Move stock front calipers to rear?

[canyons]

now that I have a BBK on the front,
Can I use the stock front calipers on the rears?


Anybody know about fitment?
Is there a magic bracket/adapter?

[wparsons]

Short answer, no.

Bigger question is why? Assuming the BBK is designed to work with the stock rear brakes, putting the front calipers in the rear would destroy the brake balance.

[ysu]

Originally Posted by wparsons

Short answer, no.

Bigger question is why? Assuming the BBK is designed to work with the stock rear brakes, putting the front calipers in the rear would destroy the brake balance.

That's an interesting thing to say; you increase the front braking power, that's fine, but if you increase the rear with it, that's not fine?

And why? The car has an electronic brake distribution system, that should deal with it pretty well. If not, and you've problems, there's still the pedal dance, no?

[cjd]

Originally Posted by ysu

That's an interesting thing to say; you increase the front braking power, that's fine, but if you increase the rear with it, that's not fine?

And why? The car has an electronic brake distribution system, that should deal with it pretty well. If not, and you've problems, there's still the pedal dance, no?

No.

Good chance you haven't increased front bias, unless the kit wasn't designed to go with stock, in which case it probably has rear brakes it was designed to go with.

[justatroll]

The real answer is 'maybe'.


What was the mechanical brake bias in the stock system?
To know that you need to know the specifics of the Master cylinder piston diameter, the front brake piston total area, the rear piston total area.


From that you can calculate the stock bias.
Now you changed the front brakes.
How much did you change the piston area by?
You should change the rear piston area by the same amount to maintain the stock bias.


There is a chance that you increased the front by just the right amount to make moving the front calipers to the rear the proper compensation, but we need more info.

In fact I did this exact thing on my Porsche track car.
The stock bias was too conservative (too much front bias for safety).
I put a set of stock front calipers on the rear to give me more rear bias (effectively equal to the front), then I put better pads on the front than on the back to give back my front bias.
I also have a manual bias valve, but have not even had to install it yet.


So it can be done, but should it?
You need to do some calculations to know for sure.

[zkv476]

Anything can be done mechanically if you try hard enough. The brackets do not already exist, you'd have to design and make them. What BBK did you put on the front that would warrant the stock fronts on the rear? Part of the reasoning for a BBK is to reduce weight. Stock fronts are cast and heavy.

Originally Posted by ysu

That's an interesting thing to say; you increase the front braking power, that's fine, but if you increase the rear with it, that's not fine?

And why? The car has an electronic brake distribution system, that should deal with it pretty well. If not, and you've problems, there's still the pedal dance, no?

EBD doesn't adjust on the fly to different calipers. It is hard-coded to behave a certain way relative to the pressures in the lines and other sensors from the car but won't know that the brakes are bigger.

[bhmax]

http://www.tceperformanceproducts.com/bias-calculator/

I used that calculator and got about 65/35 stock assuming equal friction pads front and rear. I went with higher friction pads in the rear and moved it to about 60/40. No adverse effects so far.

[ysu]

Originally Posted by zkv476

Anything can be done mechanically if you try hard enough. The brackets do not already exist, you'd have to design and make them. What BBK did you put on the front that would warrant the stock fronts on the rear? Part of the reasoning for a BBK is to reduce weight. Stock fronts are cast and heavy.



EBD doesn't adjust on the fly to different calipers. It is hard-coded to behave a certain way relative to the pressures in the lines and other sensors from the car but won't know that the brakes are bigger.

Ah, I expected the sensor feedback to be adequate for the system to determine the proper balance/distribution. Thanks for clearing it up.

[8R6]

Which bbk did you put on the front?

[mav1178]

bigger is not better, at least not for brakes on this platform with stock or bolt-on mods.

[wparsons]

Originally Posted by ysu

That's an interesting thing to say; you increase the front braking power, that's fine, but if you increase the rear with it, that's not fine?

And why? The car has an electronic brake distribution system, that should deal with it pretty well. If not, and you've problems, there's still the pedal dance, no?

It's not about braking power, it's about fluid bias based on piston areas (fluid volume). Any well designed BBK will maintain the stock bias (not power) unless it specifically says it needs to be used with a rear BBK as well.

[Rookie84]

The most common misconception about BBK is that they increase braking power. They do not unless they are designed to increase bias to the front. Increased thermal capacity by using larger calipers, rotors, and pads is the reason.

Therefore, unless you track your car, there is absolutely no reason to waste any money. Well, I guess you can spend the money if you absolutely have to have them for aesthetic reasons.

This is a good read:

http://www.cquence.net/blog/big-brak...-do-they-work/