Different in brake dise shape!

[DUCADOS]

Would like to check with the expert here. Is there a different in performance (efficiency) for different shape of brake dise.

Saw some RXK/RXZ putting those oversize brake dise. Some round shape n some flower shape,very nice so decided to get myself 1.

Went JB last night,ask shop about it and they happen to have only the round wan and when I asked they say round type more braking power compare to the flower type.

So I'm having doubt because what they said might not be true as they dun have the flower type.

[yc86]

Would like to check with the expert here. Is there a different in performance (efficiency) for different shape of brake dise.

Saw some RXK/RXZ putting those oversize brake dise. Some round shape n some flower shape,very nice so decided to get myself 1.

Went JB last night,ask shop about it and they happen to have only the round wan and when I asked they say round type more braking power compare to the flower type.

So I'm having doubt because what they said might not be true as they dun have the flower type.

 

I'm saying this based on what I know about cars.. Shd be the same for bikes.

 

Braking performance is influenced by mainly 2 things, the normal or perpendicular force to the brake disc or the clamping force (including the master cylinder, caliper n brake pad material), and the torque arm or size of the brake disc.

 

So whaever pattern the disc is, flower or star or circle, the general braking performance is the same if the disc size n caliper position plus everything else (pads etc) remain the same.

 

But... When heat comes into play, things are different. The slits and patterns might be good for cleaning up the pads, which accumulate dust over time depending on material, but one thing to note is a larger mass brake disc, ie round, is like a bigger reservoir to store heat. So for heavy braking useage like on track, round is better. Then there is the material type also, but the whole story is quite complicated. Also, u have the issue of unsprung mass.. Which is another tradeoff. But if u go that far, I wld rather remove mass from the rims n tires(and control arms, upright n shocks on car) first b4 sacrificing the brakes.

[fleas]

im not very sure about more patterns = more braking power but in term of physics if more surface area = more fiction which means more braking power however in disc brakes, if heated up at a certain temp, the disc will start to fade(less effective) thus the "patterns" are to help it cool down fast and helps if it get wet as well.

 

please correct me if im wrong ty

[DUCADOS]

I'm saying this based on what I know about cars.. Shd be the same for bikes.

 

Braking performance is influenced by mainly 2 things, the normal or perpendicular force to the brake disc or the clamping force (including the master cylinder, caliper n brake pad material), and the torque arm or size of the brake disc.

 

So whaever pattern the disc is, flower or star or circle, the general braking performance is the same if the disc size n caliper position plus everything else (pads etc) remain the same.

 

But... When heat comes into play, things are different. The slits and patterns might be good for cleaning up the pads, which accumulate dust over time depending on material, but one thing to note is a larger mass brake disc, ie round, is like a bigger reservoir to store heat. So for heavy braking useage like on track, round is better. Then there is the material type also, but the whole story is quite complicated. Also, u have the issue of unsprung mass.. Which is another tradeoff. But if u go that far, I wld rather remove mass from the rims n tires(and control arms, upright n shocks on car) first b4 sacrificing the brakes.

 

Well said dude!

Was thinking exactly the same as what u mentioned.

How could dise of the same size but pattern different affect the performance unless material different la.

So the only answer in me was the shop dun have that in pattern shape.

[DUCADOS]

im not very sure about more patterns = more braking power but in term of physics if more surface area = more fiction which means more braking power however in disc brakes, if heated up at a certain temp, the disc will start to fade(less effective) thus the "patterns" are to help it cool down fast and helps if it get wet as well.

 

please correct me if im wrong ty

 

Ya... Correct...

[yc86]

im not very sure about more patterns = more braking power but in term of physics if more surface area = more fiction which means more braking power however in disc brakes, if heated up at a certain temp, the disc will start to fade(less effective) thus the "patterns" are to help it cool down fast and helps if it get wet as well.

 

please correct me if im wrong ty

 

Actually.. Not really. In terms of surface area in contact with the pad, u can't get more area than a full circle as all the gaps mean less contact.

 

But in terms of physics, frictional force = friction coeff x normal force. There is no surface area component in this relationship so surface area does not affect friction.

[koxie]

corretc me if am wrong,those wave patten type will cool down faster.and i think those dunno what carbon compound type disc take much long time heat up.i might be wrong thou.

[MrIce]

bigger area of contacting with brake pad = more braking power

however in this issue heat play a big role here, when ur brake disc get hot it will affect your braking power, there's those after market brake disc have wavy shape to dispense heat faster,

 

so comparing round disc which can have more contact area but heat up faster but cool down slow

and a wavy disc which have slightly lesser contact area but heat up might be as fast but cool down is faster

 

i will choose a wavy disc, however in normal daily ride, round disc is more than sufficient, however everyone want more braking power, therefore if budget is not an issue to you, get a good aftermarket brake disc and good brake pad will give u good braking power, of cos braided line will be better =)

 

take note good brake pad will eat up brake disc at a faster rate,

[Demon]

corretc me if am wrong,those wave patten type will cool down faster.and i think those dunno what carbon compound type disc take much long time heat up.i might be wrong thou.

 

all things equal, a wave pattern rotor will dispense heat faster than a round rotor because the former has a longer leading edge ie.perimeter. Other methods to dispense heat more efficiently on a round rotor are slotted or cross drilled. Modern cars, at least for the front rotors, are using ventilation rotors.

 

For braking power, it's a combination of rotor and brake pads. For high performance pads, they need to be worked up to the operating temperature in order for braking to be effective. Meaning, such pads are not suitable for everyday street driving.

 

Therefore, most will actually be better off using regular pads instead of spending unnecessary money on performance pads.