Originally Posted by
Leisesturm
The seat, absolutely should be adjusted, forward or backward to achieve comfort for the rider. I don't know how you measured your x-seam, but depending on whether your back was straight, or reclined, whether your knees were locked, or even what shoes you were wearing when you measured ... it all can add up to different x-seam results. Still, your comfort on the trike trumps whatever number of inches resulted from your x-seam measurement. It sounds like you should bring your seat forward if the boom on your trike does not have adjustability to bring the bottom bracket back to you.
The boom is at the shortest possible distance. The seat cannot move forward or back; it can go higher or lower and recline can be adjusted. I have different shoes I can wear, one pair has a sole that is 2 inches (Dc Marten sneakers) and the other pair is normal sneakers. By choosing the right shoe I often can get a good fit, lol. Both shoes are extremely comfortable for me. I'm going to try reclining the seat just a little bit more, which I think will lift the front rim of the seat just slightly and maybe make me sit more "in" the seat so I don't slide. If that works to settle me, then I'll try adjusting length with my shoe choices and see if that works. If not, I might eventually have to cut a bit off the boom, but I'd rather not do that (resale value).