Tire size confusion

[twobone]

I'm going to look at some 7 " and 9" Fuchs tomorrow to replace my 6"&7" units.

The owner is suggesting that since my Pirelli tires are still very fresh, that I should just swap the tires to the new rims.

That would mean I would run 225/50ZR16 on a 9" rear and 205/50 ZR 16 on the 7" fronts.

What would the rears be like? Help me understand by giving me a lesson in what the tire size codes really mean

Thanks

Mike

[Mrdi]

I would run 245/45 and 225/55, but run the 225 and 205 until the rears are at least spent before changing out to SO3's

[jazzbass]

The "factory" combo for these wheels would be 245/45 16s in the rear and 205/55 16s in the front. 225/50s are to small to fit a 9" rim; according to Tire Rack the right rim sizefor 225s is 6"-8". Get new 245/45s - after all, that's the reason to get the 9s in the first place.

FYI, in tire numbers, the first number is the width of the tire in mm. So, a 225/50ZR16 is 225mm wide (approx). The next number - /50 - is the sidewall ratio - in this case, 50% of the width of the tire or 112.5mm. For a 245/45ZR16, the width of the tire is 245mm, and the sidewall is 45% of the width, = 110.25mm.

The next letter is the speed rating - Z = 149mph+. The R means its a radial (which is good to know these days - you don't want tubed bias plys on your 911).

The last number (16) is the wheel size, in inches.

[nostatic]

I'd get new 245/45s for the rear, then keep either the 205 or 225 for the front (which ever has more tread).

[bell]

Originally posted by jazzbass

The R means its a radial (which is good to know these days - you don't want tubed bias plys on your 911).

good info..........but this made me chuckle