Tyre problems
 

I am flying my Skymaster F15 & it is a great jet.
Unfortunately, I have a problem with my tyres coming of the wheels when I brake. They are the soft Robart 3.5 inch tyres. These tyres were to soft & foam inserts did not help very much, so I filled them with silicone.
Is there a trick to successfully using these tyres on a 23lb model? Or are hard tyres available to fit the Eurokit wheels.
Also I am using standard Futaba servo horns on the elevons. Will they be strong enough?
I have a Simjet 2250 turbine installed.

Regards
Jim