All I know is when I ran a shorter wheel/tire package at Road Atlanta(approx 5-6% gear reduction) it made one hell of a lot of differance.
olddragger

 

Are there a lot of people running the RX-8 with the smaller wheel/tire combo?

 

hmmm... Is that why the automatics have more torque? I know they run 16's, but are the tires the same height as the ones that run 18's?

 

on the track I run a 17x8 enkei wheel with toyo ra 235/40. this equels out to a 25.4 inch tall wheel/tire combo(entire wheel with lugnuts only weighs 40lb). an 18 inch wheel with the stock o40's is about 26.6 inches tall. Do the math. I did and top speed in 4th at 8.7k is approx 119mph vs 127 or so with the 18's.
The lower gearing gives the car a lot more grunt in exiting.
olddragger

 

I know this is not a apple to apple comparison but on the RX8 what would be better for acceleration:

lower rear end
smaller wheel/tire
lightweight flywheel

 

If the aesthetics of smaller wheels don't bother you, 17's are the way to go. The 4.77 gear gives shorter gearing, and the flywheel gives lower rotational inertia--but the wheels give both. Not to mention the handling benefits of less unsprung weight. Then you have to remember that you could sell your 18's to offset the cost. And of course the installation costs are lower for wheels than the other two, and replacement tires are cheaper. It's a win/win/win/win situation.

 

Sounds good to me! I would save the OEM's for winter and run the smaller wheel tire combo in the summer. I can't remember the name of the device that recalibrates the speedometer but I think they're less than $100.

I am suprised more people don't do this, must be the asthetics. Could always get different springs to lower the car a bit.

 

from looking at the .jp rx-8 sites two things that keep coming up with the lower final drive are 'Bongo' and a 'spacer kit'.

Mazda does have a 'bongo' van with a 2.77 final drive. I don't think the US has this van model. in .au we call it the E100. The van gears are used in old rotary applications regularly .

the spacer kit did two things. it made the pinion shaft thicker for the bearing in front of the gear and also shimmed the ring gear.

 

Mine came with OEM 18" just like the MT...

 

stock bridgestone is 25.9 inches.

http://www.tirerack.com/tires/Spec.j...45WR8RE040MZV2

beers

 

LET US REVIVE THIS THREAD FROM THE DEAD. I CONTINUE MY HUNT FOR RENESIS POWER BY MEANS OTHER THAN FORCED INDUCTION (mainly b/c it is my daily driver and i am scared lol).

on a more serious note.........i believe the 8 will kick some *** with a different final gear ratio. although stock we can be laughed @ by 350's, WRX's etc. with a little bit of work we can be competitive. after installing the SR motorsports lightened flywheel the 8 picks up ALOT quicker. i can't imagine what it would be like with more pull in the lower gears to go along with the lightened mass flywheel. 1st gear would probably go by reeealllyyyy fast.

 

hey swoope
and the 235/40/17 is 24.4". I knew there was a differance but just got my numbers mixed up. you ought to see my checkbook.
OD

 

funny,
it seemed odd for you to be off. i had to check twice before i posted.

beers

 

best and baddest is 285/30-18, you get it all; max width and small diameter

 

oops looks like u lost the bet.......im still here.......well i mustve missed the part on the thread where he says it doesnt work..........sorry to hear it didnt........but thats what happens when u try n transplant parts from other vehicles n try to make them work in urs.......so my mistake, had a bad night with my girl n was pissed off n drunk, n took my anger out on some of u guys my bad, but hey if anyone is fortunate enough to come across, a ring n pinion that works, let me know.......

 

lol...

 

i have 17-8 rims with a 48 offset

with 225/45/17 the gearing helped it is way quiker than before. Dont think i could go back to a bigger wheel ever again

 

would this really work???

 

bump... i'm not very knowledgable on this topic... but, i'm definitely gonna be getting some 18's soon. TeamRX8, can u explain to me how this size would be beneficial??? thanks

 

The OE 225/45-18 diameter is 25.9"

Typical diameter for a 285/30-18 is 24.8"


25.9/24.8 x 4.44 = 4.64 effective gear ratio change, plus it lowers the car by 1/2" without any effect on suspension travel, but it also opens the gap up between the tire and fender by the same amount if that matters to you.



https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/18x10s-14912/


.

 

If its a LIMIT, how come I can still go faster?

 

Would 245/40/18's make any difference? (i.e. toyo t1-s)

 

heres what im gonna go im lookin now to buy some lightweight 17's with some low pros either falken, or the kumhos im runnin have been workin good....... n then after u get them put on go to the mazda dealer n have them reprogram i believe its the DRAC..... or some acronym close to that.........which should eliminate the CEL problem u might get with aftermarket wheels, n it should also eliminate a brakin problem u might have.......by either goin to larger or smaller wheels n tires then from the factory.

 

That would effectively give you a 4.48 final drive instead of the stock 4.44.

http://gs.tolan-hoechst.com/tirecalc.htm

^-----nice little calculator.

 

What about 275/35/18 Falken 615Rts?

I think the 285/30's might rub, right?