Understanding Tires

Understanding Tires
Information courtesy of Handler at Gateway Xtreme

The following information relates primarily to motorcycle applications but may be applicable to other vehicles as well.
Radial tires are only available in a tubeless configuration. Bias-ply tires can be had in either tubeless, or tube type. Tube type tires can't hold air without a tube because the bead is not designed to seal against the wheel efficiently as it does on a tubeless tire. Also, the tire itself is not designed to hold air as some air can escape through the tread. The primary difference between radial and bias-ply is that a radial can sustain a much higher speed rating because the radial tread design generates much less heat than a bias-ply design. Another big difference between radial and bias-ply is in performance. A bias-ply is a very strong tire often (but not always) with a very stiff and strong sidewall. They are very durable and are a real working tire. A radial is a lighter tire by design and is geared around performance with a softer and more responsive sidewall and tread. For example, all sport bikes run a radial tire due to performance and speed rating requirements while many cruisers run bias-ply tubeless tires because their top speed is not very high and the performance requirements of a Harley type cruiser are not very demanding on a tire. Bias-ply are also a bit cheaper to buy than radials due to manufacturing costs. The VTX 1800 uses a radial due to its higher speed and the need for a better performing tire. The 1300C uses a bias-ply tubeless tire and the 1800S uses a bias-ply tube type tire.

Current bias ply tire designs are much different from the tires of old and are much more like a radial in design and performance. As a result, some of the old rules no longer apply - this is according to several of the major tire companies.

Fact: it is ok to mix different brands of tires on the same vehicle.

Fact: It is ok to mix radial and bias-ply so long as the radial is on the rear.

One other point that is often discussed is the use of tubes in radials and in bias-ply tubeless tires. It is thought that running a tube in a radial tire is a bad idea and indeed most tire manufactures do frown on this practice. However, in real life situations, 240 radial tubeless tires have been run for years with tubes on many custom bikes. Anytime you see an old school custom with a spoked wheel on the back, these bikes are using a 240 tube within that tubeless tire due to the nature of the spoked wheel and its inability to hold air. I have done this myself with no ill affects. In this situation the tube also gives a person an option when a perfectly good radial tire gets a puncture and won't hold air. Likewise, a bias-ply tubeless tire can accept a tube just like it's bias-ply tube counterpart. In fact, these tires are almost identical apart from the tube/tubeless designation.