I was wondering what the width of my tires are right now because they look like they are 11" wide but im not sure, They are- P285/40-17

thanks for your help

 

Well, I would recommend measuring them on the car or calculating from the tire size. The 285 is width in mm. So simply convert to inches.

Your stock wheels should be 9.5" wide.

Jason

 

285mm = 11.22 inches.

Just out of curiosity, why do you want to know?

 

Example for a P285/40/17 tire....The 285 is the width, 40 is the sidewall height in % of tire widith. example: 285 * 40% = 114 mm. The last number is 17 which is your rim size ( for those that didn't know that one) :lol:

 

Tires of the same size (width in mm) can be different widths by manufacturer. My 275/40-17 Bridgestone Potenza RE-730's are almost 3/4" wider than the Goodyear GS-C's of the same size that I removed. The Firestone SZ50's are even narrower than the GS-C.

The width of the tire can change depending on the rim width they are installed on. Go to the Tire Rack website and look at the specs of different brands in the same size and type. You will find a big difference in both tread width and overall width across brands.

 

http://www.c5-corvette.com/tirecalc.htm

 

Remember, the first number is the section width, not the tread width. The tread width is usually narrower than the section width.

 

Like Mr Mojo just stated tread width and tire width are two different things. the first number in the tire size gives you the tire width not the tread width. If you check out Tirerack they can give you the tread width of the tires you are looking at so youi can get a much better idea of what the tire will look like as far as size goes.

 

I was just wondering because i didnt know that a regular C4(non ZR-1) had 11" wide tires. And i want new rims and i am comparing sizes

 

you are confusing rims and tires... the ZR1 had 11" RIMs in the rear/... I think the tread on those measure almost 13". Regular LT1's had 9.5" rims with the standard 285/40ZR17's.... ZR1 11" rims had 315's or something

 

The '92 C4 and later year Z07 suspensions had 17x9.5 rims on all 4 corners with 275-40-17 tires. These are ideal in width for the rim. The '93-'96 had 255-50-17 on 17x8.5 rims in front and 285-40-17 on 17x9.5 rims in the rear. They did this so the car wouldn't follow truck lanes so aggressively. It did however loose some handling with smaller front tires and rear tires that were slightly puckered on the rims. They increased the size of the rear tires even though it wasn't the optimal thing to do was because the front tires were slightly larger diameter than the 275s. The 285 had the same outer diameter as the 255 so to keep it even front to back they changed to 285 rear.
The ZR-1 and '96 Grand Sport Coupe had 17x9.5 rims with 275-40-17 tires in front and 315-35-17 on 17x11 rims in the rear. This to me is the ideal combination as it grips well and looks aggressive. Also the actual outer diameter of both tires is identical. Some guys use the 285 tires on the front but these are larger diameter than the rear, which raises the front and to me looks funny and they are puckered and don't have the same lateral support as the 275s.
Tires vary by manufacturer as stated above. However, the tire sizes quoted by a maker are designed to fit a rim equally regardless of maker. My pilots in 275 are much wider than the goodyears or bridgestone re71 tires I've had. Hope this makes sense.

 

 

Thanks for your help

 

One small correction. The '96 has 255-45-17 tires on the front from the factory. :)

 

Wow ~ information overload :crazy: