Michelin PSS on OEM size
#46
Lexus Champion
iTrader: (9)
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
#48
Lead Lap
iTrader: (4)
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
#49
Tech Info Resource
iTrader: (2)
And F1 sweats over millimeters in ride height. Sure, it's negligible.
#50
Lexus Champion
iTrader: (9)
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
#54
Lead Lap
iTrader: (4)
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
#56
Lexus Test Driver
iTrader: (1)
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.
#58
Tech Info Resource
iTrader: (2)
Lou, we are totally on the same page.
#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?
#60
Tech Info Resource
iTrader: (2)
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.