Slotted Disc Rotors

[Contipro]

Just to point out that Pressure = force / area, not force x area

This formula does not apply in the example you have quoted.

 

Increasing the number of pistons increases the area of contact between pads and disc, thus increases the friction generated and results in greater energy loss.

 

 

 

 

Great that you found the error I made.... Finally... Cheers!

[Stratovarius]

For street use, just upgrade your tyres and brake pad. Or change your current discs if yours are wrapped. No point using slotted disc as those slots are there to scrape off the debris on the brake pads formed after multiple hard brakings which you will not see much in daily driving. Slotted disc also tends to wrap faster due to uneven heat distribution.

Unless you are going for looks... if so then go ahead. Like most people said, it's not going to help much (or if any) in your braking distance.

[Contipro]

 

Like my colleague, he always need to drive hard brake hard at startup..

Why, coz wan to warm up the brake pad to reach it working temperature lo..

 

Too low temperature the pad compound is hard= not effective for braking

Need to warm it up to soften it..

[Alvincsj]

It's all about science & physics, simplified in English:

1) Force applied from your foot is "little", not sufficient to stop the car weight of >1tons.

Hence brake booster/brake pump help to multiply this force.

Hence bigger booster=improvement braking power.

 

2) Rubber hose tend to expand during braking, hence caused the force applied not fully transmit to caliper.

Steel braid with better external steel reinforcement, minimize the rubber from expanded during braking. Then the force is better applied to caliper instead of the energy loss due to expanding the rubber.

Also rubber tend to expand under heat, addition of steel braid will help to minimize it.

So your will feel some improvement on pedal feel, but interms of stoping power is little improve only.

 

3) Piston on brake Calipers

Pressure required to clamp the brake disc to stop the car, and

PRESSURE = FORCE x AREA

Force is constant as it supplied from brake booster. So we can increase the PRESSURE by increasing the AREA figure.

Hence bigger or more piston on brake caliper = improve braking power.

 

4) Brake disc/rotor size

When brake disc is rotating as per car is moving, TORQUE required to stop the disc from rotate.

(2 x radius = diameter of disc)

TORQUE = FORCE x RADIUS

FORCE is the constant pressure from brake caliper.

Hence to increase TORQUE, we can increase the RADIUS of brake rotor.

Hence bigger brake disc = improve braking power.

 

4) Brake disc Surface area

When use bigger disc/rotor the surface area of contact with brake pad increase too.

same PRESSURE = FORCE x AREA = improve braking power.

 

5) Brake Disc and Brake Pad Friction

Friction is required to stop moving object.

Normally brake disc friction coefficient is fix due to machining finishing applied. Unless someone increase it surface roughness, the braking power may increase, but brake pad will wear faster and run noisy. Hence not feasible for road car.

Or someone changing "better" brake pad (= more friction), the braking power may increase, but same brake disc and brake pad will wear faster. (Like you see those brake disc with groove when not wear evenly)

Hence changing brake pad = improve slightly on braking power (but expect more wear and tear)

 

6) Slotted or Cross drill brake disc

Function to dissipate heat faster for tracking user = reduce brake fade.

Under normal driving will not feel any different.

But improve the cosmetic look = shiok feel

 

Above are some of the points, there are other we can do to improve braking power too.

Also when increasing brake force, car structural strength, suspension system also play the part or might be affected. As you know nowadays car is design up to its max limit due to manufacturing cost.

 

At the end of the day, it will depend on your investment budget and the feel good feeling which route to choose from.

 

Just to add on to what is said here, based on my understanding

 

Point 3 :

Increasing the piston size (regardless or 4 or 6 piston, the total piston surface area increase) will in theory result in better braking. However, this has to be done to both the front and rear brakes in the same proportion (or ratio) as the stock settings. For example, if your car is brake bias 70% front, and 30% rear, that ratio has to be maintained when you up the size of the brakes. Just by increasing the only the front will result in ABS being activated to prevent the wheels from locking up resulting in skid. Installing Big Brake Kit without taking this into consideration could result in worse braking distance than stock.

 

Point 4 and 5:

Regardless of the size of your rotor, the contact surface of your brake pads remain the same. Increasing the brake disc size does not improve your braking at all. The pro of having a bigger disc is cooling. Due to the surface area, it doesn't get heat up as fast and cool much faster than a smaller disc, reducing the probability of brake fade after repeated hard braking.

 

Note: Just my thought

[Alvincsj]

It's all about science & physics, simplified in English:

1) Force applied from your foot is "little", not sufficient to stop the car weight of >1tons.

Hence brake booster/brake pump help to multiply this force.

Hence bigger booster=improvement braking power.

 

2) Rubber hose tend to expand during braking, hence caused the force applied not fully transmit to caliper.

Steel braid with better external steel reinforcement, minimize the rubber from expanded during braking. Then the force is better applied to caliper instead of the energy loss due to expanding the rubber.

Also rubber tend to expand under heat, addition of steel braid will help to minimize it.

So your will feel some improvement on pedal feel, but interms of stoping power is little improve only.

 

3) Piston on brake Calipers

Pressure required to clamp the brake disc to stop the car, and

PRESSURE = FORCE x AREA

Force is constant as it supplied from brake booster. So we can increase the PRESSURE by increasing the AREA figure.

Hence bigger or more piston on brake caliper = improve braking power.

 

4) Brake disc/rotor size

When brake disc is rotating as per car is moving, TORQUE required to stop the disc from rotate.

(2 x radius = diameter of disc)

TORQUE = FORCE x RADIUS

FORCE is the constant pressure from brake caliper.

Hence to increase TORQUE, we can increase the RADIUS of brake rotor.

Hence bigger brake disc = improve braking power.

 

4) Brake disc Surface area

When use bigger disc/rotor the surface area of contact with brake pad increase too.

same PRESSURE = FORCE x AREA = improve braking power.

 

5) Brake Disc and Brake Pad Friction

Friction is required to stop moving object.

Normally brake disc friction coefficient is fix due to machining finishing applied. Unless someone increase it surface roughness, the braking power may increase, but brake pad will wear faster and run noisy. Hence not feasible for road car.

Or someone changing "better" brake pad (= more friction), the braking power may increase, but same brake disc and brake pad will wear faster. (Like you see those brake disc with groove when not wear evenly)

Hence changing brake pad = improve slightly on braking power (but expect more wear and tear)

 

6) Slotted or Cross drill brake disc

Function to dissipate heat faster for tracking user = reduce brake fade.

Under normal driving will not feel any different.

But improve the cosmetic look = shiok feel

 

Above are some of the points, there are other we can do to improve braking power too.

Also when increasing brake force, car structural strength, suspension system also play the part or might be affected. As you know nowadays car is design up to its max limit due to manufacturing cost.

 

At the end of the day, it will depend on your investment budget and the feel good feeling which route to choose from.

 

Just to add on to what is said here, based on my understanding

 

Point 3 :

Increasing the piston size (regardless or 4 or 6 piston, the total piston surface area increase) will in theory result in better braking. However, this has to be done to both the front and rear brakes in the same proportion (or ratio) as the stock settings. For example, if your car is brake bias 70% front, and 30% rear, that ratio has to be maintained when you up the size of the brakes. Just by increasing the only the front will result in ABS being activated to prevent the wheels from locking up resulting in skid. Installing Big Brake Kit without taking this into consideration could result in worse braking distance than stock.

 

Point 4 and 5:

Regardless of the size of your rotor, the contact surface of your brake pads remain the same. Increasing the brake disc size does not improve your braking at all. The pro of having a bigger disc is cooling. Due to the surface area, it doesn't get heat up as fast and cool much faster than a smaller disc, reducing the probability of brake fade after repeated hard braking.

 

Note: Just my thought

[Alphas]

alot of bad physics, since when is pressure=forcexarea?????

[Durgaprasadzone]

thanks for info.....

 

 

 

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[Volvobrick]

Point 4 and 5:

Regardless of the size of your rotor, the contact surface of your brake pads remain the same. Increasing the brake disc size does not improve your braking at all.

 

Note: Just my thought

 

Basic science would say that with same brake pad surface and same braking pressure, bigger disc would exert greater torque (force X distance from centre of wheel) and thus more braking force. If not, all cars would go for the smallest disc possible to reduce un-sprung weight.

 

Of course despite the science, the most important reason we have big disc is simply becos it looks macho and great!

[Alvincsj]

 

Edited December 23, 2014 by Alvincsj

[Unfair]

 

Can you please elaborate how does the bigger disc result in more braking force when the brake force comes from the brake pump pushing the pad against the disc?

 

Increasing the disc only helps with cooling, cos the large disc surface will cool faster with the aid of the vents. In theory, the larger disc should have higher rotational weight (assuming you are using the same material as stock, but increase in size), which means it will take more force to stop it.

 

Do correct me if my understanding is incorrect, but I dont think just installing a larger disc with all other component remaining the same would improve braking force.

 

 

The same force generated by the pistons clamping on the larger diameter disc will stop the wheels faster.

 

Similarly to a bigger steering wheel will require less human force to control a vehicle. That is why large vehicles have much bigger steering wheels.

If you imagine a steering wheel spinning out of control, would a smaller or larger steering wheel be easier to stop ?

[Alvincsj]

 

The same force generated by the pistons clamping on the larger diameter disc will stop the wheels faster.

 

Similarly to a bigger steering wheel will require less human force to control a vehicle. That is why large vehicles have much bigger steering wheels.

If you imagine a steering wheel spinning out of control, would a smaller or larger steering wheel be easier to stop ?

 

Oh ya... Got it.. Leverage. Thanks.

[Eyke]

you could easily lock up brakes on stock setup as well so it is not a limiting factor, ie. you don't need more force.

[Volvobrick]

http://www.wcengineering.com/articles/brakes.html

 

Here's a site that briefly explains various brake issues....

[Jackfoo]

Anyone uses direct fit replacement slotted disc rotors? What is the improvement gain like? I only come across Brembo & TRW slotted for Honda Stream RN6.

 

Thanks.

my experience using slotted disc will generate lot of brake dust around the rims, u might don't like it

[Hondasteam]

my experience using slotted disc will generate lot of brake dust around the rims, u might don't like it

Brake dust is attributed to what pad you use. Slotted rotor is known to increase the wear rate of pad. Generally, the response i get from fellow owners who use slotted rotor is braking is more sensitive likely because the pad eats into the slotted to gv better response

[Mercury1]

Came across this video, gives a good overall view of all three types of rotors

 

https://www.youtube.com/watch?v=78wbht355R8

[Watwheels]

I think ventilated solid disc rotors are the best all round performance choice. I dunno whether bigger disc rotors or so called bigger brakes are better. Coz if the brake booster pump only pumps out so much power, moving to bigger brakes and rotor the force coming out from the pump is still the same.

 

All the fanciful bigger, drilled & slotted are just cool looking.

 

There's always some kinda compromise. If you want barke pads that "bite" really well, there goes your rotors. Want less brake dust etc...something got to give or compromise. Anyway traction or grip from the tires are just as important. Suspension also makes a difference. So many factors when it comes to braking.

Edited August 2, 2015 by Watwheels

[jamessamuel]

This will provide Slight improvement in the applying of brakes.