i already know the weight diff. my current wheels weigh 20.9 lb.plus tires, and the rota slipstreams weigh 11.9 lb.and they are going to be mountedwith smaller tires, and the rotas come out to be around $105 a wheel which includes shipping, plus i like the way the slips look on red. the slips were designed after the spoon sports SW388's which weigh around 8-9 lbs. but are expensive and all of them are used, so the slips are a good deal. so in other words, the traclites are nowhere near the lightest 15"er's out there, there are several under 10lbs, i think there are a set of 16's that are even under 10 lbs.