1 ton calipers?

[sparg93]

Here are my thougths are the brake upgrades...definitely curious to hear what you guys think:

Pad Upgrade = Big benefit (Hawks seem to be the winner)
Slotted Rotors = OK Benefit (as long as not Chinese crap or cheapos, almost anything is ok)
Steel Lines = Little to no benefit (not sure if I buy the swelling rumor for a set of lines unless they are really old)

What is the benefit to the bigger piston on the larger calipers mentioned above? Is it simply a larger surface area "pushing" against the pad? Any idea on the true benefit?? (not trying to be difficult, I have no idea)

 

[96ProCompTahoe]

pad upgrade- great

but i do have to say i did see a difference with my SS Lines and a HUGE different with the Brembo Slotted Rotors.

 

[99Yuk]

Here are my thougths are the brake upgrades...definitely curious to hear what you guys think:
...
What is the benefit to the bigger piston on the larger calipers mentioned above? Is it simply a larger surface area "pushing" against the pad? Any idea on the true benefit?? (not trying to be difficult, I have no idea)

I'm no rocket scientist, but I think the theory goes like this.
force is the surface area * the pressure
more force on pads = better braking
An example would be 100psi pressure on 1 square inch of surface area = 100 units of force, lets call that the smaller piston. The bigger piston might be 100psi of force on 2 square inches of surface area = 200 units of force.

Now these numbers are clearly not valid for our brakes, but serve to illustrate the thoery behind the bigger calipers. If someone could take accurate measurments of the two surface areas and measure the pressure on the brake lines, we could potentially do the math and get real numbers.

 

[sparg93]

it certainly makes sense...but couldn't our smaller piston calipers exert a similiar force theoretically?

So maybe this is a better way to think about it...b/c at the end of the day we want to stop our rigs faster and a big part of that is how long the brake needs to travel in order to stop the damn thing.

If we push our brake pedal down 3" (just an example) will the smaller caliper exert the same force as the large caliper? Technically (someone correct me if i'm wrong) by pushing on the brake a hydraulic pump pushes fluid that pushes the piston within the caliper outward against the pad.

By pushing 3", are both the larger caliper and smaller caliper exerting the same force? My thought would be yes b/c the pump is exerting the same force on the liquid...but I have ZERO science to back up my idea...anyone much smarter than me that can chime in?

 

[SunlitComet]

+1
Me too. Upgraded calipers cost less than the hawks pads. 1/3 less.

After this experience, I also don't think that fancy rotors do anything for you.
Although I ended up with ATE Premium slotted, that's because they were on sale, and also cost less than the hawks pads.




Now, I'm really curious for someone to measure the thickness of the new Hawks pads vs new OEM pads?

What Hawk part # did you order?
Are you buying the bigger calipers?
How about SS lines? buying those as well? I bought some, but havn't installed them yet. Some guys can tell the difference, some can't. We'll see.

I personally bought hawk HB332P.654 which are .654in or 17mm.
They will be installed with powerslot slotted in the next 30 days.
No new lines or calipers.

 

[sparg93]

96ProComp.

The SS lines, the end of the line that attaches to the caliper, was it identical to the originals or more of a universal fit?

 

[99Yuk]

it certainly makes sense...but couldn't our smaller piston calipers exert a similiar force theoretically?

So maybe this is a better way to think about it...b/c at the end of the day we want to stop our rigs faster and a big part of that is how long the brake needs to travel in order to stop the damn thing.

If we push our brake pedal down 3" (just an example) will the smaller caliper exert the same force as the large caliper? Technically (someone correct me if i'm wrong) by pushing on the brake a hydraulic pump pushes fluid that pushes the piston within the caliper outward against the pad.

By pushing 3", are both the larger caliper and smaller caliper exerting the same force? My thought would be yes b/c the pump is exerting the same force on the liquid...but I have ZERO science to back up my idea...anyone much smarter than me that can chime in?

I'm not an expert at this either, but your correct. The pressure on the pistons regardless of size is the same for the 3" of pedal travel. Ok, thats the pressure in the equation. Now the surface area of the pistons is different, which would change the actual force measured in pounds exerted on the pads.

The actual pressure exerted on the pads is different because the size of the surface area of each piston is different even though the fluid pressure on each piston is the same.

That's how an air hoist works. It's still only 100psi in the hoist, but the surface area is much bigger, so bigger surface area * pressure = force, which has enough force to lift a vehicle.

I guess we would need to know how big round is each caliper piston, then we could use 800psi fluid pressure and then we could have some real numbers!
I guess I'll google the piston sizes.



EDIT: Dope! bpodskalny gave us the piston sizes in the first post! 75 and 79mm bore sizes.
Step1. Convert mm to inches. 75mm=2.952755905515 inches and 79mm=3.1102362204758003 inches.
Step2. Determine surface area in inches. Use formula A=pi*r2 reference found here

r=2.952755905515/2=1.4763779527575
r2=2.17969185938842690185380625
A=3.14159265*2.17969185938842690185380625=6.8477039247195154499261890895241
Surface area of the smaller piston is 6.85 square inches.

r=3.1102362204758003/2=1.55511811023790015
r2=2.41839233678989776333002948137
A=3.14159265*2.41839233678989776333002948137=7.5976035900754674075290601429554
Surface area of the larger piston is 7.60 square inches.

So now all we need is the psi pressure number on the piston due to pedal travel.
Lets say it's 800psi.
So let's do some math. 800*6.85 = 5480 pounds of force on the pads for the 1/2ton caliper, and 800*7.60=6080 pounds of force on the pads for the 3/4ton caliper.

So the larger caliper exerts 600 more pounds of pressure which stops your truck better.
Whew! Hope that helps at least someone!

 

[sparg93]

Some info on the 1 ton caliper:
http://www.azrockcrawler.com/_images/tech/2005/10-14-0534tonbrakes/34tonbrakeconv.html

This gentleman stated the 1 tons were pretty heavy and w/o significant brake boost, took too much travel for them to grab.

Question:
With the rotors you ordered...did you order 3/4 ton sized discs? Is there a difference between our stock discs and the 3/4 version? (per the article, he states the 3/4 are thinner then the 1 ton... so I thought the 3/4 may be thicker than our stocklers)

 

[sparg93]

I can't find the link now, but someone mentioned the 3/4 discs were the same size as our 1/2 ton, but were "thicker"

I'm still torn on the fluid against the piston and the amount of travel by the pedal...at least for the 1 ton caliper I know it's a problem without boost....so wouldn't the 3/4 suffer from a similiar fate, just not as severe?

Shouldn't it take more fluid against the piston to push the piston against the pad? (i.e more pedal travel for the pad to rub against the disc).

The reason I bring this up - is spending the extra $$ on the 3/4 worth it? Keeping all things equal (Hawk pads or high quality equiv), will the 3/4 caliper stop the truck faster then a 1/2 IF you need to push the pedal slightly harder on the 3/4?

I apologize for laboring this issue!!

Additional Info: The discs for the K2500 (i.e 3/4) are 8 lug and I believe our 1/2 ton are 6 lug

 

[99Yuk]

I can't find the link now, but someone mentioned the 3/4 discs were the same size as our 1/2 ton, but were "thicker"

IDK, I ordered 1/2ton rotors. I havn't seen or read anything about using 3/4ton rotors on our trucks, and I didn't want to be the first. hehe.

I'm still torn on the fluid against the piston and the amount of travel by the pedal...at least for the 1 ton caliper I know it's a problem without boost....so wouldn't the 3/4 suffer from a similiar fate, just not as severe?

Shouldn't it take more fluid against the piston to push the piston against the pad? (i.e more pedal travel for the pad to rub against the disc).

Yes, technically you are correct. The pedal will travel down more on 3/4ton calipers than 1/2ton calipers....when using cheap pads. You won't like it. However, when offset by the Hawks thicker pads, you will like it. That particular combo works for me. It feels better than when I started, which is what I was after.

The reason I bring this up - is spending the extra $$ on the 3/4 worth it? Keeping all things equal (Hawk pads or high quality equiv), will the 3/4 caliper stop the truck faster then a 1/2 IF you need to push the pedal slightly harder on the 3/4?

Honestly, I didn't find much of a difference in price in calipers sizes. A few bucks at most. The 3/4ton calipers were one of the cheapest componants. And to answer your question, Yes. IMHO it's worth it. When those Hawk pads heat up and start to grab, you can really feel it, and I actually have to back off the brake pedal. That could be the pads, could be the calipers, rotors, who knows. But I really like this combo. Makes me wish I had done this earlier.

I apologize for laboring this issue!!

No need to apologize man. That's what this place is about. Helping someone until they are happy with the answers.

I think that much like shocks, braking is a personal experience. We can talk about it for some time, but eventually you'll have to take the plunge and try it. And let's say that for what ever reason, you don't like it. Your only out less than $80 for a set of calipers, and an afternoon to swap the 1/2ton back in. You can reuse all your other new parts, then sell your 3/4ton set here. That's the cool part of running these trucks. Most mods can be reversed easily and cheaply if you don't like em.

---------- Post added at 07:25 PM ---------- Previous post was at 07:22 PM ----------

I personally bought hawk HB332P.654 which are .654in or 17mm.
They will be installed with powerslot slotted in the next 30 days.
No new lines or calipers.

Hey, I was just curious, are you in a position to measure new OEM 1/2ton pads thickness?