Michelin PSS on OEM size
02-05-16, 01:24 PM
#46
The 30 and 35 designation in the sidewall mean that number is a percentage of the cross section of the tire. Thus 35% of a tire with a cross section of 255 (a 255/35 tire) would be .35X255 or 89.25mm (3.5") sidewall height. 30% of a tire with a cross section of 285 (a 285/30 tire) would be .30X285 or 85.5mm (3.4"). However tire makers have chosen to make the sidewalls the exact same height of these two sizes so that they can be run on vehicles designed for staggered tires of the same height (like the the ISF). Running a 275/35 would make the OD of the tire 26.6" vs the stock tire height of 26.0". The 255/35/19 and 295/30/19 have an OD of 26.0" as do the stock 225/40/19 and 255/35/19 stock tires.
Lou
02-05-16, 03:42 PM
#48
You both don't seem to grasp what the sidewall height spec means. Did you both not read the specs listed by lobux above? The 30 and 35 designation in the sidewall mean that number is a percentage of the cross section of the tire. Thus 35% of a tire with a cross section of 255 (a 255/35 tire) would be .35X255 or 89.25mm (3.5") sidewall height. 30% of a tire with a cross section of 285 (a 285/30 tire) would be .30X285 or 85.5mm (3.4"). However tire makers have chosen to make the sidewalls the exact same height of these two sizes so that they can be run on vehicles designed for staggered tires of the same height (like the the ISF). Running a 275/35 would make the OD of the tire 26.6" vs the stock tire height of 26.0". The 255/35/19 and 295/30/19 have an OD of 26.0" as do the stock 225/40/19 and 255/35/19 stock tires. Lou
02-05-16, 09:53 PM
#49
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iTrader: (2)
And F1 sweats over millimeters in ride height. Sure, it's negligible.
02-06-16, 08:42 AM
#50
In response to this:
Yah, but you just stated earlier you would go 275/35 19 rear. 285/30 is smaller, but 275/35 is slightly larger and throws the speedometer off more than the 285/30.
I swear, our ISF section is the only place on any car forum that strives so hard to keep the proper stock tire diameters. People want to mod their ISF, but then want to keep it close to stock? I don't understand that logic really.
I swear, our ISF section is the only place on any car forum that strives so hard to keep the proper stock tire diameters. People want to mod their ISF, but then want to keep it close to stock? I don't understand that logic really.
Lou
02-06-16, 01:15 PM
#54
Well one is approximately half in shorter than oem and the other is half inch taller. If you care so much about oem OD u should be running stock sizes with sticker tires. Plus yeah I'll be 0.28 inch taller than oem to begin with but if my tires are slightly worn I'll get closer to oem OD than your a 275/30, haha
02-06-16, 02:20 PM
#56
Based on some of the other comments in this thread, I'm pretty sure you two are on the same page regarding this topic. I think you missed the sarcasm with his second sentence
I'm not as knowledgeable as Lance & many others on the subject, but based on personal experience, I'd have to agree with this.
When I had the 235/265 set-up, the understeer (that I was attempting to get rid of with wider tires) felt the same, if not worse than the OEM 225s. There was a significant difference in OD between the front & rear with that set-up, and I suspect it had a negative impact on the whole scrub radius/suspension geometry "feng shui"
-Mike
Last edited by mikersoft; 02-08-16 at 09:16 AM.
02-07-16, 10:15 PM
#58
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Lou, we are totally on the same page.
02-08-16, 07:44 AM
#59
After reading lots of threads / calculating etc I decided to upgrade all tires to PSS but to stay OEM size for now (225/255).
Another option which goes in my had is to buy 2 rear OEM wheels and put them in front - like that I would have perfect square setup
, 255 all four corners Will OEM 19x9 255x35x19 PSS clear the front? Anybody tried?
02-08-16, 03:56 PM
#60
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Yes. I am running them right now on 8 1/2" 2012 rims with lots of room. You will need a 10mm spacer to correct the offset.