aussieelan,
The Miata site shows everything correctly except for the tire revs/mile. To see this, enter a tire size and see the tire revs/mile. Then go to
www.tirerack.com, enter the same tire size, go to one of the manufacturers, look at the technical data that usually has the manufacturers tire revs/mile figure. There will be a difference.
Quite fortunately, the percentage difference between two tire sizes is correct since the ratio of the two incorrect figures is correct.
If you really want to be assaulted with too much data, I have a spreadsheet that has the commercially available tire sizes sorted by revs/mile so that if you enter one figure, you see all the sizes and how far apart they are. It is much too large to post, but if you PM me, I will send you a copy. There is one column of the sheet that is identical to the Miata figures, but this is never used since it is a purely geometric calculation, and the manufacturer reported data is used for all speed calculations.
collins_dan.
The quote you got from Superlite is probably for their Classic Range. The weight for a 15X6 wheel is about 18.8 lbs. Minilite quote about 20 lbs for their 15X6. The stock wheel is about 12.5 lbs, so this is a consideration. Superlite has lighter wheels, still in the minilite style, in the Ultralite and cast center series, about 14.8 lbs for a 15X6, but they are pricier. The billet series does not have a minilite style but weighs 13 lbs. And finally, they have magnesium wheels in the old 26R pattern.
As to whether they will fit, it depends on which 185/60-13 tire you have. I have run 165-13, 185/70-13, and 185/60-13 on my early S4. They all required material removal from the inner rear fenders, and, eventually, small rear springs. The 185/60-14 is the same diameter as the 155-13. The 185/55-15 is between the 155-13 and 165-13 in diameter.
Hope this helps.
David
1968 36/7988