On my 2014 RT-S the OEM tire is 225/50R15 per the Can-Am website. The Michellin that folks are talking about is 215/60R15. Right?

So, What the numbers mean is:
- tread section is 225 millimeters in width
- sidewall height is 50% of the tread section measurement so 112.5 millimeters in height
- R means its a radial tire
- and 15 is the rim diameter in inches

These number are for an unmounted and unloaded tire.

So going from a 112.5mm sidewall (the 50%) height to a 129mm sidewall (the 60%) height makes the unloaded unmounted tire about 16.5mm wider from the center of the axle to the edge of the tire. This is just over 1/2 inch. Going to the 225/60R15 will change the same measurement by 22.5mm. About 1 inch.

What I am driving at is this - if the "nanny" allow up to a 10% variance for treadwear, over/under-pressure, etc. then the 215/60R15's probably will NOT trigger the codes. Conversely, I can easily see the 225/60R15 causing issues as it is at the 10% variance I am assuming the nanny has.

I am new to Spyders and as I have almost 3700 miles on my current rear tire I read everyone's comments very thoroughly. I will probably have to my tire relatively soon.

I think it would be VERY interesting to have round-table discussions with the various engineers at BRP as to why they did some of the things they did...

Thank you, everyone for your insights, opinions, and responses.