calling everyone with rear discs, and those who know about them.

[davidf]

This will be my Xmas present to myself. I've done the S10 front with great results. Now it's time to swap the rears.
Baer Brakes - Rear 12", Brakes, BR109 | Cotton's Performance Buick Grand National Parts & Service

 

[autoguy]

I have the Baer kits on one of my Buicks and it works great. All I had to do was get longer studs and machine the axle. It was really easy to do, all I did was jack up the car by the rear end, take the wheels off, start the car and put it in gear, get out a disc grinder and grind the axle while it was spinning. Very easy to do, your only grinding it so that it can fit inside the new rotors.
The pads, rotors and caliper are off of a camaro or corvette.
It also has working parking brakes.

 

[POWERBRAKEBOB]

pressure increases for rear discs

Don't forget to replace the stock prop valve with one for 4 whl discs. The stock valve limits the rear pressure to 600psi to prevent drum brake lock up. Discs need much higher pressure, AND more volume at the master to fill the piston increase from 3/4" to 2". Ever notice that all 4 whl disc cars have HUGE vacuum boosters, Hydroboosts, or Electric boosters? They need Pressure and volume.

 

[Danno]

And mine:

Don

Looks like your rotors are on the wrong side. That is the passenger side right?

 

[JDSfastGN]

Looks like your rotors are on the wrong side. That is the passenger side right?

I didn't go back and look but if those are Baers for some reason thier rotors go the opposite to what you would think. My slotted and dimpled EBCs face the opposite way.

 

[WHITE T]

That is cause the Baer rotors are directionally vaned (curved vane center). They slot opposite the vane (strongest way to do it).

Most rears are not curved (they are straight) so it really doesnt matter which way you put them on (more cosmetic than anything).

Curved vane rotors act like a pump when they are spinning. They will pull air in from the center of the rotor (eye) and pump it out the edges.

 

[davidf]

Don't forget to replace the stock prop valve with one for 4 whl discs. The stock valve limits the rear pressure to 600psi to prevent drum brake lock up. Discs need much higher pressure, AND more volume at the master to fill the piston increase from 3/4" to 2". Ever notice that all 4 whl disc cars have HUGE vacuum boosters, Hydroboosts, or Electric boosters? They need Pressure and volume.

Thanks for this post. That thought did cross my mind.

 

[charlief1]

Well I took a pic so you can see how close the Westerns wheels fit with this set up. About 1/4" clearance on the caliper but it looks good.:biggrin: Just got to get the rear out of the car to do some mods that I'm working on now. One rear fender attached an one to go.

 

[Rell87]

I just got a pair of Aerospace crossdrilled and slotted with the e-brake for $969 (rear). I'll post pics later

 

[Danno]

That is cause the Baer rotors are directionally vaned (curved vane center). They slot opposite the vane (strongest way to do it).

Most rears are not curved (they are straight) so it really doesnt matter which way you put them on (more cosmetic than anything).

Curved vane rotors act like a pump when they are spinning. They will pull air in from the center of the rotor (eye) and pump it out the edges.

Ah yea, I did a baer brake kit before and they were backwards. Wasn't sure exactly why.

But the "more cosmetic than anything" isn't true. I'm on a couple pit crews and we run cross drilled and slotted rotors. The slots work just like directional tires. It is supposed to take the hot air and brake dust and push it to the outside.

I'm not a scientist or anything but think about it this way. Air always moves from hot to cold. If you leave the fridge door open your letting the heat in, not the cold out. Hot air will always heat up cool air (thank you grade 10 science). So trying to push the cool air from the outside of the rotor to the inside where the heat is would not be as efficient than pushing the hot air out of the rotor.


Like I said, I'm no scientist and have no fancy way of testing it but it makes sense to me and everyone is running their rotors the same way in both series (including full time race teams where racing is their career).

 

[WHITE T]

I am sure if you talk to 50 different people you will hear 50 different reasons why slotting is done and what it is for.

All I know is for years of selling it we have never stated that slotting, drilling dimpling or any surface modifications are done for any cooling. Everything I know is that is was used for pad outgassing (internal vanes do the cooling). Cooling became a myth as many I am sure didnt know what it was for in the first place.

Baer (just like Alcon) and many of the other race brakes all slot the same direction. This was done for (2) reasons that I know of (again others might tell you differently), but we got this years ago from Alcon directly. One it is opposite the cooling vane. This is the strongest way to slot as the cooling vane is directly behind the slot and will arrest any cracking. Two on many race calipers that don't have pad retaining clips the slots help draw the pad down towards the center of the rotor.

Again.. this is what I heard from other manufactures and tell my customers. I have never seen a rotor hot spot, or overheat due to slotting one direction compared to the other.

There are many ways to skin a cat Run what works for you!