[MPR]

This has been a debated topic for a while now -- some insisting the calipers are the same size, and only the rotors are bigger, some insisting both are larger. Here are some good pics of ZTK / cooling pack caliper measurements on a U.S. car. We need someone with non-ZTK calipers to do the same to close this mystery

https://g42.bimmerpost.com/forums/sh...3&postcount=52

[Winrya]

Originally Posted by MPR

This has been a debated topic for a while now -- some insisting the calipers are the same size, and only the rotors are bigger, some insisting both are larger. Here are some good pics of ZTK / cooling pack caliper measurements on a U.S. car. We need someone with non-ZTK calipers to do the same to close this mystery

https://g42.bimmerpost.com/forums/sh...3&postcount=52

Post 40 and 42 show those which are 2 inches smaller than the pic you have just posted

Although post 37 seems to be smaller calipers on Ztk car without cooling package which has the smaller caliper. No idea on disc size

[MPR]

Ah, you're right, so the ZTK's are roughly 2 inches larger.

[LivingInSalt]

every inch is important

[Winrya]

Originally Posted by MPR

Ah, you're right, so the ZTK's are roughly 2 inches larger.

Yes although post 37 is a ztk car with smaller calipers. What extra options do you guys have to add the cooling package ?

[Winrya]

Originally Posted by Nicolas05

Hi Ryan.. that’s me on IG :-)
Glad I could help.

Nicolas, did you happen to measure your discs?

[LivingInSalt]

seems like the issue is different specs for different regions

[Winrya]

I’ve compared the 12 and 14 inch calipers and there are a few give aways to see which a car has without taking the wheel off and putting a tape on it

The highlighted caliper is the larger one. The detail by the m badge is wider, various other parts are beefed up. The metal clips pins are positioned differently. Top and bottom of 3 dimples compared to middle on smaller calipers.

I also notice joe Achilles long termer even though he says has the upgraded brakes (which he says are shot by 2 laps) are actually the smaller calipers

[ryo-]

if you look at the larger calipers, the ends are just extended and the pad contact patch seems to be the same. idk if it actually makes a difference or not

[MPR]

Maybe that's why it's referred to as cooling, since the more metal mass probably contributes to that. With the same size pads, no increase in braking force.

[Winrya]

Originally Posted by MPR

Maybe that's why it's referred to as cooling, since the more metal mass probably contributes to that. With the same size pads, no increase in braking force.

Someone on the group has been researching upgraded pads. Seems the upgrade calipers have 25% bigger pads

[jpcoop]

Originally Posted by MPR

Maybe that's why it's referred to as cooling, since the more metal mass probably contributes to that. With the same size pads, no increase in braking force.

This is what I've always thought. If there is a difference I doubt it's major.

I've seen a bunch of measurements of the caliper itself but that doesn't tell you anything useful - it would have to be larger for it to fit over the larger rotors. I haven't seen anyone measure the pads.

[Thundernight]

Originally Posted by Winrya

Someone on the group has been researching upgraded pads. Seems the upgrade calipers have 25% bigger pads

Are we sure about that? I spoke about this with my dealership and they provided the following part numbers for my car with ZTK package:

Front Brake Pads: 34-11-6-889-585
Rear Brake Pads: 34-20-6-888-835

Looking at bmwpartsnow.com, the front brake pad is shared with other BMW models including the M3 competition and M8 grand coupe. There is no reference of a G42 M240 with or without the ZTK package.

https://www.bmwpartsnow.com/oem-part...nt-34116889585

Also, other sites such as Turner Motorsports have the same pad listed as compatible across all M240 cars, but the brake pads from the M3 competition and M8 are considered incompatible (part#: 34-10-7-883-265).

https://www.turnermotorsport.com/p-6...t-34116889585/

It looks like the BMW parts websites are just as confused..

[Winrya]

Originally Posted by Thundernight

Are we sure about that? I spoke about this with my dealership and they provided the following part numbers for my car with ZTK package:

Front Brake Pads: 34-11-6-889-585
Rear Brake Pads: 34-20-6-888-835

Looking at bmwpartsnow.com, the front brake pad is shared with other BMW models including the M3 competition and M8 grand coupe. There is no reference of a G42 M240 with or without the ZTK package.

https://www.bmwpartsnow.com/oem-part...nt-34116889585

Also, other sites such as Turner Motorsports have the same pad listed as compatible across all M240 cars, but the brake pads from the M3 competition and M8 are considered incompatible (part#: 34-10-7-883-265).

https://www.turnermotorsport.com/p-6...t-34116889585/

It looks like the BMW parts websites are just as confused..

Off the Facebook chat

[jpcoop]

That is a random person on Facebook parroting back info they got from a third party brake pad seller. And it doesn't exactly sound like they're 100% sure either.

The only way to end the confusion is to get the part numbers from the dealer and measure the brake pads.

[Winrya]

Originally Posted by jpcoop

That is a random person on Facebook parroting back info they got from a third party brake pad seller. And it doesn't exactly sound like they're 100% sure either.

The only way to end the confusion is to get the part numbers from the dealer and measure the brake pads.

The pads will obviously be bigger as they have a bigger diameter disc. 348 vs 376

[jpcoop]

Originally Posted by Winrya

The pads will obviously be bigger as they have a bigger diameter disc. 348 vs 376

That’s actually not that obvious. The diameter of the disk does not determine the surface area (length x width) or swept area of the pad.

[Thundernight]

Interesting, the other pads look to be taller than the non ZTK option. Even with the increase in size, the braking system from the ZTK package is still not fully up to par. I tracked the car at Thompson Speedway last week and the brakes started to fade after 5 laps (instead of Joe's 2 laps). We could benefit from a higher performance track pad that has a higher temperature range. Hopefully once the G87 hits the streets, there will be more AM support.

Perhaps what would help us more than finding the part numbers for the brake pads would be to find the pad plate number (shape number). This would help us cross reference the shape of the metal plate across all the aftermarket vendors to find a brake pad that is more suitable for the track. Does anyone know what the pad plate number is for these brake pads?

[Bee Pee]

https://www.bimmerworld.com/M-Sport-Brakes-G20-G22/