John Lye wrote:
> I'm currently running Goodyear 23.5 X 9.0 X 15 race slicks...
Hi John,
I'll make the assumption that your experiences with wheel
and tire combination on a TR4 can be extended to a TR6.
Converting "23.5x9.0x15" to contemporary tire dimensions,
I make that to be the equivalent of 225/50x15. Is that correct?
Refering to an old post from Bob Lang who gave us a very valuable
spreadsheet on tire size (I repeat here, thanks Bob!):
SW AR WS WW SW SH OD RPM RPM G GR FDR Speed Comments
-------------------------------------------------------------------------
185 80 15 5.10 7.28 5.83 26.65 780.38 6500 4 1.00 3.70 139.36 Stock TR6
225 60 16 6.20 8.86 5.31 26.63 781.08 6500 4 1.00 3.70 139.23 "Real Nice match
for ""low Profile"" TR6 tyre"
215 70 15 5.93 8.46 5.93 26.85 774.66 6500 4 1.00 3.70 140.39 Looks Ideal for
TR6 Replacement
205 70 15 5.65 8.07 5.65 26.30 790.90 6500 4 1.00 3.70 137.50
185 65 15 5.10 7.28 4.73 24.47 850.07 6500 4 1.00 3.70 127.93
205 50 15 5.65 8.07 4.04 23.07 901.57 6500 4 1.00 3.70 120.62 "Probably good
AutoX tire for TR6, like 4.30 gears"
225 50 15 6.20 8.86 4.43 23.86 871.82 6500 4 1.00 3.70 124.74 "Ditto to
above, JK Jackson endorses this."
205 60 15 5.65 8.07 4.84 24.69 842.62 6500 4 1.00 3.70 129.06 This is like
using 4.01 gears in the diff.
Legend:
SW == Section Width OD == Overall Diameter
AR == Aspect Ratio RPM== Revolutions Per Mile
WS == Wheel Size RPM== Engine Revs.
WW == Wheel Width G == Gear
SW == Section Width GR == Gear Ration
SH == Section Height FDR== Final Drive Ratio
Speed == Lower speeds indicate relative decrease in speed for equiv.
engine speed, all drive-line factors considered.
We see that 225/50 would lower the car height by approx 1.4" and change
the speedo accuracy substantially.
In other posts I've read where "..225-65-15's D40's on 7" rims that are
awesome, but they rub a little on the tops of the front fenderwells
when turning fast and hard" (Hctcbob@aol.com, his Shelby wheels have
3.75" of backspace, compared with my 7" Pana's with 3.9" backspace) and
Roger Bolick says "...215/65 or 225/60, I've seen both, the 215/65
are safe and look great. The 225/60 poke out of the front slightly..."
Finally, and we arrive at my question, what are your experiences with
the (presumably) 225/50's? Do they rub, poke out, etc? What wheels
are you using and what are their offset/backspace?
Shane Ingate tired out in San Diego
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