just need to fill in this to finish my insurance proposal form, but how do i find out which one to put? what the different?

Radial or Cross???

It would be a pretty sound bet to say they were radial pal.

Hmm cross-ply on an IS, now that would be fun....

i agree,it`ll be written in your tyres matey.

Just wonder what the different?

crossply went out with noahs ark............

It's mostly about how the bonding and steel bits are incorporated into the tyre.

Radial ply has the banding around the cirumference, cross-ply goes across the surface of the tyre.

Cross-ply tyres are not very widely used any more.