Differential tire sizes, with a twist

[MaineShark]

Usually, this is different widths, but I have a bit of an odd question...

When I bought my Shark, it came with 235-60R15 tires. These under-drive the car a bit (7%, I think), messing with my speedometer, and hurting the gas mileage, I'm sure.

So, I want to put 235-65R15 tires on. But, I'm cheap, so I'd like to just do the rear tires. That way, I'll be able to keep the front tires, and have the current rear tires as a second set for the front.

I doubt there is, but I wanted to double-check if there are any suspension issues with having different outside-diameter tires front to rear.

Or should I just suck it up and put the same tires all around?

Also, any recommendations for good 235-65R15 tires for street driving?

And, anyone know anything about "Spartan" tires? All I've been able to find out is that they are made by "Reliable Tire." Are they decent, or should I just toss 'em?

Joe

 

[Larry82]

I doubt there is a problem. I am running 255/60x15 on the front and 275/60x15 on the rear. This would be a similar size difference. I have had no problems whatsoever. This is a typical tire change for many, so doubt you will have a problem.

I wonder if the smaller tires on the rear helped in acceleration - let you get the rpm's up faster on hard acceleration. Into the power band faster.

 

[Stallion]

In the book I'm reading by Newton, I see around in the Tires section and he refers to numbers such as 235-60R15. But, what do these numbers refer to? And the "R"?

Thanks!

TR

 

[Larry82]

235 - width of tread in mm
60 - sidewall is 60% of the tread width. Also known as the aspect ratio
R - Radial
15 - Rim diameter

 

[Stallion]

Thanks, Larry!

TR

 

[patsnitrovette]

Im running 275/60/15 in the rear and 225/70/15 in the front.