Tires(again)

[passaret@sol.med.ge.com ("Mr. Mike" Passaretti x7-4485)]

What's the approximate profile number for a metric tire
(tyre)?  I've been running some numbers to see what I can fit
on the TR4 with TR6 wheels, and I'm not sure what the original
rolling radius was...

This is what I've run so far.

Specification  Sidewall  Radius  Circumference  Revs/Mile  Difference
165/75-15         124mm   314mm         1974mm        815   0.0%
165/72-15         119mm   309mm         1943mm        828  -1.6%
165/70-15         116mm   306mm         1923mm        837  -2.6%
165/65-15         107mm   298mm         1871mm        860  -5.3%
195/60-15         117mm   308mm         1932mm        833  -2.1%
195/50-15          98mm   288mm         1810mm        889  -8.4%
205/50-15         102mm   293mm         1841mm        874  -6.8%

My eyes would say that it's around the 75-72 numbers, but I'm
not sure.  
                                                        - MM
-- 
"When he pulled the trigger                          When the chainsaw started 
 Was it hard to figure?                              Was he broken hearted?"