question about tirerack and how they figureout tire size..
 

ok....searching in the forum tells me that the S4 wheel (ninja blade) is 24# and the S5 wheel (cheese grater) is 18#.

I need new tires, so I am thinking about upgrading the wheels too...partly to change the look, but mostly to reduce the wheel weight. I am thinking of a 17x8 all around, and the lightest is the SSR Competition here:

http://www.tirerack.com/wheels/Displ...2FMachined+Lip

13#!!!! That's over 10# per wheel. I do like the new silver look.

Does anyone have this wheel? Pictures?

But at $1500, pretty stiff....

Any other LIGHT 17x8 wheels you guys can recommend??

and another question:

Why does Tirerack only let me pick the 17x7.5 wheel? Lots of people think that the 17x8 should have no problem fitting all the wheel wells?? Please advise (rubbing? too wide? too ricey?).


dewey

From what i know, the back should fit fine, but the front will need spacers. not sure what amount size ect. i love the wheels, kinda look like 3rd gen wheels

I like them too...except for the price...

Are you sure the front 17x8 would need spacers? I did not come across this when searching...

May be that's why TireRack limits the wheel size to 17x7.5???

anyone??

:D

Tire Rack will not recommend any wheel that is not an near perfect fit. Non-hubcentric, requiring spacers, or incorrect offset are things they will not do.
If you want to go into the "unknown" you have to goto your local tire / wheel shop. Typically, they figure that any wheel that will bolt up is OK, and will sell them to you in a heartbeat...you may pay for this in the long run.
BTW, why must you have a 8" rim? Obviously 7.5" will be slightly lighter, and a better fit to the tire you will be running, which will likely be a 215 or 225 anyway.
If you are planning to to run a 235, then you may be in for a surprise (not a good one).
Theoretically, if you did run a 235, a 7.5 would handle it just fine, but the offset would have to be relatively low to keep a 235 from hitting the shock, and would push the wheels out, putting unhealthy stress on your suspension.
The engineers at Mazda did a lot of r/d on the suspension geometry of the RX7 for a reason, and messing with that usually is detrimental.

more data and questions
 

well you have a point....

so if I were to get 4x 17x7.5 (with 215/45-17 tires as recommended by TireRack), then what offset should I be buying for the front wheels and the rear wheels (same??). Searching the forum shows a wide variety of opinions. Actually, opinion varies anywhere from 30 to 40mm, with different values from frt to rr..

So let's go shopping....as an example, let's take the SSR Type C wheel options:

SSR Type C, what's available..

17x7.5, 5/114.3 +32
17x7.5, 5/114.3 +40
17x8, 5/114.3 +30
17x8, 5/114.3 +35
17x8, 5/114.3 +40

SSR website matches the following set for our FC3S:

front 17x7.5@+32 215/45-17
rear 17x8.0@+40 235/45-17

here are the questions (I use the wheel calculator at http://www.geocities.com/xtremephoenix/tire.htm) :

why wouldn't they pick the +40 for the front? The calculator tells me that for a +40:

Tire & Wheel Inboard increase = .445"
Tire & Wheel Outboard increase = .445"

On the otherhand, compare to a +32, the offset would be:

Tire & Wheel Inboard increase = .13"
Tire & Wheel Outboard increase = .759"

So, for the front wheels/tires, should we be biasing the wheels away from the suspension? Is the +32 then ideal for a 17x7.5?? Would it look good? Will pushing the wheel out by .759" cause the tire to rub the wheel well?

Now, if I want all 4 wheels to be the same (so I can rotate the wheels), will a 17x7.5@+32 215/45-17 at the rear be ok? Will it look funny??


other wheel size for your ref (matching for FC3S):

SSR GT1
front 17x7.0@+38 215/45-17
rear 17x8.0@+38 235/45-17

SSR Integral
front 17x7.0@+38 215/45-17
rear 17x8.0@+38 235/45-17

Lots of questions, I know...but I have to be careful since we are talking lots of $$$$. It would suck big time if I picked the wrong one..

Thanks,

dewey

I just ordered some 17x8`s I hope it is not too detrimental.

John

the wheels you ordered...what's the offset?