Slotted/Drilled Rotors - Kevlar Pads

[jmoore]

I got these from AB and put them on my '99 D2. They grip sooo much better and I find I don't have to double pump like I used too. Plus, they look darn sexy! lol!

BUT, it seems they don't brake as well when I'm in reverse. Weird.

I also changed the brake fluid at the same time. I wonder if I still have bubbles.

 

[Sirfoss]

Common

I have installed these and every one has weird braking in reverse....working on it.
Mike

 

[jmoore]

BTW- I have less than 250 miles on them, so maybe they are not broken in. I've also noticed they seem to work better when hot. Anybody else experienced this?

 

[Disco Mike]

John,
I have a 99D2 and have had the same experience, work better when hot and not real good in reverse.
Mike J.

 

[jmoore]

Thanks Mike,

hmmmm, I live on a good hill and sometimes have to back down. That's not good to hear! Also, considering we get tons of snow, they well definitely be cold, when I'm backing down that icy hill! Guess I need to make sure I'm going forward.

Well, forewarned is forearmed. Thanks for the feedback.

 

[Longshot421]

I had a thought... does the pattern of the slotting on the rotor appear to be directional (i.e. like the vanes a pump impeller, if that means anything). It is possible that the rotors don't cools as well, or grip as well in reverse. Just an idea.

 

[Cheapjeep2]

Good to hear this helped the Double pump issue, I just ordered stainless steel brake lines to help this problem.

 

[jmoore]

Mark,

The rotors are 'handed' but in reverse, I'm going so slow, I doubt it really matters. I don't know. I really can't think of why breaking power would be reduced. It's still the same amount of Lbs per square inch applied to the rotors by the pads, no matter if I'm going forward or reverse. Just because the grove is in a different direction, I don't think it should effect the grip, but maybe so.

The only other thing I can think of is that maybe the pad seats differently in reverse, but still I don't see how it can move that much in the caliper to effect the grip.

I don't know, a real head scratcher!

 

[Snwbord24]

I'm pretty sure it has to do with the power distribution between front and rear. The front brakes are made to provide more stopping power than the rears because you are going faster forward 99% of the time you're braking. You just don't normally need that good of stopping power in reverse most of the time so that's what was designed for. In the end it's cheaper for manufactures to put smaller less effective brakes in the rear because they aren't generally needed.

 

[jmoore]

Shane,

Good idea, if that was the case, I would have noticed reduced braking in reverse with the original set up. I've only noticed it, with the change over to the new set up.

 

[Lutzgaterr]

Hmmm, do tell Shane. I was not aware that the 'front' calipers were designed to exert higher pressure on the pistons than the 'rear' calipers.
Are you sure you are not overstating/oversimplifying the fact that the fronts are larger, pad-wise, than the rear, or the fact that the majority of the required force to erode foward momentum is naturally exerted on the front of the brake components as opposed to the rear?
I am not being a smart-ass, just curious.
Have you ever looked at the older French-made 'Citroens'? If so, ever notice one slam the brakes on hard? Not only the calipers were engineered differently, but the suspensions were engineered to diminish the nose-down effect of hard-braking.

I digress. So, news to me that calipers for LR were designed to differently regarding pad-psi.... is that correct?

 

[Snwbord24]

Force = Pressure x Area. The front pads cover more area than the rear so the same 'pressure' going to both applies more FORCE to the front brakes. Sorry if substituting 'stopping power' for force confused you.

 

[DiscoveryXD]

I thought...

F=ma
Force(newtons) = Mass(kg)acceleration(m/s)

1 N=1 kg x 1 m/s^2

 

[Snwbord24]

That's also true, Newton's Second Law.