Continental Revo Sealant works. I'm on my second set of GP 5000 TL tires with Revo Sealant and I am very pleased. After 10 months and 8,000 miles, I've had one flat. That one was caused by a pebble lodging in a small slice in the tread that would not permit the slice to be filled with sealant. I removed the pebble and the tire sealed. Revo is easy to use straight from the bottle as the bottle has a nozzle that fits inside the valve stem once the valve core is removed. I top up ever three or four months, but the sealant lasts well. You'll also have to reassess the sealant situation if you have a flat or loss of air and choose to use CO2 to inflate on the road. Revo Sealant solidifies when exposed to C02.