What size P-Metric tire would be the equivalent of a 8.20-15 slick in P-Metric size. I've looked for a conversion chart but can't find one. I want to find two tires that would be equal in size to do some mock up work on the Henry J.
What width wheel you mount the tire on affects the overall width as well. What wheels are you planning on running? Also, an 8.20-15 slick is most likely a bias-ply tire, there will be no exact equivalent in a P-Metric radial size, due to differences in construction, but maybe something close.
All tyre sizes are nominal but, contrary to the trend in this sort of thing and therefore surprisingly, the more recent sizing system gives us more useful information to work with than the older ones. A good strategy to follow is therefore to look up the advertised overall diameter and section width of available 8.20x15 tyres, and calculate the P-metric equivalent from there. The dimensional range of tyres advertised as 8.20x15 is in fact quite wide: they may be anything from 29½" to 31" tall, with a section anything from 8½" to 11" wide. Coker list an 8.20x15 slick at 30.92" tall and 10.7" section width. Now: (30.92 - 15) / 2 = 7.96" sidewall height 7.96 / 10.7 x 100 = 74.39% aspect ratio 10.7 x 25.4 = 271.78mm section width That gives 272/74R15 - an odd size. What we're looking for is therefore probably something around a 275/70R15 or a 265/75R15. There appears to be no such animal as the former, but Tire Rack list eight of the latter. Let's verify: 265 x 0.75 = 198.75mm sidewall height 198.75 x 2 + 15 x 25.4 = 778.5mm 778.5 / 25.4 = 30.65" overall height, i.e. very close 265 / 25.4 = 10.43", section width i.e. very close Taking a sampling from the Tire Rack page linked to above to verify further, we get 30.7" & 10.5"; 30.6" & 10.5"; 30.7" & 10.6"; etc., again very close. 265/75R15 is your answer.
Hmm, I don't think all those numbers are correct, fairly sure a B78-14 is a 195/75 R 14 or 205/70 R14. Did a quick google search, holy crap, all the charts out there do not share the same P metric equivalents.
I'm going to run a 15x8 rim. As far as what tire I'm going to run, I haven't got that far. I want to run a pie crust slick but I'm looking for one with tread. I'm basically just trying to get a BIG rough figure for cutting out the rear wheel openings & to have something to roll it around on.
Then you need to first go look at what tires are available in the style, and see what the section width and diameter is. (Or just go ahead and buy them now, because you don't know what will be available in the future....then you won't need the mock up tires.) Once you know what size tire you'll get, then you can get a mock up. I think most of the pie crust type tires available are "recaps" on modern casings. So...look at what size tire they started with. It'll probably be a 235/75 or something close
Hurst tires lists several sizes http://www.hurstracingtires.com/1093440.html They give the height and section width of the tires so it should be fairly simple to find some rollers in the 4x4 tire cast off piles. Way out of the range my wallet can handle though.
kind of what I thought... "HURST 28 3/4"x8 1/2"x15" PIE CRUST List $385.00 pair Slick This tire is available in Full Slick $385.00 pair Blackwall, Cheater Groove $385.00 pair , or one of our Custom Dirt Patterns $475.00 pair Capped on RADIAL 235/75/15 "
Thanks for the help here guys! While were on this subject what would be the best size for that Gasser look with 15x8 wheels if I decide to just go for a regular tire or even a pie crust slick in your opinion?
The Jalopy Journal
