Impala Forums banner

21 - 25 of 25 Posts

·
Registered
Joined
·
287 Posts
link doesnt work. maybe type it without the http and www and the site wont shorten it and itll function
 

·
Registered
Joined
·
287 Posts
also, since the piston are is similar, wouldn't the 4 piston rotors have about the same pedal travel?
I didnt get a chance to read through the link you provided yet to elaborate on what they say,
but to answer this question, yes your pedal travel would be basically unchanged with the ATS 42mm calipers on as compared to stock, because they have such a close functional piston area to the stock floating caliper.
 

·
Registered
Joined
·
287 Posts
Okay...
So basically most what that article says is true, but there are some serious caveats, and of course there is one glaring error.

whyhighend.com said:
The fixed caliper can apply more squeezing power and apply that power more evenly during braking as force is directly applied to both sides even if its a two piston brake
They do have the word "can" in this sentence, so I guess technically it could be construed as correct if you use the meaning of can as a qualifier, as opposed to an absolute.

Anyway...this is where they get it all wrong. Based on the rules hydraulics, and physics of brake caliper function(not material choice or manufacturing) this is WRONG . Given 2 calipers with same piston area the multiple piston fixed caliper DOES NOT apply more squeezing power than a floating caliper. It cant, Newtons 3rd law and the basics of hydraulics and pressure tells us so. However material and overall design will allow 2 calipers with same piston area to provide differing clamp loads at same brake pressure due to caliper structure, NOT piston arrangement. A monoblock billet caliper can apply more force than a lightweight aluminum floating caliper because the monoblock wont flex. Just like a massive cast iron floating caliper will apply more force than a superlight multipiece fixed caliper. Look at N-body or C5 alloy floating calipers to to see why people are opposed to them. But also look how many guys ditched the stock C6 Z06 8 piston calipers. Caliper material selection and structure/build quality have far more to do with brake feel or clamping load than piston arrangement.

In virtually all examples a fixed caliper is more expensive, they are correct, but often times packaging and mass restrictions based on other vehicle design elements determine caliper choice, this is one likely reason why youll find fixed calipers on 4cylinder Colorado trucks that clearly dont need them when we all know there are floating calipers on much heavier vehicles that would stop the truck perfectly well.

Another way we can tell a common OE 4piston caliper isnt providing significantly more brake clamping force is that GM almost always keeps the floating and fixed caliper piston areas VERY close to each other, and uses the same master cylinder for both applications, if the fixed calipers were far superior in delivering increased clamp load GM would spec a a different master cylinder in order to maintain pedal feel and pedal travel equality between the vehicles. The 2015 Camaro has no less than 4 diffeent front brake setups and engines, they all use the same master cylinder

Some add'l points of my own:
Floating calipers have less failure points, and fewer parts.
Fixed calipers often require more maintenance to achieve consistent pad wear and quiet operation.
Floating calipers typically offer increased wheel clearance.
OE floating caliper/pads typically are not significantly lighter than the floating caliper they replace.
 
21 - 25 of 25 Posts
Top