Toy

SleepR1,

i spoke to a rep at Fikse concerning the info that you posted about running 18x10 in the rear with 285/30 and 18x9 in front with 255/35. The rep says that the 18x10 in the rears won't be a problem but they generally run 18x8.5 in front with 225/40. Won't that cause understeer? Here is what he said:

"The numbers for backspacing that the person looked at to get the offsets was from our 17" wheel chart. If you can fill out a Fitment Data Sheet (download from http://www.fikse.com/cad.html) We can verify the amount of space we have if we know how much space inboard from the mounting face is and how much space out board to the fender there is. I think that's the
best way to go, because different people have different tolerances for things like rubbing. Personally I like zero or no rubbing at all, but most people can deal with a little bit. So I would strongly suggest getting
those numbers and verifying that it is exactly what you wanted. Our standard 18 inch fitment actually runs a 6.5” backspace on the front and
7.5” backspace on the rear."

So what are those measurements he's asking for? sorry for my lack of knowledge on this subject.

thanks for all the help.

Toy

SleepR1

The decision is yours alone to make. My fitment is more aggressive and dials in less understeer, Fikse's is more conservative with more understeer...

Toy

Can i still run 255/35's on 18x8.5 up front? or is the rim not wide enough? Also, how much space inboard from the mounting face and how much space out board to the fender is there?

SleepR1

Toy,

You'll need to work with your Fikse rep. That's what you're paying a Fikse dealer big money for.

I'm certainly NOT benefitting from the info I've ALREADY posted for you...

ZoomZoom

iTrader: (2)

Ok I didnt listen and bought the 285-30-18 and the 255-35-18. Still waiting for the wheels to arrive. I got my Bisteins and H&R springs like you suggested but I am going to try and fit these Pigs under the car. If I gotta Roll the fenders so be it! I just want the widest tires I can fit. I know I pushed the limits on these things but its just a street car. I never track the car. I will make them fit one way or another But I will post pics and feedback on the fitment as soon as I get the wheels. Should be within a few more weeks. 60-90 days on Volks!! I hate waiting. I will update soon once I get the whole thing together.

ARD T2

iTrader: (22)

Zoom,

Hopefully you got 245/35's for the front as the 255 will be taller than the rear 285/30. This info is available in any of the tire books or online websites. Please look into it.

The 9" with a 245 is absolutely beautiful, and the 285 on a 10" ungodly.

Hope this informs you of something you may have overlooked.

See ya, Rishie

If doing 255's up front I'll suggest a 275 in the rear as diameter and gearing or not the concern of priority.

ZoomZoom

iTrader: (2)

There isnt **** for tire selection in 245-35-18. I wanted to get the S-03's all around thats why I eneded up with the tire sizes. I wanted to go wide as well so thats the reason for the tire sizing. All the book I read at work showed the 285 30 series tires as a good fitment for 9.5 inch wheels and the 255 for 8.5 inch wheels. I do know the tire is about 2 tenths of an inch taller in the front and about the same lower in the rear. But the tire selection really kept me from doing any other sizes unless I went very conservative on width.

SleepR1

zoom zoom,

You do know those are the minimum wheel widths you're reading. IMO, minimum wheels widths (stated by tire manufacturers) are NOT ideal for performance. In most cases, a properly fitted tire will outperform a tire that's mounted on a too narrow a rim!

Generally I would NOT mount a tire on a rim unless I can get 90% coverage of the tire section width with the wheel width.

As an example, a typical 255-mm section width is 10 or so inches. 90% coverage would require a 9-inch wide rim for sufficient support of a 10-wide tire.

A 285-mm wide tire will require 10 inches of rim width to support an 11.2-inch wide tire. 9.5 inches will provide 85% which is merely adequate, but not ideal for the best support of such a short sidewall, and wide contact patch!

Aesthetically, a wide tire mounted on a narrow rim, looks too bulgey, and unattractive IMO. A too wide a tire on narrow rim gives the impression that the owner is too cheap to buy a wide rim, and so would rather "make" more contact patch by mounting wider tires (which doesn't work).

The only racers that mount the widest possible tires on narrow rims are SCCA racers who are bound by a rule book. They then get around a maximum wheel widths by mounting cantilevered slicks--which look gawd-awful, but they do add extra contact patch despite a narrow rim widths. Cantilevered slicks are designed to be mounted on narrow rims...

In conclusion, I stand by my recommendation of 225/40-18 tires on 8.5 x 18 wheels; and 255/35-18 tires on 9.5 x 18 wheels.

Put it this way...the slightly narrower tires will be cheaper than the wider tires you're wanting; and the 225/255 tires will fit properly and perform ideally from the generous rim widths.

GoRacer

iTrader: (2)

I've narrowed down my choice to Racing Hart CP035 or Fikse Mach V's. After seeing articles on the CWest and FEAST RX-7's I chose to follow with 17x9.5's-F&R.

When getting price quotes from wholesalehyper and Fikse, they insisted the staggered setup is better.

I've seen 18x10's-F&R but it does not tuck in behind the wheel well lip, it goes under it flush with the outside of the fender. It doesn't stick out past it, but I want it tucked in side of it so it doesn't hit on hard bumps (pot holes, dips).

The RS model has a staggered setup which confuses me on Mazda choice of neutral or staggered.

SleepR1

You can go 9.5 x 17 fr/rr with 50.4-mm offset, 7.23-inch backspace as taken from Fikse's own offset table.

http://www.fikse.com/offsets.html

The key is choosing the 255/40-17 tire size. That will ensure you get no rubbing issues. 255s will fit beautifully on a 9.5-inch wide rim...

FWIW, I'd do Volk CE28Ns in 9.5 x 17, 47-mm offset for a race-only setup using Michelin Pilot Sport Cup tires in 255/40-17. The Volks won't tuck in as nicely as the Fikses, because the Volks come in 47-mm offsets, so the Volks/Michelins will be almost flush with the fender lips, fr/rr.

My personal favorite Fikse wheel is the Mach V. If I had to do only one set of wheels for road and track use, the Fikse Mach Vs would be the wheels I'd choose.

http://www.fikse.com/images/machv.gif

GoRacer

iTrader: (2)

Thanks for the reply

It's a pretty hard choice. The Racing Harts are only 15lbs for 17x9.5 I'm not sure what the Fikse are but they will custom offset and they sure have the girl catching bling bling

The tires will either be Yokkohama A032's or Toyo T1S's. The A032's don't come in 18's and I love them and don't mind the slight noise.

Why does the '99 RS model have a stagered setup? Is there an advantage or is it because of demand, since alot of people dit it? Maybe i's more forgiving for the novice driver?

Ooh, if the offset is the same (50.4) of F&R, does that mean you can rotate? You can't rotate the exact same size wheels if the offset is different, correct?

SleepR1

I don't think you'll get the Racing Harts in the offset you want. The Fikse will probably be your best choice.

I don't know why Mazda staggered the setup for the late model FDs?

Yes you can rotate 9.5 x 17, 50.8-mm offsets wheels

ptrhahn

iTrader: (9)

I think a staggered setup is really for the amount of power you're making. I know its a 50/50 weight distribution car yada yada.... but theres a reason even the stock springs are heavier in front than rear.... to balance the car under power (and braking too, likely).

I ran 245/40/17s all around for a while and the throttle-on oversteer was horrendous. And, if it was a little chilly out, i'd be spinning through 2nd gear if accelerating in a straight line. Now i run the very typical 235/45 275/40 17 setup, and laying the power down is much easier. I wouldn't say the car is "unbalanced" either.

I can't imagine wanting more than a 255 up front, but i'll take all i can get out back.

ptrhahn

iTrader: (9)

Oh yeah, get the Fikse's.

SleepR1

I ran a staggered setup for the track using 245/45-17 on 8.5 x 17 and 275/40-17 on 9.5 x 17. Tires were Hoosier R3S03s, and wheels were SSR Competitions. The staggered setup, made me more comfortable and certainly kept me from spinning at all this year. The car was much easier to drive. Problem is the front tires take a beating because of the increased mount of understeer.

Next season I plan to run 275/40-17 Hoosiers all around with 9.5 x 17 Volk CE28Ns (47-mm offset)--or--255/40-17 Michelin Pilot Sport Comps (if the Hoosiers are no longer being made).

HKS_EUROPE_JAI

Hi...hmm...this is my 1st post..hehe

Just wandering if you cpuld help me clear somthing up SLeepR1?

When u mentioned for track setup u would run volk CE28N with 47-mm offest, I was a bit unclear as to the reason. I always presumed that a wider wheel track would be preferrable to an extent. I say this because I have a set of CE28N 17x9.5 +28mm offest comming next week.

I have a feeling that my confusion is the fact that I am working in +ve value and you are working in -ve for your offest. However, if this is the case, how do you work out your offest value?

The value I am using is the distance from the hub face to centre of rim along the x-axis. Is this similar to how u work out your value?

Im just a bit curious because all volk offset values are listed +ve. It would be good to know your method too.


Dominic Wai

Engineer

HKS Europe Ltd.

GoRacer

iTrader: (2)

Thanks Ptrhahn an SleepR1, that's exactly the feedback I was looking for.

Price may determine if I get the Fiske (assuming they are just as light). I don't think 275's tuck in though, at least not the ones i've seen. Maybe Fikse's custom offset could fix that. If not, i'll stick with 255's out back.

SleepR1

We're using the same definition of offset. I think the 28-mm offsets will be too little offset, and you'll get some rubbing up front. Track width is good, but you have to satisfy clearance issues with tires and fenderlips, assuming we're talking about FD Rx7 fitment clearances.

Actually my ultimate setup in CE28Ns would be driven by Michelin Pilot Sport Cup Comp 18-inch tire sizes: 9.5 x 18, 47-mm offset up front with 265/35-18, and 10.5 x 18, 44-mm offset in back with 285/30-18.

The fact is I cannot afford 18-inch Michelin Pilot Sport Cup Comps, so I'd be settling for a compromise using the 9.5 x 17, 47-mm offset CE28N with 255/40-17 Pilot Sport Cup Comps--or--275/40-17 Hoosier R3S03s (assuming they're still available in 2003).

maxcooper

The spring rates are different because the motion ratios are different for the front and rear suspensions. The wheel rate is about the same front and rear. For ride comfort, you actually want the rear wheel rate about 10% than the front, maybe a little less with stiff suspensions.

I think getting as much tire as you can get, anywhere, is a good idea. The fact that you can run 285s front and rear is great because the car sticks like glue and you can rotate the tires. I don't have any huge attachement to the same size all round except for the rotation advantage. I would go wider in the back if it was easy and didn't cost any more.

I like the fitments Manny is suggesting, too. Those CE28Ns are really light.

-Max

GoRacer

iTrader: (2)

18x10.5" in the rear! That's Corvette size (295's)

SleepR1

You could go with 265/35-18 on 9.5 x 18 47-mm offset fronts and 295/30-18 on 10.5 x 18 rears 44-mm offset. I'm referring to the CE28N wheels and Continental Contisport Contact 2 tires, which are both Porsche OE tires for the 2002/2003 996 Carreras. The 265/35-18 on 10 x 18 is stock Carrera rear fitment; the 295/30-18 on 11 x 18 is stock Carrera 4S (turbo widebody with AWD) rear fitment

HKS_EUROPE_JAI

Thanks SLeepR1

Sorry if I didnt word my post correctly. The main question was really how your -ve offset value corresponds to the +ve value I commonly use to measure offset.

My clearance issues are ok due to using arch extensions. Im trying out the Dunlop D-01 intermediate and will be comparing it to the Michelin Pilot Cups next.

Oh..ive tried contisports on my road car but wasnt too keen on them. I found BRidgestone s-03 to be very good as an everyday tyre. Which tyres have u tried out sleep? Any feedback on tyres would be much appreciated.

SleepR1

Ahh, well, if you have wheel arches and such, then you're right you can run 28-mm offsets, since you have adequate clearance for the extra track width.

I've run Bridgestones (RE71, Expedia S-07), Pirellis (P-Zero Asimmetricos), Yokohamas (A032Rs, AVS Intermediates), Kumhos (V700s, Ecsta 711s), BFGs (G-Force R1As), and Hoosiers (R3S03s, and Motorola Cup compounds). Have not tried Michelins and Continentals. I'm currently using the AVS Intermediates. They're cheap from the Tire Rack at $94 each in 255/40-17s. I plan to buy another set of five, perhaps ten tires. I've been quite impressed with the AVS I's. They're great for the road (quiet, smooth, grippy, and decent wet weather traction), and fairly decent drivers education track tires too!

I've had excellent success with track-only tires from Hoosier. The R3S03 compound is barnone the fastest US DOT-approved road racing tire on the market. I recently sold these tires and wheels (SSR Competitions) to Jaymz.

Tires I'd like to try are Bridgestone S-03 PPs, Michelin Pilot Sport Cups, BFG G-Force KDs, and Continental Sport Contact 2s.

FourtyOunce

iTrader: (15)

i am looking at these wheels for sale .. 18x9.5 all around with +45 offset. will it be a problem running them on a street FD ?? i searched .. not much to go on ..

maxcooper

That should work if you are careful with the tire sizes and are willing to do the rub-avoidance measures and accept some risk of rubbing. Michel has that setup.

Are they SE37As? Mmmm...

-Max