The 5 lug swap truth thread!!!!!!!!!!

[atmh]

moatilliatta: I'm building my car to have 1.5bar of boost. That's the goal, anyways. Definitely need bigger brakes. Weight will be close to stock e30 weight.

Ok so I finally took the time to read this whole thread and two things came up for me:

1. I'm less scared, because I've been getting the 96+ e36 M parts and that seems like it works for people
2. I'm more scared, because it doesn't sound like anyone, at least not on this thread / publicly sharing their knowledge has done a full analysis of how the suspension geometry is changing with this swap.

So I'm going to do a full kinematic analysis for my 1984 325e, which may not represent all e30s. I'm not 100% sure on what setup I'll do in the rear, but the current plan of a Z4 hub in the stock trailing arm means the geometry basically isn't changing, except for slightly wider track width, which I'm not particularly concerned about. For what it's worth, I have previous experience setting up, designing, and analyzing race car suspension. I'm no expert by any means, and I've never done a McPherson strut, but it should be fun and fruitful. I will share what I learn once I have "real" answers. I don't know what the "ideal" setup is for an e30, but I know enough to be able to compare a before and after for this swap and identify problem areas or what areas might need setup changes to compensate.

Here's a quick rundown on what I'm thinking about with the front:

• There's a lot of spitballing back and forth about caster, but caster isn't nearly as important as the resulting mechanical trail. As far as I can tell nobody is really talking about the spindle placement relative to the kingpin axis, which is also critical to how stable the car feels.
• It doesn't sound like the e36M setup changes track width, but this is also pretty important to know. Since we're hopefully just bolting this assembly on without adjusting anything (except the lollipop control arm bushing) I'm not sure what's happening to track width and camber.
• Steering geometry is also a really big deal. Is the steering pickup point in the exact same spot as on an e30? Probably not. How is Ackermann changing? Does the steering arm point still line up well to reduce bump-steer? Do we need to shim the steering rack in any direction? Up, down, front or rear?
• Does the front roll center move significantly? Do we need different roll bars to compensate? Does it irreversibly mess with the Front/Rear roll balance?
• Bonus thought: Half the "horror stories" I'm reading are also people running 17" wheels. 225+ width tires. Is there a tire in that size that's close to stock diameter? Is your rubbing issue a geometry issue, or simply that you're trying to run too big of a tire? Do we really want to take a hammer to our wheel wells when the answer might just be to run a tire closer to stock size? Are you willing to sacrifice performance just to have a big wheel and a wide tire?
• Finally, I don't think there's a "high performance" reason to do a 5-lug swap if that's the ONLY thing we want (in my case, I want bigger brakes and 5-lug is the path I'm planning on taking to get there) but I'll do a quick calculation on wheel forces and lug bolts. Pretty sure even a heavily modified e30 is still light enough that the stock 4-lug is fine. Since I'm only doing this for the brakes, it's really important to know that I'm not unwittingly messing up the geometry in other ways. Bigger brakes with crappy handling is not the end goal.

If the e36M stuff screws up the geometry in unacceptable ways, then I'll probably just go back to stock suspension bits and use a kit to fit a 5-lug hub on the stock e30 spindle with a caliper relocation bracket. Not my preferred solution, but a better one than messing up suspension geometry.

If anyone reading this has gone through all the trouble of measuring all the parts and comparing before/after in CAD or some other software package, please let me know! No need to reinvent the suspension if it's already been done.

[moatilliatta]

1. Ignorance is bliss
2. Ignorance is bliss

You'll need bigger rear axles.

I am an Club level racer and have setup many cars at a high Club level for 10+ years. I would be interested in helping or bouncing back and forth ideas on your setup.

I have complete "Z3M" Setup. I believe the E36 knuckles and uprights are a lot stronger than E30's, less deflection and fatigue. I am still learning the differences of the E36 vs E30 suspension at a higher level. But The caster / Mechanical trail is what the key difference is and probably why the E36 runs less caster and so on. I'm looking forward find in out more.

I am pretty sure with E36M you're using E36 fitment wheels.

Bump steer and roll center is your choice of ride high, and many options out there if you want to go low, pick your poison.

As noted before the Z3M rear runs an inch wider in the back. I'm over half there but my 245/40r17's (17x9et30) fit with rubbing. 1/2 way to go with the hardest the last 20% of getting a proper fitment (Early body).. Standard ops. Its just the convenient tire size with lots of options of compounds.

There are many 4 lug brake kits, but I'm not to interested in wearing pads diagonal with wilwoods..


My reason for 5 lug.
Z3M - rear axles with Big bearings, Passenger side reinforcement hits the gas tank hose... no low hanging fruit there... Bigger rear brakes (E36M)
E36M front has stronger uprights and knuckles, bigger bearings. Any car with camber plates will eventually crack the towers. Eventually Raised towers custom adj in the future so strut position not a big deal.

Many good BBK packages around for E36 that have a good balance and pad options.


End goal sub 2700 street track car, 1/2 cage S54 350WHp. 245's Maybe 275's widebody. Getting 1/2 way there. You'll need 275's if you really want to put down 350+ whp. Separates the Form vs Function.
If the car cant make it around the track at its HP with out over heating, Blowing up, Breaking axles, Loosing brakes, not putting down traction its not a balanced package. IMO

But the E36M 5 lug stuff I think has a chance, and it'll take work to optimize, and compromises will be made from and OEM to make work. The recipe is not bolt on, Just have to match the pick up points that the E36 used...

Racers who optimized their setup rarely post on forums, but can be found at the track. Other parts are just tossed on, Ignorance is bliss. Sure, 9* of caster is fine on E36M 5 lug setup. Sure, people do live on fast food. And, Life goes on. It works.. I WANT BETTER.

I drove my car around the block in the snow with 12* of caster, you'll learn what weight jacking is and how the rear grip goes away quickly due to it in low traction conditions.

[atmh]

moatilliatta - cool man! When I'm through with it I'll give you the full analysis of how the points change and kinematics throughout the range of travel. Might make a good compliment to your track experience.

I would rather not run camber plates, but I'm also not building a serious track weapon. I'm really only aiming for 225 tires on 16" wheels. The MK60 ABS/DSC plus Megasquirt TCS are both for putting the power down without drama. Plus I'm doing dial-a-boost since honestly I don't want to run the car at full boost most of the time. IMHO it's more fun to drive a lower power car fast, but sometimes you just really want the juice, and it's nice to have both options available.

As for the need for bigger rear axles... Maybe. Would be cool if there were stronger axles for the stock e30 track width. I don't plan on doing a lot of drag racing or spending a lot of time at full boost, so just replacing them every year or something like that would be a fine plan. Would love to try and find some bigger axles that fit the e30 rear end, but I'm not going for the Z3M stuff based on the prices I see these days. Would probably just design, laser cut and weld my own rear TAs based on the prices I see for Z3M stuff.

Oh, and with my build if the jacking is too much I'll have to figure something else out, but for starters I'm going to try and do it without cutting, drilling, or welding any of the hard points. On the car I designed the suspension for we had I think 13 degrees of caster, or somethign close to that. The jacking was a lot, and while the car was small and light enough it was OK, it did result in a lot of steering effort. I'm sure it would be too much on an e30 with wide tires and perhaps a lot of scrub radius. The subsequent car had slightly less caster in favor of shorter front view swing arm lengths, I believe (at least that's the advice I gave the guy taking over for me when I left the team). Double wishbone so more ability to tune it than the McPherson strut on the e30.

[moatilliatta]

225 tires are too small, they're just enough for stock power. IMO. And there is plenty of room for 245's in an early car.

Its good to have camber caster plates to dial in the alignment, As most bmws, you'll just need to reinforce as needed. And these cars aren't getting any younger. Strut towers are moved and are pulling away on any stiffly sprung car over time.

The Pro of the Z3M trailing arm is the bigger bearing, stub, axle, and 5 lug with E36M packaged brakes, The con is the track width, the questionable toe or geometry change (I had over 1/8 toe out when they were initially installed). . I think MRT maybe coming out with Late DTM arms. Which would have bigger bearing and bigger stub axle that will probably use E28/E34 axles. Any upgrade is going to be costly.

The Z3M arms wont be cheaper tomorrow.

Genuine E30 axles are getting hard to come by and aftermarket ones done last. And i'm pretty sure both aren't as good as original ones.

TC doesn't put power down, it limits wheel ship.

If you don't move your pick up points, you'll end up with the same E36M 5 lug specs as everyone else.

E30's are far from racecar suspension. Design a Superstrut for the E30, maybe the closes thing to a double A arm a front strut car would get.

I have Camber gain and Bump steer measurements in my build thread of my 2021 setup. 2022 will see roll center addition minus 4.5 degrees of caster (7.5)

[///M_US_E30]

Why not just get the new KW E30 M3 front spindles that come complete? All is needed is the bearings and brakes of your choice.

T

[moatilliatta]

The KW E30M front kit isn’t a bad recent option, I think it’s the best bolt on option if you can match the rear and not shooting for bigger bearings, sub 275 whp.

If one can sort the pickup points I think the E36M / Z3M parts are a good option into the future with current part supply. (+300whp) The future only knows if E46 3l or Z4M stuff maybe an alternative when the E36M stuff drys up.

The 4 cylinder rear Z3 stuff seems like a waste. Mismatched track, smaller bearings. Fine probably for a 4cyl car that is trying to stay light.

The MK60 abs sensors have been fitting to E30 uprights / trailing arms.

[DEV0 E30]

Since this is probably the best place to put this.

What about just new hubs? As in an adapted hub. We've seen the IRP/other 5 lug hubs that are essentially an adapter.

Tim's Classic Parts - Sells a 4+5 lug hub. I've been talking with him some and I'm getting closer to going this route. I know some here have run this kit, I think Catuned ran a car with it?


==============================================

I reached out to a few who run adapters (4 to 5 lug) but with many wheels, you're spacing the wheel out to a point where your tire sizes are very limited.

One of them pointed me to this kit from Tim / Clipz.

I was leaning towards this as a possible solution for my wheel whoring tendencies. This + air/coilover mixmatch + new brakes + new rack + other suspension goodies = happy car?

But the more I read on the thread I missed on this, most feel it's not really the safest way as there isn't a lot of material left for the bolts I see now.

==============================================


https://www.timsclassicparts.nl/en_G...s-4x100-5x120/

BMW E30 multi-lug kit made by Clipz Motorsport.

With this kit you can fit 4x100 and 5x120 wheels on your E30 with the original e30 geometry and offset. This set is plug and play and bearings are replaceable.

Major advantage over standard:

• Easily switch from 4x100 and 5x120 wheels (the best of both worlds)
• No E36 struts or anything else needed
• Replaceable bearings
• Original E30 specifications (geometry, offset, brakes, etc.)
• Also new bearings (so no maintenance required in the short term)

This set contains:

• 2 front hubs 4x100 and 5x120 (including bearings)
• 2 rear hubs 4x100 and 5x120
• Optional, select your desired kit:
  • Rear wheel bearings from Meyle
  • With or without ABS
  • Zimmerman brake discs, set of 4, with 4x100 and 5x120 * recommended setup *
  • 16 or 20 Studs kit system (multiple sizes available), for even easier mounting of your wheels. See also Studs Kit
• Front hub mounting nuts
• Cover caps
• Bearing slots for different available wheel bearing diameters

==============================================

[dadsbmw]

This is very interesting. Sounds like a stock E30 BBK would be needed if bigger brakes are desired?

I've been doing a bit of research recently as I've been more seriously considering a 5 lug swap for better brakes and different wheel selection. So many of the options just aren't good though, as they create issues with front offset, ABS functionality, and e-brake compatibility. ABS and ebrake are a must have for me, and whats the point of going to 5 lug wheels if none of the 5x120 options will fit under the fenders in the front!

edit: Ok so I'm realizing e30 BBK wont work because all the rotors will be 4 lug. Does anyone make caliper adapters to run larger rotors/calipers? I'm guessing this would still create issues with the ABS/ebrake? Just concessions everywhere!

[atmh]

This is very interesting. Sounds like a stock E30 BBK would be needed if bigger brakes are desired?

I've been doing a bit of research recently as I've been more seriously considering a 5 lug swap for better brakes and different wheel selection. So many of the options just aren't good though, as they create issues with front offset, ABS functionality, and e-brake compatibility. ABS and ebrake are a must have for me, and whats the point of going to 5 lug wheels if none of the 5x120 options will fit under the fenders in the front!

edit: Ok so I'm realizing e30 BBK wont work because all the rotors will be 4 lug. Does anyone make caliper adapters to run larger rotors/calipers? I'm guessing this would still create issues with the ABS/ebrake? Just concessions everywhere!

IMHO after doing a bunch of research:

If you just want to run different wheels, get them filled and drilled. That's way easier, cheaper, and less likely to mess with brake balance or suspension geometry.

If you just want bigger brakes, then just use an e30 big brake kit.

The 5-lug swap is, as far as I can tell, not a true performance upgrade unless you're dramatically increasing the power or weight of the car. Obviously it's not worth nothing since the e30 M3 is 5-lug, but there's buttloads of compromises and lots of expense to get it to work.

At this point the only reason I'm still sticking with doing it is because I'm running a turbo car that should be ~400+hp when complete, and I want it to be a sleeper, so the OEM brakes from an e36/e46 and OEM wheels from the 7-series are highly desirable to me, to keep a stock appearance. I'm also running a Mk60 ABS unit (2003+ e46 M3), so having late model stuff for the ABS sensors is a mild bonus, but with that said I'm probably sticking with stock e30 rear TAs (with welded-on reinforcements) with Z4 hubs and e46 325i rear rotors... it's a mish-mash of parts and I'm not particularly fond of that. It will make it difficult to remember what parts to buy in the future when things wear out and need replacing.

Just my $0.02.

[dadsbmw]

IMHO after doing a bunch of research:

If you just want to run different wheels, get them filled and drilled. That's way easier, cheaper, and less likely to mess with brake balance or suspension geometry.

If you just want bigger brakes, then just use an e30 big brake kit.

The 5-lug swap is, as far as I can tell, not a true performance upgrade unless you're dramatically increasing the power or weight of the car. Obviously it's not worth nothing since the e30 M3 is 5-lug, but there's buttloads of compromises and lots of expense to get it to work.

At this point the only reason I'm still sticking with doing it is because I'm running a turbo car that should be ~400+hp when complete, and I want it to be a sleeper, so the OEM brakes from an e36/e46 and OEM wheels from the 7-series are highly desirable to me, to keep a stock appearance. I'm also running a Mk60 ABS unit (2003+ e46 M3), so having late model stuff for the ABS sensors is a mild bonus, but with that said I'm probably sticking with stock e30 rear TAs (with welded-on reinforcements) with Z4 hubs and e46 325i rear rotors... it's a mish-mash of parts and I'm not particularly fond of that. It will make it difficult to remember what parts to buy in the future when things wear out and need replacing.

Just my $0.02.

I've called shops to inquire filling/drilling in the past and the feedback I've gotten is that they won't do it as it's not safe due to the size of the 5x120 hub bore.

E30 BBK on 4 corners is like $2500, which is quite a lot more compared to swapping to later model 5 lug, not to mention the fact that you're killing two birds with one stone

I'm S52 swapped, so yes I have added significantly more power and some more weight

[Staszek]

Since this is probably the best place to put this.

What about just new hubs? As in an adapted hub. We've seen the IRP/other 5 lug hubs that are essentially an adapter.

Tim's Classic Parts - Sells a 4+5 lug hub. I've been talking with him some and I'm getting closer to going this route. I know some here have run this kit, I think Catuned ran a car with it?


==============================================

I reached out to a few who run adapters (4 to 5 lug) but with many wheels, you're spacing the wheel out to a point where your tire sizes are very limited.

One of them pointed me to this kit from Tim / Clipz.

I was leaning towards this as a possible solution for my wheel whoring tendencies. This + air/coilover mixmatch + new brakes + new rack + other suspension goodies = happy car?

But the more I read on the thread I missed on this, most feel it's not really the safest way as there isn't a lot of material left for the bolts I see now.

==============================================


https://www.timsclassicparts.nl/en_G...s-4x100-5x120/

BMW E30 multi-lug kit made by Clipz Motorsport.

With this kit you can fit 4x100 and 5x120 wheels on your E30 with the original e30 geometry and offset. This set is plug and play and bearings are replaceable.

Major advantage over standard:

• Easily switch from 4x100 and 5x120 wheels (the best of both worlds)
• No E36 struts or anything else needed
• Replaceable bearings
• Original E30 specifications (geometry, offset, brakes, etc.)
• Also new bearings (so no maintenance required in the short term)

This set contains:

• 2 front hubs 4x100 and 5x120 (including bearings)
• 2 rear hubs 4x100 and 5x120
• Optional, select your desired kit:
  • Rear wheel bearings from Meyle
  • With or without ABS
  • Zimmerman brake discs, set of 4, with 4x100 and 5x120 * recommended setup *
  • 16 or 20 Studs kit system (multiple sizes available), for even easier mounting of your wheels. See also Studs Kit
• Front hub mounting nuts
• Cover caps
• Bearing slots for different available wheel bearing diameters

==============================================

Has anyone tried these? I am thinking of going 5 lug in the future, JUst not sure which avenue. This seems like a great solution.

[atmh]

The rear is easy, apparently. It sounds like you can just swap Z4 hubs into the e30 325i trailing arms, then use a e46 rear brakes (caliper relocation kit required) and it's only a few mm wider track width. That's the route I'm going with the rear.

Front all seems to require a sleeve on the spindle, which I'm not a fan of, so for now I'm still planning on going with the e36 M3 front setup.

I guess point being: you can't just swap hubs without having to also change a bunch of stuff with the brakes, so it's kind of a pick your poison sort of thing.

[jbontke]

Front all seems to require a sleeve on the spindle, which I'm not a fan of, so for now I'm still planning on going with the e36 M3 front setup.

Why not the sleeve on the spindle?

[atmh]

Why not the sleeve on the spindle?

They just kind of weird me out, mostly around strength/stiffness of the front outboard suspension:

• I personally don't like relying on these kinds of very custom parts that are critical to function. If for any reason you would ever need to replace the sleeve, you might have to have it custom machined, since there's no guarantee it will be available in the future
• These parts have to be extremely precise. Any play in the sleeve will contribute to play in the steering of the vehicle, not only that but if they're not well made it could damage the spindle over time
• These parts probably also need to to be corrosion protected. If they start rusting at all, they're both buried in such a way that you can't see them, and critical to function.
• Any other materials than steel are not appropriate for the application, if for no other reason than the fact that the coefficient of thermal expansion needs to be the same.
• I don't know how a sleeve will interact with the retention nut / how much of the nut will still overlap the bearings. I wouldn't want the nut to be too small to retain the bearings. This is unlikely, but still, a factor.
• The hubs are sized for a bigger spindle, so it makes me a little nervous using a smaller spindle. Granted the sizing here is mostly due to the weight of the vehicle, so it's probably not an issue, but still.
• If the bearings fail it could result in spinning the sleeve, and thus destroy the spindle.

It just feels a lot like a band-aid fix to me. A well made part is probably totally fine, and I'm not claiming I have the most rational explanation. I just personally like to keep a lot of the suspension and brake hardware using as much OEM parts as possible (not necessarily e30 OEM, but BMW OEM parts). I'm bummed out that the best solution I have for the rear right now uses a caliper relocation kit, but at least that's easy to inspect and it's on the back so I'm not as worried about a little bit of reduced stiffness or stuff like that (a rear brake caliper having a little more mounting flexibility is a way different thing than play between the front wheel bearings and the spindle). With that said, I haven't taken a super close look at how the e36 M3 front setup changes the suspension geometry, and I may decide in the long run that the geometry changes are a worse trade-off than a sleeve on the spindle, and could change my mind in the future. Plus e36 M3 front parts seem like they're getting more expensive and it might not be long before it's a cost prohibitive option. Again: pick your poison.

[AexD]

Whats up guys, im a long time lurker here but decided to sign up and ask a couple of questions.

Im currently restoring a 320i Cab.

I have all 96+ M3 Evo Hubs & LCA's. with Polybushes etc. I didnt realise when researching the swap that there is an issue with the Tie Rods rubbing on the Oil Sump / Pan. Is this a major issue? I have an M50 swap & purple tag rack to go in the car as well. Worst case you get the oil pan modified? Does the angle on the tie rods make it handle like ass? Its just a street car but its going to be a built M50b28 Turbo so i want it to handle correctly or as best it can.

Thanks

Alex

EDIT: I forgot to say i already have a custom set of BC Coilovers with E30 Top Mounts & E36 Lower Mounts so i dont really want to not use the stuff i have, i already also completely restored the parts.