105 11 speed chainset with 10 speed chain/cassette?

gingermagician

The big chain ring on my FSA Gossamer chainset is reaching the end of it's life and, given the prices I'm finding online for a replacement, I'm considering replacing the whole unit with the new 105 5800 version (rest of my groupset is currently 5700, the winter bike's a Cannondale).

Before I get into the whole issue of adaptors for the BB30, does anyone on here have experience of running an 11 speed Shimano chainset with a 10 speed chain/cassette drivetrain? I'll likely end up upgrading the existing 5700 to 11 speed as parts continue to wear out, so it seems pointless to go with 10 speed right now if 11 speed works ok.

The official view seems to be that it's not cross-compatible, but others seem to have taken the plunge with no issues...

k-dog

That will work fine.

The official table of cross compatibility says it's not because for that to be true it has to work both ways. The internal dimensions of a 10 or 11 speed chain are the same so the chainrings will work fine with a 10 speed chain.