Now I'd be the first to admit that I'm not a skill rider, or indeed a knowledgeable one; the finer points of a degree here or there in geometry terms doesn't mean much to me. But I do ride enough to know what feels 'right' for me.
A few months back I changed my 853 Inbred frame for a 853 Sirius, I'm also riding a rigid fork instead of my sus. forks (the rigid fork is fractionally taller a-c than the sus. fork with a bit of sag). Most of the other kit was transfered across. The thing is, something just doesn't feel 'right'.
The Inbred frame was a couple of cms longer in the top tube than the Sirius, I brought across the original 80mm stem and rolled my riser bars forward reclaiming at least a cm, so the reach is similar and actually feels better on the Sirius.
When I try and work out what doesn't quite feel right it turns out that what's actually bugging me is that during riding I'm finding my feet too far forward on the pedals (the axles are behind the balls of my feet rather than under them). The thing is that the seattube angles of the two frames are very similar (73 on the Inbred, 72.5 for the Sirius) and using the same inline seatpost I should be positioned pretty much the same relative to the cranks. In fact on the Sirius I've got the saddle back to it's maximum and the 'knee of pedal axle with the cranks horizontal' approach places the front of my kneecap behind the pedal axle so I'm actually further back on the Sirius than I was on the Inbred; I'm pretty sure that my legs/feet haven't lengthened in the meantime. I could try a layback seatpost but my weight distribution feels right and I don't want shifted back any more. I do occassionally get a niggle of lower back pain which usually indicates to me that I'm a little cramped.
So, what do I try? I could get a longer stem, or a layback seat post or even longer cranks but that could be costly if that doesn't solve anything; I could also spend an age fiddling rather than riding. Is it just the case that a new frame and forks essentially makes a new bike and I need to just ride it and get used to it, or is there something else I could try? I do have a habit when something's not quite right, or I think somethings not quite right, (an errant squeak etc.) of focusing on what's wrong rather than what's right; it could be psycholgical.
When I set my bikes up I use a tape measure to triangulate the nose of the saddle to the front of the stem to the BB centre. This gets everything in the ballpark and I use the same bars on all three. They still all feel different and I suppose they should being 2 full sussers and a hardtail. My advice would be to forget what your old bike felt like and focus on whats good on the new one, making small adjustments as necessary till it feels right.
SPDs to keep your feet in the right place?