45mm offset: http://www.good-win-racing.com/mazda.../21-1051b.html

 

just got a set, they are f'ing awesome especially fo the price

18" has better sizings available over 245 than 17", the idea that 17" will be faster just isn't true in the real world results using the Enkeis Goodwin is selling, there's only one set left and it took 6 months to get that order so you might have to wait a while if you miss out

usin anything over 245 on the stock 8" wheel won't result in a larger contact patch, just more tire mass and in the case of the 275/35 taller diameter too, the 245/35-18 Kumho V710 barely fits as it is, most tire shops can't get them mounted

 

ok guys reviving this thread as I just goit a GREAT deal on some 17" enkei rpo 2 wheels (new) 17x8 from edge racing at approx $105 apiece ---thats right! They have some more!
Now my question is the tires. do i run a 245/45, or 245/40? I dont want hoosiers as they wear too fast. I am looking at the Kuhmo's (victoracers or the v 710's) and the yokohamas. I run Road ATlanta and Roebling(Savannah) I know th 245/40 will give me a little more gearing but that size comes in limited choices.
olddragger

 

245/45 will give you near the same rolling Diameter. The Gearing you'd pick up with the 245/40 would probably be better suited to AutoX than tracks with long straights (just my 2¢).

...you know the 275/40s fit on the 17x8

 

Oh, and incase anyone missed it...

 

Olddragger, thanks for the tip on the RPO2s! I took a look at edge racing's site, and it looks like the wheels you got have a +40 offset. I've been concerned about what this would do to the steering/suspension geometry. Any info you can share about your decision to to with this offset? I've been trying to get +45 and above, but if +40 is good for track use then it opens up a lot of options!

Marc

 

huh?

 

40 offset is no problem. I presently run a 18/8 35 offset for the street and I have tracked the car with those on (o40 tires. Had a professional alignment done--absoulutely no problems. Little wider stance never hurt anyway. And yes my car is lowered with konis and tein h springs.
OD

 

see alex's earier entries
od

 

Alex: that last bit is interesting....u sure about that?? sounds like a bit of a tire-mounting stretch...This wasn't on your own car was it? Assuming you saw this mounted on an RX8, do you know what offset the 17x8 wheels were? The Enkei rp02 is 40ET I'm wondering if that's sufficient or if less offset is needed to get 275s into the RX8 front&rear.

 

I have seen 275-40-17 Kumho V710s on 17X7.5, some of the 350z guys run them.

Tire Size Sidewall Diameter Circumference Rev/Mile Difference
225/45-18 4.0 in. 25.97 in. 81.59 in. 777 0.0% Stock
245/45-17 4.3 in. 25.68 in. 80.68 in. 785 -1.1%
275/40-17 4.3 in. 25.66 in. 80.62 in. 786 -1.2%

 

Wow! I guess my question woulda been better phrased: "given an 8" rim, does squeezing a 275 tire__instead of a more typical 245__ really get me all of that extra tread width on to the ground?". I'm sorta referencing TeamRX8's assertion earlier in the thread that this would be a losing battle. <hope I'm not starting a flame war>

 

While it is not the best setup, big tires on small wheels, there are a lot of guys that have great results with it. The 2003 AS champ ran 315s on 9.5" wheels. All the fast guys in CS Miata run 225s on 6"s. 04' FS champ ran 275s on 8" wheels. Its not a new thing.
Its one thing to do it in a stock class when you have to deal with a small wheel. If you are not going to worry about a race class you should go for the biggest wheel you can afford/will fit and then get the tire for it. To sum up, yes a 275 will have a tiny bit more foot print then a 245 on the same wheel.... However put that same 275 on a 9-10" wheel and you will get way more out of it.
If you are thinking for one second about 245s you should stay with 18", they get you some gear and will turn in better.

 

I 100% agree... That being said... Yes Gulaman, I am running 275/40/17s on my 17x8" rim with a 42 offset. You can see them on my cardomain page in my sig. I didn't think (nor have the cash to experiment) that a wider wheel/offset combo would fit with the 275s and lowering the car on the front.

The rears are 17x9 for the reasons ULLLOSE stated.

 

For you BSP/SM/STU or open track guys: https://www.rx8club.com/showthread.php?t=79804

 

get this for track days I will be running 17x8 rpo2 with a 40 offset. And on them I found(with a friends help) a grand am hoosier 225/45x17. Doesnt sound too bad right? Ok a little futher--the tire only weights 20lbs--gets better=== the tread front is 9.1 inches ---that right 9.1 AND the tire circumfrance(sic) is only 24.6 inches! There is my 4.77 final drive! (approx)
I am really excited about getting this on the track and finanlly using my xp/bobcat brakes to their full potential.
olddragger

 

unfortunately on an RX8 and an 8" wheel you won't put down any more rubber than a 245/40-17, but you'll see that for yourself by the scrub patterns as you use them

 

I am satisfied for now with that type of tire patch contact. Its the weight and circumfrance i am more excited about.
OD

 

Sounds like way to narrow of a tire for a near 3000 lb car to run laps on.

Tire Size Sidewall Diameter Circumference Rev/Mile Difference
225/45-18 4.0 in. 25.97 in. 81.59 in. 777 0.0%
225/45-17 4.0 in. 24.97 in. 78.45 in. 808 -3.8%
245/35-18 3.4 in. 24.75 in. 77.76 in. 815 -4.7%

You also gain less gear than we do with the 245-35-18. On top of that the 225-45-17 is not going to turn in as good and you have made your whole car softer, the tire also acts as a spring and you just put on a bigger softer sidewall.

 

just as well i didnt win the ebay bid anyway. so I am looking again for some good 17 inch tires. got to admit the 17's are cheaper than the 18's. An I aint no rich man. matter of fact got 3 teenagers.
I agree its not the best--absoulute best setup but for $250 it was a reall good deal and it was an adequete tire for someone running about 6-8 tracks days a year.I may go with the toyos or the kuhmos 710's. Unfortunely I cant get a 40 sidewall in the kumhos--at least --havent found them yet. sources?
olddragger

 

Kumho has a 245-45 and 275-40 17" right now. They will be adding a 245-40-17 V710 later this year.

 

and I didn't read the whole thread, under the circumstances I see where you're coming from

 

Yes---The rest of the story!
I have been looking at the K710's before I found out about the hoosiers on e bay. Grassroots MAg had a really good writeup on them in comparasion with the other R tires out there(except the toyo's for some reason). Seems the hoosiers new compund can wear out very fast under the right conditions. And the 710's where actually faster by just a bit but they also said there are not any BAD r compunds. They all are close. the 245/45's is exactly what I was looking at.
What is meant to be is meant to be. Anyway my rims are to be here on Monday 1/9! One step at the time.
olddragger

 

it's more than a bit, don't take everything you read in GRM as absolute fact