Shimano 105 FD to Sram Force FD

Hey guys,
i’m wanting to change my 105 FD to a Sram force one to complete the set, but i’m not sure which option will fit the seat tube, my seat tube is approx 11.5cm/4.5 inches. The two options are a 31.8mm one or a 34.9mm one…

i’m so confused! Please help!

Thanks alot guys!

take it to a bike shop.

what frame is it? braze on or clamp on FD?

what is 11.5cm/4.5inches?

thanks i was planning to AFTER i know what FD i needed…

its a CAAD9 and its a clamp on FD

oh and 11.5cm is what i got from measuring the circumference

34.9mm diameter clamp on I’m guessing, assuming 11.5cm is your very inaccurate measurement of the circumference.

Also, I googled “CAAD9 front derailleur clamp size” and it said 34.9.

Thread over.

(Why bother changing, shimano mechs shift better!)

oh they do? i dont know because my crank is a sram red 53/39T and when i change it to the 53T is slips.

but yeah, THANKS for your help Blakey :slight_smile:


It’s prolly not set up well if it’s slipping… Take to the bike shop and get it dialed in right

The Force FD plates are made of steel rather than Ti so it will be an improvement on Red. But still not Shitmano quality.

why? they could have figured it out for you. I suggested seeking professional advice since it was quite obvious you weren’t sure of what you were doing. problem?

^ i think the one with the problem is actually you. Take it easy mate.