Thread: Cup 2"s vs 4S
View Single Post
      04-21-2021, 07:33 AM   #89
VisualEcho
Banned
VisualEcho's Avatar
United_States
6643
Rep
4,145
Posts

Drives: '18 M2 6MT
Join Date: Sep 2019
Location: Missouri

iTrader: (1)

Garage List
2018 BMW M2  [10.00]
Quote:
Originally Posted by Djphonics View Post
This tread width makes no sense to me.

A 255 tyre should not be narrower than 245 tyre.

Thats 10mm more it doesn't make sense that its .2" narrower. Yes, I see the chart, but it doesn't make sense with the same tyre model.
You're right, it doesn't make sense, but it's a reality, and has been for as long as I can remember. Tire tech in sizing has always been wonky, and sometimes it's on purpose...


Quote:
Originally Posted by F8SEVEN View Post
The Michelin site says 9 inch section width for both with the 245 being on an 8.5 inch rim and the 255 being on a 9 inch rim. Both are PS4S.
TW is really what you want to use when it comes to where the shoulder of the tire will sit compared to the lip of the fender/quarter (for rubbing purposes).


Quote:
Originally Posted by DanG View Post
So the .2 less for the 255 was caused by it being more stretched by being on a 1/2 wider rim. On the same width rim the 255 should be wider.
The shoulder should be the same, it's the sidewall that'll crown a bit. I imagine if you mount the tire on a wheel that's 2" wider there might be a bit of variance, but not a half inch, which is only 6mm per side, and not nearly enough to change the measurement.


Quote:
Originally Posted by F8SEVEN View Post
I'd think so, and I can tell you from having an M4 and now an M2C, the narrower tires do look a tad stretched on the rims.
You're seeing the sidewall crown a bit, not the shoulder of the tread.


Quote:
Originally Posted by ///M TOWN View Post
I was interestingly enough just looking at my fronts and they definitely look stretched as well as the back
Keep in mind that how stretched a tire looks is mostly due to the sidewall, and that has to do with the size of the bead (near the wheel rim). Some tires have a huge bead, some have almost a nonexistent one, and it even varies by size. Go look again and see how far the bead comes out, then crowns back towards the tire shoulder where it should be almost straight.

Notice the bead difference between the Michelin (huge) and the Avon (tiny).
Attached Images
  
Appreciate 2
Fugly M35251.00
///M TOWN21693.00