Copied and pasted here:
Had a chat with the Michelin reps at Amerivespa. First off I must have been living under a rock because I'd thought the tires actually had rubber in them. Nope, nothing found in nature at all.
But more to the point, they didn't suggest changing tires before 10 years. Yes, they admitted that performance faded somewhat, so that if you really press your tires you might want to change earlier. I'd just changed out 7 or so year old tires out of concern, so the info was perhaps a bit late, but still a good idea IMO.
The other factor he mentioned was that riding is good for the tire....will stay more supple apparently with regular use...something about regular stress on the chemical structure is a helpful thing.
I thought this was interesting.
Tires with worn out treads are one thing - replace - but actual tire life of a scooter tire may be somewhat longer than what we been led to believe by ......etc.
Stig
