you may have to lower the front end. if you have lowered the rear already, you will definetly need to lower the front. there are a few threads about a 21 rubbin the inner fender at highway speeds. With that in mind, you may need to raise the front fender a bit. 1/4 " If you can keep the trail similar to stock, you shouldnt see any difference in handling. This would be done by lowering, or raising front or rear to keep bike level.