<VV> Tired of tires?

[airvair]

If you calculate it right, the 825 RPM figures out to a rolling diameter
of 24.44 inches. THAT is what you should be looking for.

-Mark

Bruce Schug wrote:
> 
> I think a 205/60 is a nice size for a street Corvair. It is, however,
> smaller in diameter than a stock 7.00-13. The 205/60 is
> (mathematically) 24.69" in diameter whereas the 7.00-13s were closer to
> 25.3 or so.
> 
> Your '66 speedometer should be calibrated for 825 rpm, although it
> won't be accurate at that rpm because they weren't accurate as shipped
> by GM. But, if you want a tire that is "matched" like a stock tire,
> look for 825 rpm. You'll really have to look over some tire specs to
> find what you're looking for. As you look over the tire manufacturer's
> specs, pay attention to whether or not they measure the rpm's standing
> still or moving. You'll be more accurate to find one that's measured
> moving, typically at 50 mph.
> 
> An 825 rpm 15" tire might not be easy to come by. Look at 205/65's.
> Some might be tall enough. You might end up with a 215/60 which just
> looks too "big" for me ("big" being defined as a combination of width
> and diameter). But depending on their construction, that's about where
> you'll be.
> 
> Now if you really want the speedometer to be accurate you might want to
> shoot for a rpm of closer to 840. This is easier to come by. Despite
> its smaller-than-stock diameter you might find a 205/60 that is 840
> rpm. You might have to go to a 195/65. It just depends on the
> construction.
> 
> If it were me, I'd probably get a good set of 205/60's and then if the
> speedometer wasn't close enough I'd get a converter for it.
> 
> Good luck. I'd be interested in knowing what you end up with and why.
> 
> Bruce
> 
> On May 24, 2004, at 5:02 PM, Robert Marlow wrote:
> 
> > One of the perennial threads on VV is, "what size tire fits my car?"
> > Today, it's my turn.
> >
> > I already have the wheels and my own idea of what the ideal tire size
> > is.
> > But I am interested in the opinions and experiences of others.
> >
> > The wheels are 15x7.  The car is a '66 coupe.  The goal is a
> > speedometer/odometer that is reasonably accurate.  For general highway
> > use,
> > so don't worry about specific tires that are suited for autocross or
> > racing
> > or the like.
> >
> > And, for those who may wish to point me toward Bryan Blackwell's site,
> > it
> > is one of the sites I have visited already and it has influenced my
> > thinking thus far.
> >
> > --Bob
> >
> > Robert W. Marlow
> > nortechcorp@optonline.net
> >
> Bruce W, Schug