I want to replace the chainrings of a group set Shimano Ultegra FC-6703. Unfortunately, I can't find the external chainring anymore. Can I use an external chainring FC-6700 (two-speeds) to replace an external chainring FC-6703 three speeds? According to bikeimport.ch the bolt distances are the same.
1 Answer
The FC-6703-specific 52-tooth outer chainring is Shimano model number WP-Y1LK98030.
The FC-6700-specific 52-tooth outer chainring is Shimano model number WP-Y1LJ98150.
Yes, the FC-6700 outer chainring will bolt up and would likely work. However, the difference in the model number indicates a difference in the part, likely the positioning of the shifting ramps (I have seen a similar difference in a Shimano big ring before where logic would seem that it should not be, but Shimano does what it does for a reason). If indeed the ramping is different, the shifting could be affected negatively, but I stress the "could."
As for availability, I have found two locations with the 52-tooth FC-6703 ring. It is not inexpensive as it is over $100 USD in both locations.
FC-6703 52-tooth ring via Amazon
FC-6703 52-tooth ring via Universal Cycles
The chainring you seek on the UC link is at the bottom of the page.
Both links are based in the US, not Europe.
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1I too have high praises for Universal Cycles. Beware the Stack Exchange rules discourage what appear to be product or business endorsements.– JeffCommented Nov 25, 2022 at 22:50
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1@Jeff - good point. I will remove the endorsement for Universal Cycles from the answer. It’s a challenge to not endorse a resource that has been dependable to me in order to help others, but understand the boundaries, and applying them consistently.– Ted HohlCommented Nov 26, 2022 at 18:55
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1Aside - Shimano has some particular rules about resellers selling their stuff to another market. I used to be able to buy from Wiggle (UK) to NZ and even including shipping it was 1/3 cheaper. Now I can only buy locally.– Criggie ♦Commented Nov 26, 2022 at 20:04