Steve the outback gear has 5.00-5  main wheels. These are "proper" aviation
standard.Thus your main gear tyre and nose tyre will be different sizes.

I had my 320 converted as a retrofit-there is quite a bit of work involved including a flap
modification but the kit itself is very good value. Prior to having the outback gear I had
constant problems with flat tyres. The new gear and tyres have been on for 4 years and I
have never had a flat since.

Hope this helps

Gerard