The Comprehensive E30 5-Lug Swap Guide

Overview

This is a detailed parts and information guide on converting an e30 to a 5-lug setup. Read the whole guide before attempting this project. Make sure you understand, what you’re doing all this work for, whether it’s brakes upgrade or more wheel options etc. Depending on the goal, one option might be better then another. Most of the information and images in this guide are credited to asmagitman ( www.extradrei.com)  and R3Vlimited members that contributed to it years ago. Being that the guide is no longer hosted, we are putting a cleaned up and updated version of this original guide. We hope that it can be seen again on the internet and help the next generation of E30 enthusiasts . 

If you are doing this swap purely for selection of wheels, STOP. Regardless of which option you go with, it will be cheaper to find and buy any wheels your heart desires in 4-lugs, even filling/redrilling.

1. E30 M3 Bolt-On

This conversion requires no imagination, as it is a bolt-on. Literally, bolt on suspension and brakes and you are good to go. Many people consider this to be the "right way" to do this swap. In a perfect world, if finances allow, you’ll be going this route.

Pros: Ability to run stock-offset wheels 15" and up. A slight improvement in brakes. Untouched ABS system. 

Cons: Expensive and rare. Only a slight improvement in brakes. Parts are starting to be discontinued.

 

Without much explanation, here’s the gist.

FRONT:

 

REAR:

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2. E36 5 lug Options

This guide focuses on these swap options the most. There are a few ways of doing this and I will cover all of the ones I have attempted on several cars. I recommend to have a basic understanding of what you’re working with and understand basics of your suspension. A lot of knowledge here has been compiled from dozens of swaps from many members of the e30 community, and information in section is correct.

Pros: wide selection of wheels from street to racing applications. A significant improvement in brakes. Depending on how resourceful you are, this swap will cost significantly less. 

Cons: You must run wheels 16″ and higher. More reading and work involved. It’s very easy to lose count and spend more money than your e30 is worth.

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From here on, this conversion will be broken into steps: Fronts and rears. Both are quite simple, but it becomes a huge mess when you try to summarize everything as one big process.

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FRONT 5-LUG SETUP

Front is very simple, but due to use of e36 m3 parts, it is the more expensive part of the build. It is not unlikely to score all of the parts used fairly cheap.

Parts List

Very important to find a ’96+ e36 m3 to source parts from, but if you can’t find all of these parts in one place, put this kit together.

 

***Remember that MZ3 models came with control arms stamped 465/466, and they are exactly the same as e36 m3 control arms. Very important to have right control arms for front caster to be correct.***

I. Spindles and Brakes

You definitely want to use e36/Z3 M-spindles. Make sure spindles you’re getting have good bearings and donor car hasn’t been smashed in the front. Bent parts are no fun to work with, not to mention, potentially dangerous. Makes sure rotors and calipers are in good shape, if you’re installing used parts.

***I originally used standard e36 spindles and brakes, but caster just does not work out. Wheel sits too far back and very often rubs. However, you may use standard e36 spindles and brakes, I did for a good number of months, but you HAVE to figure out caster. I used camber plates to fix caster just enough to reduce rub. Personally, if you’re going through this conversion, do it right the first time. This is one of the solutions that I have seen. Notice camber plate and where shock is mounted. If that camber plate wasn’t so awful and functionless, I’d recommend people to do this on the cheap. The way this works is, that it moves entire strut assembly over outer ball-joint forward. I’ve seen people drill new holes for strut mounts right in the strut tower. This method can be used as resolution for using standard e36 spindles OR using stock e30 control arms, BUT NOT BOTH.***

 

II. Struts
If you’re planning to reuse your current springs, you MUST have e36 m3 struts or, at least, strut housings. New ones are expensive. Prices on these start at $170 for Bilstein Sports each, and that’s “STARTING AT” on eBay.

I was able to come up with a more affordable solution and at the same time allow affordable strut insert replacement in the future. Link bellow will take you through my e36 M3 strut build. http://www.r3vlimited.com/board/showthread.php?t=139412 I’ve made two sets, one is for DD/Eibach Pro-Kit and one for coil-overs. Gave me versatility to switch between suspensions, whenever I feel like, because swaps don’t take more than 30 minutes up front.

***Warning of wisdom: I have yet to receive/find a set of stock e36 struts that aren’t blown. You better have a very good relationship with the seller if buying used. You’ve been warned***

III. Control Arms

This is a very specific set of parts. You MUST use 96+ e36 m3 control arms and offset CABs (Control Arm Bushings). Note the year, this is a very important bit of information.

e36 M331-12-2-228-461 (left) and 31-12-2-228-462 (right)

or MZ331-12-2-228-465 (left) and 31-12-2-228-466 (right)

 

These are standard e30/e36 control arms compared to proper e36m3 control arms. You can easily spot the difference in the shape around outer ball-joint. e36m3 control arm doesn’t only move wheel forward, but it also moves wheel outward by a few millimeters e30/silver – e36m3/ black ***Read the red box in the Spindles section.***

$100 Control Arm Solution Prices on these control arms aren’t low. I couldn’t imagine spending $170+ per side on control arms, so I looked for other possibilities… Parts Needed: 1. Used ’96+ e36 m3 control arms from your local BMW shop’s scrap bin. 2. e30 Ball Joints. I spent $72 on Lemforders at Carquest (WorldPAC). Tools Needed: 1. Press and a good large socket selection to use with the press. Save $200 and keep original equipment on your car.

WARNING: Do not buy Chinese or off-brand control arms. This is a very crucial part of your suspension and you do not want to take chances. BMW and factory control arms are forged, but it is very common with Chinese knock-off to be cast. Cheap imitations appear to have forge line, but then you can easily see cast mark running through the forge mark. This happens, because counterfeiters use mold of a forged control arm to cast theirs. A lot of those brands mislead by using "OE" in their names. Don’t fall for that trap. This applies to all suspension parts. USE: BMW, Lemforder, Meyle or TRW.

 

Hardware

When sourcing your parts, make sure you get all of the hardware: brake caliper bolts, strut/spindle bolts, caliper rattle clips, etc… There’s nothing more frustrating, than trying to find all this hardware while your car is already taken apart. Get all these bolts with your parts, because all of these bolts are high strength and cost a pretty penny from dealership. You don’t want to try and find parts at a great price, just to have to spend over $100 on bolts. Think smart, think ahead.

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REAR 5-LUG SETUP

You have three true and tried options.

I. Use 318ti/Z3(I4) trailing arms.

This is a quick and easy bolt-on using nothing, but trailing arm assemblies.

Pros: cheap, $250 gets you in. As easy as replacing trailing arms. 

Cons: smaller rear wheel bearing.

 

To answer all basic questions about this option:

You Need: trailing arms, brakes.

You DON’T Need: anything else.

 

II. Use hubs and brakes.

Quick and easy and get’s my nod for being a slightly better option.

Pros: do not have to remove trailing arms or disconnect parking brakes. ABS is untouched. Proper size rear wheel bearing. $300 is still a fair buy-in.

Cons: same size brakes as 318ti.

 

Here are two different setups depending on your model year. Combine "Universal Parts" list with your model application list for full parts list.

Universal Parts

 

84-85 325e (small bearing)

 

86+ 318/325 (factory bearing)

 

Legend: e36/7 – e36 (3-series) and e37 (z3 chassis) z3(I4) – 4-cylinder Z3 (1.9L) z3(I6) – 6-cylinder Z3 (2.5L, 2.8L and 3.0L)

 

3. Use MZ3 parts.

Converting to M-Roadster/M-Coupe rear 5-lug = MONEY. Aside from being the best swap option, it is also by far the most expensive. 

Pros: complete bolt-on. Enormous rear brakes. Improved rear wheel bearings. reinforced trailing arms. 

Cons: expensive (easy $1000) and rare to find. Have to spllice-in ABS sensors.

 

Parts List:

1. Trailing Arms w/hubs and ABS sensors

2. Brakes (same as e36 m3) including Parking Brakes

3. CV Axles

4. Differential Output Flanges

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Now let’s explore rear swap in depth.

Trailing Arms and Hubs

Not all trailing arms (TAs) are created equal. There are some fundamental differences in trailing arms and hubs.

1. 1984-85 325e

These TAs use small 72mm bearings (like 318ti and Z3(I4)). Plugging in 318ti hubs or Z3(I4) and brakes is a great plug and play. ABS sensors wouldn’t have to come out, and

84-85 318i models had drum brakes and had no provisions for calipers.

 

2. 1986+ 318s and 325s

These TAs use standard 75mm bearing, that’s used on BMW 3-series for nearly 2 decades and Porsche’s. Plugging in Z3(I6) hub with brakes, is quick and easy.

3. 318ti/Z3(I4)

TA’s themselves are identical to 84-85 325e with one exception: ABS bung is shaved down to fit e36 ABS sensor. From this point on, if you use trailing arms that are non-e30, you will have to wire up e36 ABS sensors.

Z3(I4 and I6) (23.2mm wider than e30)	318ti (18mm wider than e30)
As you can see, there’s a difference in height of the rotor. That difference is due to the height of the hub itself. Very often, you see people debate on what offset wheels they car run, and this debate is largely due to this very significant difference.
Vice of Z3 hubs: you have to do a lot of rear quarter work to fit ET20/23 wheels. Bonus of Z3 hubs, you can easily run many e36/e46 staggered wheels and not shy away for putting a lot of meat (tire) on them. 245/40-17 comfortably fits under rear quarter panel on wheels ET41-ET50.	318ti hub is 5mm shorter, than Z3 hub. This is a hidden advantage/disadvantage of running 318ti TAs/hubs. On one hand, you are able to run lower offset wheels, and some run offset as low as ET20 (most ET23) with stretched tires and rolled fenders. Some even resort to running higher offset wheels with spacers.

 

4. Z3(I6) 2.5L, 2.8L and 3.0L

Putting legends to rest with logic: Z3(I6) models are wider, than their 4-banger counterparts. Z3(I6) received wider rear arches for that aggressive look, BUT along with that, trailing arms and CV axles were also widened. These trailing arms are a whopping 20mm wider per side. That added to hubs also being 23.2mm wider, you’ve officially moved e30’s ET20 perfect offset to ET63.2mm

Personally, I don’t know of any BMW or aftermarket wheels in that offset and still be 5×120. This setup is simply not plausible without doing wide-body conversion.

5. MZ3

Geometrically, these TAs are exactly the same as Z3(I6) from previous section. They’re 20mm wider, than all other trailing arms. Unlike all other trailing arms, MZ3 got giant wheel bearings and e36 M3 hubs and brakes. Significance of getting e36 M3 hubs is, that hubs are the same height as standard e30 hub, which results in ET0 additional offset. Do quick math and you’ll see that final offset of using MZ3 rear results in ET40 final result. ALSO, these TA’s are reinforced with A-support beam, and extra support at the shock mounting and bearing housing.

Unlike Z3(I6), you can use this option. Along with trailing arms, you must also use: CV axles and Diff Flanges from MZ3.

I strongly recommend using trailing arms that you have on the car. Not having to remove them, saves you a lot of time and aggravation. On top of that, you also get to keep your ABS sensors in place, simplifying this conversion.

BRAKES

This is a very important part of the project, as there’s no point to have larger brakes and have worse stopping distance.

We’re going to cover only standard non-M e36/7 calipers:

 

From "Universal Parts" chart above, you see that all non-M e36/7 rear brakes use same pads and all caliper carriers that bolt up are also the same.

BUT NOT ALL CALIPERS ARE THE SAME

318ti	Bolts right up. Uses 32mm caliper piston.
Z3(I4-I6)	Bolts right up. Used 34mm caliper piston. Improvement.
325i/328i	Because on e36’s brake lines come from under the CV axle, these calipers have to be flipped over. Right to left and left to right, makes them bolt right up. 34mm caliper piston. Very easy to find. Once calipers are swapped from side to side, you will notice that the bleeder screw is on the bottom. To bleed rear brakes, you have to bleed calipers off the trailing arm, holding them upside down and using a 10mm spacer between the brake pads before installing them back onto the trailing arm. This is very easy to do, but should not be overlooked. The result of not properly bleeding your brakes will be a mushy pedal, and erroneous diagnosis of other brakes components.

 

ABS

e36 use 3-wire ABS sensors, while e30’s use 2-wire. That is because e36 used ABS sensors as ABS and speed sensors for brakes and traction control. Color-match the wires and cap off extra wire.

Brake Lines

Use e30 brake line.

Parking Brake Cables

Use stock e30 cables.

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WHEELS

http://r3vlimited.com/board/showthread.php?t=132194

http://r3vlimited.com/board/showthread.php?t=139231

FAQ

What else can/should I do while there?
Depends on how much you’re spending…
1. Urethane subframe, diff, trailing arm, control arm bushings
2. Stainless steel brake lines
3. Sway bars
4. Adjustable toe/camber weld-ons
5. Camber plates and shock mounts
6. e36 steering rack

7. Upgraded master cylinder.

Parking brake cable?

This has been asked too many times. I reuse stock e30 cables every time. They fit, and that’s all that matters.