Hey guys, so recent threads about fitting track & lightweight wheels pointed out the need to modify the fender in the Rear to fit 17x8.5 et 40 wheels such as APEX or D-force LTW. (NOTE: 17x8 et 40 will fit, but wide tire choice may cause some issues, still less that 8.5 wheels)
Having accepted the facts and in general how hard it is to fit wheels for the 1 series coupe i parked the issue. Than randomly, I had to search for a 1 series manual in digital form and I found this file and it talked about wheel hubs!!
See Pg 18 - Wheel hubs :
http://www.1addicts.com/goodiesforyo...le_Manual1.PDF
This diagram essentially shows that 1 series e82 coupe, not the e81/e87 hatchback, has a 20mm wider rear track than a e9x 3 series car and e87 hatchback. The result is a rear rotor that adds height to the hat in order to cover the wider rear hub and reduces wheel fitment.
I believe BMW did this probably to make the coupe handle better than e87 when using the same style wheels across the 1 series, thus making the e87 wheels work on the e82 better with wider track, as if they had a 10 mm spacer on each side.
So, my question to you is to verify my logic of the following statement:
If one swaps to e9x rear hubs & new brake rotors, that one can run wheels with lower offsets like et35-40 without fender work, like 17x8.5 from APEX .
I believe the answer is YES. So let me show you why it works with part numbers.
Before writing this up I compared visually my car (I have135i rear rotors) to a 335i. The 335i rotor vs 135i rotor has about 10mm less height in the rotor hat. This confirms the rear track difference.
(So TL; DR - It works, you get 10 mm each side)
So let's start
Part numbers first for e8x and e9x:
Wide Hubs
135i/123d e82 Hub - 33416771082
128i/125i Hub (smaller hand brake shoes & wheel bearing) - 33416771081
Narrow Hubs
130i/335i/330i/328xi Hub -
33416760058
328i/325i/323i/120i Hub (smaller hand brake shoes & wheel bearing) -
33416760056
Therefore swapping to narrow hubs, gives us 10mm each side of room.
The nice thing about hubs is that you can find them used, or from numerous OEM's if you search by BMW part number. At most its about $100/side, but I have seen some as low as $50/side from FEBI brand. ( NOTE: If you are a 128i/125i/other 1seires with 135i rear calipers & no hand brake, you should swap to the small handbrake hubs because of rear wheel bearing size.)
This also explains why the 130i needs to swap the hub to run the 135i rear brakes & rotors. Because the 130i/335i hub is too narrow/short for the rear 135i rotor with the tall hat.
We now need to find appropriate rotors to work with our calipers. Here is where I discovered that the 128i/125i has the advantage over the 135i (Finally LOL).
I will start with the 128i/125i and similar e82 coupes:
128i/125i Rear rotor 300x20 - 34216855005
128i/125i/130i/123d/120i/328i/325i & xi/323i Rear Calipers -34216768697 & 34216768698
128i/125i/130i/123d/120i/328i/325 & xi/323i Rear Caliper Carrier - 34216768696
Therefore, these rear rotors will fit, given that they use the same caliper & carrier
328i/325i/323i/120i Rear Rotor 300x20 -
34216764651 / 34216855007
(NOTE: For the adventurous 125i/128i owner with 335i front brakes, this also mean you can run 335i rear Calipers/ carriers & rotors !!!! You just need to swap to a narrow hub and modify the small handbrake brake shoes. See e90 forums about 328i's running 335i rear brakes)
Finding Rotors for the 135i:
135i Rear rotor 324x22 - 34216855003 or the older 34216778649
The problem is that there are no 324x22 rotors with the smaller/ shorter hat.
EDIT: There are 324x22 rotors for e9x hubs!!
http://www.e90post.com/forums/showth...ht=34216795755
130i, e91 & e9x xi Performance rears 324x24 -
34216795755
EDIT 2015:
New rotor discovered for narrow hubs in 324x22, same size as OEM 135i !!!
Along side the e91 Perf rotor 34216795755 there is/was a Blank face rotor for 130i !!
Its part number is
34216787931 , and it gets better because ZIMMERMAN made a copy as part # Zimmermann 150.3477.20
More alternate part numbers for this
http://www.findpart.org/part/bmw-34216787931/
My Guess is that it costs under $150 USD which is the current ECS cost of the e91 euro Performance slotted & dimpled rotor. Interestingly, perhaps because of exchange rates, the e91 rotors cost about $50 less today then they did when I made this article.
edit 2019
For dimpled/slotted OEM 34216795755
FEBI BILSTEIN 43800
brembo 09.C246.11
JP GROUP 1463202900
NK 3115106
sbs 18153115106
SWAG 20 94 3800
and Textar may have a part number
https://partsfinder.bilsteingroup.co...cle/febi/43800
For blanks in 34216787931 style
https://www.onlinecarparts.co.uk/oen...216787931.html
https://www.autodoc.co.uk/car-parts/oem/34216787931
e90 325i had some unknown OEM rotors machined to fit 165mm small handbrake
https://www.e90post.com/forums/showthread.php?t=1584338
Alternative rotor information:
Fortunately, an e90post user did something great. He made 135i calipers work on a 335i ( Same hand brake diameter & Knuckle) using alternate rotors
http://www.e90post.com/forums/showth...ht=135i+brakes
He used washers as spacers to mount caliper and a F10 5 series rear rotor
F10 Rear Rotor 330x20 - 34216775287
The washers are what i believe at least 1.5mm wide or most likely the USA SAE spec 0.065 inches wide (1.65mm)
The F10 rear rotor's hat's back side edge hits the dust shield, so you can cut the shield, remove the sheild or grind off the hat like the e90Post user myE70 did.
Alternitively a e46 330i rear rotors might also fit if they line up with Caliper. It already uses the same diameter handbrake brake shoes, the part numbers are the same as 135i brake shoes.
But its size is 320x22 vs 135i's 324x22 and i don't know how well the rotor goes over the hub, and how the rotor lines up with the caliper.
e46 330i rear 320x 22 Blank -34216855157 / 34216864052
e46 330i rear 320x 22 Cross Drilled Performance rotor- 34212282873
The cross drilled would look great with the DieselBoost carriers/ CSL disks
Maybe even the Z4 forum has insight - one person used x3 rotor machined to fit ( I will edit this if I find solution - EDITED - See above): http://www.zpost.com/forums/showthread.php?t=442217 && http://www.zpost.com/forums/showthread.php?t=751080
Maybe even e83 rear rotor 320x22 34213332217
OR z4 e89 rears 324x20 - 34216782607
OR e60 rears 320x20 - 34216772085
OR M3 e46 rears 328x20 - 34212229379 or CSL rears 328x20 282303304 - ECS / 34212282303 / 34212282304 or e39 euro floating 328x20 - 34212228801/34212228802
(NOTE: this would require a spacer like myE70 did to his caliper to make it work, handbrake spread adjustment may be needed too e46 m3 rotors are 183 mm hand brake vs 185 mm of 135i)
Another approach would be to use RacingBrace RB and have them use a rear rotor hat from 335i and the rotor disk from 135i for a two piece solution
Overall RESULT:
You can now enjoy 10 mm per side of extra room allowing you to fit 17x8.5 et 40 wheels from APEX or Dforce LTW with little or no fender work. Or Other 17's 8.5's with ~et30 offsets would mean that the same pull/roll is needed as in the past would be used to fit et40
.
This also means that certain e9x rear wheels, and after market concave wheels can fit.
But note, we did change the rear track width at the hub to be the same as e9x. So if you care and wish to regain the difference, you must use appropriate wheel offsets. Therefore, If you used to run et52 OEM 18x8.5 rear, you now must run et 42 18x8.5 to keep the OEM Track width or use a 10 mm spacer. Overall, fitting aggressive wheels in et 40 or similar offset would compensate for this track change.
Keep in mind this would compromise Apex 18' rear 1 series specific fitment, it would need 10mm spacers to fit like it used to.
This hub mod now will allow e82 to use more rear wheel options - possibly some e9x wheels, especially the lower offset wheels, which will not change the Track width ( the offsets compensate). So say hello to more track wheel options and more Concave rear wheels.
Any feedback is welcome, especially about concerns about track width. I am not knowledgeable enough to know issues this causes on the track or certain wheel fitments.