Save [MENTION=152773]noglider[/MENTION] some labor, my 1996 rigid 850, with 1 1/8 threaded steering tube measures 39.5 cm from axle to crown. Without actually measuring, the unicrown clearance over a standard 2.1 inch MTB tire across my various rigid MTBs, which includes Trek 850, HardRock, Stumpjumper, Miyata, and Rockhoppers all look to be about the same for mid 1990 bikes.