Protect that front rotor!

[werase643]

what is the thickness of your rotor?
actually the grooves give you a larger contact surface area if you think about it for a while

are the grooves heavy or light

if light grooves and thicker than min spec.....
you are wasting $ and time worrying about it.

if you really think a couple of little grooves will kill you...get a new rotor

good luck and ride safe

[JB848]

what is the thickness of your rotor?
actually the grooves give you a larger contact surface area if you think about it for a while

are the grooves heavy or light

if light grooves and thicker than min spec.....
you are wasting $ and time worrying about it.

if you really think a couple of little grooves will kill you...get a new rotor

good luck and ride safe

I guess this is debatable whether there is more surface or not with grooves vs smooth. You make a valid point. I am going off of years of training from my father who was a certified mechanic in CA. That doesn't mean he or I could not be wrong.

Your concept of more surface with grooves has merit but the principal behind disk brakes is smooth surface to smooth surface give the greatest "potential" for friction which is the basics of all brakes.

[qwertydude]

The purpose of drilling and grooves is to provide extra surface area for cooling not braking power, and also to release outgassing of the brakes. Newer pad formulas make outgassing almost a non event so all those fancy designs like scallops, waves, drills and dual rotors and grooves is purely for cooling to prevent fading or possibly for wet weather braking. Motorcycles are lightweight to begin with and even with a single disk brake you can easily do a brakie where you use 100% of the available braking power.

So in the ideal world a solid disk provides the best braking power but it'll fade quickly if it can't shed heat which the fancy designs are for. One thing I do notice is slotted rotors almost never glaze brake pads, though they do go through pads a bit quicker. I think the slot going across literally scrapes any glazing built up on the pad which is nice but at the expense of pad life.

[JB848]

So by your definition I am right. Grooves bad smooth good excluding the cooling effect by holes and venting etc?

[qwertydude]

Exactly surface area and brake rotor diameter determine ultimate braking power. How fast you can shed heat determines braking endurance. Wanna see tremendous stopping power? Check out a Buell with their ZTL rim mounted brakes you've got so much brake leverage so close to the tire surface the braking is outstanding in terms of feel, responsiveness, and the large rotor diameter also means lots off cooling time before the same rotor patch gets squeezed again. Pure engineering genius.

[KasbeKZ]

wow that ztl really is sweet. i had to look it up.

grooves are not good at all. you might have more surface area for a bit, but the big picture is that you should be replacing the pads before the grooves appear, so if there are grooves, they reduce the surface area that the new pad meets the rotor with, and kills the life.

[cstilt]

So by your definition I am right. Grooves bad smooth good excluding the cooling effect by holes and venting etc?

I think it depends on what kinds of grooves we're talking about. If it's grooves like a slotted rotor on some performance cars, then yes, that will help with some cooling and venting like the holes that are drilled do. However that take away a bit of the surface area of the rotor, same has holes do. Grooves running in a continuous circle around the rotor, like you get over time. They would add surface area giving you a greater area of friction.  I think of it like this. Say you have an area this big _______ and that is a flat rotor. That has less surface area than one that does this /\/\/\/\/\ . Of course you have to remember the brake pad will take this shape and fit the contours of the rotor.

In the end, will that extra little wave in the rotor help you. Doubtful. Will it hurt. Doubtful.  If it bothers you, change it. As long as your happy and it's safe, I say roll with it.

Chris