Does anyone know if a set of 17x10 +38 RPF1's will clear a Stoptech ST40 kit? I know they fit over EVO and STI brakes. Looking to pick up a set of these to replace my NT03's for track.

Print out the template off of their website. I have the same wheels and checked the template and it worked. I don't know if it was the st40, it was the fd kit.

The ST40 I have is the smaller of the calipers so that means I should be good to go! The problem with the template is you need the wheel to check the clearance.. which I don't have lol.

I contacted someone ("King"?) at Enkei via their facebook page before I got my PF01s to make sure they cleared my ST40 calipers. He was able to give me the swept profile to ensure they don't interfere. You should do that before purchasing.

Can anyone confirm that an 18x10 +15 will work on the rear with a roll?

I have 18x10.5 +15 all around on my car with pulled fenders. Pictures in my build thread

Funkspectrum Can anyone confirm that an 18x10 +15 will work on the rear with a roll?

Depends on tire width really. Offset centers the tire...

... and that offset is far off center toward the outside, so a narrower tire will be required versus ideal +45/50 offset.

You will need just a roll with -1.5+ camber to fit 245 on that 18x10 +15.

You will need a roll and a pull with -1.5+ camber to fit 255 on that 18x10 +15.

You will need a roll and huge 3/4" pull or flare with -1.5 or roll and pull with -2.5+ camber to fit 265 on that 18x10 +15.

Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

Thank you,

I'm gonna err on the side of caution and go with a higher offset wheel. I'm not sure I wanna toss on wider fenders in the rear.

As far as how "flush" or "stance" you want it.

I can tell you from my experience, with my 18x10.5 +38 and 265/35-18 or later my 18x11 +45 285/30-18 (same fitment to fender) with -1.5 camber rear and -2.4 camber front-

a straight edge across the face of the wheel with car at ~25 1/4" ride height to fender arch just touches the top of the fender arches (rolled lip under) as well (flush).

So, using that site you can adjust how much more you want the wheels to stick out or sink in.

Each degree of camber will pull in/push out the top of the wheel ~4mm and the top of the tire ~6mm.

Can one completely avoid rubbing with a 265/35/18 on 18x11 (on 2.5" OD coilovers) with low camber on the right offset (+45) and running ~5" of ground clearance?

Depends on the 265/35-28. Some are too tall and will want to rub on mudflaps at the back of the wheel arch if you have them and on the front inner fender liner. You are looking for tires as close to 25 tall as you can.

I don't mean to sound like your mom, but a 265/35-18 on an 18x11 is 1/2" more stretch than I would run.

If you rolled the front fender lips under and the 265 wasn't too tall you would still need around -2 degrees camber up front and -1.5 camber rear with stock fenders (or no rear camber if rolled rear fender lips) from my experience.

You can roll and pull the fronts to run a little less camber, but you would have to cut the fender liner at the wheel arch or slot the mounting holes and move it outward or find a way to tuck the fender liner up if you don't want it to hang down over the tire and rub on bumps.

Understood on the stretch, I'm used to looking at the section width and going to the nearest half inch of wheel. The tires I'm looking at are 10.7" section width, which rounds out to 11", but 10.5" would work just fine, just make the breakaway a bit less progressive.

Without rolling, would the 10.5" and 2.5" OD springs without being slammed allow for low camber numbers and no rubbing at all?

No rolling on the front along with low camber?

Nope, can't fit too much on an FD that way. The front wheel arch lip really catches tires turning going up steep inclines.

If you are trying to do that best to stick to full 50 offset which will limit you to 10.5 wide wheel before you start hitting suspension. Short 265/35-18 on 18x10.5 +50 and -1.5 camber *might* clear stock front fender lips turning sharp up inclines.

255/35-18 on 18x9.5 +50 would be the safe fitment for low camber and no front fender lip roll.

Finally think I've got it.

255/35-18 Fronts on Enkei PF07 18x9 +40 (highest offset this wheel comes in)
295/30-18 Rears on Enkei PF07 18x10.5 +15 + spacer (Pettit rear flares are on the car)

Will the front fit with no issues? Will backspace be sufficient to clear suspension bits? Any other things I need to keep in mind?

Nemo128 Finally think I've got it.

255/35-18 Fronts on Enkei PF07 18x9 +40 (highest offset this wheel comes in)

Front will fit with stock front fender lip and not catch if lots of camber (-2 degrees +).
Or
Front will fit with rolled front fender lip and low camber.

295/30-18 Rears on Enkei PF07 18x10.5 +15 + spacer (Pettit rear flares are on the car)

Rear 10.5" w/295 will be one inch from anything suspension related at +15 offset and ofc further by the amount of what ever spacers you add.

Thanks! What if I bring it in with a lower offset to avoid rolling? Can I clear the inside?

EDIT: Sorry, I see you answered similar before. Looks like you suggest 255/35-18 on 18x9.5 +50 but this wheel only offers a +40 max. Maybe I can't avoid rolling...

Nemo, pretty sure I saw your FD over in the paint booth by the old shop location right?

Which tires are you looking into? The 255/295 split is a good choice in size, only issue is most 'appropriate' tires available will probably run you about as much as the wheels--- R888, AD08R.

Yep, that's the one. I'm not worried about the tire cost, only the best option for the job.

Chris right? I like the way you think ;)

Recommend Yoko Advan AD08R....... more streetable than the R888 and just as sticky on the street :icon_tup:

Rolling fenders
 

So how many of y'all have been successful with rolling/pulling fenders without paint cracking or damage?

|o


What I do is score a line with a sharp hobby knife to the metal on the inner fender lip around the fender lip at the edge and then do the usual heat and roll.

The paint does chip off on the inner lip, but stops at the score line. I have had to use crazy glue at the score line where the paint on the fender side started to lift. Then I use touch up paint on the inner lip.

So, I can't say paint isn't harmed with this method- just not paint you can readily see.

If I want to run 17" 255s all around without rolling the fenders, without changing the geometry, and with optimal rim width (for the tire) and tire diameter (for the suspension geometry/gearing), what would I need?

255/40/17 on a 17X9.5 +50 back and front? Or what?

Yep, you got it.

17x9.5 +50 front and rear would be ideal for 255/40-17 and will clear stock fenders (might need to be on the higher side of stock allowable front camber around -1).

It won't be "flush", it will be functional.

I don't care if it's flush, but it absolutely needs to not stick out or scrape. And ideally I don't want to make the steering heavy or flighty...

If you find out what the offset for zero scrub radius is, let me know. ;)

+50

Awesome, have a citation?

It's the stock offset...

Right, but offset is a variable that only has meaning in the context of width.

Ie, oem wheel (16x8) has 52mm front spacing and 152mm back spacing---- call it 2 inch front and 6 inch back.

17x9.5 +50 yields 71mm front spacing and 171mm back spacing---- 2 3/4ish front and 6 3/4 back.

you're basically adding on 1.5 inches of width, and retaining the same offset splits the difference...... 3/4 of an inch on each side.

If this is retaining the scrub radius at zero then maybe it's party time :djcelebra

:D

The offset is what the tire sees in relation to the suspension. Having the same offset will keep the same scrub radius even with different widths as the tire "grows" around the scrub radius in equal directions.

Most people run positive scrub radius (lower offset wheels) which when large enough can lead to the tire grabbing the road and pulling the steering wheel, especially under braking.

Try to run a minimal positive scrub radius or run stock where possible. with aftermarket suspension a 17x10 +50 is a good bet or 18x10 +50. +45 is also pretty minimal...I am running +42 with 11.5" wheels up front and I don't have any negative effects from it that I can tell.

GoodfellaFD3S

If this is retaining the scrub radius at zero then maybe it's party time

Well, we should not assume the stock FD has zero scrub radius.

In fact, that would be impossible because it supposes one could keep the tire contact patch (not even just the wheel) perfectly parallel to the road surface and have the front and rear steering axis move with the contact patch to maintain a static scrub radius.

I think what most people are interested in is very little change in scrub radius in the range of suspension movement they drive in for normal/relaxed driving.

Yes, if you stick to stock alignment settings, stock suspension height, stock tire diameter, stock bushings, stock tire sidewall and stock offset you will have zero change in scrub radius from stock (and a stock FD :lol:).

Stock offset is a good start if you are trying to maintain (excellent) stock driving characteristics though.

Citation needed. Assuming something without data is counterproductive.

I'd like to see where about zero would be, want to see where I'd lose all negative scrub that I'm assuming is built in to +50 offset.

Sorry, I took "zero" to mean "the correct (stock) amount."

This video explains the terms nicely:

17x10 +38 over stoptech ST40 Kit

https://c7.staticflickr.com/8/7566/2...6540be8e_b.jpg20160621-DSC_1277 edit by chronumn, on Flickr

https://c4.staticflickr.com/8/7325/2...7a476203_b.jpg20160621-DSC_1263 edit by chronumn, on Flickr

Show us how well they fit in the fenders!

I will report back Saturday once I get my tires mounted!

Edit: in the air with no tire, probably doesn't help much though.

https://c8.staticflickr.com/8/7704/2...983188ca_b.jpg20160621-DSC_1274 edit by chronumn, on Flickr

Same wheels and specs as above...


https://cimg7.ibsrv.net/gimg/www.rx7...86f7601ea.jpeg

https://cimg8.ibsrv.net/gimg/www.rx7...90e6061a2.jpeg

Would those tires touch a plum bob suspended from the edge of the fender?

Any rubbing on the track?

I'll take a better pic tmrw. Track duty coming soon, I'll let you know how they do.

What tires are you running and sizing?

Bridgestone Re11a 255/40/17 all around. Really nice tires

Yup RE11's are a great street tire. My RS3's that I'm getting should be just a hair wider to fill out the wheel.

I considered RS3s but since I have 17s I decided against them because of their softer side walls. Might be overthinking it tho

I didn't get the plumb bob pick but here is a better pic showing fitment from the rear.


https://cimg2.ibsrv.net/gimg/www.rx7...a1439f3f5.jpeg


https://cimg3.ibsrv.net/gimg/www.rx7...a8ddfdd7e.jpeg

I only asked about the plumb bob because it's illegal to have tires that poke out past the fenders here.

shop manual lists the offset. i'll have to look, but scrub radius might be mentioned in the yamaguchi book.

you're kind of right, we are assuming scrub radius is near zero, but not sure we actually know its curve, and its a PITA to measure

I checked it with a straight edge on the wheel extending up past the fender, and it does stick out about 1/4"

I'd greatly appreciate if you'd check to see what the stock scrub is/ where zero is at in that book. Thank you!

Stock scrub radius specification is not in the Yamaguchi book.

The only incidental mentions of scrub radius are page 98 where it is mentioned that there is positive scrub up front.

"Braking force generated by the car's brake system is applied rearward at the tire's road-surface contact. When subjected to this force, the suspension produces toe-out moment which stabilizes the car's braking attitude because of its kingpin axis position, which is inside the point of application of the braking force."

And page 99 where it is mentioned the rear scrub varies from negative (under braking) to positive (under throttle) as the kingpin axis is behind the center of the contact patch and the rear has the variable toe bushings.

"During braking, the combined effects of geometry (the kingpin axis is outside of the braking force input point of the tire's road-surface contact), the vehicle's tail-up (lift) attitude and the tire's slight rearward movement caused by the trapezoidal link effect (formed by the toe-control link and the lower transverse I-arm, induces a toe-in moment. This enhances stability under braking."

"The toe-in moment induced by the combined effects of geometry (the kingpin axis extension is now inside the force's input point) and the vehicle's slight squat attitude when driving torque is applied to the rear wheels, is moderated by the toe-out from the trapezoidal link effect which displaces the wheels slightly forward. This produces an optimal toe attitude for combining agility and stability when the driver "plays with the throttle" while negotiating a corner or a bend."


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Is finding out what the stock scrub radius was really important?
Keep it as close as stock (50 offset) as possible and you will have stock like road manners.

The FD is an old car that was on 225/50-16 tires and anything other than cruising that contact patch is moving inches away from the steering axis anyways (scrub radius changing).

If you haven't worked trackside and watched tire sidewalls, it looks like this (watch 1:20-1:30)-


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More interesting to me is to read pages 98-103 in the Yamaguchi book about how the front and rear goes through constant toe changes to keep bad drivers from crashing in an era before Dynamic Stability Control.

Well, some people would call a car that does what the driver intends rather than what they command it to a good handling car. I say those people should learn how to command a car or get a non sports car or better a self driving car.

Replace those variable toe bushings with single axis bushings and you get a more pure handling car (like a modern Mazda sports car with DSC turned off).

Replace the multi-axis spherical bearings with bushings (rear toe and lower transverse arms) and you get a car with bound-up rear suspension that tries to kill you...

On an old car like the FD it is possible to improve the handling, but it is also still very easy to worsen it.