Hey D.
I very much like the idea and implementation on this piece. I noted at Renderosity you added backwheels. 
Thoughts.
I like the texture of the padding. Uncomfortable looking.
There is a distinct poly corner to the curves of the mesh itself. I’m asuming you haven’t done any subdiv on this yet.
Like the hardware.
Nice textures. (a bit stretched in places, but again I think a little subdiv would assist in that area.
An added bump map to the wheels would be nice.
I think the shadow is off for the light direction. (Or I need new glasses)
Nice old metal textures.
Excellent build though. I’m impressed.