 You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Will a 9spd front mech work on an 8 speed set up?
I recall once being told it won't, but the cage looks pretty much the same width.
Any advice?
Short answer: yes.
Long answer: yes, but it might rub a bit.
World-weary answer: yes, about as well as any two pieces of metal designed to hit a chain sideways.
So the cage IS narrower?
Just got a front and rear Tiagra mech in a deal at a good price and was going to sell the front as I didn't think it would work - should I now use it? I'm running a triple up front on 8 speed. Is there roadie front mechs that don't do triple?
Front derailers + triple/double = ****ing minefield.
Just try what you've got, it'll probably work. See the 'Long answer' above.
Good luck!