(Relatively) Low cost Big Brake Kit (BBK) for the non 35i E89s
Posted: Sat Aug 08, 2020 1:39 pm
The title is quite a mouthful..but hopefully self-explanatory!
This also falls into the camp of ‘cause I can’
The 18i and 20i come with 300mm by 20mm (the 28i has a 330mm by 20mm disc)
The 30i came with a 330 by 24mm front disc.
On the back the 18i, 20i, 28i, 30i all had a 300mm by 20mm rear disc.
The UK spec 35i came with 348mm by 30mm front and 324mm by 20mm rear dics.
All these systems were single floating caliper with an electronic parking brake fitted to the rear calipers.
The braking power on my 20i has seemed perfectly acceptable for street use, well balanced and adequate without being obviously either powerful or ‘grabby’.
I had already fitted a pair of 28i front discs and calipers from someone who was tracking a 28i and had fitted a BBK. I struggled to perceive any effect from the ‘upgrade’.
Despite that, and regretting that I had painted my calipers a bright yellow, this emphasised the ‘uncool’ look of the OE single piston calipers.
Looking cool is very important so many sleepless nights followed..
Fast forward on, and running out of things to do to my ‘Yellow Peril’ and see that Boltz had posted pictures of his BBK using second hand standard BMW parts
viewtopic.php?f=23&t=123131&p=1758845&h ... z#p1758845
So I started down the same route and discovered that BMW make lots of BBK for all sorts of their cars. They all seem to be based on various forms of Brembo BBK in 4 and 6 pot versions with various size discs.
The issue that drove my logic was that I have both 17” wheels primarily for winter tyres and 18” wheels for summer tyres. Most of the BMW BBK only fit 18” and upwards wheels.
This front BBK ( BMW # 34110444738) was designed for 3 series E90/91/92/93 as a ‘performance upgrade’ and has 6 pot opposed calipers with 338mm by 26mm discs, ventilated as usual with slots and holes..
I know that there is much discussion about the veracity of holes etc..but since they came with them I’m not filling them in!
The important point for me is that despite the sizer of the calipers and discs the design of the caliper has been ‘bent’ to suit the curvature of the wheel and hence fits 17” BMW wheels.
Price wise is got these brand new for just over £1,100 including all parts (in theory) to fit an E90.calipers, discs, pads rear shields etc.
The different wear sensor pad fitment and connector fitment is to be resolved..Boltz’s garage simply forced the E89 sensor into the slightly different shaped slot in the BBK pads!
The unknown is whether it will fit my Team Dynamics Pro Race 1.2 17” wheels..hopefully they should.
I had already found out that my 103 BMW OE Daisys did not fit over the 330mm 28i disc configuration! Well they did but the wheels didn’t turn!
The back brakes on the E89 are very problematical because of the built in electronic braking system. Very few cars have comparable/compatible brake systems.
Normally on the E90 series when the BBK kit on the front is fitted either an equivalent BBK on the back is fitted or the DCS is re-programmed to suit.
Clearly there is no programming available for the E89 using this BBK and the rear BBK cannot be fitted due to the electronic parking brake.so..
I decided that I would fit the UK spec 35i calipers and discs. Nearly fell of my chair when I tried to source new 35i rear calipers (around £600 just for a caliper). After a couple of failed attempts secured a used pair in the USA for $100.
I bought a pair of new Zimmerman drilled discs to suit and will treat the car to fresh hoses all the way around.
I’ve had those freighted to the UK and Bigg Red a brake overhauler in Worcester is going to overhaul them and paint them matching Phoenix Yellow to match the front BBK.
So today we have most of the parts..a couple of weeks time the front BBK goes on at a local garage along with some fresh M series trailing arm bushes and a final alignment check.
When the rear calipers come back in 3-4 weeks’ time they will be fitted too!
So up from 330/330mm by 20mm single caliper to 338mm by 26mm 6 opposed pots with much bigger pads on the front and from 300mm by 20mm to 324mm by 20mm on the back
I’ll let you know how it goes..
This also falls into the camp of ‘cause I can’
The 18i and 20i come with 300mm by 20mm (the 28i has a 330mm by 20mm disc)
The 30i came with a 330 by 24mm front disc.
On the back the 18i, 20i, 28i, 30i all had a 300mm by 20mm rear disc.
The UK spec 35i came with 348mm by 30mm front and 324mm by 20mm rear dics.
All these systems were single floating caliper with an electronic parking brake fitted to the rear calipers.
The braking power on my 20i has seemed perfectly acceptable for street use, well balanced and adequate without being obviously either powerful or ‘grabby’.
I had already fitted a pair of 28i front discs and calipers from someone who was tracking a 28i and had fitted a BBK. I struggled to perceive any effect from the ‘upgrade’.
Despite that, and regretting that I had painted my calipers a bright yellow, this emphasised the ‘uncool’ look of the OE single piston calipers.
Looking cool is very important so many sleepless nights followed..
Fast forward on, and running out of things to do to my ‘Yellow Peril’ and see that Boltz had posted pictures of his BBK using second hand standard BMW parts
viewtopic.php?f=23&t=123131&p=1758845&h ... z#p1758845
So I started down the same route and discovered that BMW make lots of BBK for all sorts of their cars. They all seem to be based on various forms of Brembo BBK in 4 and 6 pot versions with various size discs.
The issue that drove my logic was that I have both 17” wheels primarily for winter tyres and 18” wheels for summer tyres. Most of the BMW BBK only fit 18” and upwards wheels.
This front BBK ( BMW # 34110444738) was designed for 3 series E90/91/92/93 as a ‘performance upgrade’ and has 6 pot opposed calipers with 338mm by 26mm discs, ventilated as usual with slots and holes..
I know that there is much discussion about the veracity of holes etc..but since they came with them I’m not filling them in!
The important point for me is that despite the sizer of the calipers and discs the design of the caliper has been ‘bent’ to suit the curvature of the wheel and hence fits 17” BMW wheels.
Price wise is got these brand new for just over £1,100 including all parts (in theory) to fit an E90.calipers, discs, pads rear shields etc.
The different wear sensor pad fitment and connector fitment is to be resolved..Boltz’s garage simply forced the E89 sensor into the slightly different shaped slot in the BBK pads!
The unknown is whether it will fit my Team Dynamics Pro Race 1.2 17” wheels..hopefully they should.
I had already found out that my 103 BMW OE Daisys did not fit over the 330mm 28i disc configuration! Well they did but the wheels didn’t turn!
The back brakes on the E89 are very problematical because of the built in electronic braking system. Very few cars have comparable/compatible brake systems.
Normally on the E90 series when the BBK kit on the front is fitted either an equivalent BBK on the back is fitted or the DCS is re-programmed to suit.
Clearly there is no programming available for the E89 using this BBK and the rear BBK cannot be fitted due to the electronic parking brake.so..
I decided that I would fit the UK spec 35i calipers and discs. Nearly fell of my chair when I tried to source new 35i rear calipers (around £600 just for a caliper). After a couple of failed attempts secured a used pair in the USA for $100.
I bought a pair of new Zimmerman drilled discs to suit and will treat the car to fresh hoses all the way around.
I’ve had those freighted to the UK and Bigg Red a brake overhauler in Worcester is going to overhaul them and paint them matching Phoenix Yellow to match the front BBK.
So today we have most of the parts..a couple of weeks time the front BBK goes on at a local garage along with some fresh M series trailing arm bushes and a final alignment check.
When the rear calipers come back in 3-4 weeks’ time they will be fitted too!
So up from 330/330mm by 20mm single caliper to 338mm by 26mm 6 opposed pots with much bigger pads on the front and from 300mm by 20mm to 324mm by 20mm on the back
I’ll let you know how it goes..
