I always hear that is not a good idea to mix radial and bias ply tires.
Here is proof to the contrary. Direct from Metzler MC Tire .
No corporation would maintain in print the potential for "class action" if it were not tested safe. This information has been in print for several years. It's just hard to find on their site because it's under custom fitments.
Note: Never mount a bias in the rear with a radial up front. No-no-no-no!
http://www.us.metzelermoto.com/en_US/browser/attachments/pdf/2008_METZELER_VTWIN_UPGRADE.pdfAlso, I believe it's Avon Tire that urges reverse rotation of a rear tire designation when mounted to the front regardless of Radial or Bias.
