So sweamrs has decided she wants in on the power meter training this winter. We’re going with 4iiii so that’s decided. Her crankset is 105 5700; I could send off her crank etc, etc. or I could buy one pre-installed on a 105 5800. The price seems to be the same. So assuming I get the same colour is there any reason that won’t work?

5700 is 10-speed and 5800 is 11-speed. That said, as we know, chain rings aren’t really usually an issue for 10-11 speed conversions so it’d probably work

Thanks – I’m only going to be replacing the Left Hand crank so the fact that one is 10 speed and one is 11 speed shouldn’t matter providing the attachment etc is the same.

I use a 5700 Stages power meter with both 5800 and 6800 cranks with no issues. You should be fine.

No difference. I ran a Stages Ultegra 6800 with a shiny Ultegra 6600 from two generations earlier. It’s also been weeded to Dura Ace 9000 and Ultegra 6700 as well.

Thanks all. I suspected as much but nice to make sure.

+1 for all the above. I think the G1 105 Stages I had was 5700 which I been using with 5800, 6700, 6800 and whatever the previous version of Ultegra was prior to 6700.