I'm confident that Gen 5 forks will fit straight up to Gen 4 triple tree, however you would also need either the m50 brakes off the Gen 5 or some other brakes as Gen 5 is 100mm spacing not 108mm like Gen 4, also you would either need a Gen 5 front wheel or the spacer kit one of the forum members was selling as the front wheel is different on the Gen 5. Hope that helps