Would you run 18" wheels if you could have Tundra sized brakes? (1 Viewer)

[sbman]

I'm a big believer in OEM parts, but you already knew that.
I just finished doing all 4 corners of my LX450. New rotors, new pads, rebuilt all 4 calipers, changed all soft lines, ran about 2 pints of brake fluid through the system.
While I never really had complaints about the brakes on this truck, it is still somewhat new to me and I am going through each system as time permits. The freakin' truck STOPS now. It's awesome.

Are you still running stock tire sizes? The only significant difference in drive-ability that I found when moving from stock tires to 285s was degraded braking performance. Even after completely rebuilding the front brake system, replacing all soft lines, the calipers still can't apply enough clamping force to the discs to engage the ABS. I'm thinking maybe my master cylinder is weak and that's my next step in getting good braking.

 

[jonheld]

Are you still running stock tire sizes? The only significant difference in drive-ability that I found when moving from stock tires to 285s was degraded braking performance. Even after completely rebuilding the front brake system, replacing all soft lines, the calipers still can't apply enough clamping force to the discs to engage the ABS. I'm thinking maybe my master cylinder is weak and that's my next step in getting good braking.

The LX450 is fully armored, 4" IronMan lift, 315/75R16 Goodyear Duratracs and she stops quickly and straight with mild pedal pressure. Even though the front brakes do the majority of the stopping, you need to address the rears as well as the LSPV. New rotors also make a huge difference. It's all about thermodynamics. The more heat dissipated the better the brakes. If your rotors are worn then there is less mass.

My rotors were in pretty poor shape when I pulled them off and there was a visible difference in thickness between the old and new. I also don't believe in cutting rotors. Again, less mass=less heat dissipation.

 

[sbman]

The LX450 is fully armored, 4" IronMan lift, 315/75R16 Goodyear Duratracs and she stops quickly and straight with mild pedal pressure. Even though the front brakes do the majority of the stopping, you need to address the rears as well as the LSPV. New rotors also make a huge difference. It's all about thermodynamics. The more heat dissipated the better the brakes. If your rotors are worn then there is less mass.

My rotors were in pretty poor shape when I pulled them off and there was a visible difference in thickness between the old and new. I also don't believe in cutting rotors. Again, less mass=less heat dissipation.

With the stock brakes, all OEM parts refreshed and the 315's are you are able to induce the front wheel ABS to trigger (lock the wheels)? For endurance/hills/long term braking all of the thermodynamic properties come into play, certainly. For minimum stopping distance, you need clamping force and the ability to bring the wheel to (near) lock.

 

[Hornd]

I finished the hats and just received the calipers. I'm out this weekend but will work on it next week.

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Would love to see FEA (Finite Element Analysis) on those lil bolts.
Momentum = Mass (6000#) x Velocity (70mph) that is a tremendous amount of shear stress.
There is no more important safety item on these trucks than brakes.

 

[jonheld]

I've not tried to lock up the wheels, but it certainly stops faster and straighter than it ever has. The Duratracs also grip exceptionally well and there is a lot of rubber in contact with the road. The truck just stops. I've never triggered the ABS on my wife's BMW and that thing just stops.
Heat dissipation is in play in all scenarios. These aren't bicycle brakes.

 

[VuickB6]

Would love to see FEA (Finite Element Analysis) on those lil bolts.
Momentum = Mass (6000#) x Velocity (70mph) that is a tremendous amount of shear stress.
There is no more important safety item on these trucks than brakes.

There are 2 piece rotors on some very fast cars that will put more shear stress than a 6,000 lb Land Cruiser at 70 mph. Think of those 2,000 hp TT Lamborghinis standing on the brakes at 200 mph.

I'm thinking it's a moot point.

 

[1FZj80]

Would love to see FEA (Finite Element Analysis) on those lil bolts.
Momentum = Mass (6000#) x Velocity (70mph) that is a tremendous amount of shear stress.
There is no more important safety item on these trucks than brakes.

^^^Yes

The rotor/hat bolts will be ARP 8740 chromoly 200ksi bolts. And they are not in shear loading as it is not a sliding joint. It is a bolted rotor/hat assembly. The lil bolts are preloaded (torqued) to create friction in the hat/rotor joint. The rotor surface at the bolt hole is serrated to create friction. This joint resists shearing thru friction to transfer the load from the rotor to the hat/wheel hub. The rotor/hat setup allows compliance between a hot rotor and hat to reduce warping and is far superior to a single cast disc assembly. Safety is the reason I want to upgrade.

 

[Tapage]

I would love having this brake option in a bolt on kit for 60 and 80 series ...

 

[Hornd]

^^^Yes

The rotor/hat bolts will be ARP 8740 chromoly 200ksi bolts. And they are not in shear loading as it is not a sliding joint. It is a bolted rotor/hat assembly. The lil bolts are preloaded (torqued) to create friction in the hat/rotor joint. The rotor surface at the bolt hole is serrated to create friction. This joint resists shearing thru friction to transfer the load from the rotor to the hat/wheel hub. The rotor/hat setup allows compliance between a hot rotor and hat to reduce warping and is far superior to a single cast disc assembly. Safety is the reason I want to upgrade.

The bolts are 100% in shear unless the rotor portion is inset into the hat section.

Brakes turn kinetic energy into heat energy. The more mass to dissipate heat the better.
Are you comparing these to Carbon Fiber which is nothing the same?

http://www.tirereview.com/carbon-ceramic-rotors-boast-many-advantages-and-a-high-price-tag/

The OEM system will lock up my tires all day which means the tires to pavement is the limitation.

 

[dogfishlake]

The smaller rotor will overheat with prolonged braking force, then fade. They may be able to lock up, but that is not normal braking. When the rotor hat bolts are tightened, they are in stress and that pulls the hat and rotor together, essentially locking them together. There will be shear on the bolts as well, but not nearly as much because of the friction created by the hat and rotor being locked together.

 

[dogfishlake]

@1FZj80, I like what you are doing, keep it up. I would be very interested in this as well. Did you mod the stock hats, or make custom ones?

 

[1FZj80]

@1FZj80, I like what you are doing, keep it up. I would be very interested in this as well. Did you mod the stock hats, or make custom ones?

Thanks...

I used a oem brake disc to make a hat. The photo in my earlier post is the final product. An aluminum hat would be best, but they are not available in the aftermarket world for an 80 hub.

 

[Glenn-BJ74]

I have installed the Australian DBA 4x4 Survival rotors with 100 pads upfront and it stops on a dime

 

[jaymar]

I have installed the Australian DBA 4x4 Survival rotors with 100 pads upfront and it stops on a dime

Been looking at their slotted rotors. Good stuff!

 

[RDC76]

I have installed the Australian DBA 4x4 Survival rotors with 100 pads upfront and it stops on a dime

I have been running the same rotors (cant remember if I went T2 or T3 rotors at the moment)with hawk pads, with the same results. x2 for this reasonably priced setup. And I pull a 3500 trailer at times. follow the brake in procedure and properly bed the pads and she STOPS... And I roll on 35's.
Not to say I don't like what @1FZj80 has done. I do, its a superior setup. Nice work! just commenting on the other DBA users.

 

[jaymar]

No experience with Hawk, but on my radar; thanks for the info!

 

[TexasJack]

My reasoning is very simple. My truck weighs 6800 lbs today. I plan to add a roof top rack and roof top tent soon. That will put the truck somewhere around 7500 lbs. The vehicle was 4700 lbs off the lot and the brakes were built for a truck of that size, not 7500 lbs. If you doubt that, try stopping a 7500 lb truck in rush hour traffic with existing brakes. I leave a LOT of extra space between me and the vehicle in front of me these days. My truck is only used for hunting and wheeling for just that reason. If I could have a heavier, more capable braking system I would do so. As RhinoFZJ80 says above, I am probably going to get more aggressive pads sometime very soon.

 

[jaymar]

My reasoning is very simple. My truck weighs 6800 lbs today. I plan to add a roof top rack and roof top tent soon. That will put the truck somewhere around 7500 lbs. The vehicle was 4700 lbs off the lot and the brakes were built for a truck of that size, not 7500 lbs. If you doubt that, try stopping a 7500 lb truck in rush hour traffic with existing brakes. I leave a LOT of extra space between me and the vehicle in front of me these days. My truck is only used for hunting and wheeling for just that reason. If I could have a heavier, more capable braking system I would do so. As RhinoFZJ80 says above, I am probably going to get more aggressive pads sometime very soon.

ICON runs a super-beefy setup on their FJ44 models; redesigned Brembo brakes with six-piston calipers up front, four in the rear. Also hydro-boosted (for non-ABS). That stops REALLY fast. The catch is, they're also running 18-inch wheels. I'm happy with stock-size wheels--but if your main concern is braking (and your smallest concern is cost), that kind of setup might be something to look into, if the wheels and tires are strong enough for your loads.

 

[TexasJack]

I would prefer to keep the stock setup and just use better pads. I know that will mean changing the pads more often and I am OK with that. The ICON suggestion is a good option if I don't feel I am getting what I need from stickier pads.

 

[AutoCraft Aus]

I think Scott is onto it.

We went that route, bigger 14" rotor and use a bigger Toyota caliper as a bolt on set up.

I have struggled with bringing it to market though, because our carbon fibre pad and rotor upgrade work so well already on the later bigger 80 [and 100] brakes and you get to keep 16s. Ideally, you need good metallurgy rotors, and not be putting good pads onto rotors that have already had lesser pads running on them, as the metal gets impregnated with the poorer pads material, effecting the new pads.

The carbon fibre pads have a higher friction co efficient cold, than alot of the good pads have when up to temp.

The brakes become so good, if your suspension isnt good in the handling dept, it can move the vehicle around pretty savagely under hard braking, working the bushes if sft, the rear of the car going up and the panhard pushing it across, etc.

So make sure the rest of the truck is up to speed, if wanting to be able to pull up so hard, if you dont have your seat belt on, you wont be able to get off the brake pedal, from the G's.