I built up an xtracycle with an older Trek 930 mtb frame. It originally had a Rock Shox Indy S fork (apparently 48mm of travel) on it. I don't have that so what I did is put a 700c cyclocross fork on there w/ a 700c wheel. I was hoping the crown-to-ground would be around the same with that combo as it would with an indy s shock and a 26" wheel. But it's not.
I don't know if the front end needs to come up or go down, but this is how it steers: It wants to turn, the front wheel, that is. It wants to turn and it wants to turn all the way. If I were to let go of the handlebars while riding the front wheel would completely turn in on itself and I'd crash.
So what would that be attributed to? Front end too steep? (meaning it needs to come up) Too slack (needs to come down)? Or could it be a trail thing?