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  #11  
Old 01-28-2011, 09:28 AM
SteveH SteveH is offline
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I get ~12K on my '95 FZJ out of standard front 80 series pads and rotors - mostly in-town stuff by my non-road-racing wife. This truck (and my brother's '94) have never done any better on pad life.

I compared 100 and 80 series pads side by side at the dealership last week. The 100 pads are thicker and have 15-20% (my guess) more surface area. I can see how the 100 series pads would last longer, and why you cannot use shims. If I were starting with new or turned rotors, I'd switch to 100 series pads.
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  #12  
Old 01-28-2011, 09:59 AM
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I am running the Powerstop rotors, that Slee sells, on all four corners. I took them to Mountain High and had all of the rotors cryoed. Pads are OEM 100 up front and OEM 80 in the back. I do not take it easy on my brakes and everything is holding up very well compared to cars I have owned in the past. You could run the Hawk performance pads and increase your stopping ability as well as your rotor life but, the pads wear faster and will need to be replaced more often. So far my rotors are not wearing and my brake pads look new. I think I have about 25,000 miles on them so far.
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Old 01-28-2011, 10:16 AM
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The only reason your getting more life is because the pad is thicker. Your not going to get any extra performance from 100 pads because your still squeezing them with the same calipers. The shims are there for a reason. Yea it wo t effect braking mechanically but. Geeze. Your talking 1/32 - 1/16 of an inch of extra pad. Thts nothing in the form of life. And I'm sure the 100 pads are also more expensive. So unless your just wanting to say u have 100 pads on a 80 I dont see the point.

Like the hilux trucks and minis. We upgrade the solid axle calipers to IFS calipers. Because they have a larger bore diameter = more pressure on pads = better braking.
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  #14  
Old 01-28-2011, 11:12 AM
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For the record, 80 and 100 series pads (for 1995 and 1999) are priced the same price at my dealership.
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Old 01-28-2011, 12:24 PM
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Force = Pressure * Area. Increasing the pad area with 100 series pads, while maintaining the same pressure of the 80 series calipers, equals higher clamping force.
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Old 01-28-2011, 12:56 PM
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Quote:
Originally Posted by subzali View Post
Force = Pressure * Area. Increasing the pad area with 100 series pads, while maintaining the same pressure of the 80 series calipers, equals higher clamping force.
I think this may be a bit off. Pressure (as in PSI) already includes a dimensional component (Square inch).

For braking, the force due to friction (ie the rotor and pad) = the coeffiecent of friction of the two materials and the normal force pushing them together. (IE the force coming from the Master cylinder, through the fluid, and into the caliper, and then through the piston). There is no area component to the frictional force.

So on paper, given the same pad materials between the 80 and 100, there would be no change in braking force because the surface area of the pad doesn't play into the equation. Now how the theory and math translate over into real world experience, is anyone's guess, as some folks do report better braking with the larger pads.
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Old 01-28-2011, 01:19 PM
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:MEH:

carquest rotors and 80 pads.

IMHO toyota pads are too much $ now. probably go with hawk pads in the future.
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  #18  
Old 01-28-2011, 01:29 PM
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Quote:
Originally Posted by coax View Post
I think this may be a bit off. Pressure (as in PSI) already includes a dimensional component (Square inch).

For braking, the force due to friction (ie the rotor and pad) = the coeffiecent of friction of the two materials and the normal force pushing them together. (IE the force coming from the Master cylinder, through the fluid, and into the caliper, and then through the piston). There is no area component to the frictional force.

So on paper, given the same pad materials between the 80 and 100, there would be no change in braking force because the surface area of the pad doesn't play into the equation. Now how the theory and math translate over into real world experience, is anyone's guess, as some folks do report better braking with the larger pads.
Okay, I agree with you that the clamping force (normal force) is not higher with larger pads because the piston diameter of the caliper doesn't change in the case of using 100 series pads in 80 series calipers. But wouldn't the coefficient of friction change due to the different pad size/shape?
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  #19  
Old 01-28-2011, 01:42 PM
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Good choice Corbet with the slotted rotors, staying away from the drilled ones. Drilled rotors aren't good for 80's that plan on a lot of Moab creek crossings, from my experience.

I'm swinging mine back the other direction though... vatozone rotors and stock pads in back, still have slotted/drilled DBA's in front though, 100 pads, though when/if they warp again I'll probably go cheap on the rotors. Only reason I'd stick with 100 series pads at this point is because I've also got a 100 series. I tear my axle down at least once every 2 years, I may as well just do $25 rotors. ymmv
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  #20  
Old 01-28-2011, 01:45 PM
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Quote:
Originally Posted by subzali View Post
But wouldn't the coefficient of friction change due to the different pad size/shape?
I don't *think* so. Coefficient of friction should only be primarily affected by material composition, and then secondarily by wet/dry, temperature, etc. I think the big exception to this would be when the area is reduced to the point where the given pressure is enough to make the one of the surfaces deform. (IE each of 4 pistons would be capable of giving X lbs of force, and then divided by the surface area of the 2 pads, giving you a PSI pressure.) Like if you got a rock stuck in between and it started scoring the rotor. (At which point the area would decrease drastically, increasing the pressure on a given spot on the rotor. But as long as the rotor and pad don't deform (this may actually happen to a small extent) the braking force should remain the same regardless of pad area. Real world I'm sure its much more complicated and that's what the engineers get paid the big bucks for. Kinda fun to think about though!
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