Lets say you have a Trek Elite 9.9 that weighs 18.75lbs with Bontrager XXXlite wheels and Maxxis Aspens. But if you mount up a pair of Maxxis Maxxlite 285's on Stans Podium MMX wheels you can drop a huge 1.5 lbs from your bike. All in rotating weight. That is pretty noticeable in the pick up your bike test, and even more noticable on the trail. They make your bike take off like a rocketship. 17.25 lbs is getting close to roadbike weight. The only problem is that those tires are only made to last a couple of races and are paper thin. Is the risk worth it???