da big hills
iMTB Rockstah
The fork diameter is the most important aspect. Wheel diameter and tire OD is not as important. Tire width is important too. the fork diameter keeps the bike on line. Small diameter forks allow the front to shimmy creating an oversteer condition. A large diameter keeps the front where you place it. Of all the components; the fork is what keeps you on line when cornering. There is a weight difference but if you do not like oversteer (I hate oversteer) and want to carry speed on the downhill single track there is no other option. The only time tire diameter plays is in tight switchbacks, and that can be overcome with understanding the SB and how to drive it, (up or down).