XRAY - Model racing cars

8.5 is overkill imo, but beyond that. Try scraping the surface where the bead contacts the rim, and cleaning the rim and tire where they contact one another thoroughly so there is a good connection.

I never used the Pro-line but used the Losi version with some success. Dont know if this will be any help, but Trinity offers stiffer foam inserts for 1/18th tires that you can find around. These mostly help with reducing tire rollover, but it also could help keep the tire from warping so much at those higher RPMS.

You might purposely throw CA on your side walls to help stiffen them up. THough this will change the driving characteristics dramatically in the corner.

Oh, and use the CA meant for tire gluing. There does seem to be a difference in how well it sticks versus just a generic general CA.

Otherwise, you can use the M18T Foams. Just use one of hardest compounds, and soften your suspension slightly to make up for the lack of dampening in the tire.

I honestly don't know how long they would last on tarmac. There are some pretty stiff purple and orange compounds.

M18MT Foams are an option, but thats going to effect the way the car handles as it adds unsprung weight, and the gyro rotation is more pronounced.

I use strapping tape on the inside of the tire to help keep the tires
from balloning.