Anyone have any experience replacing the stock 225/55-19 Toyo's on the CX-5 with a lower profile tire on the stock wheels? Say a 255/50-19?? I love my car and the way it drives but I think that a little more aggressive rubber would look better filling out the wheel wells...

Thanks,
Carl
2018 CX-5 GT Soul Red

 

The stock tires are pretty darn low profile as it is. I would think you would be ok doing what you suggest since you are going up three widths. Usually you can drop half an aspect ratio for each width increase. So in your case you could theoretically drop from 55 to 40. I would stick with 45 or 50 though. Your only issue is will the stock wheels accept a 255 tire? Not sure what the wheels width allows.

 

The change your suggesting will actually increase the height of the sidewall of your tire (from 4.87" to 5.02"), kind of contrary to what it sounds like you're attempting to do.

 

Yes, the height of the sidewall will be slightly greater as you suggest--which may actually make the tire fill in the wheel well better. More importantly though, the wider tire (and slightly reduced aspect ratio) will make the tire look more aggressive. What do all those Volvo and BMW's have, 245/45's?? I'm just concerned that the stock wheel diameter would be sufficient to mount the wider tire and that I'm not compromising ride quality or (already a bit mediocre) fuel economy, or anything else. I wonder what Mazda would say?

 

The tires in the width and height you are talking about will compromise ride quality to a certain degree; actual fuel economy may not suffer much, however, because your speedometer and odometer will be somewhat off on the low side (i.e. will record lower speeds and fewer miles), the OBC will calculate lower fuel economy as well. I ran the numbers yesterday and while I don't remember exactly, I'm pretty sure 245/45 R19 tires are a closer match to your OEM rubber in diameter.

 

Yep, exactly what I said. Come down 5mm on the aspect ratio for every 10mm extra width. 245/45 would be the correct "Plus two" upgrade for the CX-5 if the rim is wide enough to accommodate it.

 

What am I missing here?

Stock: 225 x .55 = 123.75 mm (nominal sidewall height)

245 x .45 = 110.25 mm (way too short in height??)

245 x .50 = 122.5 mm (closest in diameter to stock but slightly shorter in the wheel well)

255 x .50 = 127.5 mm (slightly taller but certainly will fit--and accomplish what I'm looking for1)

 

Just because the 255/50 R19s "fit" doesn't make them an appropriate option; the tires will look a bit wonky unless you buy new (wider) rims as well, that and your speedometer and odometer will both register low.

 

https://www.1010tires.com/Tools/Tire...ismetric=False

 

Thanks Reaper! Looks to me like the 245/50-19 would be the plus size closest in diameter and speed variation to stock. They recommend 7 to 8.5 inch wide rims. I'll have to look up what our stock GT wheel is...