Re; <E36> Tire selection

[Matthew Tremmel <tremmemm@xxxxxxxxxxx>]

Steve,
I am going through this same exercise.
Any tire xxx/55/15 is tough to find and expensive.

I am looking for a good tire to use for
autocross that will leave me in stock class.

Here is a table I worked up that lets you
compare different tire sizes to the limit
of your current setup.  I just read in this
month's Roundel that you should stay within
0.5" (12.7 mm) of your current setup to avoid 
speedo changes or rubbing.

h=WD+2*f*w

where WD=wheel diameter (15in or 381 mm)
f is sidewall height/wheel width (the 60, 55, 50 etc.)
w is the width of the tire
h is the total height of the wheel/tire.

So, your current setup has a 628.5 mm diameter

Here are the diameters with different tire sizes (in mm)

     | 205 | 215 | 225 | 235 |
     ------------------------- 
  50 | 586 | 596 | 606 | 616 | 
  55 | 607 | 618 | 629 | 640 |
  60 | 627 | 639 | 651 | 663 |

Compare these with your current 628.5 +/- 12.7 mm. 
If you are trying to go for the wide and low profile look,
15" rims won't cut it.

The 205/55/15 would work, but I think it goes the wrong
way in trying to put more tire on the ground.

For street use, I think the best way to go is to move
up to in wheel size.  The choices and tire availability
improve if you want low and wide.  


For what it's worth...


Matt Tremmel
tremmemm@domain.elided
'94 325is

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