[RCP57]

I'm not sure if you guys have figured out a solution to your tire issue but after trying many different things(including stiffer foam) the best thing I've come up with is to use foam weather stipping. I was having trouble with my front tires so I bought some 1 1/4"x 3/16" weather stripping, put some plastic rap over my rims(so it I could slip it off) and rapped it around until it was the right diameter for the inside of the tire. Then I slid it off the rim and carefully shoved it into the tires. It's amazing how strechy those tires really are as the weather strip it quite stiff. Works really well for me, it still has some give but will hold its shape under load even when turning.

Reg