The mk1 and mk3 had different geos, i am pretty sure of it. The Mk3s are also not current, i don't think they have made them since 01. They were really nice, in fact I still have one, but the geo is very outdated, even for it's intended purpose of dual slalom. The chainstay for instance is 17.5 inches (if i remember correctly) more than an inch longer than most similarly styled current frames and 2" longer than most trials bikes.