Awesome. Will make the switch.


I like the staggered look for the car but thanks for he idea. If I go down one tire size as suggested above, think I can lose the camber in the front?

I didnt really get the bolded statement above, can you rephrase?

Ive never heard above the Ventus TD but wow thats quite a difference! Ill look into them.

Im not scared to change the offsets if you guys think I should

Thanks for the suggestions!

I didnt really get the bolded statement above, can you rephrase?

18x11 +45 295 sticks out only ~2mm further out than 18x10 +35 265.

This site shows you the effects of wheel/tire widths and offsets.
Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

I like the staggered look for the car but thanks for he idea. If I go down one tire size as suggested above, think I can lose the camber in the front?

You can roll and pull the front fender and run less camber with the 18x10 +35 and 255. With just rolling the fender lip under you would still need max camber from my experience.

Thanks


New plan

18x10 +35 with 255/35r18 r888 front

18x11 +45 with 285/30r18 r888 rear

with rolled and pulled front and small pull rear.

Ill look into the ventus td. Is it new? I cant find many comparisons online.

No, its not new. It has been the fastest time attack tire for a couple years now (DOT-R with full tread pattern).

Ventus TD Z221 - Racing Tires | Circuit Semi-Slick Tires | Hankook Tire Global

It is not as cheap as the 295/30-18 R888 is (reason I bought those).

Grinch Post pics with the r888, same setup I'm run once wheels show up.

I know not on my 7 yet, but here is how the 295/30-18 R888 looks on an 18x11.
https://www.rx7club.com/attachments/...184505_005.jpg

you can fit the 295/30/18 on the 18x11 wheel if you want.

Can anyone tell me whether the 17x9.5 +38 RPF1s will clear stoptechs? The second post says the 18x9.5 +45 will, so I can't think of a reason why the 17s wouldnt with an extra 7mm to work with. Just wanted to get some confirmation before I plunk down the money in case there's something I'm not thinking of.

They clear my 17 x10 +38. According to the template I printed from their website.

Can someone shed light on how 18x11+45 w/ 285/30/18s fits up front? Im sure it "fits" but how much room is there for suspension travel during track days?

Assuming the car has rolled fenders (not pulled), relatively stiff spring rates, -2.5 degrees camber and appropriate ride height.

ArmenMAxx Can someone shed light on how 18x11+45 w/ 285/30/18s fits up front? Im sure it "fits" but how much room is there for suspension travel during track days?

Assuming the car has rolled fenders (not pulled), relatively stiff spring rates, -2.5 degrees camber and appropriate ride height.

Sure.
I spent a lot of time measuring and moving steering/suspension to come up with the 18x11 +45 fitment. Sound reason and a really nice wheel/tire fitment website were my inspiration to start measuring for the fitment.

I reasoned 18x10 with 7.5" backspace (or 18x10 +50 if you prefer) with 285 wide tire has been the standard for track fitment for the last decade on the FD.

The 18x11 +45 shifts the tire 5mm outward toward the fender over the 18x10 +50 so there is MORE tire clearance on the inside toward suspension. Meanwhile, the wider wheel changes the tire sidewall profile favorably (less sidewall bulge) so it also fits better up to/past the rolled front fender on compression.

Here is a visual representation of the old standard and what I hope to make the new standard.
Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

It was all just a matter of would the wider wheel fit without interfering with suspension components.

I found I had to put a shorter tube in my Tripoint swaybar to get full steering lock.

The 7.77" backspace of the 18x11 +45 just cleared the Ohlins coilovers up front at full lock and -2.5deg camber and just barely cleared the rear stock trailing arm at full droop and the rear Ohlins at -1.5deg camber.

I don't track, but I do race and the only thing the front rubs w/ 295s Ventus TD is the edge of the fender liner where it no longer fits up to the rolled fender edge (ie its hanging low). I did tuck my wire harness above the unibody as a precaution.

Set a record here in very under-prepared car on Kart track-

Set a record here in a very under-prepared car on poor pavement Hillclimb-


As I said before, I am really pushing for more people to try this fitment and make it the new standard as I want to keep elevating the FD's performance.

That extra 1" of front wheel width helps a bit with the same size 285 Hoosier on tracks/Autox.
Running the 295 Ventus TD up front instead of the 265 at time attack really helps.

The bad noises in the hillclimb vid are from having a broken power plant frame rubbing on the trans cross member (and ofc my bad shifting) and the front tire rubbing the outside edge of the unsupported fender liner as mentioned. The hillclimb was July 2013 and the Kart track October 2013, so the PPF was fixed and the fender liners worn down for the Kart track.

fits relatively easy. I am on +42mm 18x11.5" 285 width and clea the fenders and spring.

Thanks man that really helps,

My pettit track pro's travel a lot more than i'd like. Even with 12k springs F/R and a tanabe sway bar, it feel like im on 8k springs. My 99spec lip kisses the ground on hard cambered corners even with my pretty high ride height. The dampening is just not aggressive enough for what I do. However given what you guys have said 18x11+45 is what ill go for to run 285's. Its perfect because most RWD time attack classes limit the tire size to a max 285 section tire.

Less bulge on a wider wheel gives *less* clearance to the fender lip, not more! 5mm less offset means the outside of the tread is 5mm further outboard, and mounting on a 1" wider wheel means that the sidewall is stretched still further outboard going toward the rim. Also, while the wider wheel with less offset gives slightly more clearance to the suspension at the tire tread, there is *less* clearance to the inner wheel lip and part of the sidewall.

This shows it, the wider lower offset wheel puts the outer sidewall further outboard and nearer to the fender lip, and at the same time the inner wheel lip and a portion of the inner sidewall are closer to the suspension.

Not saying it won't fit, but it's not a foregone conclusion that if a 285/30-18 on an 18x10 +50 fits, that the same tire on 18x11 +45 will. The wider wheel with tire mounted occupies a greater volume and there *may* be clearance issues on either and/or both sides.

At some point I have to think that what may be gained in tire width is being lost by having to run higher ride height. I was rubbing the fender liner with 255/40-17 on +40 up front. I'm going to shorter/narrower 245/40-17 fronts this year in a much grippier compound (either R7, A7, or R1-S vs. NT01 last year). But it's not like wider is an option for me on my skinny 17" wheels anyway!

Blue TII talked to me about this setup and he is running the ohlins recommend height on there coils. 25-25.5. This is why I went with same size wheel setup. Can't wait to put them on and try them out.
Attachment 627330

Less bulge on a wider wheel gives *less* clearance to the fender lip, not more! 5mm less offset means the outside of the tread is 5mm further outboard, and mounting on a 1" wider wheel means that the sidewall is stretched still further outboard going toward the rim. Also, while the wider wheel with less offset gives slightly more clearance to the suspension at the tire tread, there is *less* clearance to the inner wheel lip and part of the sidewall.

True the 5mm less offset does not help the tire fit on the outside at the fender, it just allows you to run the 1" wider wheel.

The 1" wider wheel does help fit the tire to the fender on the outside though.

Its something learned from the hellaflush guys (yes, you can learn from things you hate).

It is how the stretched sidewall shape interfaces with/moves past the shape of the rolled fender edge as the suspension compresses with camber gain.

When you have the tire mounted on a narrow wheel the max section width of the tire occurs up closer to the tread block. Basically, the sidewall becomes rounded between the sidewall hinge point and the wheel bead seat. The narrower the wheel the closer the max section width is to the tread surface.

As a result this max section width passes by the fender edge with less suspension movement and therefore less camber gain.

When the tire is "stretched" on a wide wheel the max section width moves down toward the wheel bead seat and the suspension gets to move another 2" or so and the resultant camber gain over that extra suspension movement means there is now more clearance to the fender edge.

I know, it kinda blows the mind that the clearance gets so tight you have to factor in camber gain, but that is what makes it a "max fitment" thread and not a "safe fitment" thread.

Some work required to make it all fit together and work.

Blue TII talked to me about this setup and he is running the ohlins recommend height on there coils. 25-25.5. This is why I went with same size wheel setup. Can't wait to put them on and try them out.

Sexy!

So... if those don't fit I will buy them from you :lol:

OK, but on the same offset wider wheel, that same point on the sidewall will no longer be the max section width, but it will be further outboard, *less clearance* to the fender. And the new point of *max* width on the wider wheel will be still further outboard than that continuing toward the rim. Less clearance at the previous point of max width on the narrower wheel, and even less minimum clearance with more suspension stroke.

Same tire, wider wheel, less clearance.

The hellaflush guys don't run uber-stretched fitments because wider wheels give more clearance, they do it because *narrower tires* give more clearance.

Will these fit my car?
 

I'd really like to get rota p45 r2's for my 1990 FC but not sure if they will fit. They are 18s with 12, 20, and 35 offset options. Here's the link http://www.rotawheels.com.au/wheels/rota-p45r2#!prettyPhoto

Pdornellas
Will these fit my car?
I'd really like to get rota p45 r2's for my 1990 FC but not sure if they will fit. They are 18s with 12, 20, and 35 offset options. Here's the link ROTA P45R2 (18 inch) Wheels | ROTA Wheels Australia

For an FC start here-

https://www.rx7club.com/suspension-w...thread-950447/

End up here-

https://www.rx7club.com/suspension-w...467447/page33/

OK, but on the same offset wider wheel, that same point on the sidewall will no longer be the max section width, but it will be further outboard, *less clearance* to the fender. And the new point of *max* width on the wider wheel will be still further outboard than that continuing toward the rim. Less clearance at the previous point of max width on the narrower wheel, and even less minimum clearance with more suspension stroke.

Same tire, wider wheel, less clearance.

The tire sidewall changes profile depending on the forces acting upon it and the placement of the radial tread ply to sidewall and sidwall to wheel bead hinge points.

I am sure I won't be able to describe it to you convincingly, so I am posting these drawings.

The drawings show the tire profile drawn to scale and I attempt to explain the forces acting on the tire.

You will note from the magenta close up balloons- even with the same offset the narrowest 10" wheel makes the tire widest where it matters most (closest to the fender edge) not despite pinching the tire in, but because it is pinching the tire in at its intended hinge point at the wheel bead.

The 10.5" wheel offers the most clearance to the fender edge in these drawings.

The 11" wheel still offers more clearance to the fender edge than the 10" wheel in these drawings.

I am not asking you to believe I can draw exactly how a tire fits on a wheel, but look at my drawings yourself and pictures of actual tires mounted and I think you will see what I am trying to show.
https://www.rx7club.com/attachments/...res2-model.jpg
https://www.rx7club.com/attachments/...res3-model.jpg

Think Muffin-top

Ideal is having the tire beads located outside of the treadwidth. 11.5" wheels would be great for the above;)

I know this has been asked many times but I feel like I need some expert opinions before I drop some cash on some new wheels. My front fenders are rolled, rears are stock (but I will roll if required). I have Eibach Springs with Koni Yellows. I am looking for maximum performance without having to buy new coilovers, massively trim liners or alter the body lines (pull fenders). This is a street car, driven in nice summer weather ~40F+.

Wheels (Work VS-XX):
A:
Front: 18x10 +47
Rear: 18x10.5 +39

B:
Front: 18x9.5 +53
Rear: 18x10.5 +45

Tires:
A: Dunlap ZII Star Spec Front: 255R35 Rear:285R30 (narrower tread widths)
B: Yokohama Neova AD08R Front: 255R35 Rear:285R30

Looking for answers like "Wheels: A Tires: A" with any additional comments. Thanks all.

I would do

front: 18x10 +47
rear: 18x10.5 +39

front: 255/35/18 AD08R
Rear: 265/35/18 AD08R

That is what I would do and it would work VERY well. 9.9" front treadwidth, 10.3" rear treadwidth. tire beads just slightly outside the treadwidth. That is with the widths you provided.