Tire sizing?

Simon · 07-14-03, 01:09

I have a chance to pick up a set of winter tires and was wondering if they would fit.
The rims I have have 205/60/15 tires on them know and the winters are 195/60/15. I'm pretty sure they will fit on the rim, but I just want to make sure before I go ahead and make a decision.
Thanks.

Nikon · 07-14-03, 01:47

The first number in the tire size represents the cross section width of the tire, the second number represents the sidewall height, expressed as a precentage of the cross section width.

For example the 205-60-15 would have a sidewall height of 123mm (205x0.6)

On the other hand the 195-60-15 will have a sidewall height of 117mm

Therefore, installing the 195-60-15 winter tires will result in a smaller overall wheel diameter than what is presently on your car causing your speedometer to read incorrectly.

Otherwise, yes they will fit.

(Note: Its been awhile since I've had to explain this so if I'm off base any where please pipe in.)

lunasea · 07-14-03, 01:48

You asked one question, but their are two answers.

For 195mm width tires 6.5" rims are ideal, but you can go as low as 6" and as high as 7". You did not mention the width of yours wheels.

The circumference of the your 205/60/15 is 24.685" and the 195/60/15 is 24.213". This 1/2 inch difference would be too much difference for me. Both Discount Tire Direct and Tire Rack have information on plus sizeing.

Simon · 07-14-03, 01:52

I know there will be a bit of variation in sizing. But there are allowances in sizes per rim size.
But I'm wondering if I can go from a 205 to 195. A bit smaller, but better for a winter tire anyway. Right?

Nikon · 07-14-03, 02:03

Like Lunasea said check to see the rim widths the tires are designed for (I forgot about that).

If that is OK then I think you'll be good to go.

I have a set of winter tires and wheels and I find it makes a big difference.

TortoiseAWD · 07-14-03, 04:13

The speedo difference between the two sizes is only 1.9% on the fast side (when you're traveling an indicated 60 mph, you'll actually be doing 58.9 mph). As long as the narrower tire fits the rim OK (as others have mentioned), the speed difference really shouldn't be enough to worry about.

Useful link for comparing tire sizes: http://www.miata.net/garage/tirecalc.html

Tort

Simon · 07-15-03, 06:41

Thanks guys. I'll go measure the widths and go from there.

lunasea · 07-15-03, 06:57

Look for the size marking on a wheel, unless you know how to measure a wheel. Last year for my Lexus SC300 (5speed) I purchased, on ebay, a set of wheels that "measured" 17 x 8, and if you measure outside to outside in both directions it measured 17 x 8. Marked on the wheels was 16 x 7. I learned my lesson, the hard way.

4DSC · 07-15-03, 01:27

I hope you didn't just take a tape measure and measure the outside dimensions of the wheel, right?

Wheels are measured at the bead seats where the tire goes as far as I know....