Putting down serious mileage on your trainer isn't just hell on your brain, it's equally destructive to your rear tire. The severe heat generated by the drums of stationary trainers or rollers devours the rubber and causes the tread to break down and the casing to split. Continental wants you to save your race tires for outdoor riding. For indoor workouts they've developed the Ultra Sport Hometrainer Tire. It has a cold running compound and a substantially stiffer casing than what you get in a GP 4000. It'll last all winter long, but make sure to take it off before you ride outside. Continental specifically states that it's strictly for indoor use. Available in 700x23 only.

The actual weight of the Continental Ultra Sport Hometrainer Tire is 292g.

• Three-ply construction keeps wear to a minimum
  
• 84 TPI offers a real-road feel, even though you’re on a trainer
  
• Specifically designed for hometrainer use and NOT suitable for on-road use