I have new D90 cross drilled and grooved rotors and new calipers. Since I just installed the new SS brake lines and front brakes I am going to replace the rear. Should I get solid brake rotors or cross drilled and grooved for the rear? I hear that rocks and mud can muck up the rotors but I wanted some first hand experience with guys that have it or have used it. Thanks.

 

What you state is what I have seen posted also, guess it depends what you plan to use it for

 

I read that dimpled was better than cross drilled...

 

Well my front upgrade kit came from Justin at Lucky 8 and it came with drilled and grooved rotors. So, I figure if he sells it then that junk works, yeah?

 

The solid grooved on the rear will be fine. The the bigger issue, at least for me, is the vented rotors in the front. Mine pack full of mud.

 

Does it severely limit your braking abilities on the trail? I know when I ride I'm always going between 5-10mph so it's not so bad to brake anywho.

 

No it won't effect you on the trail. But I have had vibrations due to the amount of mud packed in them at highway speeds.

 

Drilled and vented rotors are designed to assist in cooling your rotors and pads under prolonged and sustained braking under conditions such as one would find on the race track. They actually provide REDUCED surface area for the pads to grab on to and therefore LESS braking ability except under the most strident conditions where brake fade due to overheating would become an issue. They are also much more susceptible to developing hard spots due to localized overheating at the edges of the intersteces in the rotor, leading to famous "warped rotor" pulsating pedal issue. (Rotors don't warp, they develop excessive runout due to uneven wear as the metal around the hard spot wears away.)

I would stick to the plain ol regular rotor unless you plan on attending local track days with the rover racing club. Plus they are a lot cheaper too.

 

Yup, my impression is that grooving, drilling, slotting, etc. are marketing gimmicks. I haven't seen any empirical evidence that it matters at all for DD vehicles.
On the other hand, I don't use my brakes a lot. I anticipate stops as much as possible, don't tailgate and downshift when needed.

 

Thanks guys. I'm going solid then. I don't race in my rover that's why I had my WRX or G35 haha.