I've got a 18" mmmbop frame, running 120-150 u turn revelations with a tapered steerer.
I love my bike but I feel like it gives me a bit of a battering on longer days (25 miles +) and I end up feeling generally rattled with a sore backside and small of my back. I've changed my saddle from a specialized one to a charge spoon, and it's very comfy, so I don't think it's that that's causing the general ache. I think the frame is sized correctly as my knees are slightly bent at the bottom of the pedal stroke, and my arms are slightly bent when I'm sat in the saddle.
I'm thinking of doing a frame transplant with my existing kit, and getting a full sus bike as a replacement.
What frame would you recommend where I wouldn't have to change my fork, or can you suggest (other than mtfu) a way of making my bike a little more comfy on longer rides. Riding is mostly in the Peak, and I'm not technically very competent.

