Wheel Width + Offsets for 305 square?

[ment4t]

Hey fellow track rats; I have an F82 riding on JRZ RS Pro 2-ways, GC plates (sitting at -3.5 front, -2 rear), all the great SPL bits front and rear, along with AP/Essex Brakes (9668/9449).

I'm currently running the tried-and-true 18x10 ET25 fronts and 18x11 ET44 rears. I would very much like a way to fit a square set under the car to make rotating and prolonging my tires lives a possibility.

What offsets/suspension mods am I looking at to get either 295 square AR1s, or 305 square Pirelli DHs underneath the car comfortably? I've researched the M4 GT4's wheel set, but I was looking for some data from the experts here.

Thank you!

[BMMMW14]

I have a similar setup and moved from a square 18x10 ET 25 to 18X10.5 ET36 square with 295/30s works great, depending on tire brand a 15mm front spacer works but I run a 20mm.

[CanAutM3]

Originally Posted by BMMMW14

I have a similar setup and moved from a square 18x10 ET 25 to 18X10.5 ET36 square with 295/30s works great, depending on tire brand a 15mm front spacer works but I run a 20mm.

That's not a true square setup, you cannot do front to rear rotations on the fly...

[BMMMW14]

Originally Posted by CanAutM3

That's not a true square setup, you cannot do front to rear rotations on the fly...

How not? 10.5 ET36 with 295/30s all around - just a spacer in front

[fanatic1]

Running the same square set up as the BMMMW14 from Bimmerworld, but on MCS 1w. No clearance issues with DH305 and 20mm spacer, 15mm is close. But DH do run small.

[stevehifi]

I would assume that even with the 18x10.5 in the front you have to make sure that:
1) you have a tire diameter that is 26" or less (660 or 645mm slick) to prevent rubbing
on the inner fender plastic liner (unless you shape it with a heat gun)
2) the front coilover threaded perch sits ABOVE the tire so the tire tucks in
close to the shock body. (otherwise you have to run a big spacer 20+mm)

[BMMMW14]

Originally Posted by stevehifi

I would assume that even with the 18x10.5 in the front you have to make sure that:
1) you have a tire diameter that is 26" or less (660 or 645mm slick) to prevent rubbing
on the inner fender plastic liner (unless you shape it with a heat gun)
2) the front coilover threaded perch sits ABOVE the tire so the tire tucks in
close to the shock body. (otherwise you have to run a big spacer 20+mm)

True on both accounts, I think these are 25.3" tires and if much larger it would interfere with the perch. I run TCK coilivers

[stevehifi]

Originally Posted by BMMMW14

True on both accounts, I think these are 25.3" tires and if much larger it would interfere with the perch. I run TCK coilovers

295/30/18 is a pretty short tire (exactly 25"). Any issues with ABS or Traction control on the car (MDM)?

[stevehifi]

Originally Posted by ment4t

Hey fellow track rats; I have an F82 riding on JRZ RS Pro 2-ways, GC plates (sitting at -3.5 front, -2 rear), all the great SPL bits front and rear, along with AP/Essex Brakes (9668/9449).

I'm currently running the tried-and-true 18x10 ET25 fronts and 18x11 ET44 rears. I would very much like a way to fit a square set under the car to make rotating and prolonging my tires lives a possibility.

What offsets/suspension mods am I looking at to get either 295 square AR1s, or 305 square Pirelli DHs underneath the car comfortably? I've researched the M4 GT4's wheel set, but I was looking for some data from the experts here.

Thank you!

M4 GT4 rear wheel is the problem. The 30mm offset requires you to install shorter upper rear control arms on the back to pull in the wheel carrier by about 5-10mm to get you back to a more reasonable offset (in this case 37-40mm is optimal for 18x11)

[BMMMW14]

Originally Posted by stevehifi

295/30/18 is a pretty short tire (exactly 25"). Any issues with ABS or Traction control on the car (MDM)?

Have not run with traction control on, but the few times the ABS saved my hide it worked fine.

[CanAutM3]

Originally Posted by BMMMW14

How not? 10.5 ET36 with 295/30s all around - just a spacer in front

Sorry, I interpreted your post as if you had different wheel width and offsets front and rear. Read too fast

[stevehifi]

I might try the following setup myself:

(2) M4 GT4 OEM front ET30 and (2) Richland Forged M4GT4 Replica ET44.

Yes two of the rims won't have the red SAI motorsport and 'M Performance' imprint in the wheel but I doubt no one will notice.

This way you don't have to worry about the problematic ET30 rear offset.

[ment4t]

Originally Posted by stevehifi

I might try the following setup myself:

(2) M4 GT4 OEM front ET30 and (2) Richland Forged M4GT4 Replica ET44.

Yes two of the rims won't have the red SAI motorsport and 'M Performance' imprint in the wheel but I doubt no one will notice.

This way you don't have to worry about the problematic ET30 rear offset.

Issue here is that you can't swap front to back and vice versa. The idea is to prolong the life of stickers/takeoffs as much as possible.

[stevehifi]

Originally Posted by ment4t

Issue here is that you can't swap front to back and vice versa. The idea is to prolong the life of stickers/takeoffs as much as possible.

That's true, in your case since you have the adjustable SPL arms in the rear you should be fine in running the ET30 wheel in the back.

For others that don't want to mess with changing all the arms in the rear, then having the ET44 option in the back solves this problem. You could always go to your tire shop and swap the tires for $80. (20 per wheel).

I'm curious though, how many times do regular track junkies with square setup rotate their tires on average?

[F80Speed77]

I follow the wear, if its hot or there is a heavy bias of left or right turns ill move the front to the rear (maybe just one side) halfway through a weekend.

My 305/30/19 Square RE71R was still building tons of heat in the front on high 85-90deg days.

These are coupled with 19x10.5 Apex Arc8 in +35mm (25mm front spacer, no rear spacer). Been thinking about throwing on a +5mm spacer on the rear for full StanceBoi looks on the street haha. Im running -3deg camber in the rear with my spl arms.

[chriskeefe]

Bimmerworld TA5R 18x11 ET44 square setup requires a 25-30mm front spacer depending on spring perch height and I run a 12mm in the rear to give extra warm and fuzzy.

These are with Pirelli 305/680R18 scrubs.

[ment4t]

Originally Posted by chriskeefe

Bimmerworld TA5R 18x11 ET44 square setup requires a 25-30mm front spacer depending on spring perch height and I run a 12mm in the rear to give extra warm and fuzzy.

These are with Pirelli 305/680R18 scrubs.

Has anyone given you a hard time about running spacers that large? From my research, it seems like it's a non-issue; however there seems to be some contingent that swears them off.

[F80Speed77]

With extended hub spacers I dont see how there could be any issues?

[ment4t]

Originally Posted by F80Speed77

With extended hub spacers I dont see how there could be any issues?

I would assume there's some increase in load on the bearings; but with the GT4 car running such large spacers, it seems like the difference is negligible.

I don't have the math skillz to prove it, but maybe others do?

[chriskeefe]

Originally Posted by ment4t

Has anyone given you a hard time about running spacers that large? From my research, it seems like it's a non-issue; however there seems to be some contingent that swears them off.

I was weary at first, but ordered extended studs with just enough length to grab every thread on the nut and that's it. Then the M2 CSR came out and it runs 40 or 41mm spacer in the front. I immediately felt better about my decision and never gave it another thought. I will however have extra studs on hand.