[johnung]

Originally Posted by Runner340

With my suspension setup with a conservative drop on Eibach Pro Kit springs and Koni Actives with a BMW dealer spec alignment done last year. I would not use my 8.5" ET38 ARC-8's with a 255x40 tire. I would need a minimum 5mm spacer for my comfort level. ET35's might be better for that tire size. But you do need to be careful with spacers. Do some research with the folks at APEX. BMW's are hubcentric. Having the wrong spacer can lead to vibrations/excess wear on your wheel mounting hardware. With my current staggered setup I do have some (within tire mfg range) tire stretch and a slight poke. I don't have any rubbing, vibrations or unusual wear patterns. I will say given the MPPSK 340i performance even though it's xDrive does wear the rears a little faster. So I'd say based off my driving habits I've ended up getting about 25K miles out of the rears and the fronts will probably last me 10k-15k miles more.

Nah, I’ve been researching this for over a year with APEX and with Alohasurftoad. I’m 100% confident in this setup with 18x8.5” ET40 VS-5RS and 255/40-18 MPS4S summer tires. After I mount them, if the fronts aren’t perfectly flush with the fender, I may decide on little 3mm or 5mm spacers to bring it out of the front wheel well just a smidge. I’d use Apex spacers so absolutely zero spacer compatibility concern.

To put this all in perspective, 1/4” equals 6.35mm. So 3mm is less than 1/8 of an inch and 5mm is less than 1/4”. Hairs are being split in this discussion.

I’ve got the same suspension setup of Koni SA’s with Eibach Springs, and alignment to stock specifications. Nothing out of the ordinary. I’ve done more than enough research. This will be a snap.

[alohasurftoad]

18x8.5 ET38 255/40/18 MPSS
https://f30.bimmerpost.com/forums/sh...83&postcount=4

here is 18x8.5 ET40 with 235/45/18(26.3"),
https://f30.bimmerpost.com/forums/sh....php?t=1368226

a 255/40/18 sidewall will be vertical/slight bulge and closer to the strut than the inner wheel lip.

in post #43 of the thread below, the member had no rub with 255/35/18(25.0") at +42, but rubbed with 255/40/18 MPSAS3+
https://f30.bimmerpost.com/forums/sh...1244827&page=2

with 255/40/18, the highest offset is probably ET42 but it's depends on the actual tire. also, identical cars are identical to the millimeter, in a perfect world...and a perfect world, it is not. so when things are this close, one person may not rub and another with the exact same setup, may rub. cars are also not symmetrical left/right and i've seen where one side rubs but not the other.
.

[Runner340]

Thanks! This pic link in your post was a helpful visual. I think you are spot on having the option available for 3 or 5mm spacers "if needed" to customize any fitment variances to achieve that beefy square DD setup.

APEX ARC-8 18x8.5 ET38
Michelin Pilot Super Sport 255/40/18

[johnung]

Originally Posted by Runner340

Thanks! This pic link in your post was a helpful visual. I think you are spot on having the option available for 3 or 5mm spacers "if needed" to customize any fitment variances to achieve that beefy square DD setup.

APEX ARC-8 18x8.5 ET38
Michelin Pilot Super Sport 255/40/18

That photo does look good. Just eyeballing the photo, the tire/fender gaps look close to my XDrive with the Eibach Spring kit E10-20-031-06-22 installed. There’s just about 1/2” more gap in the front which shoul be eliminated when I swap out the -06 front springs for the -05 front springs.

[Runner340]

Here's a pic I dug up of what an 18" APEX VS-5RS style wheel with 255x40's would look like.

[johnung]

ONLY TWO DAYS LEFT IN THE APEX GROUP BUY FOR THIS NEW SIZE
Join now: https://bit.ly/3Sn3uMZ

Besides great looks, the Forged APEX VS-5RS 18x8.5” ET40 wheel is the lightest that I found at only 17.2 lbs. This provides a huge weight savings where it really matters: Unsprung Weight/Rotational Mass.

STOCK WHEELS/TIRES
26.0 lbs BMW 400M 18x8 ET34
25.0 lbs Runflat Pirelli P7 225/45-18
————-
51.0 lbs Total weight per corner

APEX UPGRADE
17.2 lbs APEX VS-5RS 18x8.5” ET40
24.0 lbs DWS06+ 255/40-18
————-
41.2 lbs Total weight per corner

9.8 lbs SAVED PER CORNER.

[johnung]

SAVINGS IN ROTATIONAL MASS
There are many obvious benefits to go with the square forged APEX VS-5RS 18x8.5” ET40 size. But as I got deeper into researching all of the wheel options on the market, the benefit that really convinced me was the huge savings not just in unsprung weight, but also in rotational mass/inertial mass.

There are numerouse articles/videos highlighting these points below. This much lighter wheel/tire setup makes a HUGE noticeable difference behind the wheel. Basically there is less to move to accelerate and less momentum to slow down to brake.

At 17.2 lbs, this VS-5RS is the lightest forged wheel in this size, resulting in as much as a 10 lb per corner savings in wheel/tire rotational mass. I felt an improvement when I saved just 3 lbs in each front wheel by switching to full floating rotors. The benefit behind the steering wheel from the APEX wheels will be monumental.

INCREASED HORSEPOWER & ACCELERATION!
Gains back horsepower that was being wasted by moving extra rotational mass.
0-60 times up to 0.5 second faster. 1/4 mile up to a car length improvement.

IMPROVED HANDLING & COMFORT
Less work for shocks & springs to do, so suspension reacts more quickly.

IMPROVED BRAKING
Less mass & momentum to slow down.

IMPROVED STEERING TURN-IN
Less to move means steering reacts quicker

IMPROVED FUEL ECONOMY
Less inertial mass to move means better miles per gallon.

Can’t wait for my new APEX VS-5RS wheels! Group buy is closing tomorrow, March 14th. Link below.

Anyone who is interested can still join now: https://bit.ly/3Sn3uMZ

[johnung]

Today (3/14/23) is the last day for this APEX Group Buy.
Join now: https://bit.ly/3Sn3uMZ

BIG BRAKE KIT FITMENT
Another benefit of this 18” wheel is that it was designed to fit all of the Paragon Big Brake kits available for the BMW F3x.

This is a big deal because other F3x big brake kits like the BremboGT cost thousands of dollars more and require a minimum of a 19” wheel. Many guys who track their M2/M3/M4 cars are switching from AP Racing brakes to Paragon Brakes.

There isn’t an AP Racing kit available for the F3x, but Paragon makes BBK’s for the F3x that all fit under the new APEX VS-5RS 18x8.5” RT40 wheels. I’m going to write a separate post with more details on Paragon Brakes. See photos.

Hope this helps!

[Runner340]

Originally Posted by johnung

ONLY TWO DAYS LEFT IN THE APEX GROUP BUY FOR THIS NEW SIZE
Join now: https://bit.ly/3Sn3uMZ

Besides great looks, the Forged APEX VS-5RS 18x8.5” ET40 wheel is the lightest that I found at only 17.2 lbs. This provides a huge weight savings where it really matters: Unsprung Weight/Rotational Mass.

STOCK WHEELS/TIRES
26.0 lbs BMW 400M 18x8 ET34
25.0 lbs Runflat Pirelli P7 225/45-18
————-
51.0 lbs Total weight per corner

APEX UPGRADE
17.2 lbs APEX VS-5RS 18x8.5” ET40
24.0 lbs DWS06+ 255/40-18
————-
41.2 lbs Total weight per corner

9.8 lbs SAVED PER CORNER.

I decided to sit out the sprint line wheel group buy last month and check in to see your post and pics of your square VS-5RS 18x8.5” ET40's with 255x40 tire setup when it arrives. The $300 dollar savings for a 4 wheel pkg and full price for a spare wheel was not enough for me take a chance and drop ~$4k with tires, after market tpms's and cost for a local shop to mount and balance the tires. I scored a pair of 18x8.5 et38 ARC8's a few weeks ago on the cheap that were in perfect condition from a seller the next town over. I'll use them in the rear for a square setup on my car to replace the current 18.9.5 et35's with 255x40's. I had a couple of spare 225x45's MPS AS3+ I bought on sale from tirerack 2 years ago installed but plan on replacing the tires on all 4 corners with 255x40's in the future.

[johnung]

Originally Posted by Runner340

I decided to sit out the sprint line wheel group buy last month and check in to see your post and pics of your square VS-5RS 18x8.5” ET40's with 255x40 tire setup when it arrives. The $300 dollar savings for a 4 wheel pkg and full price for a spare wheel was not enough for me take a chance and drop ~$4k with tires, after market tpms's and cost for a local shop to mount and balance the tires. I scored a pair of 18x8.5 et38 ARC8's a few weeks ago on the cheap that were in perfect condition from a seller the next town over. I'll use them in the rear for a square setup on my car to replace the current 18.9.5 et35's with 255x40's. I had a couple of spare 225x45's MPS AS3+ I bought on sale from tirerack 2 years ago installed but plan on replacing the tires on all 4 corners with 255x40's in the future.

That’s cool. I’m expecting my new wheels to ship to me in May. For my long trip spare, I use an 18x8 BMW 400M wheel with a stock Pirelli runflat tire that’s got the same 26.0” diameter as 255/40-18

[imkevg]

All these setups look super clean.

[Runner340]

Looking forward to seeing this setup with the new APEX VS-5RS 18x8.5” ET40 with 255x40-18's myself.

[johnung]

Originally Posted by Runner340

Looking forward to seeing this setup with the new APEX VS-5RS 18x8.5” ET40 with 255x40-18's myself.

Me too! I’ve seen other sizes before I ordered them. But my shipment with this new size has been delayed a bit until late June/early July. Patiently waiting.

[Runner340]

Originally Posted by johnung

Me too! I’ve seen other sizes before I ordered them. But my shipment with this new size has been delayed a bit until late June/early July. Patiently waiting.

Any updates?

[johnung]

Originally Posted by Runner340

Any updates?

UPDATE:
Yes! Got my new wheels and tires less than two weeks ago. 2015 335i XDrive. I dropped the front the week before with the Eibach European kit E10-20-031-05-22. So the front drop is now ~1.4” (35mm ) and the rear drop is ~0.6” (15mm).

That makes the tire/fender gap just about equal when measured from center of wheelcap straight up to fender lip. But there is an optical illusion that makes it appear like the car has a slight rake, meaning a smaller front gap. I think it’s a combination of the front & rear fender arches being different, and also the front & rear wheel alignments being different.

I actually took both a completely stock 400M wheel with a Pirelli runflat (my full size spare) and a new APEX with new 255/40-18 MPS4S tire to the local post office to get accurate scale weights. 53.1 lbs versus 43.3 lbs for a 9.8 lbs per corner for a huge unsprung weight & especially rotational mass savings. This means noticeably improved acceleration, braking and handling.

My front 370mm x 30mm full floating rotors also save another 3.5 lbs per front wheel.

All of the rubber mounts and suspension bits having to do with the struts, shocks and springs were all replaced with new OEM. Rubber deteriorates even if it looks okay. Nine years since the car was built was enough.

I am extremely happy with the comfort level of the ride now. Stock it was a bit stiff and jarring on rough patches of pavement. Highway road seams were especially annoying. Now I’d say it’s very close to some E-Class Mercedes that I’ve driven.

So the components that contribute to the comfort level are the new rubber bits, Koni Special Active Struts/shocks, Eibach -05 Spring Kit, and Michelin Pilot Sport 4S 255/40-18 tires.

At the same time it handles like a beast with the KoniSA/Eibach setup, MPS4S 255/40 tires, Weichers Front Strut Brace, H&R Sway Bars and BMW M Performance LSD. Next week I’m adding KC Design adjustable end links.

I plan on writing some separate posts on prepping & installing new wheels. And on wheel bolts, spacers & wheel locks.

Thanks again to Alohasurftoad for the many conversations and his expert advice over the past 18 months. Wish they all could have been over a beer or one of those Hawaiian little umbrella drinks.

Attached are some recent photos.

[Boostedphil698]

Possible to fit a 10 inch wide in the rear? At the offset offered in the VS-5RS?

[johnung]

Originally Posted by Boostedphil698

Possible to fit a 10 inch wide in the rear? At the offset offered in the VS-5RS?

APEX has a 18x10 ET40 VS-5RS and a MPS4S in 285/35-18 would meet the XDrive diameter requirements with the front 255/40-18 size.

But that would defeat the purpose of having a square setup to be able to rotate front to back to have a long full life of perfectly even performance out of the tires. And a staggered setup would be much more expensive and some of the rotational mass savings would be sacrificed as well.

I really like the look of the rear with 255/40-18. See photo. I have the option of adding spacers too.

[Boostedphil698]

Originally Posted by johnung

APEX has a 18x10 ET40 VS-5RS and a MPS4S in 285/35-18 would meet the XDrive diameter requirements with the front 255/40-18 size.

But that would defeat the purpose of having a square setup to be able to rotate front to back to have a long full life of perfectly even performance out of the tires. And a staggered setup would be much more expensive and some of the rotational mass savings would be sacrificed as well.

I really like the look of the rear with 255/40-18. See photo. I have the option of adding spacers too.

It does look good. I'm just worried with the 700hp build I'm planning, 8.5 won't be enough rubber.

[alohasurftoad]

the pics below were sent to me by new member strawhatdan. lowered F32 with 255/40/18+285/35/18 on 18x9 ET30+18x10.5 ET40, no rub

at ET40 a 295/35/18 will fit but the shoulder will poke 5mm more(than 285) and might rub under compression, as it is taller also. 295 will fit better at offset ET45 and is the maximum rear width for this platform.

imo, 285 is the maximum practical width to use in the rear.

[Blurr58]

Originally Posted by johnung

UPDATE:
Yes! Got my new wheels and tires less than two weeks ago. 2015 335i XDrive. I dropped the front the week before with the Eibach European kit E10-20-031-05-22. So the front drop is now ~1.4” (35mm ) and the rear drop is ~0.6” (15mm).

That makes the tire/fender gap just about equal when measured from center of wheelcap straight up to fender lip. But there is an optical illusion that makes it appear like the car has a slight rake, meaning a smaller front gap. I think it’s a combination of the front & rear fender arches being different, and also the front & rear wheel alignments being different.

I actually took both a completely stock 400M wheel with a Pirelli runflat (my full size spare) and a new APEX with new 255/40-18 MPS4S tire to the local post office to get accurate scale weights. 53.1 lbs versus 43.3 lbs for a 9.8 lbs per corner for a huge unsprung weight & especially rotational mass savings. This means noticeably improved acceleration, braking and handling.

My front 370mm x 30mm full floating rotors also save another 3.5 lbs per front wheel.

All of the rubber mounts and suspension bits having to do with the struts, shocks and springs were all replaced with new OEM. Rubber deteriorates even if it looks okay. Nine years since the car was built was enough.

I am extremely happy with the comfort level of the ride now. Stock it was a bit stiff and jarring on rough patches of pavement. Highway road seams were especially annoying. Now I’d say it’s very close to some E-Class Mercedes that I’ve driven.

So the components that contribute to the comfort level [...]

I have a F31 xdrive and I’m new to this stuff, I do not plan on lowering the car.

I’m thinking of doing the exact same square setup with the same tires and wheels.

My question is do I need spacers if putting the 255 tires up front or will it fit no problem?

[johnung]

Originally Posted by Blurr58

I have a F31 xdrive and I’m new to this stuff, I do not plan on lowering the car.

I’m thinking of doing the exact same square setup with the same tires and wheels.

My question is do I need spacers if putting the 255 tires up front or will it fit no problem?

The square setup with 255/40-18 Michelin Pilot Sport 4S will fit fine over the APEX VS-5RS 18x8.5 ET40. I got the Brushed Clear finish.

You don’t need spacers. It’s your preference.

I recommend putting wheels/tires on the car and then getting an alignment if you haven’t had one in a while.

Then it’s easy to measure how close you are to a flush fitment. Tie some washers to one end of a 2 foot piece of string. Use blue painters tape to attach the other end to the fender lip so the washers dangle right in front of the wheel center cap. Use a millimeter ruler to measure distance from fattest part of tire sidewall to the string.

This is the thickness of spacer needed to bring them out to a perfectly flush fitment.

Mine looked fine. I didn’t need spacers but I’m glad that I got them

I only needed a front 3mm and a rear 5mm spacer. It’s a tiny amount but visually it gets it closer to the fender curve- so to me anyway it was worth it.

I highly recommend Turner Big Pad Spacers. Their diameter matches the wheel diameter perfectly. Most spacers are too small in diameter and leave an unsightly gap between wheel pad and rotor hat surface.

Hope this helps!

[triax37]

Resurfacing this to ask about 235/45/18 tires - any reasons to avoid these? The diameter starts at 26.33" (1.36% larger than 225 tires and 1.13% larger than 255 tires), but as the 10/32 tread decreases to 9/32, my calculations suggest the diameter would decrease to 26.264", or just 1.01% larger than 26" tires. Other data:

Sizes (width, sidewall height)
- 225/45/18 - 8.86", 3.99"
- 255/40/18 - 10.04", 4.02"
- 235/45/18 - 9.25", 4.16"

Yes, I'm totally over-thinking this! Hahaha!!!