<VV> Tire size

[Bruce Schug]

On Aug 1, 2005, at 6:29 PM, Bryan Blackwell wrote:

> A 205/60-13 is way too small for a Corvair.  The 185 is pretty short 
> as well.  A 195/70 is tolerable, but still shorter than spec.  A 
> 205/70 is great, but they aren't available in the US as far as I'm 
> aware.  A 185/80 is better, but still a bit small as well.  If you 
> want something that really looks correct where you have some 
> selection, moving to a 14" x 6" wheel and 195/70 (or thereabouts) tire 
> with a Chevy wheelcover is a nice option.  But I stand by the 
> statement that 13" tires are difficult to find (at least much in the 
> way of selection), assuming you're looking for something that appears 
> and functions mostly the way Chevy intended, which, it would seem to 
> me, is the whole point of staying with 13s in the first place.

Well... not quite. Bryan, I know you understand this stuff pretty well, 
but here's a review of "Corvair Tire Size 101".

1. 6.50-13 tires were about 24.5" diameter.

2. 7.00-13 tires were about 25.3" diameter.

Some common 13" tire diameters that are within 1/2" of a 6.50 or 
7.00-13 are as follows:

175/80-13 - 24.0"

205/70-13 - 24.3"

185/80-13 - 24.7"

Some common 14" tire diameters  that are within 1/2" of a 6.50 or 
7.00-13 are as follows:

195/65-14 - 24.0"

185/70-14 - 24.2"

215/60-14 - 24.2"

205/65-14 - 24.5"

195/70-14 - 24.7"

205/70-14 - 25.3"

Some common 15" tire diameters  that are within 1/2" of a 6.50 or 
7.00-13 are as follows:

195/60-15 - 24.2"

205/60-15 - 24.7"

195/65-15 - 25.0"

215/60-15 - 25.2"

205/65-15 - 25.5"

Some common 16" tire diameters  that are within 1/2" of a 6.50 or 
7.00-13 are as follows:

205/50-16 - 24.1"

245/45-16 - 24.7"

205/55-16 - 24.9"

225/50-16 - 24.9"

215/55-16 - 25.3"

245/50-16 - 25.6"

205/60-16 - 25.7"

Wheels larger than 16" can be fitted to a Corvair. I have omitted them 
because they are not of general interest to Corvair people and must be 
fitted very carefully, as do even the 16's. Email me if you would like 
to see a list that includes larger wheels. Other tire diameters can be 
quickly computed using a handy calculator such as the one at: 
http://www.powerdog.com/tiresize.cgi

Based on this we can conclude the following:

1. 205/70-13 or 185/80-13 are good replacement sizes for 6.50-13's.

2. There are no currently available 13" tires that are good 
replacements for 7.00-13's.

3. 205/70-13, 185/80-13, 205/65-14, 195/70-14, and 205/60-15 are all 
close to 6.50-13's - check actual tire manufacturers dimensions. 
(245/45-16's are a good replacement in terms of diameter, but probably 
far too wide to fit most wheel wells originally occupied by 6.50-13's).

4. A 205/70-14 is essentially exactly the correct diameter to replace a 
7.00-13 as are 215/55-16's.

5. 205/70-14, 215/60-15,  205/65-15, 215/55-16, 245/50-16 are all close 
to 7.00-13's, although all may not fit the wheel wells. Check actual 
tire manufacturer's dimensions.

Of course we all know that different manufacturer's tires will vary 
some from these mathematically figured sizes. Also, we understand that 
correct diameters don't necessarily result in an accurate 
speedometer/odometer because of differences between bias ply tires and 
radials and the fact that Corvair speedometer/odometers weren't 
accurate from the factory. But correct diameters will give the correct 
appearance and be close in speedometer/odometer accuracy.

I don't believe there's anything wrong with someone using a tire that 
is a lot lager or smaller than the original tire, I just think it's 
important that they understand that they are doing so. I think a 
205/60-15 is a good size for a Corvair, even though it is about .6" 
smaller than a 7.00-13. I really like my 225/50-16's on the rear on my 
'67 even though they are .4" small. That's not too far off.

If you really want a stock look, use a 185/80-13 on cars that came with 
6.50-13's. To replace a 7.00-13, get 14" wheels and mount 204/70-14's. 
The beauty here is that you can get wire wheel covers that look just 
like 13's. The car will look very original. Most people will never 
notice that you're using 14" wheels. But you'd better hurry up and get 
those 205/70-14's, in ten years they probably won't be available!

For those who have seen so many under-tired Corvairs that you have 
forgotten what a stock, original Corvair looked like with its big 
7.00-13 tires, did you see the picture of the original 11 mile Corvair 
coupe that sold in that auction in Ohio recently? I'll send the jpg to 
anyone that requests it.

Bruce

Bruce W. Schug
CORSA South Carolina
Greenville, SC
bwschug at charter.net

CORSA member since 1981

'67 Monza. "67AC140"