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Bigger tires = brake upgrade?

21K views 50 replies 22 participants last post by  NC25T 
#1 ·
Over the last couple weeks I've read and learned a lot about lifts, suspension, tires, re-gearing, etc. but I haven't seen much mentioned about brakes. Is it necessary to upgrade your brakes when going to bigger tires? Or is tire size less of a factor and it's mostly dependent on vehicle weight? At what point does it go from "it's not necessary" to "it would be a good idea" to "you need to do that ASAP"? Just curious what everyone thinks since I haven't seen much talk about brakes.
 
#2 ·
I have a heavy jku with 35s and am just fine on stock brakes. They will just wear out a little quicker. The biggest factor seemed to be the tire size (unsprung weight?). But, I think when I switch to 37s it will probably jump to "I should probably do this"
 
#4 ·
This is a good point. Driving style matters. I drive very lazily and not in a rush, keep my following distances larger than average. Mostly cuz I'm just enjoying the ride with the top down and never in a rush.

If you're commuting on a freeway and have a particular time your job requires you to be in at, that driving style may require a brake upgrade more (this used to be me).
 
#5 ·
IMO the factory one's stop my 35's fine, they probably don't stop as well as the smaller factory tires but I haven't had any problems, however I will probably upgrade to EBC's greenstuff pads when due and see if there is much difference.
 
#7 ·
JK brakes are actually decent. I have never had a problem stopping 37s. At 40k on 37s, I did rear pads. They still weren't too bad and would've gone a while longer but would rather do them before they need it. Had pads to do front, but they were in great shape, barely worn so we left them. When this set of pads goes I will do the big brake upgrade.
 
#8 · (Edited)
Questions to ask yourself. What is your normal driving style? Do you tow with your Jeep? How big of tire are you planning on running?


The Euro/export spec JK/U have larger front brakes so the question is why? Well largely because the European countries feel our US standards are mediocre and the brakes we have not good enough to meet their safety standards with no lift and stock tires. Also consider most of these countries do not even allow for tires in the 33" - 35" range and forget about a 2" or more lift = crazy unsafe handling and braking in their eyes.

Add our 2"+ lifts and 35"+ tires and well you get the point.

On a side note it is interesting that the Euro spec JK/U have a higher tow ratting? Could it be because of the larger brakes?
 
#9 ·
I have a 2dr jk rubicon with a 2.5" lift and 35" tires that weigh about 75lbs per tire, I DD my jeep with an hour commute to work one way, also during the summer I tow 19ft bay boat around with the jeep (never above 55-60mph).

I think the brakes are just fine. Yea they wear out a little quicker but will stop you in an emergency.

I run an hour everyday on I-85 and literally no one knows how to drive here in SC so I've had to slam on my brakes a few times, I CAN get the ABS to go off so impo if you can get the abs to go off, your brakes are as good as they need to be, adding bigger brakes will just lock up the tires with less pushing on the pedal. Oh and they will cool quicker but who's tracking their JK?
 
#13 ·
I have a 2dr jk rubicon with a 2.5" lift and 35" tires that weigh about 75lbs per tire, I DD my jeep with an hour commute to work one way, also during the summer I tow 19ft bay boat around with the jeep (never above 55-60mph). I think the brakes are just fine. Yea they wear out a little quicker but will stop you in an emergency. I run an hour everyday on I-85 and literally no one knows how to drive here in SC so I've had to slam on my brakes a few times, I CAN get the ABS to go off so impo if you can get the abs to go off, your brakes are as good as they need to be, adding bigger brakes will just lock up the tires with less pushing on the pedal. Oh and they will cool quicker but who's tracking their JK?
I agree for the most part. If your ABS goes off you have locked up your tires and any extra braking power would be 100% useless. I engine brake 99% of the time with my manual anyway, but there are times when I was off-road coming down off an obstacle that I wish I could have a little more braking power while in 4lo 1st gear that could warrant a BBK so I wouldn't be doing a three foot pedal dance to go a pinch more slower. I can't even get my engine to shutter standing on my brakes in 1st gear on level surface.

With that being said, a BBK is far down the list of upgrades for me.
 
#10 ·
I find the stockers to be fine unless you're thinking to drive Dukes of hazard style. I DD my 35's on stock like brakes, 130 miles round trips, zero issues. my tires do weight 62lbs each + 25 lbs per wheel, 76k miles and counting, I bought my Jeep used with 30k miles or so, so I don't know if the previous owner changed rotors and pads, but the only ting I've changed is the rear pads so far, my rotors are just conventional blanks, and I don't see oversized anything in them.
 
#11 ·
I have a JK and though I found the stock brakes to be OK as I added weight and height to my Jeep they became marginal. 35s, skid plates, bumpers, armor and winch, etc... I install the front AND rear Teraflex Big Rotor package with EBC green stuff pads. This made a significant difference to my Jeeps braking and as far as I am concerned is absolutely worth every penny. I drive slow in general anyways (it's a Jeep I have no choice) and believe myself to be a cautious and aware driver but you just never know when a little kid comes chasing a ball into the street in front of you. I want to make sure I have done what I can in that situation.
 
#12 ·
Stock brakes are fine until you compare them to something like tera flex big rotor kit or the other upgraded brake kits then you realize they really do suck, kinda like the headlights they are fine until you drive behind a set of LEDs
 
#14 ·
I DD my 5500 lbs (just weighed it last month, so that's a cool 1,000 lbs over stock) on 37s. My wheel/tire combo weighs in at 113 lbs each. I think the stock brakes are fine. would bigger brakes stop me quicker, sure.

Hitting ABS (which my stockers still do) is not the definitive test if your brakes are adequate though. ABS is the last line of defense and a better braking system will stop you faster without hitting ABS.

Bigger brakes equal better stopping power at the same pedal pressure equals ABS not engaging as much.
 
#15 ·
I DD my 5500 lbs (just weighed it last month, so that's a cool 1,000 lbs over stock) on 37s. My wheel/tire combo weighs in at 113 lbs each. I think the stock brakes are fine. would bigger brakes stop me quicker, sure. Hitting ABS (which my stockers still do) is not the definitive test if your brakes are adequate though. ABS is the last line of defense and a better braking system will stop you faster without hitting ABS. Bigger brakes equal better stopping power at the same pedal pressure equals ABS not engaging as much.
But ABS isn't ever going to stop you quicker. I don't have ABS on my JK. I can lock up my 34s very easily even after 40k of wear on my brakes.

Pedal travel has nothing to do with braking performance. It's like saying vehicle X is faster than my JK because I have to push the gas pedal further to floor it.

Better tires and a stiffer suspension are more likely to decrease your braking distance than upgrade brakes for daily driving. Fact. Until your factory brakes are incapable of locking up your wheels, bigger brakes will do absolutely nothing for your stopping distance.

Bigger brakes will help you on a track where you are repeatedly braking from extreme speeds without adequate time to allow the components to cool, and maybe help decrease wear
 
#16 ·
I'm on 35's with a pretty heavy 2dr...
It stops a thousand times better than my 17 year old Jeep Cherokee did, and that was a race car in comparison to my '69 F250
I'm good.
 
#20 ·
A good driver will be able to reduce speed/stop in a SHORTER distance (without locking the wheels) than ABS can accomplish given a decent production car with a high performance brake system. Serious race cars like F1 are different since money is no object. ABS modulates because it doesn't have the ability to find the line between locked and not locked. Under very slick road conditions ABS will most likely win.
 
#21 ·
My testing with ABS disabled and enabled was fairly eye opening - ABS stopped in about 20% shorter distance than without ABS. (Disclaimer: a street car, not a Jeep).
The thing is that usually not all tires have equal braking traction. Usually they are nowhere close. Also the brake bias front to rear is seldom perfect - if nothing else it changes based on the braking force of the tires and CG height. So in the real world the ABS beats any driver because the driver has one control for all 4 wheels whereas the ABS can brake each wheel to the edge of traction.
The main thing with ABS is to keep pressing harder on the brake once you start to feel the ABS start to modulate the brakes. You will stop quicker. Most people don't do this so OEs have recently added 'braking assistance' so that when you brake moderately hard the ABS controller goes all the way for you.
I have a track car which I added ABS to. It is fantastic. You can out brake a car on the inside and get two wheels into the rubber 'marbles' off line, and just stand on the brakes as hard as you can and then let the ABS take care of each tire, so that you still stop very well. Without ABS you'd tend to not stop and under-steer into the car on the outside. Same with braking with two wheels up on the curb - ABS keeps the car straight.
PS pet peeve: breaks vs brakes.
 
#28 ·
Yep.

Sorry for the length...
Now... "the enough power to lock up the tires" bit... I used to believe this too.
I'll equate this to mtn bikes... where I am a very competent rider, and ride at the edge. Not bragging, stating a fact.
Back in the cantilever days, we could lock the tire up just fine, and disk brakes came out, I though pfff... whatever. Then I bought a DH bike with the biggest baddest brakes on the planet. Well, I could still lock up the brakes, but I could threshold brake with such greater ability. Stopping became fierce. I now run a 6.5" bike with even more badassed brakes, same size as the DH bike had. My buddy runs a 6" bike with badassed brakes, but in 6" flavor (mine are 8"). I can lock those up too, real easy, but I can threshold brake better with the larger brake... harder braking with more control.
So, even back in the days of 4 wheel drums you could lock the wheels up, but the bigger more efficient brakes allows you to sneak up on and hold that "threshold" point with so much more control... modulation.
Having said all that, and knowing that larger brakes will decrease your breaking distance because they allow more control at the threshold, allowing you to hang onto that last bit of braking traction, I will say this... I'm going to go ahead an "assume" that if simple old me is able to better brake at the threshold with larger brakes, then so to a computer/ABS programed to do nothing but brake.

So, a panic situation is just that, lets assume you are a careful driver (I am) and leave lots of room, always have an out planed, and watch your mirrors to know exactly where everyone on the road is... I do this... but in a panic, or unforeseen event, none of that matters. Are big brakes going to help you?
I'm going to say no, because your reaction time will be great enough that often times in panic situations you do not get to the break, or are way to late to the brake to have any positive effect. In these situations you driver training, decision making and vehicle control are going to benefit you in a more positive way.

So, big brakes, are they better? Absolutely?
Are they required? Only you can decide.
I have a heavy 2dr on 35's, I've had a couple situations (Phoenix AZ yahoo's) that scared me, and yet the braking is far better than any Jeep or truck I have owned previously. I must say that in one situation it was actually the stability control probably saved my life. Still cannot believe I did not go into a skid at 70mph... and F1 brakes would have been of no benefit in that situation... by the time my foot was getting to the brake it was already time for evasive action.
Off road I hate hate hate ABS and stability control... on road I'll take it thank you.
Big brakes, "I" do not feel the need for them just yet. Maybe when I go to 37's and bead locks... maybe if I towed... maybe if I had a heavy 4dr... maybe if I carried every toll I ownn, and enough spare parts to fix absolutely anything and everything on the trail... maybe if I was a pre-runner type...
But for a cautious/responsible daily driver... I see no need for "my" use.
Agreed.
 
#23 ·
Sorry for the length...
Now... "the enough power to lock up the tires" bit... I used to believe this too.
I'll equate this to mtn bikes... where I am a very competent rider, and ride at the edge. Not bragging, stating a fact.
Back in the cantilever days, we could lock the tire up just fine, and disk brakes came out, I though pfff... whatever. Then I bought a DH bike with the biggest baddest brakes on the planet. Well, I could still lock up the brakes, but I could threshold brake with such greater ability. Stopping became fierce. I now run a 6.5" bike with even more badassed brakes, same size as the DH bike had. My buddy runs a 6" bike with badassed brakes, but in 6" flavor (mine are 8"). I can lock those up too, real easy, but I can threshold brake better with the larger brake... harder braking with more control.
So, even back in the days of 4 wheel drums you could lock the wheels up, but the bigger more efficient brakes allows you to sneak up on and hold that "threshold" point with so much more control... modulation.
Having said all that, and knowing that larger brakes will decrease your breaking distance because they allow more control at the threshold, allowing you to hang onto that last bit of braking traction, I will say this... I'm going to go ahead an "assume" that if simple old me is able to better brake at the threshold with larger brakes, then so to a computer/ABS programed to do nothing but brake.

So, a panic situation is just that, lets assume you are a careful driver (I am) and leave lots of room, always have an out planed, and watch your mirrors to know exactly where everyone on the road is... I do this... but in a panic, or unforeseen event, none of that matters. Are big brakes going to help you?
I'm going to say no, because your reaction time will be great enough that often times in panic situations you do not get to the break, or are way to late to the brake to have any positive effect. In these situations you driver training, decision making and vehicle control are going to benefit you in a more positive way.

So, big brakes, are they better? Absolutely?
Are they required? Only you can decide.
I have a heavy 2dr on 35's, I've had a couple situations (Phoenix AZ yahoo's) that scared me, and yet the braking is far better than any Jeep or truck I have owned previously. I must say that in one situation it was actually the stability control probably saved my life. Still cannot believe I did not go into a skid at 70mph... and F1 brakes would have been of no benefit in that situation... by the time my foot was getting to the brake it was already time for evasive action.
Off road I hate hate hate ABS and stability control... on road I'll take it thank you.
Big brakes, "I" do not feel the need for them just yet. Maybe when I go to 37's and bead locks... maybe if I towed... maybe if I had a heavy 4dr... maybe if I carried every toll I ownn, and enough spare parts to fix absolutely anything and everything on the trail... maybe if I was a pre-runner type...
But for a cautious/responsible daily driver... I see no need for "my" use.
 
#24 ·
Like I said until you try them you don't know bad stock brakes are.
 
#26 ·
I just put BFG TA KO2's at 35x12.5R17 on my '15 JKUS. Big brakes are on my list. While the stock brakes stop the vehicle... there is a noticeable difference in the length of time it takes to stop it. The vehicle also feels heavier to me while driving. Granted I'm running 3.73 gears and will likely end up upgrading to 4.56 to help with that.
 
#29 ·
Thread summary:

1. Big brakes will help
2. The world won't end without them
3. Whether they're worth the money depends on how much or little disposable income you have, and if there's anything else you want to or should be spending that money on.
 
#30 ·
As I initially stated, bigger brakes would help my braking performance, but I don't think at the point that they are needed. I can tell my stopping distances are longer, but not out side my ability to compensate as a driver. As Mike H. state above, the panic stops don't matter as much as your typically beyond braking segment of the situation anyways.

It all comes down to cost and performance with mods, so only you can decided if you need more braking power.
 
#35 ·
Disagree with a bunch of what people state in regards to bigger brakes

- stating I can lock my tires up now thus I am OK with stock is a bad example. Often times a panic stop occurs at highway speeds and that is where better brakes will shine. Going 65-0 where the 65-20mph portion is 10-20ft shorten vs oem. That's the difference between driving into the drivers seat of the car in front of you vs stopping several feet short.

- yes these are hugely beneficial on cars at a roadcoarse or spirited mountain drive however for reasons stated above being able to slow down those really heavy wheel/tire setup at a much faster rate at highway speeds is what matters.

- a good BBK should be designed to use the OEM master cyclender. For a street driven car there is no reason for that much for volume to be required to push those pads in. Many kits (4 and 6piston) state works with oem master cylinder. The piston size is smaller then stock thus the overall piston area is similar to oem.

- ABS can and does stop most people quicker/shorter. The vast majority of people if in. A panic stop would just stomp on the pedal and lock up the tires once they hit low speeds. That's where ABS will shorten the distance and also allow the driver to maintain control. Someone that's more familiar with modulating brakes... can stop shooter w/o abs but again, the majority of people in this world need ABS.



- being safe and following by a larger then safe distance sure sounds great. But it's not a perfect work, people cut people off and do some really dumb things.

- I think tread compound and tread design is much more important then width of a tire. If a 2ft wide tires compound is as hard as a rock (500+ treadwear) Mud tire vs a 10in wide sticky tire (under 200 treadwear) summer or all season... the narrower tires will work better for stopping. The brakes goal is to stop the wheel/tire combo from spinning and the quicker it does this (without locking up) the shorter the distance. Takes a LOT less energy/force to stop a 50lb 30in wheel/tire combo vs a 115lb 37 or 40in combo. Not just the added 60+ lbs but the larger diameter. Obviously the amount of grip between the tire and whatever your driving on being often times the most important factor in stopping distance especially at lower speeds....

I had a AP Racing BBK on my last two cars, yes the cars did spend time are the local roadcoarse and my last one was a daily driver for 12 years. It was amazing how much better/safe the car was with those brakes even though with both cars I could lock up my OEM brakes, and that was with summer performance as well as some R rated tires. The decrease in high speed stopping ability was totally amazing....

I just wish someone besides willwood offered a BBK for JK's, stock JK brakes are mediocre I would say. Huge improvement from past generations though.

Often times just better pads can have great results in shortening the stopping distance
 
#36 ·
I think tread compound and tread design is much more important then width of a tire. If a 2ft wide tires compound is as hard as a rock (500+ treadwear) Mud tire vs a 10in wide sticky tire (under 200 treadwear) summer or all season... the narrower tires will work better for stopping. The brakes goal is to stop the wheel/tire combo from spinning and the quicker it does this (without locking up) the shorter the distance. Takes a LOT less energy/force to stop a 50lb 30in wheel/tire combo vs a 115lb 37 or 40in combo. Not just the added 60+ lbs but the larger diameter. Obviously the amount of grip between the tire and whatever your driving on being often times the most important factor in stopping distance especially at lower speeds....
Tire design/compound is important - especially so when comparing NASCAR tires to street tires. I don't believe the compound variation is that extreme in Wrangler tire options. Going from 10 to 12.5 is an increase in 25% of friction (if you have not overwhelmed the brake system ).
 
#40 ·
Here is a link.


Speed, speed limits and stopping distances - Brake the road safety charity

http://www.brake.org.uk/assets/images/facts/stopping-distances.jpg

Here is an important point.

"Speed and mass are the properties of energy exchanged in a road collision in the form of kinetic energy, the level of energy exchanged has a significant impact on the severity of the crash. It is believed that the exchanged of energy can be calculated equal to half the vehicle’s mass times the vehicle speed squared; which means that even smaller increases in speed can lead to an increase in impact severity [11]."

This is why sport cars have big brakes for high speed braking. It is better to down shift engine brake at high speeds.

Based on the above quoted info can you imagine the amount of heat and energy generated based on the higher speed. You have to halve the wt. increase, but square the speed increase.

And,

Lifting your Jeep with a cheap lift will hurt stopping distance while slapping on MTs for a daily driver will for the worst too. It is why I did not lift and run Nitto ATs.

If you can't set off the Anti skid in emergency stop I might upgrade brakes, but that depends on the results. And the results are based on the speed you emergency stop and distance. Anti skid is for stability and control.

Wide tires with lots of rubber that grips helps and looks better. 33" to 35" I would have 12" width minimum. Above that 14+ width. Width can help for stability too. Width has some disadvantages, and grip can even be one of them depending on type of application like a race car.

Speed affects braking more than weight especially above 100 mph.

Weight is in that formula as Mass. I read that wheel size is more about the Brake's distance from the ground than the weight of the wheel and the rotational weight of the wheel. We can add the weight of the wheels and tires to the weight as a weight increase to the total weight of the Jeep vehicle and then halve it in the formula.

Not a physics professor or brake engineer. So any links to info would be appreciated.

Look at the charted increase in stopping distance (I.E. energy) with every 10 MPH increase in speed.
 

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#41 ·
Regular Rush hour bumper to bumper traffic I am not worried about in a Jeep with stock brakes and good grip tires with stock suspension or a good lift job.

Now if you drive like a nut in highway traffic with a 1 second following distance and constantly apply brakes and constantly keep them hot and constantly slam on them then big brakes are for you. You might want to consider other cheaper alternatives like patience and increase your following distance from the minimum of 2 seconds to recommended 3 to 4 seconds for any average vehicle.

If you don't know how to find your following distance in terms of Time you need to.
 
#43 ·
Regardless of your driving habits, you can't control what others do.

I've driven everything from overloaded work trucks to luxury sport cars in traffic.

Better brakes increase safety.
There is no denying that.

Bang for the buck.

Maybe better brake pads, tire selection vs. $2000 upgrades to calibers, disks, brake lines and Master cylinder.

Just cause it is safer does not mean it is worth the money. It is about acceptable safety and probably common sense to that.

I have driven MTs and they are a horrible choice for the roads. So slippery especially with bad lifts. Brakes won't help that, but following time will. You have to account for it cause some drivers can't afford to put MTs on just for mud and then back to ATs for Monday commute to work.

To spend $2000 on brakes cause you think they will help with your MTs seems like a bad concept, but some people are rich.

You might want to just up the insurance. Bang for the buck most people do not have enough. I am maxed out with an umbrella policy ;)
 
#44 ·
There is a whole bunch of stuff here that might look good on paper but in the real world means nothing. The simple fact that we mod our Jeeps, lift, add weight and larger tires means if we are concerned about safety at all you will up grade the brakes. As a point of reference a stock Jeep as about a 60-0 stopping distance of about 140ft.

In the following linked article they install the Dynatrac ProGrip Brake System. There test mule is modded like many of ours are. Stopping distance of the test mule prior to installation is 172ft. After installation of the system it is 140ft.

Dynatrac Delivers Greater Grip For Jeep Wrangler JK Brake Systems - Off Road Xtreme

I can tell you this system does improve braking over the stock system in all driving modes and IMO is a good upgrade if you have modded your Jeep or are towing.
 
#45 ·
There is a whole bunch of stuff here that might look good on paper but in the real world means nothing. The simple fact that we mod our Jeeps, lift, add weight and larger tires means if we are concerned about safety at all you will up grade the brakes. As a point of reference a stock Jeep as about a 60-0 stopping distance of about 140ft.

In the following linked article they install the Dynatrac ProGrip Brake System. There test mule is modded like many of ours are. Stopping distance of the test mule prior to installation is 172ft. After installation of the system it is 140ft.

Dynatrac Delivers Greater Grip For Jeep Wrangler JK Brake Systems - Off Road Xtreme

I can tell you this system does improve braking over the stock system in all driving modes and IMO is a good upgrade if you have modded your Jeep or are towing.
That is a nice test bed. If the mods were done right for 37s probably $15,000 to $20,000 in mods. Someone with that kind of money probably has the Jeep as more of a toy than a daily driver. Probably has lots of insurance for the cars they own especially the ones for the roads.

It is just to say that upgraded brakes should be at the top of the list vs. other mods and choices seems a little out of touch with the reality of the majoriry of owners, the situations they face with their wallets, and on the roads with a sluggish type driving vehicle.

My Jeep has so much deceleration when I just take my foot off the gas.
 
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