to have it installed.

[ultraman6970]

+1

Shops from what I been reading for years always tells you that you need a news cassette, a new chain and new chainrings. New shimano chainrings last less than the old ones but if its almost new would be good to take the bike somewhere else or with somebody that knows what is he looking at.

[Pete Mckeon]

Without seeing it I can not offer a definitive but I have never seen just the big one wear out.

DO not know where you are located so can not see it BUT I would just keep on riding it unless you start to notice a hop or something while in big chain ring.


I have never wore one out:bike:. AS RN said, go to another dealer mech or look at another one that a friend has

pete

[thunderworks]

If the arms looking minimally used, it's hard to imagine the chainring needs replacing. They are usually good for thousands of miles. A bike ridden that much would most likely also show scuffs and marks on the arms tool.

[oldpotatoe]

I purchased a Shimano FCC 6750 compact crank from Craigslist. I took my bike to local shop yesterday to have it installed, and the tech told me the big ring needed replacement. The crankset was sold to me as almost new, but i could see that some teeth had a saw blade look. After looking at some photos online, this appears to be the way they are designed. BTW, the crank arms look new, no scuffs at all. Can I get some opinions!

Have the guy install and go ride. If there is a bunch of noise when on the big ring, then maybe replace but chainrings/cogsets when new look worn, due to all the CR prep, shaping pins, ramps and stuff.

[oldpotatoe]

+1

Shops from what I been reading for years always tells you that you need a news cassette, a new chain and new chainrings. New shimano chainrings last less than the new one but if its almost new would be good to take the bike somewhere else or with somebody that knows what is he looking at.

BIG brush there...in my former shop, we checked the function of the CR and cogset, by test riding it. We never just looked at it and made any decision.

Used a Rohloff chain checker as well.