Apex ec7 18x9 et31 tire size

[wellcraft]

What should be the correct tire size for the apex ec7 18x9 et31 square setup for a coupe?

I'm thinking about 245/35/18 and I was looking at tire rack and see that different tires of the same size are wider than others and I don't want a stretch tire look and I don't want the tire to stick out as minimum possible as I was told this set up sticks out a bit in the front, rear shouldn'tbeany problem. .

Thanks.

[san]

I run 245 on 8.5, so you maybe ok? But on a 9” wheel, I’d likely run 255 at least.
But I were you, I’d send an email to apex and get their input.


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[YoitsTmac]

The correct tire size for a 9" wide rim is a 255/35/18. Also, ET31 is a little aggressive for non-M. I have ET42 on my non M and the front is a tight fit with -2 camber.

[jolsen16]

That setup will work, but you're gonna need some camber with that offset and likely a fender roll. 245 tire will be an easier fit than 255's. 245's fit fine on a 9" wheel... If you'd like to have more tire, the 255 will work but may require more work to fit.

FWIW, 9.5's and 255's fit on non-M e46's with the right offset and setup.

Here's a useful link to what fits (according to Apex) https://support.apexraceparts.com/hc/en-us/articles/360003547213-E46-Non-M-Wheel-Tire-Fitment-Guide

Per Apex:
Front & Rear 18x9" ET30 or ET31 (EC-7) with 245/35-18 tires

Requires at least 2 degrees of front negative camber.
May require front spacers with certain aftermarket suspensions, see below.
May require front bumper trimming to prevent rubbing.
Requires rolled rear fenders to prevent rubbing.

[YoitsTmac]

I have 18x9ET42 at -2 camber and barely rub under tire expansion. I have two credit card widths from strut. ET32, I’d love to see it. I also have z4m bushing which widens the front track

[jolsen16]

I have 18x9ET42 at -2 camber and barely rub under tire expansion. I have two credit card widths from strut. ET32, I’d love to see it. I also have z4m bushing which widens the front track

You don't state what tire size and what suspension... these are important factors for fitment (as well as any brake mods).

Also, are you referencing FCAB from Z4M, cuz that does not change front track. Not sure how you came up with that. I have same bushings, just installed a few months ago. Nothing changed in the front track.

[YoitsTmac]

You don't state what tire size and what suspension... these are important factors for fitment (as well as any brake mods).

Also, are you referencing FCAB from Z4M, cuz that does not change front track. Not sure how you came up with that. I have same bushings, just installed a few months ago. Nothing changed in the front track.

The offset moves the control arm forward and outward. You pivot the control arm.

Fortune auto 500 coils. Tire is under the spring perch. PS4S 255/35/18. Brake mods should’nt effect fitment…only potential clearance issues. I can fit F80 calipers on.

[jolsen16]

The offset moves the control arm forward and outward. You pivot the control arm.

Fortune auto 500 coils. Tire is under the spring perch. PS4S 255/35/18. Brake mods should’nt effect fitment…only potential clearance issues. I can fit F80 calipers on.

Brake mods certainly can... the lower the offset, the tighter the clearance to the caliper (based on wheel spoke design), which may require spacers... which would affect fitment of wheel. You prob don't have this issue with et42 wheels. His are et31... read the OP.

Also, I think you are talking about a different bushing or something. The FCAB mounts to the chassis. The only thing it CAN change is castor... I measured the spec's on my Z4M bushings and they were identical to OEM. So either you are talking about a different part or somebody told you something incorrect.

[YoitsTmac]

Brake mods certainly can... the lower the offset, the tighter the clearance to the caliper (based on wheel spoke design), which may require spacers... which would affect fitment of wheel. You prob don't have this issue with et42 wheels. His are et31... read the OP.

Also, I think you are talking about a different bushing or something. The FCAB mounts to the chassis. The only thing it CAN change is castor... I measured the spec's on my Z4M bushings and they were identical to OEM. So either you are talking about a different part or somebody told you something incorrect.

A lower number offset pulls the wheel further out. ET31 will have more clear any for brakes than ET42. But yes, sorry. Normally on these cars people talk fitment for strut and fender clearance.

Z4M FCAB gives you faster by moving the front wheels in relation to the body. The pivot point is the subframe center CA mount. If you wanted more caster with no alignment adjustments, you’d have to move the entire front axle forward while the top strut mount stays constant. If the Z4M bushings were geometrically identical to stock…you would get no additional caster. The Z4m mount hole is offset while stock mounts in the center.

SLR’s adjustable FCABs which alter the front geometry in the same way a Z4M FCAB does states that adjusting the bushing position will “allow for adjusting caster and wheel position.”

[jolsen16]

A lower number offset pulls the wheel further out. ET31 will have more clear any for brakes than ET42. But yes, sorry. Normally on these cars people talk fitment for strut and fender clearance.

Z4M FCAB gives you faster by moving the front wheels in relation to the body. The pivot point is the subframe center CA mount. If you wanted more caster with no alignment adjustments, you’d have to move the entire front axle forward while the top strut mount stays constant. If the Z4M bushings were geometrically identical to stock…you would get no additional caster. The Z4m mount hole is offset while stock mounts in the center.

SLR’s adjustable FCABs which alter the front geometry in the same way a Z4M FCAB does states that adjusting the bushing position will “allow for adjusting caster and wheel position.”

wow, this is just wrong all over the place... Good luck to the OP. Follow the guidelines on APEX's site and you should be golden.

[t.er]

Z4M FCABs probably do change the track width some negligible amount (the angle of the line from the hardpoint on the knuckle to the subframe, with the line from the subframe to the FCAB probably isn't a perfect 90 degrees). For the most part it's caster, offsetting the FCAB hardpoint in Y (laterally) largely moves the hardpoint on the knuckle in X (fore-aft) which is why you get the caster change

[wellcraft]

I contacted about 2 member from another forum when I was ordering these wheels and was told it was ok being a coupe with a bit of poke in the front, they had the same set up.

I'm on stock suspension and don't have any plans on lowering the car.

Will negative 2 camber cause a lot of tire wear?

My thoughts was to basically go with a lower tire thread with to avoid any tire rub or too much poke. Continental has the lowest tire thread width of the few I was searching last night

Thanks for the input guys.

[YoitsTmac]

Zero your toe and you’ll be fine. My alignment shop who aligns tons of BMW race cars says 0.04 is as high as he’d go. I drive with zero toe non issue.

If you’re on stock suspension and not lowered, I can see how you wouldn’t rub. Best of luck