I have a '97 Rocky Mtn Cardiac. Nice light cromoly frame (2.1 kg), and I would like to upgrade the front forks. This bike came with either a cromoly fork or a Rock Shox with 48 mm of travel). Any advice on the effect of fork length on frame geometry would be appreciated. I presume it is best to keep the fork travel to a minimum, but most forks I look at seem to have somewhere between 80 and 100mm of travel. Any thoughts of the effect of 80 mm of travel? Thanks.