yell0w

Specs:
Car: 97sc300
Rims currently on the sc300: Rota Grids 18x9.5 +24 all around with 225/40/18 on front and 235/40/18 on rears.

I'm purchasing new rims, SSR sp1 sbc. I'm getting the fronts in 18x9, +19 offset and on the HyperDisc. As for the rears they'll be 18x10, +24 offset and on the Normal disk/Low disk. My sc300 is lowered and rolled. So would 225/40/18 in the front and 245/40/18 work?

I was reading this post https://www.clublexus.com/forums/the...00-poll-2.html

And it was quoted by asnatlas

"Aftermarket
245 / 40(98mm) / 18(457mm) = 555mm*
285 / 35(99mm) / 18(457mm) = 556mm*
*= the total diameter from top or tire to bottom (including rim)
As you can see from the ex above both fronts / rears about about the same (1mm does not matter)
Now if you would have did the same ex. as able but had 285/40/18's on the rear you would have a 15mm (1/2in in total) / (1/4in) on each side of the rim larger sidewall...
Stock setup
215(mm) / 60(129mm) / 15(381mm) = 510mm* in diameter x 215mm width
So you want your aftermarket rims and tires to come as close to the 510mm diameter as you can get since the cars speedo was set for that size wheel to run accurate... "

is this true and would my set up work?

Please help!

Thanks!

kphu

iTrader: (8)

According to www.miata.net/garage/tirecalc.html your better off running these tires.

225/40/18 (front)
265/35/18 (rear)

If you run 245/40-18 for the rear, your speedo with be off by 2.2% which isn't a whole lot but, if you want to get it as close as possible then the 265/35/18 is better.

Specification Sidewall Radius Diameter Circumference Revs/km Difference
215/60-15 129mm 320mm 639mm 2007mm 498 0.0%
225/40-18 90mm 319mm 637mm 2002mm 500 -0.3%
245/40-18 98mm 327mm 653mm 2052mm 487 2.2%
265/35-18 93mm 321mm 643mm 2019mm 495 0.6%