Bolt-on Big brake kit

[Vitaliy]

^^ Besides increasing unsprung weight, What was the point of putting bigger rotors if the pads only contact half of the rotor? I cant wait to see that huge groove on the rotor when you start wearing down the pads and rotors.

[Zepticon]

^^ Besides increasing unsprung weight, What was the point of putting bigger rotors if the pads only contact half of the rotor? I cant wait to see that huge groove on the rotor when you start wearing down the pads and rotors.

It will be easier to break when the radius is bigger. The bigger the radius, the more area the brake bads get to cover for each rotation of the wheel. The force is spread over a bigger area, causing less heat. But the more important point, is that your breaks get stronger.

The inertia of the car is channeled through the brake rotors. This force is meassured in N (newtons). Since the rotors are rotating around a axis/hub, this force is a torque force (Nm). This means that the longer distance the brakepad (our force) is from the center of the axis, the smaller it has to be to equal the torque comming from the rotors.

(or in our case, with a constant size break pad, moved away from the center fo the rotor, we will apply more "anti torque", and thus be able to stop faster given the wheels dont lose the grip)


Its the same princeiple as when you use an extension bar to get more torque to remove a rusted nut. In the same way (but inversed), the brake pad also use an "extension arm" (bigger rotor) to stop the wheel.

[Vitaliy]

It will be easier to break when the radius is bigger. The bigger the radius, the more area the brake bads get to cover for each rotation of the wheel. The force is spread over a bigger area, causing less heat. But the more important point, is that your breaks get stronger.

The inertia of the car is channeled through the brake rotors. This force is meassured in N (newtons). Since the rotors are rotating around a axis/hub, this force is a torque force (Nm). This means that the longer distance the brakepad (our force) is from the center of the axis, the smaller it has to be to equal the torque comming from the rotors.

(or in our case, with a constant size break pad, moved away from the center fo the rotor, we will apply more "anti torque", and thus be able to stop faster given the wheels dont lose the grip)


Its the same princeiple as when you use an extension bar to get more torque to remove a rusted nut. In the same way (but inversed), the brake pad also use an "extension arm" (bigger rotor) to stop the wheel.

Did you not read my post and or look at the pictures? The pads are the exact same, only the rotors were changed for a set of larger diameter rotors. Puny pads on a big rotor is not better then puny pads on the correct size rotor.

[KnezicDex]

The pads are the exact same, only the rotors were changed for a set of larger diameter rotors.

Where?

[Vitaliy]

Where?

http://s7.postimage.org/bcqo26vgr/20122012714.jpg

In this picture, it looks like the pad is only contacting 70-80% of the rotor from the outside edge to the inside edge of the rotor.

Where as for example, a properly designed brake system will have the pad contact the rotor 95-100% of the rotor from the outside edge to the inside edge of the rotor. see pic http://0.tqn.com/d/autorepair/1/0/Q/...s-wheeloff.jpg

I dont know the exact set-up your running, bigger rotors & original caliper bracket & pads or bigger rotors and different caliper brackets but according to the pic you posted, your brakes are going to look like this when you start to put some miles on the set-up. http://www.trustmymechanic.com/pics/rotor1.jpg Your going to end up with a huge groove on the rotor near the hub of the rotor and honestly if your going to waste that much surface area, the brake system is poorly designed.

[Zepticon]

Did you not read my post and or look at the pictures? The pads are the exact same, only the rotors were changed for a set of larger diameter rotors. Puny pads on a big rotor is not better then puny pads on the correct size rotor.

Yes, but the pads are irrelevant if you move the pads longer from the center of the disc the pads will cover more area on the rotor per wheel revolution.

But that is given you change brackets aswell, if the only thing you do is change the rotor size, without changing the caliper or bracket (moving the pad away from the center), it wont help anything.

But i might have misunderstood you im not a native english speaker.

[KnezicDex]

@Vitaly
Rotors, calipers, caliper brackets and pads are all from a 2010 mazda 6.
Talk to the mazda engineers and post them that picture.

[Vitaliy]

Yes, but the pads are irrelevant if you move the pads longer from the center of the disc the pads will cover more area on the rotor per wheel revolution.

But that is given you change brackets aswell, if the only thing you do is change the rotor size, without changing the caliper or bracket (moving the pad away from the center), it wont help anything.

But i might have misunderstood you im not a native english speaker.

Ok, that makes sense to me. But do you understand what I'm saying that the pads seem to small for that rotor? Must be a Mazda thing.

@Vitaly
Rotors, calipers, caliper brackets and pads are all from a 2010 mazda 6.
Talk to the mazda engineers and post them that picture.

Ok thanks for clearing that up. Yeah I think its a very poor design on Mazda's Part. I've done a lot of brake jobs before and most set-ups are designed so the pad is big enough to utilize the whole width of the rotor. Usually there will be a 1-2mm groove on the very outside and inside of the rotor due to manufacturing differerces but in this pic --->>> http://s7.postimage.org/bcqo26vgr/20122012714.jpg There is like a 15mm gap from the inside of where the rotor surface starts to the edge of where the pad starts.

[KnezicDex]

The rotor was loose in this picture. But still it is a big gap.

[KnezicDex]

Anyways. I'd say the upgrade is worth it if you can find the parts for under 200$ and if you were about to change the rotors anyways. Breaking power is good and the difference is obvious on higher speeds. Since the rotor is bigger, it needs more time to warm up but it does not fade as fast.
I'm happy. Also, the bigger rotor looks dope on my 5 spoke 16's

[Zepticon]

Ok, that makes sense to me. But do you understand what I'm saying that the pads seem to small for that rotor? Must be a Mazda thing.

Yeah, and it is even worse for the Mazdaspeed 6. They use the same calipers and brake pads on the rear wheel as the normal Mazda 6, but just move the pads longer from the hub center by changing the caliper brackets.

But from a physics principle, moving the pads from the centre is cheap and effective way of improving the braking capableties. Going form 10 to 11 inch rotor, given the same size pad, is a 10% increase in breaking force, and would only require a new bracket. While doing the same by increasing the pad area, would require a bigger caliper, and that gets more expensive to produce, especially if the parts could otherwise be reused from another production line.
Another point is that the calipers are single piston design, and that using big brake pads on single pistons is not very optimal, since the piston will only cover a smal part of the pad, causing uneven wear. So going bigger pads is complicated, while increasing the rotor size is not. And they have the same effects on braking force.

If the goverment here had not ben so nazi about modding cars, i would go for a two piston design. But since it needs to look stock, i need to stick with factory parts, and that makes the Mazda(speed) 6 the best option, even with the flaws it has

[supercharged3.0]

I agree with Vitaliy, as bigger the contact surface as better the stopping power.
You are not going to see a big difference by putting a huge rotor, but not replacing the caliper on a bigger one with a bigger brake pads.

For an example, I have a big brake kit for my Probe sitting in the garage with 13" rotors and BMW 740 IL calipers and brake pads. The reason I went with BMW's calipers and pads, because that was the LARGEST caliper with the largest brake pad contact surface I could get.

if someone want to see, I can take some pictures and post.

BTW, the Mazda 6 brake design seems really poor to me.

[Vitaliy]

I agree with Vitaliy, as bigger the contact surface as better the stopping power.
You are not going to see a big difference by putting a huge rotor, but not replacing the caliper on a bigger one with a bigger brake pads.

For an example, I have a big brake kit for my Probe sitting in the garage with 13" rotors and BMW 740 IL calipers and brake pads. The reason I went with BMW's calipers and pads, because that was the LARGEST caliper with the largest brake pad contact surface I could get.

if someone want to see, I can take some pictures and post.

BTW, the Mazda 6 brake design seems really poor to me.

Thats exactly my thought! Mazda deserves a

[white94gt]

I agree with Vitaliy, as bigger the contact surface as better the stopping power.
You are not going to see a big difference by putting a huge rotor, but not replacing the caliper on a bigger one with a bigger brake pads.

For an example, I have a big brake kit for my Probe sitting in the garage with 13" rotors and BMW 740 IL calipers and brake pads. The reason I went with BMW's calipers and pads, because that was the LARGEST caliper with the largest brake pad contact surface I could get.

if someone want to see, I can take some pictures and post.

BTW, the Mazda 6 brake design seems really poor to me.

good luck with it. hopefully your ready to change out the master cylinder as well. You'll still get better braking from those but the fluid displacement will negatively affect the gains from the bigger surface area. I think you guys should reread zepticons post a little closer, Its not in the coverage as it is in the diameter and the length of the pads. I've seen 6 piston calipers that have a bigger gap than the mazda 6's but they are on 14inch and above rotors and cover about 35% of the diameter.

[MonoxideChild]

Yea, Zepticon had it right about the rotor size also. Larger rotors wont heat up as fast also, which can make a huge difference on the track. Much less likely to warp also.

Its easy to hate on something you have never tried. (Typical PT style) The fact that everyone that has done it has said nothing but good things really says it all though.