Geared Bike so Much Harder Than Fixed?

Stormy it feels about the same, fixed cranks are 165mm road ones are 175mm so the saddle on the road bike is 10mm lower, not sure if this is correct though, the seat tube angle is more relaxed so maybe I should tinker with moving the saddle forward a bit
saddle position can be quite critical. hippy says on the fixed you need to be slightly lower, which I didn't know about. I think saddle height is usually measured from centre of bb to top of saddle, but as you say, different crank lengths must make a difference because your leg will be straighter.

On the bike that you're most comfortable with, measure the distance from the tip of saddle to the centre of the handlebar. Then use this distance to adjust the saddle fore aft on the road bike. If you do have the wrong distance you'd probably have back discomfort as well as a lack of pedalling efficiency. A 1cm difference can have a big effect.