tire question
Thread Starter
Racer
Joined: Jun 2013
Posts: 348
Likes: 27
From: Stony Brook NY
tire question
hi all
I looking into new tires for my 93 I currently have p255/45zr17 on the front and p285/40zr17 on the rear. Can I replace all 4 with the p255/45zr17 and will they fit on the rear rims. Will it affect anything if they are all the same size?
thanks
I looking into new tires for my 93 I currently have p255/45zr17 on the front and p285/40zr17 on the rear. Can I replace all 4 with the p255/45zr17 and will they fit on the rear rims. Will it affect anything if they are all the same size?
thanks
Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 276
From: Melbourne, Victoria, Australia
Or you may have 9.5 inch all round. You can use 275 40 17 tires on 9.5 inch rims, you can fit the 255 tires on 9.5 inch wide rims (I had the 255 50 16 on the old 16 x9.5 rims). It's your choice put the 255 all round however your speed may show slightly different, going from 285x40 to 255x45 tires they may have a slight height difference.
Last edited by gerardvg; Jul 24, 2014 at 08:13 AM.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
The 255/45/17 will fit on a 17"x9.5" wheel. Some people think they look a little stretched, but it is within most manufacturer's recommended wheel widths for the tire. Some tire brands/models are wider than others even though they have the same size designation. For example Firestone SV50 255's seem smaller and Sumitomo HTRZ seem wider even though they are the same size 255/45/17 tires.
The height for common C4 sizes are
285/40/17 = 26.0"
275/40/17 = 25.7"
255/45/17 = 26.1"
Basically they are close enough that they can interchange without a lot of difference in the speedometer. If it came with 285's, when you have 255/45/17 the speedometer at 60mph will have an actual speed of 60.2mph. With 275/40/17 tires the speedometer at 60mph will have an actual speed of 59.3mph. So with any of the three tires your speedometer will be within a mile of being correct at 60.
Running the same size tires is not a problem on C4's. Many cars had the same on all four wheels. In '93 they changed the base wheels and tires to the staggered sizes to help reduce tram lining and "improve" feel.
If you do run the same size tires, you may still not want to rotate tires since generally people keep the wider wheels in the back.
The height for common C4 sizes are
285/40/17 = 26.0"
275/40/17 = 25.7"
255/45/17 = 26.1"
Basically they are close enough that they can interchange without a lot of difference in the speedometer. If it came with 285's, when you have 255/45/17 the speedometer at 60mph will have an actual speed of 60.2mph. With 275/40/17 tires the speedometer at 60mph will have an actual speed of 59.3mph. So with any of the three tires your speedometer will be within a mile of being correct at 60.
Running the same size tires is not a problem on C4's. Many cars had the same on all four wheels. In '93 they changed the base wheels and tires to the staggered sizes to help reduce tram lining and "improve" feel.
If you do run the same size tires, you may still not want to rotate tires since generally people keep the wider wheels in the back.
Last edited by QCVette; Jul 24, 2014 at 09:04 AM.
Race Director
Joined: Oct 2005
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From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
I wouldn't put the 255/45-17 on those 9.5" rear rims.
If your doing this because the 285/40-17 tire is getting harder to find, you can use a 275/40-17 which still has lots of choices.
The factory used a 275/40-17 on a lot of the C4's with 9.5" rims.
Yes, it worked and was within spec.
But it looked like crap.
