front derailleur compatability

[Tiddy1]

Is there any reason why an ultegra 6800 11 spd front mech will not work with a 6700 10 spd shifter?. Merlin web site says that the 6800 mech is only compatable with a 6800 lever or 9000 durace,

has any one run this combo?

[yellowjack]

I don't know it for a fact, but talking to a bike shop dude the other day, he reckons Shimano have made the lever action 'softer' on the new 6800, in that it pulls the same amount of cable for less movement at the lever. If true, it might mean that the pull ratio is incorrect for the derailleur? But then I'm left thinking that if the derailleur moves the same distance, it won't matter which shifter is on the bars, it'll just feel different at the lever end, with the exact same result at the chainset?

I don't know, is the honest answer...

[upsidedownmark]

I'm fairly sure not - they've messed with the cable pull ratio. Not sure why you'd want to anyway?

[Tiddy1]

The answer is no, as you say the pull ratios are wrong

as to why, just picked up a new frame and the front mech is bolt on, my old one is not, I have 6700 levers but a 6800 front mech is as cheap/cheaper than a 6700 so if i decided to go up to 11 speed I would ok

[upsidedownmark]

If cost is an issue, get a 5700 front mech (6700 should still be cheaper than 6800 if you look around).

It's not 'A' compatibility, but if you were to go 11 speed, you don't actually *need* to change the front end at all. You would of course need an 11sp rear shifter and mech which matched the pull ratio.