[pikcachu]

Originally Posted by moldcad

Yeah - most of the Internet sources will tell you 245mm tire is the maximum width for an 8" rim. However, I did find a reputable source (Mitsubishi website; can't remember which page exactly so sorry - won't post the link right now) took the opposite approach, advising on the rim width suitability for a given tire width. They're advising that the rim width should fall between 70%-100% of the tire width. So let's do some maths here, using the formulas also posted on that webpage:

- for the minimum tire width on an 8" rim: 8"x 25.4 x 1.1 = 223.52 (a 225mm tire)
- for the maximum tire width on an 8" rim: 8"x 25.4 x 1.3 = 264.16 (a 265mm tire)

So as you can see, while 256mm would be just so slightly outside the recommended range - a 255mm tire would be OK...

With that said, I've just ordered my BC Forged RS43 wheels and PS4S tires in the "Dinan approved" fitment, i.e.:

- Front: 19x8 ET45 with 235/35 tire
- Rear: 19x9 ET48 with 265/30 tire

This will give more grip my 400 HP M235i really needs, why not being as aggressive (and not poking which I hate)... But were I unable to pay for those wheels, I'm positive my next set of tires after the OEM ones are completely worn out would be 255mm at the rear.

Piotr

PS. For those thinking (rightly, BTW) the sidewall height (tire profile) should also be taken into consideration, i remember the Mitsubishi site also said: with modern low profile tires with short and stiff sidewalls, rim widths closer to 70% of tire width will work best. So in the above example, even the 265mm tire would be fine on the OEM 8" rear rim of the M235!

Well... if Michelin says for 255 you need 8.5" and for 265 you need 9" https://shop.michelinman.com/upload/...-TechSpecs.xls
Are you going to trust more some Japanese Auto maker than the manufacturer of the tire ??

Also putting a wider tire than your rim is kind useless as the contact patch will not be any bigger as the tire will just bulge and the extra piece of rubber will never contact the ground...

[moldcad]

I just presented an esteemed car maker opinion which differs from the mainstream ones Trust your own gut feelings, man! Didn't I also say which size I'm buying myself?



Piotr

[Maynard]

I think you got your math wrong, and the basic info also seems flawed - DK where the 1.1 and 1.3 factors came from. An 8" wheel is 203mm. So if that is 70% of tire width (widest tire possible) it would be a 290 tire (70% of 290 is 203, right?). And smallest would be a 205. This seems extreme on both ends, especially vs. the chart already posted (and common sense - that's about 11.5" tire).

Not sure I'd consider Mitsu to be especially esteemed in this department, either. I think that more important than what is possible, is what would work well - good driving dynamics/handling, and maintain safety. For that you are going to want to be in the ranges listed on that Michelin chart. Unless it is a show car trailer queen, you don't drive bragging rights for the widest, or show points for radical looks.