Big Brake kit.

[Clark Kent]

This discussion will probably go down the same path as the steering damper threads. A lot of argument about benefits but ultimately a personal decision.

The point about stopping distance I make and Powerbrake claim is one of before and after upgrade. That's on a heavily loaded vehicle or towing when the factory brakes are working hard. For all the reasons stated a BBK should hold up better in those conditions by being less affected by heat due to improved dissipation. That translates to better comparable stopping distances by virtue of having less or no fade at the bottom of a long downhill (versus factory brakes). I'm talking of course about the useful ability to still have enough brakes left to be able stop at the bottom of the hill. Not the 60 to 0 style minimum stopping distance figures that auto review websites like to quote.

My input is about the lack of objective data from the manufacturers but I'm from an engineering background so that's a given. It's not hard to stick a deceleration meter on the windscreen and get some numbers and run some temperature tests as well. Alcon and Powerbrake must have done those tests as part of their own validation. But none of that matters. If you like what you're hearing here and elsewhere then go for it

 

[C-Mack]

In terms of an outright reduction in braking distance I doubt a Big Brake kit is going to offer much of a difference. The entire hydraulic system is designed to generate the same amount of pressure and move the same volume of fluid regardless of the caliper type hanging off the end of the circuit. To increase pressure and volume would require a redesigned master cylinder and all associated plumbing and valving.

Stock system is more than capable of locking up the wheels at any point so the tires coefficient of friction with the road is the ultimate determinant of stopping distance. Now in terms of heat dissipation the thermal mass a big brake kit should offer some benefit. Take two Grenadiers loaded to max and perform 10 repeated stops from 60 mph and in theory the vehicle with the bigger brakes should experience less overall brake fade.

With regard to initial brake bite the larger diameter rotors offer more leverage but only up until the point of tire lockup but feel and modulation might be improved giving the sense of higher performance or more stopping power. But this brings up a larger point about how subjective all of this can be. Like most aftermarket products they are engineered to fit a specific application and may be tested on a sample vehicle for functionality. Most engineering work would have been done on a brake dynamometer in a controlled environment to generate base performance numbers not out in the wild in various weather conditions, vehicle weights, terrain types, towing, driving styles, long term durability, etc…

Big brake kits aren’t going to stop your Grenadier like an F1 car or produce enough braking force to stop the world from rotating but should offer better heat management and less fade during repeated and prolonged use such as on steep grades or with a heavily loaded setup where any increase in safety margins would be welcome.

 

[parb]

That is my use case, heavily loaded and driving on mountains and climbs.

 

[AWo]

That all is physics, proven physics and no one can evade physics. Just have a look at racing. They use larger break surfaces solely for heat dissipation. That of course leads to better braking in terms of you can longer use the standard brake power. For braking force they change the brake disc to carbon or ceramics and other very expensive stuff because its friction coefficient is much higher than that of steel (and they also cope better with heat).

It all may look complicated, but it isn't.

With a smaller brake pad the pressure applied to the brake pad is higher, but the surface which acts is smaller. By changing to bigger pads the pressure per square mm is reduced, but the the surface areas is larger. That equals out.

That is also expressed in the formula for friction:
Friction FR = friction coefficient of the material μ x Pressure N - there is nothing about the surface area size.

Now let's check how braking power is calculated:
Let's start at the main braking cylinder. The driver pushes the pedal and generates Force F onto the surface of the main brake cylinder piston A. This force is applied to the brake fluid:

Brake Fluid Pressure P = Pressure Power F / Surface Area of the main cylinder piston.

At the wheels Pressure P presses onto (larger) pistons therby multiplying the force:
Brake Force F = Brake Fluid Pressure P x Brake Piston Surface A

Let's take some real world numbers. Strong braking can generate 180 bar of brake fluid pressure. We have a wheel braking piston surface of 40 mm2 and 22 mm2 at the main braking cylinder piston.

180 bar = 3,960 N / 22 mm2 at the main brake cylinder (3,960 N is the power pushing onto the piston, so the power the driver applies and the leverage which is applied, typically 4:1 or 6:1).

As the brake fluid pressure is the same everywhere in the system the brake cylinder pistons at the wheels are the factor which makes up the braking force:

7,200 bar = 180 bar x 45 mm2 at the wheel brake piston.

Change the piston sizes and you got it.

Nothing to argue here. Physics don't care about arguments. Or simply try to get hold on someone who is in this business and have a chat.....

AWo

 

[MileHigh]

How much of a detriment to braking are steelies versus similar looking Aluminum rims? Is there some weight/distance relationship?

I do Berthoud pass in Colorado. Up and down about 2000ft in 30 minutes, with a bunch of braking on the up for switchbacks. Never noticed brake fade, but it’s also at most 80F, but peaks at 11,100 feet. (Less air for cooling). I’ll get out my FLIR gun and see what I can.

 

[Brad@SuperiorCO]

I have always experienced that the stock brakes are soft feeling, and has been said no matter how hard you push, they are spongy. Mine seem to be particularly soft, I just had a loaner for a few days and the 2025 had a much superior feedback. I am going to have mine looked at again by the dealer, but I am really thinking about new brakes.

I think both Alcon and Powerbrake would be an improvement, and as I continue to add weight to my Grenadier, they make sense. I was up in the mountains today, and I did worry a bit when my pedal goes almost to the floor.

I have the Fox stabilizer and decreased turning radius and I really like it. But there is a good portion of owners who say stock stabilizer is fine, and the same for brakes. Do I worry too much?

Is there any good argument for one brand vs the other. Alcon vs Powerbrake?

 

[DaneJa]

I have always experienced that the stock brakes are soft feeling, and has been said no matter how hard you push, they are spongy. Mine seem to be particularly soft, I just had a loaner for a few days and the 2025 had a much superior feedback. I am going to have mine looked at again by the dealer, but I am really thinking about new brakes.

I think both Alcon and Powerbrake would be an improvement, and as I continue to add weight to my Grenadier, they make sense. I was up in the mountains today, and I did worry a bit when my pedal goes almost to the floor.

I have the Fox stabilizer and decreased turning radius and I really like it. But there is a good portion of owners who say stock stabilizer is fine, and the same for brakes. Do I worry too much?

Is there any good argument for one brand vs the other. Alcon vs Powerbrake?

That doesn't sound right. I've never had my brake pedal go to the floor, but I agree that they don't have great feedback. It's pretty hard to finesse the thing down rocks. If they changed anything in the brakes with the '25s that would be news to me.

I'm still waiting to see what 74 Weld cooks up as that would surely incorporate a brake upgrade (probably the Powerbrakes since they've used them on other packages).

 

[LazarusTheGrenny]

I have always experienced that the stock brakes are soft feeling, and has been said no matter how hard you push, they are spongy. Mine seem to be particularly soft, I just had a loaner for a few days and the 2025 had a much superior feedback. I am going to have mine looked at again by the dealer, but I am really thinking about new brakes.

I think both Alcon and Powerbrake would be an improvement, and as I continue to add weight to my Grenadier, they make sense. I was up in the mountains today, and I did worry a bit when my pedal goes almost to the floor.

I have the Fox stabilizer and decreased turning radius and I really like it. But there is a good portion of owners who say stock stabilizer is fine, and the same for brakes. Do I worry too much?

Is there any good argument for one brand vs the other. Alcon vs Powerbrake?

Fix sponginess:
I would have the dealer bleed/flush the brakes and do a good general check, they shouldn't be always spongy or soft. Likely just a couple air bubbles in the system, sometimes when the brakes are cool there is a little bit of a warm up application so they land in the thermal operating window, I noticed this with any Grenadier I drove and is just the nature of those OE brakes from Brembo (heavy duty brake system with more aggressive pads, with cost/value engineering considered).

Kits:
Once you have that done, and are still keen on a brake upgrade: either the PowerBrake or Alcon will do wonders for you. Can't go wrong either way, only your wallet will hurt for a little.

I went PowerBrake because I've had them before and they're fantastic. I also know their design process and ethos for 4x4 applications and overall service and performance are top notch. You're maintenance schedule for front brakes will likely improve.

The Alcons are also fantastic and if PowerBrake didn't have a kit I would have gone with Agile's Alcon BBK.

Conclusion:
Both will offer a major upgrade in overall feel and modulation, in addition to response. I know the brakes have saved my bacon on SoCal freeways more than once and perform superbly on mountain descents and repeated application/heat cycles. In fact the brakes "like" to be a bit hotter and perform better when they come in. That said, initial braking and cold application far exceeds that of the OEM brakes.

Rear brake upgrade:
No need to get a 4 wheel big brake kit, nearly all braking is on the front brakes due to load transfer under deceleration, rear brakes are present for balance and yaw control, and going in reverse (this is slow speed). Both the Alcon and PowerBrake kits are designed to be balanced with the stock rear brakes, ABS/ESC, and master cylinder (math is a wonderful thing). And this saves on cost and complication with the rear parking brake. I.E. the Rotora brake kit and the Buzz overland kit have unnecessary cost baked in for little to no gain in performance. With modern electronic brake force distribution systems the proportion of braking force is balanced dynamically by the vehicle, unlike the old days. That said the rear's could likely benefit from a proper pad/rotor upgrade if desired or it becomes difficult to get parts.

That said, there's nothing wrong with going with the Buzz kit, it's just substantially more expensive and has a few odd design decisions on external fluid cross over pipes, etc. that are exposed to rocks or similar.