Sora fd on 105 group.. Advice

redscouse

After a few offs in ice last winter.. Put together a second hand 5700 105 groupset and am rebuilding my spesh allez fie winter and learning all the time..the 105 came with band on fd but spesh is braze on fd..so have left shamans sora fd on spesh.. Having problems getting it to shift to big ring and then when it does crank hits the derailleur cage on rotation.. Cage seems wider than than the 5800 105 on my other bike..not sure if it is me not finding h limit sweet spot or need to purchase a 5700 105 fd

ugo.santalucia

I think it's more of a sweet spot issue

The Rookie

Unless the Sora is for a lower number of speeds, it will be the same width as the 105 FD cage.

redscouse

Yes sora fd was for 8 speed 5700 fd of 10 speed. Difference in cage size/ shape ?

The Rookie

Yes, the 8 speed chain is wider so the distance between the cage plates is wider, making it work with the narrower 10 speed chain will be much harder and may not be possible. Get it right shifting to the bigger ring and it has to move further the other way before it contacts the chain to shift down.

My sons 9 speed had an 8 speed front mech, we could make it work, but literally 1 click either way and the shifting performance degraded a lot, we ended up putting the right one on.

redscouse

Thanks for that rookie.. Off to get a 5700 fd..Cheers

redscouse

Got a 5700 fd from Evans ex display stock for a tenner..works like a charm..ta rookie

The Rookie

Glad it worked out.