what would be the difference in 2 identical frames made out of steel and aluminium, i know the physical/mechanical properties of the 2 but what would the difference in ride be?

steel would feel softer, aluminum has more of a whippy feel.

does that help?

Depends how you’re defining “identical”
Same:-

strength
stiffness
weight
tube diameter

when you say 2 identical frames – i assume you mean identical in geometry?

given the geometries same. it would come down to tubing profiles and diameters.

i wouldn’t like to say if there is a difference.

there’s certainly an assumed difference. i’m more dubious.

Ali… harsher ride, with bumps less easily absorbed by frame, but more direct and much siffer ride. Also lighter for the same strength/stronger for same weight.

Steel, more compliant ride, with less trail shock transfered to the rider, feels softer and hence more flexy. Can be a nice lively feel from a good steel frame, or can be just flexy and twisty from a bad one.

steel you can repair, and ali just goes bang very quickly.

Depends on how the frames are built, a good well built steel frame will have a bit of a zing to it, a badly built frame with rubbish tubing can feel a bit solid and dead.
Aluminium can be really stiff and harsh but with teardrop rear stays and the like can soften it up a bit.

i personally prefer the kind of spring feel of a good steel frame.

i find my ally bikes are a bit dull to ride, i don’t really notice the difference in ride, just the ride is alot harsher

they will both feel harsh on the metalised roads around rivvy and not massively noticeable IMHO alloy does not rust when your paint is chipped so that is a plus for me. quick view here
http://www1.epinions.com/content_3704660100

I was getting at same geometry more than anything else.