I'm surprised to see such a limited selection of tire's in 235x55x16. It's kind of an odd ball size but I want to keep the car as stock as possible. Goodyear even stopped making the Nascar series in this size. Does anyone have any good recommendations?

Thanks!!

 

What was that a stock size on? Weird... I had always thought all the 16 inch wheels on these cars got 245/50/16s?

 

This is a stock 1992 z28 Z03 with the original tires. The 245's were optional and from what I've found were included on cars with rear disk brakes, I have drums.

 

245x50 16 were stock on my 89 IROC. I also had rear drum brakes since have upgraded to LS1 disks.

 

At Allen Tire's web site I entered year make and model and got this response:
Iroc-Z (16 Inch Option) P245/50ZR16
RS P215/65R15
Iroc-Z P215/65R15

but for 92 I got this:
Original Equipment (O.E.) Tire Sizes
RS P215/65R15
Z28 P235/55R16

Optional Tire Sizes
RS P235/55R16
Z28 P245/50ZR16

 

Yeah, that's the same I got on all the tire sites. There are several more 245 options, but that is going to throw the speedo off a bit. One of the other posts said there was a 3mph difference. I'll keep searching.

 

3mph is likely within the margin of error. By my own calculations I'm getting a 1.2 mph difference at 60mph. I also would imagine the vss is likely set to the same calibration as the 245/50/16 cars, especially for that small of a difference. So I figure your speedo is probably wrong now more than it would be later.

But if you want to go stock (And I did verify that that is a stock size, it's buried in the tech data on the main page) then that's a noble pursuit in and of itself. But dont be afraid to go to a better tire that was stock on the vast majority of our cars over a 1.2 mph speed difference at highway speeds. Tire pressures probably have a bigger affect than tire size at that point.

 

235-55-16 was an extremely oddball size - both in availability and the fact the diameter is not within spec. Good luck finding anything in that size today - there are only a dozen choices left in the more popular 245-50-16. 3% is nothing - actually I'm not even sure GM adjusted the trans speedo gears for that tire honestly...

You should be more worried about getting a decent tire than keeping an original size - tires are easy to change and are not a permanent thing.