Rear brakes wear down before front? 37K miles

[Ghostrider]

Is there a write up that includes the torque specs for the bolts? The last time I looked the write ups did not included this

 

[Jetboy]

The 4Runner brakes are 338mm front 318mm rear.

For comparison the biggest brakes on any production car is claimed by Bently to be 420mm.

LS500 brakes are 400mm.

Cadillac Escalade: are 330mm front 345 rear.

F250: 363 front 363 rear.

Ram 1500: 336 front 352 rear.

Tundra: 353 front 345 rear.

Grand Cherokee: 330 front 330 rear, "HD" brake models 350 front 330 rear. SRT models vary up to ~380mm.

BMW X5: 348 front 332 rear.

So... I'd say the 4Runner brakes are properly sized for the vehicle.

 

[1996_Valencia_Owen]

The 4Runner brakes are 338mm front 318mm rear.

For comparison the biggest brakes on any production car is claimed by Bently to be 420mm.

LS500 brakes are 400mm.

Cadillac Escalade: are 330mm front 345 rear.

F250: 363 front 363 rear.

Ram 1500: 336 front 352 rear.

Tundra: 353 front 345 rear.

Grand Cherokee: 330 front 330 rear, "HD" brake models 350 front 330 rear. SRT models vary up to ~380mm.

BMW X5: 348 front 332 rear.

So... I'd say the 4Runner brakes are properly sized for the vehicle.

I think you're agreeing with me, but even that said, those dimensions still don't account for rotor thickness. The 4runner is pretty solid there as well. My guess is more solid than the Grand Cherokee or X5, even... altho the X5 is set up for performance driving.

 

[Jetboy]

I think you're agreeing with me, but even that said, those dimensions still don't account for rotor thickness. The 4runner is pretty solid there as well. My guess is more solid than the Grand Cherokee or X5, even... altho the X5 is set up for performance driving.

We're in agreement. Put a 4Runner rotor on a table next to almost any other rotor of a comparable SUV or truck and you won't say they're too small or undersized.

Diameter doesn't tell anything about thickness which is important or brake pad swept area which is also pretty important.

Mostly I just kinda shake my head and ask WTF do people want? Rockwell axles with 22.5" 10 lug wheels to fit gigantic semi truck brakes? It's a mid size SUV. The brakes are more than enough for both normal use and pretty much any other use that's within the realm of reason for the vehicle.

 

[1996_Valencia_Owen]

Weird side note:

Why are the Tundra axles 5 lug? So odd. One would expect they'd be at least 6+ for weight-bearing per bolt, but no....

I would otherwise wonder if some folks could put new Tundra brakes on a 4runner.

 

[Jetboy]

Weird side note:

Why are the Tundra axles 5 lug? So odd. One would expect they'd be at least 6+ for weight-bearing per bolt, but no....

I would otherwise wonder if some folks could put new Tundra brakes on a 4runner.

The lug nuts should really bear any of the weight. They're only there to provide a clamping force. The friction between the wheel and hub is what provides the weight bearing. It's a bit different from fasteners that rely on the shear value of the stud. The studs themselves can't support the forces. That's why they break off if they get loose. I think choosing the 5 stud pattern was mostly because it was already a production rear axle.

The 5 lug tundra rear axle was a slight modification of the off-the-shelf rear axle used by Hino and Toyota medium duty trucks. Like the DYNA series. What's cool about them is that they're ridiculously strong and have a lot of OEM parts that are compatible. For example you can buy OEM gears all the way into the 6.xx range. And there's even a matching 10.5" front solid axle that makes a Dana 60 look like a toy. If Toyota ever did build a 1 ton ish truck I think we might see the matching front solid axle. But I'd rather just have a Dyna myself if I needed one. (IMO the Tundra is kinda half way between a half ton and 3/4 ton - it has a small displacement big block engine, low gearing, heavy duty rear axle, and wheel bearings bigger than any 3/4 ton truck - what does that make it?).

What I find most interesting about the 10.5 front axle is that it's centered diff. Would be ideal for rear steering. But you'd have to track one down in a foreign market so I don't know what the cost would be.

 

[enyce]

I was about to leave for an overnight wheeling trip when it sounded like my rear brake pad wear indicators were making noise. I didn't think it could have been my rear brake pads because my front pads were still good. Every other car I've had, the front brake pads wore out first, so I was shocked when I inspected my rear pads and found my back brake pads were worn down to the indicator.

Did some research and found this:

"Another factor that has accelerated brake wear (especially rear brake wear) in certain late model vehicles is the change to electronic brake proportioning. The proportioning valve that normally reduces hydraulic pressure to the rear brakes has been eliminated so the rear brakes will handle a higher percentage of the brake load and be more aggressive. The antilock brake system performs the job of brake proportioning by keeping an eye on how the rear brakes are behaving. If the rear brakes start to lock up when braking hard, the ABS system kicks in and cycles pressure to the rear wheels to prevent them from skidding." Knowyourparts.com

As my buddies will attest, I am not an aggressive driver and am pretty mellow on the accelerator and brakes.

Just wondering if anyone else experienced the same. Searched through 10 pages but didn't find anything similar.

My rig has lotsa after market parts, so maybe the extra weight contributed to it, assuming the 4R has electronic brake proportioning.

Appreciate your thoughts.

Just replaced front and rear brakes pads on '15 Trail with 30k miles. All pads looked just like the one in the your photo. I will strongly suggest to anyone driving in NYC or heavy city traffic to check your 4runner brakes every 20k miles.

 

[MidnightOffRoad]

This is not true at all.

If you're going by diameter only, you may have a point -- but brakes aren't just about diameter.

The 5th Gen 4runner's brakes are not only pretty big diameter-wise, but also vented in front AND in back... plus they have a ton of rotor thickness, which gives them a lot more heat capacity than most passenger-car brakes.

That said, if your daily driver car is a Corvette or Z06, then maybe.

BTW, consider this -- the 5th gen brakes are the identical parts as what the Lexus GX460 has on it. Considering the Lexus is 500+ lbs more than the 5th gen, and has to meet Lexus' higher level of performance and feel standards, that means the brakes must be pretty darn good on a car that's essentially carrying 2-3 passengers less in weight.

As for rears wearing so fast -- my guess is you tend to do a lot of light braking while in traffic. Do you have long commutes where you're on and off the brakes but only doing light braking?

Sigh, always someone wanting to argue.

The amount of braking force capable in a modern disc brake system is DIRECTLY proportional to A) the number of pistons (i.e. how much clamping force given typical hydraulic system pressures and limitations) and B) the size of the rotor.

A 5500 lb vehicle is going to require the brakes working VERY VERY hard to stop similarly to other vehicles where the car weighs less, ESPECIALLY when you try to fit a brake package that clears within 17" wheels.

What you find generally is that it's the size of the wheels that ultimately limit you on how much brake you can run.

My point is, for such a heavy vehicle, the brakes are SMALL, small rotors (calm down people, slotted, drilled, etc, isn't that much of a benefit or factor).

Braking is about turning kinetic energy into heat energy. The larger the rotor, the more conversion. It's not rocket surgery and it's inescapable.


For how MOST people are accustomed to driving and for the amount of brake usage these days (again, stoplights are murderous on brake life, as are widespread use of stop signs) the brakes on the 4R are woefully undersized.


My ex drove an F-150 and went through a transmission and 2 sets of brakes before 100k. I just couldn't get it through her thick skull that you can't drive a 3 ton truck like a sports car. When people STOMP on the accelerator at green light and mash on the brakes at red light, it's GOING to eat up pads (and eventually rotors) on a vehicle where the weight and rotor size aren't a healthy ratio.

 

[Jetboy]

The larger the rotor, the more conversion.

This is not correct. Might be a source of confusion.

 

[Peakbagger]

Did you "level" your suspension?

It would seem logical that if you "level" the suspension by raising the front, the position sensor will think that you have it loaded down with more weight in the rear and the base line proportioning would likely start by sending more pressure to the rear brakes. It can't identify a proportioning change requirement without some slip at one of the tires. So the default would likely be to identify the condition as being heavily loaded and wear the rear brakes much faster than it would with OEM rake. Unless you reset the sensor's zero point.

Interesting observation. Yeah, I got my rig lifted and leveled (mostly). Most of my driving is in town. Hardly take the freeway anymore since I live close to my job. Drive in to work is downhill and drive back is uphill, so I might be on the brakes more (and harder) than the average commuter. Thanks for pointing that out.

 

[Maitre]

2012 original owner. replaced front and rear pads and rotors at the same time at 75k miles.
All wore out evenly.

 

[KAK707]

Rear pads are gone !

I had breaks done at Toyota dealer at 50k, just because I could.
Now at 110k rear break just made noise. Pulled all 4 wheels, both front pad have half like, both rear pads are completely gone...wtf

 

[mo_mo]

Fronts at 90k miles
Rears at 50k miles
With the fronts having quad pistons and the rears a single, the rears don't need nearly as much fluid to engage than the fronts.

 

[Bmnorm2]

I had breaks done at Toyota dealer at 50k, just because I could.
Now at 110k rear break just made noise. Pulled all 4 wheels, both front pad have half like, both rear pads are completely gone...wtf

Modern braking systems apply more power to the rear brakes during typical “daily driving” braking. Yes, yes, the fronts have significantly more effective stopping power, but most daily driving doesn’t require the additional capability. By sending more power to the rear the vehicle dives less and improves handling. The risk of locking up the rear is also handled by these systems.

The variable system can proportion braking power for the best stopping and handling. Old school just had a constant split.. something like 70/30 F/R.

 

[Gstick]

Very interesting thread. I now seem to understand why my rear brake pads wore out @ 30K+ miles on both my 2010 & 2019 4R's. Lots of stop & go traffic, stop-lights & stop signs. I've lived in the same house for the last 14 years so driving the same roads over & over.