QuestionHello,
I recently bought a used 1994 Yamaha FZR 600cc. This is my first bike and my question is about tires. How do I know when the tires are worn or "rotted out." The tread looks descent to me, but then again there are only 2 wheels. Also, the bike has odd sized tires that are not really in use anymore and so their hard to find and expensive. (rear = 140/60 18) (front= 110/70 17). Is it ok to use different brands on back and front (as a result of bargain shopping) and how much flexibility with height do I have. I also heard using sport touring tires will increase their life-span, is this true?
Answer"When in doubt, throw 'em out."
Regardless of the tread left, if they're more than three years old they should be replaced. They get hard, cracked, and blue, and they're what connects you to the road and keeps you upright.
It is not uncommon to have trouble finding tires for an older bike. Oftentimes available rubber can be fit to rims they're not meant for, but it requires some research. If I were you, I'd find an Internet forum of FZR enthusiasts (Google search words "Yamaha FZR discussion forum tech") and you'll probably find one or three. There'll be enough tire threads for you to find what you need, or you can join the group and ask what the solution is. You could also contact customer service at the tire distributor you want to use and find out what other people with your bike are running.
The motorcycle's geometry can change somewhat if you're using different tire profiles than it was designed for, but a suspension tuner could help you sort that out by changing the fork height and/or rear shock height to get the geometry set up like you want.
Mixing brands is generally discouraged. Tire profiles differ from model to model, and from manufacturer to manufacturer. You should run the same model tire front and rear if at all possible, or at the very least, run two tires from the same manufacturer.
The sport touring tires will generally give you longer tire wear at the expense of being less "sticky." However, a sport touring tire manufactured in 2007 will probably be stickier than any tire that bike could have used in 1994.
Plan to get about 7000 miles out of a set of tires. If you don't think you'll put on 7000 miles in three years, get the stickiest tires you can find. If you think you'll put on 7000 miles a year, go with sport touring rubber.
On my VFR (800 Honda sport tourer) I run a sport-touring compound (Bridgstone BT021) on the rear and a sport compound (Bridgestone BT014) on the front. I have been using this basic combination for the life of the bike (60,000 miles) and have been satisfied with it.
Hope that helps.
Pat
