radial or bias?

[Gillbilly]

Looking to buy new rears,running brand new stock tires which are radials on front.I have heard not to mix radials & bias is this true,if so is a tire a radial if it dosnt say bias?When I look in Rocky Mtn catalog some say bias ply but didnt see radials.Also I want to buy used stock 400ex wheels,I found some that are pretty rough what is a fair price?

[ReconRider25]

bias is just 2 ply. i dont think it would matter seeing that the stock radials are only 2 ply also.