Why Big Brakes Won't Stop You Faster but Wider Tires Will - Friction and Surface Area Explained

"My 3,000lb sports car with sticky high performance tires stops way faster than my 4,200lb truck with off-road biased tires."

 

https://www.tacomaworld.com/threads/brake-upgrade-stoptech-rotors-trd-performance-pads.523829/

 

I love apple to walnut comparisons.

 

This is always what I've understood, ABS makes big brakes not add much, like modern ECUs making CAI useless. There is something to be said for bigger rotors stopping fade, not sure about the differences in airflow, the Toyota engineers are pretty good about that sort of thing. However a bigger rotor is a bigger heatsink and has more surface area to transfer heat into the air so physics says it must shed heat better. Just my 2 cents. I have also always thought the Tacoma brakes where pretty overbuilt already, it has as many pistons in one caliper as many cars have on all four wheels.

 

TRD Sport, SR5, and SR has better brakes than Pro and TRD OR, aleast over the trucks with atrac, SR and SR5 have skinnier 245 tires that weigh less than the 265 on OR and Sport. 4cyl SR has the greatest braking performance it's the lightest truck with out atrack on 245s, and the access cab SR is lighter than a DCSB. RWD AC 4cyl will have the shortest braking distance of all Tacomas. Pull the air dam, the truck will stop even quicker.

 

Is that because of the way the ABS is designed? The brake hardware is the same between an off-road and an sr5.

 

Pretty sure the TRD OR & the Pro's have a beefier brake booster system than Sports or other truck trims due to the ATRAC/MTS system needing it to operate effectively.

Not sure about pads & calipers, my guess is they would be the same across all of the trims.

 

That's my line of reasoning. I believe the less complicated ABS system provides better stopping power. IDK if that's true or not.

Same hardware across all trims pads, calipers, drums, and shoes. I'd like to see the stoping distances between the two systems.

 

I'll say that I think most of the [meaningful] information here feels right. I locked up the tires on my tacoma with stock brakes (this was built, pushing the weight limits of a taco). BUT, when I drive over Vail Pass (either direction really, and other passes in the area), going down them is a noticeable difference (feel and fade). I did used to race cars, so I appreciate the *feel* of brakes quite a bit (maybe not more than most, but probably more than many), and I'll say the BBK generally feels better with the additional weight of the camper (general around town driving as well as the passes). Lastly, given the additional weight and regular mountain driving, it's given me a level of confidence in the brakes I didn't have, and I have to say that's worth quite a bit as well.

 

I am glad this topic came up. I was pretty much sold on a BBK kit and was dreading spending the money.

I watched the OP’s video and understand the math. I just always figured you have more clamping force and more leverage with a BBK. So with a heavy truck and bigger tires (38’s) a BBK was a necessity.

I regularly drive a “mountain pass” but my brakes never get hot enough to fade. So that part I don’t need bigger brakes.

Perhaps I’ll just get one of those rotor/pad kits and call it a day. It’s getting close to brake time anyway.

 

Was in same exact spot

 

Forget the BBK, you really want an improvement ditch all the rubber hoses. That is where you loose a lot of brake power. Go for hard lines and steel braided hoses and see the difference.

This is not scientific and I am not a brake advisor. Information here is for entertainment only.

 

I love when only some of the physics is applied and yet a lot of the equation to what really will happen isn't applied. These youtube experts help add to the confusion and OP if you're skeptical about a company posting data you should vet your sources before relying on them as your sole source of information.

 

Brakes are overrated......

 

I skimmed through it.
I saw no mention of the effect moving the braking force away from the center of axial rotation when larger diameter discs are used.

 

Good video. F= u * N is well known in basic physics but adhesive is rarely discussed. Always left me wondering why larger tires were better if friction coefficient was all that mattered.

Another thing he left out was that larger brakes usually have larger pistons, and then F = piston area * pressure, so for same pedal force you get more brake force with same pressure from the master cylinder. Nothing comes for free so in this case it takes more pedal travel to move more brake fluid.

 

I think the point of your second paragraph is if you can lock up the stock brakes and activate ABS, any extra clamping force isn’t going to help. Maybe just lock up easier I guess?

As for your tire comment, if you watch the first video the second half dives into tires and why that equation doesn’t work for everything.

 

Brakes? Never heard of them. Lol.

 

I'm sure most have viewed this video and this is an extreme circumstance of brake fade but upgrading brakes should always be part of the upgrade path, just adding SS lines improves huge.
https://www.youtube.com/watch?v=5oO226PgSkg

 

Actually, when we increase rotor size with a BBK, we typically reduce the piston surface area. (If we add 20% to the effective radius, we'll decrease the piston size by about the same amount). The objective is not to increase the brake torque for a given pedal effort/hydraulic pressure....if we do that, we'll destroy the balance/bias front to rear. Torque does not need to be increased since most OEM system can lock up the wheels on dry pavement. The smaller pistons result in less fluid volume requirement to apply the brake, which results in a firmer, higher pedal. The firmer pedal is what allows the driver to better modulate the brakes, and is the prime factor in reduced stopping distances. The rest is heat capacity due to the larger heat sink (rotor).

Edit:...In some cases where we're dealing with woefully inadequate brakes (think an application that uses an 11" rotor with a single piston caliper running 40" tires with 3000lbs worth of extra armor and crap bolted to it...like a Jeep TJ), we NEED more torque, so it gets bigger everything.