question on tire sizes
#1
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question on tire sizes
I have an 89 C4 with 17 x 7 inch front rims with 215/45/17 tires on presently. I would like to use Michelin Pilot ps2's which only come in 225/55/17. Has any one tried this size and or this tire?
#2
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I'm running 205/50x 17 on the front, so 225 sounds a little wide for the rim...I do recall however that a few C4 owners run wider front tyres to reduce understeer...
#3
RL Community Team
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225/45 is fine for the front on a 7x17 rim - I run this on both my cabrio and race car with no problem (note they are 92's with the different steering stops), matched to 255/40 rears. 225/55 is too big of a tire, though... unless you go to a larger rear tire, you're likely going to have ABS and PDAS issues.
#4
Three Wheelin'
Originally Posted by garrett376
225/45 is fine for the front on a 7x17 rim
I know that one of the Smart Groupers recently had to abandon plans to fit 225/45 tyres because the car had 7J rims. The maximum size tyre that can be (safely) fitted to a 7J rim is a 215/45.
As Garrett said, the 225/55 tyre is the wrong aspect ratio - there is a 8.64% difference between it and the 215 already fitted - the maximum diffrence allowed is 2.5%.
Hope that helps.
Regards
Dave
#6
Originally Posted by Computamedic
According to all the information I can find on the Net, the MINIMUM rim size for a 225/45 is 7.5J. The tyre is too big for a 7J wheel and will run the risk of running off the rim under cornering.
I know that one of the Smart Groupers recently had to abandon plans to fit 225/45 tyres because the car had 7J rims. The maximum size tyre that can be (safely) fitted to a 7J rim is a 215/45.
I know that one of the Smart Groupers recently had to abandon plans to fit 225/45 tyres because the car had 7J rims. The maximum size tyre that can be (safely) fitted to a 7J rim is a 215/45.
#7
Three Wheelin'
Originally Posted by Devils_son
I very much doubt that 7J is not wide enough for a 225 tyre. The 964 small body came with 8J on the rear, with a 255 tyre, which is the same ratio...
If you look at the rim width calculator (here ) you will see that the range of rims suitable for a 255/50 tyre on a 17" rim is 7J to 8.5J but the range for the lower aspect 225/45 tyre is 7.5J to 9J. There seems to be a major difference once the aspect ratio drops below 50%
Making assumptions in this area is very dangerous - it pays to check the facts.
Regards
Dave
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#8
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Not to start any flame wars, but a 7" rim is perfectly acceptable for most 225/45 tires. If you look at the specs on the tire rack or Michelin sites, Michelin says the 225/45x17 PS2 may be used on 7-8.5" rims.
I have used 225/45's (MPSC) on my 7" rims at the track for years without issue.
Rather than using a generic calculator, it helps to check the manufacturer's web site or other sources for information specific to the tire in question. Note that the original post has a typo as PS2's come in 225/45 and not 225/55 x 17 (at least according to Tire Rack).
I have used 225/45's (MPSC) on my 7" rims at the track for years without issue.
Rather than using a generic calculator, it helps to check the manufacturer's web site or other sources for information specific to the tire in question. Note that the original post has a typo as PS2's come in 225/45 and not 225/55 x 17 (at least according to Tire Rack).
#9
RL Community Team
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Originally Posted by Tom W
I have used 225/45's (MPSC) on my 7" rims at the track for years without issue.
#10
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You could probably get them to wear more by driving too fast in slow turns so the car pushes like a pig and you scrub the rubber off the tires. Not that I have any experience with such driving, of course...
#11
Originally Posted by Computamedic
If you look at the rim width calculator (here ) you will see that the range of rims suitable for a 255/50 tyre on a 17" rim is 7J to 8.5J but the range for the lower aspect 225/45 tyre is 7.5J to 9J.