Truth about using STI Brembos on the twins

[churchx]

@CSG Mikes: but what degrades in calipers? Doesn't rehauling/cleaning/replacing seals and guide rubbers/regreasing restore them almost like anew? Trying to imagine, what can wear/degrade in metallic parts in calipers/pistons to be noticeable in braking, if there are no scratches or alike at time of overhaul? :/

[NoHaveMSG]

Originally Posted by churchx

@CSG Mikes: but what degrades in calipers? Doesn't rehauling/cleaning/replacing seals and guide rubbers/regreasing restore them almost like anew? Trying to imagine, what can wear/degrade in metallic parts in calipers/pistons to be noticeable in braking, if there are no scratches or alike at time of overhaul? :/

They could be scoring the piston and piston bores which would tear up the seals.

[RayRay88]

Originally Posted by NoHaveMSG

They could be scoring the piston and piston bores which would tear up the seals.

Seals also degrade with high heat. It's the main reason most "proper" aftermarket calipers don't come with them.

[NoHaveMSG]

Originally Posted by RayRay88

Seals also degrade with high heat. It's the main reason most "proper" aftermarket calipers don't come with them.

I should clarify I was mostly talking about why you would replace the whole caliper as opposed to just swapping the seals. Could cause them to get sticky too.

[CSG Mike]

Originally Posted by churchx

@CSG Mikes: but what degrades in calipers? Doesn't rehauling/cleaning/replacing seals and guide rubbers/regreasing restore them almost like anew? Trying to imagine, what can wear/degrade in metallic parts in calipers/pistons to be noticeable in braking, if there are no scratches or alike at time of overhaul? :/

when you massively overheat the metal over and over it fatigues over time, and eventually you'll get non-plastic deformation.

Generally, if you are burning off outer dust boots, you are MASSIVELY overheating calipers.

Originally Posted by Brembo

For those running fixed, multi-piston calipers (Brembo GT, for example), recommended working temperature is < 200°C (392F), whereas the maximum acceptable working temperature is 220°C (428F);
Over 240°C (464F), the seals fitted into the calipers can be overheated and they will not guarantee the right performances of the caliper (sealing, roll back, fluid absorption,…);
If the caliper temperature goes over 240°C (464F), the dust seals and pressure seals should be refreshed.

Brembo, AP, Alcon, Advics, Project Mu, PFC, etc. all have the same recommendations.

[CSG Mike]

Originally Posted by NoHaveMSG

Are they scoring the piston bores that badly?

The caliper itself is getting soft and flexing

[CSG Mike]

Originally Posted by RayRay88

Seals also degrade with high heat. It's the main reason most "proper" aftermarket calipers don't come with them.

Race calipers dont have outer dust boots. Street/mixed duty calipers do.

[NoHaveMSG]

Originally Posted by CSG Mike

The caliper itself is getting soft and flexing

Ahhhh. Thanks for the clarification.

[Ohio Enthusiast]

Originally Posted by CSG Mike

when you massively overheat the metal over and over it fatigues over time, and eventually you'll get non-plastic deformation.

Generally, if you are burning off outer dust boots, you are MASSIVELY overheating calipers.



Brembo, AP, Alcon, Advics, Project Mu, PFC, etc. all have the same recommendations.

Although this sound correct, I wonder how does that jive with track-oriented pads for stock calipers? If dust boots need temps lower than 400 F, why bother with non-stock pads? If you run track pads that can handle higher temps, are you ruining the calipers in short order? Or is it that the calipers don't come close to the friction surface temperatures?

[churchx]

There are people that need to use for various reasons stock brakes (eg. class requirements or street legality for dual-used car in some countries). Dust boots are there mostly to keep road salt out & maybe some extra dirt/sand/dust, no? And in winter there are way less load/temps on brakes. Seeing no relation of using or not track pads when, well, tracking, and street pads elsewhere, related to if calipers have or haven't dustboots. One just needs to understand, that proper braking on track (even if with stock pads, that may underperform in several areas on track) most probably will burn off those dustboots. Though it seems beneficial to replace burnt off dustboots in autumn, when summer tarmac tracking season ends. They don't cost exorbitant sums (eg. SU00304523 + SU00304098)

[CSG Mike]

Originally Posted by Ohio Enthusiast

Although this sound correct, I wonder how does that jive with track-oriented pads for stock calipers? If dust boots need temps lower than 400 F, why bother with non-stock pads? If you run track pads that can handle higher temps, are you ruining the calipers in short order? Or is it that the calipers don't come close to the friction surface temperatures?

Often times, you don't get the choice (luxury) of more caliper and rotor. It may not fit the budget, or the rules of a certain class, or such a system may just straight up not exist.

Then you have to accept that the calipers are going to get hot.

Have you ever seen a brake change in pro level endurance racing? They often change out the entire assembly during stops. Guess what's going to happen to that caliper? Straight to rebuild.

Here's an example.

[53Driver]

Originally Posted by CSG Mike

Often times, you don't get the choice (luxury) of more caliper and rotor. It may not fit the budget, or the rules of a certain class, or such a system may just straight up not exist.

Then you have to accept that the calipers are going to get hot.

Have you ever seen a brake change in pro level endurance racing? They often change out the entire assembly during stops. Guess what's going to happen to that caliper? Straight to rebuild.

Here's an example.

Man, I wish those guys would show up at my garage and do a brake, wheel/tire swap like that for me. Jeez, only took them about 70 seconds. I could easily done it in an hour and a half by myself.

[Captain Snooze]

Originally Posted by 53Driver

Man, I wish those guys would show up at my garage and do a brake, wheel/tire swap like that for me. Jeez, only took them about 70 seconds. I could easily done it in an hour and a half by myself.

You want to swap wheels quickly? Here, have this. Admittedly they are not changing brakes but still.
Don't blink.

[RayRay88]

Originally Posted by Captain Snooze

You want to swap wheels quickly? Here, have this. Admittedly they are not changing brakes but still.
Don't blink.

Red Bull hold the record at the moment, 1.82 seconds. It's astounding.