DIY guide on X5 35d/35i to 50i brake upgrade and rebuild

[DuSh]

I just realized now what 44/24 means lol. Yewlock I remember you asking about it and I didn't know it at that time.

[Maverik259]

Originally Posted by DuSh

I just realized now what 44/24 means lol. Yewlock I remember you asking about it and I didn't know it at that time.

Do tell! Lol

[DuSh]

Originally Posted by Maverik259

Do tell! Lol

Lol the truth is I don't know, but I meant i realized what he was asking lol. He was asking me about if it's ok to use 44/24 calipers and at that time I had no idea what 44/24 meant - I was thinking it's some kind of brand or something. Now i realized it's just a lettering on oem 50i calipers lol - so he was essentially asking that if it's ok to use 50i calipers. I still don't know what it really stands for BMW doesn't make it easy with all the variety of options and calipers.

[Maverik259]

Originally Posted by DuSh

Lol the truth is I don't know, but I meant i realized what he was asking lol. He was asking me about if it's ok to use 44/24 calipers and at that time I had no idea what 44/24 meant - I was thinking it's some kind of brand or something. Now i realized it's just a lettering on oem 50i calipers lol - so he was essentially asking that if it's ok to use 50i calipers. I still don't know what it really stands for BMW doesn't make it easy with all the variety of options and calipers.

Haha I'll have to look on the M calipers on my garage and see what they say as they should be a bit larger

[yewlock]

Originally Posted by DuSh

Lol the truth is I don't know, but I meant i realized what he was asking lol. He was asking me about if it's ok to use 44/24 calipers and at that time I had no idea what 44/24 meant - I was thinking it's some kind of brand or something. Now i realized it's just a lettering on oem 50i calipers lol - so he was essentially asking that if it's ok to use 50i calipers. I still don't know what it really stands for BMW doesn't make it easy with all the variety of options and calipers.

After you told me that you don't know. I found out that 44 means 44mm piston/ 24 means 24mm rotor

50i has 44/24 rear caliper.

MPBK has 42/24 rear caliper

[Maverik259]

Originally Posted by yewlock

After you told me that you don't know. I found out that 44 means 44mm piston/ 24 means 24mm brake pads

50i has 44/24 rear caliper.

MPBK has 42/24 rear caliper

So the 50i has larger piston and same size pads? That's interesting

[kmac77]

Thanks,
great DIY and very thorough!

[DuSh]

Originally Posted by yewlock

After you told me that you don't know. I found out that 44 means 44mm piston/ 24 means 24mm brake pads

50i has 44/24 rear caliper.

MPBK has 42/24 rear caliper

Ah, I see it now! Thanks man!

[Maverik259]

Originally Posted by DuSh

Ah, I see it now! Thanks man!

Rear Says 42/24 on the F85 which I think is the same as the MPBK if I recall. What baffles me is that the rear caliper and rotor is even larger in the M5 than the X5M. That makes no sense to me.

[DuSh]

Originally Posted by Maverik259

Rear Says 42/24 on the F85 which I think is the same as the MPBK if I recall. What baffles me is that the rear caliper and rotor is even larger in the M5 than the X5M. That makes no sense to me.

Yes, I was kinda envy when I saw that. Maybe it's because M5 is RWD and bmw decided to go all in for rear brakes? Not sure lol

[Maverik259]

Originally Posted by DuSh

Yes, I was kinda envy when I saw that. Maybe it's because M5 is RWD and bmw decided to go all in for rear brakes? Not sure lol

Idk if Id quite call floating calipers being all in yet lol. They're still cheaping out on the consumer but saving maybe $100-200 on better calipers. Which baffles me. Even on the carbon ceramic package. Hell im contemplating just getting the adapters for the F85 calipers so I can get the rotors and pads as they're more readily available in aftermarket applications

[Maverik259]

Originally Posted by DuSh

Ah, I see it now! Thanks man!

I'm also curious as to how the piston would be larger than the brake pad. Is it possible the numbers are reversed? 44mm pad and 24mm piston?

[DuSh]

Originally Posted by Maverik259

I'm also curious as to how the piston would be larger than the brake pad. Is it possible the numbers are reversed? 44mm pad and 24mm piston?

Just tried to google it and it's really obscure, but I think I got what it means: 44mm is piston diameter and 24mm is rotor thickness caliper is made for.
But I'm still not sure, the article I found is too detailed for me right now to read - I'm just relaxing before the bedtime and can't focus on it lol. Hopefully someone can clarify

https://www.bimmerforums.com/forum/s...brake-calipers

[Maverik259]

Originally Posted by DuSh

Just tried to google it and it's really obscure, but I think I got what it means: 44mm is piston diameter and 24mm is rotor thickness caliper is made for.
But I'm still not sure, the article I found is too detailed for me right now to read - I'm just relaxing before the bedtime and can't focus on it lol. Hopefully someone can clarify

https://www.bimmerforums.com/forum/s...brake-calipers

Now that makes more sense. 24mm is the thickness if I recall.

[mikew2069]

Originally Posted by Maverik259

Rear Says 42/24 on the F85 which I think is the same as the MPBK if I recall. What baffles me is that the rear caliper and rotor is even larger in the M5 than the X5M. That makes no sense to me.

Why in the world would the 50i caliper have a 44mm piston and the F85 have a 42mm piston?

[Maverik259]

Originally Posted by mikew2069

Why in the world would the 50i caliper have a 44mm piston and the F85 have a 42mm piston?

Not sure. I did measure the rotor surface of the M rotor vs the 50i rotor and they both measured to 2 5/8" so perhaps you are correct and they are the same essentially but to accommodate a wider rotor it required a different bracket. This would mean the brake pad was the same I bet.