Recently, I switched to Schwalbe Marathon Supremes, and also bought Schwalbe Tubes as part of the transaction.

Previous tubes, cheapies, Kenda, Forte, and Specialized, all seemed to lose 5% to 10% of their air every day, if inflated over 85#.

Since switching to the Schwalbe, I find they lose little, if any, air - during a weeks time.

And, they were only a couple dollars more than the cheapies.

Guess which company gets my tire and tube money from now on.....