just got 17x8 and 17x9 rims for my FD with +35 offset. the rears came with 255/40/17 on it. my car has racing beat springs and tokico illumina shocks and RB F&R sway bars. just wondering if i can run 245/40/17 up front and 275/40/17 in the rear ??? or am i totally wrong ?

 

Run 245/40 up front, stick with 255/40 or go down to 245/40 for the rears. 275/40/17 is almost an inch too tall and you will probably rub, not to mention reducing your axle ratio and causing your speedo to be off. In addition, you should run atleast 9.5 to 10 inch wheels for a 275.

 

245/40-17s sound good up front. Though 8" is listed as the minimum rim width for the tire models I looked at. You might also consider a 235/45-17 tire, but I would rather have the smaller diameter 245/40 even if it is a little wide for the rim, to avoid rubbing.

I was looking at the spec sheets on the Tire Rack site, and the few tires I looked at in 275/40-17 indicate that the rim should be 9-11" wide, so they should work okay on a 9" rim. You might actually get better handling with 255/40-17, though, as the sidewall won't be rolled under as much. You might also consider 265/40-17 as they are somewhere in the middle. The tire diameter is very important in front, but there are a lot of people running 275/40-17 in back without any rubbing problems, depite the larger overall diameter. The tire spec sheets also have diameter on them, so you might seek a tire model that has a small diameter for the nominal size (actual tire sizes vary even for the same xxx/yy-zz number).

-Max

 

I have 275/40-17's on the back of my FD and have never had any rubbing. On the front I have 235/45-17 and they have rubbed once so it is no big deal. I have seen 245/40-17's on the front of an FD but the guy told me he had the fenders flared a little bit so they wouldn't rub.

 

i am trying to get the widest rear tires as possible for as much traction i'll decide soon which size to go with. thanks for the help

 

anybody else have an opinion ?

 

225/45-17 for the 8 x 17 and 255/40-17 for the 9 x 17

 

9" will work fine for 275s.

 

i think i'm going with 245/40 front and 275/40 rear

 

9 is too narrow for a 275 width tire; 8 is too narrow for a 245 width tire. The overall diameters are off between the 245 and 275...24.5 for the 245/40-17 and 25.7 for the 275/40-17...your car will have negative rake, and will look jacked-up...but that's up to you...it's your car...I stand by my original recommendation...

 

there are stock FD's out there with stock rims running 245/45/16 with no rub in the front. i'm surprised you think i won't be able to run 245/40/17 up front. i have drag racing tires on two stock rims 305/40/16 and they fit the rear without hitting anything. i'm fairly confident it will work. saying it won't work and actually having it not work are two totally different things. my car should have about 500rwhp when its all done. i just want to have as much traction as possible. this car will be used for drag racing and road racing along with normal street driving

 

My friend's 96 FD type RS, came stock with 17-8" 235-45-17 in the front and 17-8.5" 255-40-17 in the rear. He has no problem with rubbing

 

Vosko--If you're going to do what you want, then why do you ask for everyone's opinion?

I'm not referring to rubbing, I'm referring to the lack of support a narrow rim will provide a wide tire.

Please note that 245/45-16 has a taller sidewall profile allowing that tire size to fit a narrower rim. The shorter the sidewall, the less amount of rubber available to become squashed by a narrower rim for the tire to fit. Think about the measurements. 245 mm is 9.7 inches wide. 275 mm is 10.9 inches wide. So now you want to mount a ~10-inch wide tire onto an 8-inch wide rim; and an 11-inch wide tire on a 9-inch rim? Now consider that shorter sidewalls...sure you might get the tire to fit (barely), but performance will not be ideal for cornering traction or handling feel.

As for Mazda choosing their RS fitment, I can only assume that they want to minimize weight mounting the narrowest rim possible. It's not necessarily the best fitment, but I have no arguments against what Mazda engineers come up with. I assume they have to make compromises based on weight expectations and ride comfort, etc, thus they chose the wheel fitment that meets those compromises.

IMO, for road racing applications, ideally, you want the tire bead-to-tire bead width to be the same width as the wheel rim's nominal width. If you measure a 245/45-16 Hoosier R3S03, from tire bead-to-tire bead, that dimension is 9.25 inches. Ideally you should mount that Hoosier tire size on a 9-inch wide rim to fully appreciate the extra contact patch of that tire size. Yet most everyone runs a 245/45-16 Hoosier R3S03 on a 8 or 8.5 inch rim width. That's ok, according to Hoosier Racing Tire, but you're not generating much more contact patch than a Hoosier R3S03 in size 225/50-16 mounted an 8-inch wide rim, so you're wasting your money (IMO).

Now for drag racing applications--drag slicks have very compliant sidewalls. Your 305/40-16 is 1-inch taller than a street 245/45-16, thus affording at least 0.5 inch more sidewall height. This extra amount of sidewall rubber, coupled with very soft sidewalls, allows such a wide tire to be mounted on a very narrow rim.

You're asking about a street setup, NOT a drag racing setup...the points above explain my original recommendation...

 

I've got a set of 17x8 F and 17x9 R SSR Integrals with 235/45/17 F and 275/40/17 R. I'd say the rear tires fit the rim just fine although ideally I think they'd be 265/40/17 (check the prices and availability in that size).

Anyway I've got a set of Fikse 17x8.5 F and 17x10 R that I'll be putting the same tires on. I think that 275 on the rear might not fit the rim as well. I know the 235 won't fit the 8.5 wheel as well, I'd like to go 245 in front. I used to have some MOMOs with the same brand/type tire with 235 on 8.5 wheel. The rim stuck out slightly farther than the tire.

Jeff

 

I had up to a 255 on my 8" wide rim and it looked and worked just fine, I cant see why a 9" wide rim wouldn't hold a 275 easily.

 

You're not getting it...it's ok...your "special" fitment works for you, so don't sweat it...

 

i'm not questioning you sleepR1. just trying to see what everyone thinks. eveyone is entitled to an opinion. i'm sure you know far more than me about road racing and handling. this car will be mainly street driven. i have attended one road course event. i plan on attending the mazda drivers event in september. i might go with your tire recommendation after all. i just wanted to know what other people were running. 17x8 and 17x9 is a very popular size

 

OK, good luck with the MADS September event. It'll be fun, and there will many more knowledeable FD enthusiast brains to "pick" there

FWIW, and IMO, the absolute ideal road/track setup is 9 x 17, 45-mm offset SSR Integral A2s with 255/40-17 tires (pick your favorite) The handling balance is completely preserved, but the cornering stick is just amazing. Out on the street, I have much more trouble kicking the tail out coming out of a dead stop to make a turn in 1st gear redline...which was usually very easily done with my 225/50-16 tires on 8 x 16s all around. Aesthetically the setup looks fabulous. I love the very thin spokes of the SSR IA2s. They show off my '99 Type RS brakes (fr/rr) to excellent effect If you're into 18s, you could get the SSR Integral A2s in 9 x 18 in 45-mm offset with 255/35-18 tires. Unfortunately the 9 x 17s and 18s are sold out at the Tire Rack, so you'll need to find some other setup. I'm not aware of anything like that, short of going with Fikse FM/10s...None of the Volks will work as their 9 x 17s/9 x 18s have 40-mm offsets, which is slightly low, and might cause some rubbing up front. The 45-mm offsets are perfect and have not rubbed at all during the time I've had the setup (since Feb '02).

 

i already bought these rims

they are 17x8 +35 and 17x9 +35. the rears are 255/40/17. didn't come with front tires. these are rims are very rare. i think only like 3 sets exist!

i think 3 piece racing hart wheels should suffice

before you recommended 225/45 and 255/40. you still recommending the same size ?

i could have gotten SSR 17x8.5 and 17x9.5 last year. bacon was gonna buy them but decided not to. i convinced him to buy them and he LOVES them. i got a deal i couldn't refuse for the RB rims

 

Yeah, those are nice, and ARE rare! I wondered who snapped these up from Racing Beat's "garage sale"

With an 8 x 17, 35-mm offset for the fronts, I'd stay with 225/45-17 tires. The 35-mm offset is a bit far outward, and you don't want to risk any rubbing with a slightly wider/taller tire! You can probably find a match for the rears--225/45-17 is a very common 17-inch size.

Best of luck!

 

i picked up the miata rims for my mom's miata too

 

well, I have 17/8 and 9 on my RX now

Believe me, you need 235-40 on the front 265-35 or 255-40 on the rear.

this is suggest offset from Advan Tire Co in Japan!!

Shingo

 

why don't you just rb what they ran when they had those wheels.

luigi

 

i don't know what they ran on the front. the fron was 255/40. i could call them but i doubt they know what it is LOL

 

Probably 225/45-17...which is what I've suggested