Can wheel textures be seperate from car-body texture?

[system]

Hi, noobish question here; but I've textured a carbody on a 1024x1024 texture map, do the wheels have to be on a seperate map or do they have to be on the same map as the rest of the car? (we're making a browser-run game for uni- so i'm guessing performance is an issue?)

-we have 3 cars in the game, each around 5,000 polys...

-if i can get away with using a seperate map, what size can i get away with?

many thanks in advance :)

[Ashkan_gc]

generally you need to have multiple textures when you want to use different materials/shaders for different parts of the model and having less number of textures is faster. 1024 is okay in nearly all cards but you can reduce the size for the webplayer to keep the game's size smal if needed.