Using a Slightly Different Spec Tire
 

The standard tires for my car are 185/60/15, which is somewhat of an oddball size.

Is it a big deal if I use 185/65/15 instead?

I used a tire size calculator and it estimated it to be approximately 3.1% bigger than stock.

For the most part, it shouldn't. But being that the new tire is taller, you might run into issues of rubbing the fender liner.

Also, if you are going to change, make sure you change all 4 tires or else it might fool the ABS as the tire speeds will vary.

I would be changing out all four tires for sure.

I think the difference in height is about 9mm... and I have plenty of wheelgap on my stock Yaris. :p

I would say make sure you have enough clearance from the bottom of the strut perch so the tire doesn't rub against anything. It'd have to be a fairly large and incorrect upsize to start rubbing the fender lining, at stock height :)

so long as the top of the tire doesnt rub or touch ur suspension, its ok to go slightly oversized.

but most ppl keep the aspec ratio, but go a tad wider. and in this case, make sure ur wheels are offset enough so that the tire again doesnt touch ur suspension

You can also recalibrate your speedo so it shows the correct speed after your new tires are on :thumbsup:

So I went ahead and got the slightly larger 185/65/15 tires today... and before I did, I tested my speedometer against a GPS, and I found that it was approximately 4% slow. When the speedometer said I was going 100kmph, the GPS said I was actually going 96kmph.

I thought this was because my tires were bald, so that the circumference of the wheel has been reduced... and that after I got the new larger tires on, the speedometer would actually be too fast...

But to my surprise, the speedometer is now almost PERFECTLY calibrated. :eek: It seems like it's at most 0.5% off.