

| Subject: | Re: Yokohama tires: math lesson |
| From: | Malcolm Holser |
| Date: | Wed, 21 Oct 1998 10:53:15 -0700 |
Well, I'll let you guys debate the math (and what is meant by "10% larger") but I would like to point out that we usually don't run 195/60 tires -- rather we run larger tires like 195/75. The "195" or "205" refers to the width of the tire in millimeters -- about 8" for these guys. The 60, 65, 70, 75 (or 40 for you Viper-drivers) refers to the percentage of the width the sidewall has. You can add up these to sort of get the diameter -- the wheelsize + (2*width*ratio/100) once you convert all the terms to similar measures. In any event, a 205/70 tire is not much different in diameter than the 195/75. Both tires are suitable, but if you go to a 195 width the pressure needs to be up to a 50lb rating, and you must get a reinforced or LT tire. The wider tires need lower pressure (since they have a larger width and hence larger contact surface to spread the weight out over). The contact area goes up basically by the square of the width (kinda, sorta), so the pressure should be reduced by a similar ratio. There are limits to how wide a tire you can mount on a Vanagon rim. You can use wider rims, 15" or 16" and get lower profile tires to get wider tires without a serious change in tire diameter. For all wider tires, though, you will need to reduce the tire pressure. Tire dealers will have books on this, and Michelin, at least, lists some wider passenger tires at lower pressures as suitable for Vanagons. I run these on my GL. Michelin offers their full (80,000miles?) warrantee, so they must feel fairly confident -- at least the place that installed them said so. That said, on my other Vanagons, I run truck tires. The Westies are overloaded sitting empty, and I have overloaded both my transporters on a routine basis. On my doublecab, I am running 225/75-15LT tires. I'd run the same on the Kombi but I need to find some wheels eventually. Do they even make 195/60-14 tires? They must be cute. Malcolm H.
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