Originally Posted by
sledmaster
Back when we were riding the original prototype units, they were all fitted with Dunlop car tires. You can still see this on the P0, P1, P2 and P3 prototypes when they are on display in Valcourt. Of course, for production BRP had to find a tire manufacturer that was willing to build tires for them that were inexpensive, allowed by the very light load requirements. The OEM tires are light and cheap in comparison to car tires, which have far greater load capability. Most will ride stiffer as well, even with low air pressures, but should be far more durable and reliable. That has been the experience of thousands of us here on the forum. Many of us have tried numerous car tires over the past ten years, front and rear, with excellent results. It seems BRP selected sizes that were obscure, perhaps in an effort to thwart riders from using non-OEM tires, as they do make good money selling tires. There was discussion a few years ago about trying to find a new vendor other than Kenda, even to offer a premium tire as an accessory right from BRP, but I guess this never went anywhere.
So do not be wary of using a car tire, even if it is of slightly different size. Ideally you want to stay within 3% of the original diameter. The width can be fudged, as long as it fits in the fender. Up front I've used 155s and 175s instead of the stock 165s, the 155s looked narrow, the 175s are what I like best on my 2013 STS. There are many other sizes to use on the rear, which is kinda wide to begin with so it works well to go slightly narrower (215, 205) than the stock 225 width. There have to be thousands of posts over the years detailing options here. One caution is to pay attention to the traction and temperature ratings, I wouldn't use anything less than A temperature and A traction, AA traction is better. Stay away from B ratings. IMO. And the lighter load rating the better, since the car tire is already way more than a Spyder needs. Mike's suggestions on pressure are right on, tried and true.