if not, what are the performance implications of
> mounting a given tire on a wider or narrower rim?
>
> thanks!
>
> Ben.

Hi Ben

If you put a wide tire on a narrow rim you get the tirewalls to protect the
rim from being damaged, probably better load capacity and better flotation
on sand, mud and snow with low airpressure ( ok, ok I�m an offroader too).
The drawbacks are that it allows the rim to slightly move around in the
tyres which feels like innacurate steering, sliding when cornering and
sensibility to sidewinds.
It�s not as much a fact as a feeling and could often be cured by raising the
airpressure but then you�ll have a bumpier ride
With matching or narrower tyres on wide rims you get the sidewalls stiff
which does the opposit to the above, you�ll get a accurate steering and so
on, compare with a sportscar ( no not some streetrodder, NASCAR or INDY - or
a Porsche ) and you�ll see that they have almost no rubber outside the edge
on the rim !
Then, if it�s on a Vanagon, this is off small importance since you never put
that much G-forces on your wheels but you should try to match wheels and
tyres, make a decision about which is the more important - loadcapacity or
soft ride - and buy tires according to this if you�re allowed to by the laws
where you live.
The manufacturer of the car has often optimized the wheels with the handling
and overall transmissionratio though, to get as good capacity and economy as
possible so try to stick with something that is not too far away from
original !

Calle
-88 Volgon
Mullhyttan, Sweden