Mercedes-Benz ML320


Death Valley Trip

April 25, 1998

April 26, 1998
CAUTION
road conditions
you need to bring...
temp. spare
tire quick math


 

 



 

 

 
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How 4ETS works
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 alternative tires to replace the ML320's temporary spare

"how to get home fast"

 I have had a blown tire during my first Baja California test drive in 1997 - 500 miles away from any source for new tires. Installing the temp spare was no fun at all. Since I did not want to drive on that mountain bike tire (aka MB spare) at mountain bike speeds I had a used tire for $20 mounted.

The used tire allowed for decent highway speeds and got me home quick and safe.

After the trip I threw that tire away and replaced it with a new one. Eventually I upgraded to a much more reliable off-rad tire.

The Mexican "tire shop" I got the replacement from had an inventory of about 45 used tires to chose from.

Nothing that would fit the ML insisted the owner of the "shop". But he had his mind set only at 255/65R16. But some other configurations have a similar diameter as the 255/65.

I picked a tire that I figured would do just fine: 245/70 R 16


Here the quick math:

sidewall height of a 255/65 tire is 65% of 255mm tire width or roughly 166mm

sidewall height of a 245/70 tire is 70% of 245mm tire width or roughly 172mm

166mm vs 172mm or 6.53" vs 6.75" is a decent match.

Check here for quick math vs real tire size

DO NOT use tires with diameters larger than the ones listed below. Two significantly different tire sizes on one axle will eventually destroy the axle's differential. A single replacement tire at least10% larger than the other 3 tires could get 4ETS confused and render the vehicle inoperable.
 Here are some other sizes that could temporarily replace a damaged 16 inch stock tire or the 155/90R18 spare:

 tire size  diameter  difference to stock size  
 6.00 R 16 **  27.82 " -1.4  %  
 215/80 R 16 **   28.70"  1.8 %  
  225/70 R 16 **   27.70"   -1.9 %  
  205 R 16 *  28.13 "  - 0.1 %  
 225/75 R 16 *   28.26"   0.2 %  stock on ML230 and non US ML320
 255/65R16 28.21 "   0.0  stock tire size on US ML320 
 235/70 R 16 *   28.13"   -0.1 %  
 6.50 R 16 *  28.39 " 0.6 %   
 225/70 R 16 ** 27.70 " - 2.2 %  
  245/70 R 16 **    28.70"    1.8 %  
 215/85 R 16 ***   29.45"  4.5 %  larger diameter - inflate to 25 psi
 215/70 R 16 *** 26.88 "  - 4.8 %   
 245/75 R 16 ***   29.58"   5.0 %   larger diameter - inflate to 25 psi
  255/70 R 16 ***   29.39"   4.3 %  larger diameter - inflate to 25 psi  
  265/70 R 16 ***   29.70"   5.4 %   larger diameter - inflate to 25 psi 

*= perfect match ** = very good match ***= decent match

 To keep 4ETS from acting up DO NOT mount larger replacement tires than listed here.

 Caution:

A single used tire of a different size is only intended to be a cheap temporary fix.

Replace any temporary spare as soon as possible with a perfect match.

If you intend to replace all 4 tires with a different size you'll find all available brands in my 16 inch or 17 inch and 18 inch charts