Bored Bleedsblue: "budget" minded Brembo BBK

[E38740iMD]

I have been seeing people making brackets to put 135i brembos on E36s. Could you put those over a E39 M5 rotor or something? The euro rotor looks like it has the lighter hub like the N'ring brakes.

^^ i was about to comment on this

a company makes the braket now for the e36 and works for the e34s and e32s. 135 m sport 6 pot brembos using the e34 m5 rotors

according to all the research stopping power is a slight slight less than the either the e35 m5 brakes or e31 brembos. advantages is a light weight calliper and more brake pad options

here is the link for those who want it. there is a m3 and non m3 version

http://rebooteng.com/parts/bmw-135i-...ackets-e36-m3/

[BleedsBlue]

I like to hear options and alternatives, so keep 'em coming.

Is there a kit for the 135/M Performance 6 piston other than the Turner kit? I can't find an E34-approved kit, and don't find the Turner E36/46 kit that impressive. For $1600+ you've still not got floaters (about $1750 for floaters), it's a 325x25mm rotor a bit smaller than the US E46 M3. Two more pistons, sure, but I'm not shooting for maximum pistons here. But I'm only seeing E36/46 fitment there, I must be missing this other E32/34 kit.

If it uses E34 M5 rotors, though, that defeats part of my mission here (larger, floaters, weight savings). Research on the 996 Brembo front is that it will out-stop a stock E36 M3 a little bit on 60-0 or 100-0 for the first two stops; stops 3-5 the gap widens considerably in favor of the Brembo. Partially due to four pistons, partially to a better rotor.

[E38740iMD]

THE E34 E32 fitments not really advertised. throught the same research you provided the kit does indeed work for the e32 e34 also. because the e36 m caliper will work on the e34. spkoe to one of the representatives and he did confirm this a while back. the problem is is sourcing the 135 msport 6 pot front brakes. they are pretty expensice new/ used or where ever you get them. i like them becase they say "bmw" on them. but now i may just get some e36 m brake calipers for my e34 that has the casting "///M" on them until the 135 start going to the junk yards...

sorry this info is not helpful for your goal. just thought some one may want to do this if they have the parts available

[BleedsBlue]

No, it's all good man! It does help, remember my 996 idea is only valid providing it can either out-perform or undercut other BBKs.

I see what you're saying--the 135 6 pot "should" fit over the E34 M5 rotor in the same way an E36 M3 caliper, flipped, "should" fit over an E34 M5 rotor. I'm not sure how often you will find those calipers used, but they are way cheaper than an equivalent Brembo 6 piston, or the like. And many will like the BMW sticker/stamp, for sure. Given similar cost and wheel fitment, 6 is better than 4

[E38740iMD]

No, it's all good man! It does help, remember my 996 idea is only valid providing it can either out-perform or undercut other BBKs.

I see what you're saying--the 135 6 pot "should" fit over the E34 M5 rotor in the same way an E36 M3 caliper, flipped, "should" fit over an E34 M5 rotor. I'm not sure how often you will find those calipers used, but they are way cheaper than an equivalent Brembo 6 piston, or the like. And many will like the BMW sticker/stamp, for sure. Given similar cost and wheel fitment, 6 is better than 4

here is the responses from the represenitive:

they should work with e31/e32/e34 since they all use the exact same dimensions for brake mounting

You would be surprised how similar the brake bias stays. There are more pistons but they're all much smaller than the single piston these cars come with. Also consider the fact that BMW put large 4 piston ATE's on the m5 without really upgrading the rear very much.

after doing some calculations:
total caliper piston area for the 135i Brembo 4873.28mm2
total caliper piston area for the stock m3/m5 caliper is 5652mm2

The brake bias will go slightly towards the rear of the car. if you don't upgrade the rear at all.

more even clamping force, larger pad surface area, more heat dissipation, and and all aluminum caliper making this an over upgrade to even though the brake bias is slightly less

[BleedsBlue]

^Sweet! Good to have a trusted technical resource like that lay some knowledge down. I think the 996 Brembo will be the same effect of less total piston area/front bias. I don't think I would upgrade just the caliper honestly, and am really looking at the rotor options as half or more of the upgrade. But the Brembos I bought will be in soon and I'll do some test-fitting with a stock E34 M5 rotor and spacing.

[UnrulyGrace]

I really want floating rotors ��

[E38740iMD]

^Sweet! Good to have a trusted technical resource like that lay some knowledge down. I think the 996 Brembo will be the same effect of less total piston area/front bias. I don't think I would upgrade just the caliper honestly, and am really looking at the rotor options as half or more of the upgrade. But the Brembos I bought will be in soon and I'll do some test-fitting with a stock E34 M5 rotor and spacing.

im in to see the results.

[BleedsBlue]

I really want floating rotors ��

I know, broham. Per my logic, I'm pretty sure these 996s and the Rally Road bracket would bolt right up to an E31 rotor, but there is no point to that.

The real trick will be if the 996 and Greg's F50 bracket aligns with a late M5 345mm floater. Not that those are easy to find, and they are heavier than the E46 rotors, but it would be a significant increase in thermal capacity.

im in to see the results.

I'll post up for sure.

[BleedsBlue]

Just some more weight comparisons:

Rotors

• E34 M5 315mm rotor: 20.6#
• E34 M5 345mm rotor, floating: 20# (4mm thicker than the E46 345m)
• E31 324mm rotor: 22.9#
• E46 M3 325mm rotor, floating: 16.75#
• E46 M3 345mm rotor, floating: 18.8#

Calipers (not including pads, typically 4#)

• E34 M5 single piston: 9.3#
• E34 M5 four piston: 14.75#
• E31 Brembo four piston: 7.1#
• 996 Brembo four piston: 5# (+3# steel RR bracket; Greg's 7075 is maybe half of that, though, so back close to E31 Brembo)
• Brembo F50 four piston: 7# (piston size equivalent to E34 M5 four piston)

[UnrulyGrace]

Just some more weight comparisons:

Rotors

• E34 M5 315mm rotor: 20.6#
• E34 M5 345mm rotor, floating: 20# (4mm thicker than the E46 345m)
• E31 324mm rotor: 22.9#
• E46 M3 325mm rotor, floating: 16.75#
• E46 M3 345mm rotor, floating: 18.8#

Calipers (not including pads, typically 4#)

• E34 M5 single piston: 9.3#
• E34 M5 four piston: 14.75#
• E31 Brembo four piston: 7.1#
• 996 Brembo four piston: 5# (+3# steel RR bracket; Greg's 7075 is maybe half of that, though, so back close to E31 Brembo)
• Brembo F50 four piston: 7# (piston size equivalent to E34 M5 four piston)

Lets get the E46 M3 345mm rotors work with the e31 calipers

[BleedsBlue]

Lets get the E46 M3 345mm rotors work with the e31 calipers

I've been reconsidering using those floatin' beauties, at least for a street car. They are so affordable compared to the alternatives, too!

With the E31 caliper you would need a strange offset bracket, that would essentially be either an L or a slant to get the caliper both further outboard (horizontally) of the strut, and further outboard radially from the rotor center! Doable with threads in the bracket, and Loctite on the bolts for sure--I've seen something similar.

I would think it will be easier to accommodate the radial mount calipers with a 90 degree offset between caliper and carrier bolt holes, but who knows. I'm betting Greg's F50 caliper will just need a dozen mm/couple cm or so added to the carrier side for fit the E46 345mm rotor.

[sugaki]

Just some more weight comparisons:

Rotors

• E34 M5 315mm rotor: 20.6#
• E34 M5 345mm rotor, floating: 20# (4mm thicker than the E46 345m)
• E31 324mm rotor: 22.9#
• E46 M3 325mm rotor, floating: 16.75#
• E46 M3 345mm rotor, floating: 18.8#

Calipers (not including pads, typically 4#)

• E34 M5 single piston: 9.3#
• E34 M5 four piston: 14.75#
• E31 Brembo four piston: 7.1#
• 996 Brembo four piston: 5# (+3# steel RR bracket; Greg's 7075 is maybe half of that, though, so back close to E31 Brembo)
• Brembo F50 four piston: 7# (piston size equivalent to E34 M5 four piston)

Oh man those 95 M5 brakes weigh a ton. I sold those because the F40/Brembo GT brakes on the car were so much lighter, but never saw the numbers. Really happy with the setup, but doubt it's that big of a jump from the E31.

Can you use the Wilwood rotors from their BBK on the E31 calipers? They have 2-piece options. You can always splurge more and get custom AP rotors, but that'd cost $$$.

From a sheer performance perspective, you'd want the smallest rotor that doesn't have you cooking the brakes. For casual street driving the regular 324mm size would be plenty. Ditto for 6-pot--the rotors are small enough on our cars that a 6-pot seems to just add more weight and cost for no performance improvement.

[BleedsBlue]

Oh man those 95 M5 brakes weigh a ton. I sold those because the F40/Brembo GT brakes on the car were so much lighter, but never saw the numbers. Really happy with the setup, but doubt it's that big of a jump from the E31.

Can you use the Wilwood rotors from their BBK on the E31 calipers? They have 2-piece options. You can always splurge more and get custom AP rotors, but that'd cost $$$.

From a sheer performance perspective, you'd want the smallest rotor that doesn't have you cooking the brakes. For casual street driving the regular 324mm size would be plenty. Ditto for 6-pot--the rotors are small enough on our cars that a 6-pot seems to just add more weight and cost for no performance improvement.

Man, the 3.8 E34 M5 weighed a ton! Those late 6-speed variants with those brakes were knocking on 4,000#, just ridiculous.

I've never seen photos of your setup--just the classic "GT" F40 kit with two piece rotor?

Intriguing option on the Wilwoods! The problem (and it's a common one) would be sourcing the rotors (with hats) separately, since so many BBK suppliers won't sell individual parts. Thus, Greg's inability to find a Brembo F50 supplier after Ford Racing stopped carrying them. I would be highly interested in a bolt-up Wilwood two-piece rotor if it was anywhere near the $4-500 mark like a pair of OEM E46 floaters.

I agree about your general BBK points, for sure. For a Touring, I'm tempted to try the 345mm size (note that Wilwood says their $2k kit with 348mm fits under 17s, but they have slim calipers as well), but nothing bigger/no more than four pistons, personally.

[sugaki]

Man, the 3.8 E34 M5 weighed a ton! Those late 6-speed variants with those brakes were knocking on 4,000#, just ridiculous.

I've never seen photos of your setup--just the classic "GT" F40 kit with two piece rotor?

Intriguing option on the Wilwoods! The problem (and it's a common one) would be sourcing the rotors (with hats) separately, since so many BBK suppliers won't sell individual parts. Thus, Greg's inability to find a Brembo F50 supplier after Ford Racing stopped carrying them. I would be highly interested in a bolt-up Wilwood two-piece rotor if it was anywhere near the $4-500 mark like a pair of OEM E46 floaters.

Yep, it's the Brembo GT with F40 calipers and two-piece Brembo rotors (I wish they were slotted instead of cross-drilled). I thought this would be more economical in the long run for rotors/pads, then realized that these rotors are even more expensive than the 345mm Euro M5 rotors, argh. But there was also fear of the 345mm ones becoming NLA, and they're hard to source to the US unless you can prove you own a car that has them standard I think.

For Wilwoods, I wonder if you can say that you want a "backup set"? :-)

There was also a ~324mm Compbrake floating rotor on the M5board awhile back, probably you can just order the rotors for those? Not sure how much but the guy said it was cheaper than Brembos. Here's a pic of my brakes.

e34-brembo-brakes.jpg

[BleedsBlue]

Yep, it's the Brembo GT with F40 calipers and two-piece Brembo rotors (I wish they were slotted instead of cross-drilled). I thought this would be more economical in the long run for rotors/pads, then realized that these rotors are even more expensive than the 345mm Euro M5 rotors, argh. But there was also fear of the 345mm ones becoming NLA, and they're hard to source to the US unless you can prove you own a car that has them standard I think.

For Wilwoods, I wonder if you can say that you want a "backup set"? :-)

There was also a ~324mm Compbrake floating rotor on the M5board awhile back, probably you can just order the rotors for those? Not sure how much but the guy said it was cheaper than Brembos. Here's a pic of my brakes.

Nice looking set-up, for sure!

I though Stoptech and other brand rotors would all bolt up to the Brembo hat? Either way, it's definitely better to pay extra for rotors versus them being NLA and an impossibility to source!

I will certainly investigate the Wilwood rotor option more, I appreciate the idea. As well as the Compbrake! When it's all said and done, I may still prefer the OEM options of E46 floaters for ~$420-500/pair, but I want to investigate everything thoroughly.

On that note, as expected since most Brembos share mounting bolt spacing...



Every time I pick up Greg's F50 brackets, I laugh at how light they are. Pretty awesome.

Since my M5's strut had to come out this weekend, I played with fitment a bit on the stock M5 carrier + F50 bracket + 996. One initial observation is that the 996 Brembo has two pegs per side of caliper, visible in the picture above on either side of the silver piston inserts on the lower caliper. The 28mm thick 315mm M5 rotor fit between the pegs with very few mm to spare (the 996 uses a 28mm rotor as well), so I can probably write off the late M5 345x32mm rotor from a fitment perspective--it's likely too wide to fit between those pegs, without milling the pegs (I suppose that is an option). There is room for a 30mm E31 rotor, for sure.

Fortunately the F50 bracket places the 996 Brembo too far outboard (multiple cm) of the standard 315mm M5 rotor, so it's closer to fitting an E46 rotor than I thought! Based on the bracket fit, with all of that unused space between caliper and bracket + the somewhat raised 996 bracket surfaces), I'll bet this caliper will sit too far out for even a 345mm rotor, but that would be just another small dimensional tweak for Greg.

[Wishno87]

Just out of curiosity does anyone know why the M5 hub has those metal pegs? The regular cars don't have them so why does the M5 rotor need them?

[BleedsBlue]

^I certainly second that question. Especially when the factory put a rotor retaining screw in the hub, I really don't get it!

[Tre0Tre34]

Those retaining screws are the worst.

Will have quite the fight when it comes time to replace my front rotors (thank god there is plenty of meat left for now).

Dont actually recall what i was working on at the time, but definitely stripped one of them out, then broke off a hardened, "easy-out" bit in the damn thing... Hoping i can just beat the shit out of the rotor enough to break the thing when the time comes.

Love all the bbk talk, but my need for a smaller winter wheel and tire set will definitely keep me away from such an upgrade for the time being. Maybe this will be ready by the time i have located my land cruiser.

[BleedsBlue]

^Hilarious how many of us want/own a Land Cruiser!

10 years ago I got in the habit of never reinstalling rotor set screws, after fighting with one too many. I would end up hammering a bigger bit into them, and once had a friend weld something to it. With the brake caliper on, there is really no point--and when you torque a wheel down on top of that, the set screw is superfluous x2.

On the subject of wheel fitment: it seems the 324mm E31 Brembo setup will fit under a well-clearanced 16" wheel (think Style 5s), so I will try the E46 325mm + 996 Brembo for 16" wheel clearance as part of my testing. And then the 345mm rotors are known to fit under most 17" wheels after all, at least with Brembo F40 and F50s--likely the same scenario with the 996 Brembo. I think I will end up trying the 345mm rotor with the 996s under my 17s, actually.

[Tre0Tre34]

Exceptionally well designed/built vehicles are incredibly attractive to me and probably many on this site. Fj80 aint no speed demon, but it does just about everything else very well. Including serious off-roading in bone stock form. Tough to beat.

Definitely keep me posted on brake fitment (specifically with 16" style 5's) as i will need to upgrade the 15" 5's i currently have as my winter set. It is getting a bit ridiculous to find a decent 15" tire no matter what season.

[BleedsBlue]

Will do for sure, my opinion on wheels matches that of rotors--as small as possible to retain effectiveness. Though we are getting squeezed on 15 and 16" tire fitment, at least over 225 section width in 16. That was a big "problem" in the air-cooled 911 world as well.

[5mall5nail5]

IMHO if you're not changing cylinders and want to match similar bias and pedal feel, the 6-piston SL6R from Wilwood are the way to go. My stock brake E34 525i and my 6-piston SL6R Wilwood E34 525i feel absolutely identical in pedal feel.... the difference is on stops harder/longer/more-better than the other.

[Billyj]

Are we all comfortable with aluminum caliper brackets? No fear of metal fatigue? Just thinking out loud

Mountain roads + failed brakes = unhappy blue bleeder

[BleedsBlue]

IMHO if you're not changing cylinders and want to match similar bias and pedal feel, the 6-piston SL6R from Wilwood are the way to go. My stock brake E34 525i and my 6-piston SL6R Wilwood E34 525i feel absolutely identical in pedal feel.... the difference is on stops harder/longer/more-better than the other.

Wow that kit is not that expensive, either... good data point there, thank you!

Are we all comfortable with aluminum caliper brackets? No fear of metal fatigue? Just thinking out loud

Mountain roads + failed brakes = unhappy blue bleeder

Yeah this usually comes up with any BBK. Long story short, I've both done enough research and talked to enough engineers that I feel comfortable with aluminum brackets, but YMMV and everyone can make their own decisions based on their knowledge and comfort levels. There is some good reading on this topic over on Pelican Parts 911 forums, and elsewhere.

The Rally Road bracket is actually steel I believe.