Brembo GT Kit and CSL/ZCP Wheels fitment question

[AWE46M3]

Get an 18MM spacer in the front. Rears will have ample space and will only need a spacer if you want a more filled out look.

20MM is the absolute max up front. I ran a 20MM with my 8" ZCP's. It was at the limit, and I could feel the feedback in my steering wheel.

25MM would be nice if it did not come at the expense of scrub radius and the wheel bearings.

[Bimma360]

I was this close to ordering a set of EBC 6 piston BBK fronts. Was going to just pull the trigger, bc “no way should I need more than a 12mm spacer.” Good thing I decided to print out the template, bc nope… need 20mm spacers at minimum. So disappointing, I think I am just going to rebuild my comp brakes instead.

[CarbonBlkM3]

Here's my 380mm / 4pot Brembo GT on OEM ZCP fronts. Had to utilize 20mm spacers.As you can see it's a tight fit, but does clear.

[liam821]

Ease of pad swaps is the only benefit, but it's a HUGE benefit. Needing to take the caliper off to change pads sucks. I'd say easy pad swaps is at least 50% of the benefit of a BBK over the stock brakes, if you're tracking the car.

I'm not sure of the pad selection for the 6-pot, but for the 4-piston calipers there is a massive massive selection of available pads.

[Obioban]

Is the ease of the pad swap the only benefit? I remember speaking with Dave Zeckhausen, he mentioned there were other benefits using the 4 piston over the 6 piston. I just can't remember what they were.

I have a vague memory, that the 6 piston were 2 piece vs the 4 piston which were 1 piece which improved on pedal feel at the limits?

Ease of pad swaps is the only benefit, but it's a HUGE benefit. Needing to take the caliper off to change pads sucks. I'd say easy pad swaps is at least 50% of the benefit of a BBK over the stock brakes, if you're tracking the car.

[bmw m3 s50]

380mm GT Kit

I will be listing my full Brembo GT kit which is 380mm front 4 piston and 345 rear 4 piston for sale soon. Not sure what you paid, but I have a feeling the price I plan to set for my full kit will be the same or less as the 380mm front kit new.

[bmw m3 s50]

Easier to swap pads, which you're doing at least twice every track weekend.

... and 19s are a huge downgrade from 18s on track, and 380s generally force 19s, so 380s are pretty terrible outside of looking cool.

Is the ease of the pad swap the only benefit? I remember speaking with Dave Zeckhausen, he mentioned there were other benefits using the 4 piston over the 6 piston. I just can't remember what they were.

I have a vague memory, that the 6 piston were 2 piece vs the 4 piston which were 1 piece which improved on pedal feel at the limits?

[Obioban]

I’ve always assumed something like this isn’t ideal for handling. Am I off?

Nope, not off. Increasing the front offset in particular (ala spacers) degrades the geometry pretty quickly.

[liam821]

My memory is that with a 355/4 up front and 345/4 in the rear…
ZCP wheels need 15mm front, 12mm rear
oe 18s need 12 front, nothing rear
oe 19s don’t need anything

When I bought the car, it had a 20mm front (but agree, 15mm would work) and no spacer in the rear (plenty of clearance). I had the Brembo 355/4 up front and Brembo 345/4 in the rear. I added a 12mm rear spacer because the rear fitment was pretty sunk-in (see above pictures, no rear spacer)

[9kracing]

IDK if this helps, but I just went from the 4-pot Brembos pictured above to the 6-pot Brembos, and the wheels I use went from requiring a 10MM spacer, to a 3mm spacer... so on my car, the 4-pots stuck out 7mm more than my 6-pots.

This is 355mm kit.

[Bimma360]

My memory is that with a 355/4 up front and 345/4 in the rear…
ZCP wheels need 15mm front, 12mm rear

I’ve always assumed something like this isn’t ideal for handling. Am I off?

[Obioban]

My old M3 had the 355/4pot Brembo GTs, and I ran a 20mm spacer in the front to clear the calipers with the stock front ZCP wheels. I could have probably gone down to a 15mm (maybe), but they definitely don't clear without a spacer.

Here are a few pictures of my old car...

My memory is that with a 355/4 up front and 345/4 in the rear…
ZCP wheels need 15mm front, 12mm rear
oe 18s need 12 front, nothing rear
oe 19s don’t need anything

[liam821]

My old M3 had the 355/4pot Brembo GTs, and I ran a 20mm spacer in the front to clear the calipers with the stock front ZCP wheels. I could have probably gone down to a 15mm (maybe), but they definitely don't clear without a spacer.

Here are a few pictures of my old car...

[Obioban]

lol indeed.

I just went from 4-pot to 6-pot and the wheel fitment is much better.

Why would 4-pot be preferable for the track? Easier to modulate?

Easier to swap pads, which you're doing at least twice every track weekend.

... and 19s are a huge downgrade from 18s on track, and 380s generally force 19s, so 380s are pretty terrible outside of looking cool.

[9kracing]

lol indeed.

I just went from 4-pot to 6-pot and the wheel fitment is much better.

Why would 4-pot be preferable for the track? Easier to modulate?