Braking power

mbrockus

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Did the factory folks fill up the brake fluid reservoir? From the Service Manual CT uses DOT 4 BASF Hydraulan 404 (part number 1012041-10-C) is the approved brake fluid.
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Bartman

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brake fade? were you on a race track? There shouldn't be any fade under normal conditions.
Yes. Trucks have brake fade too. Can make a big difference, in stopping distance, after brakes get a little hot. And 60-0 braking distance is arguably more important that the 0-60 sprint time in a truck.
 

Joecool789

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Anyone have to do an emergency stop yet? Had to push the brakes fairly hard yesterday when a large object flew onto the highway causing traffic in front of me to suddenly stop and swerve. I had good follow distance at 70mph but did not have enough stopping power to avoid the car in slowing front of me that any of my previous cars would’ve easily avoided.

Luckily i was able to switch lanes before impact.

I will try to purposely make some hard stops later and see whats going on.
I got my truck exactly a week ago today, and in playing around with sport mode, I found myself overshooting my desired stopping zone. Not sure if it's because i was just not used to the truck yet, or if the stopping is just worse than my RAM 1500. Obviously, the weight of the CT plays a factor. However, I have been more cautious in my driving, and more aware of my distances, since my trial runs :)

Ive also noticed that at low speeds, the truck stops too easily, and I feel someone is going to rear end me with how fast it stops.
 

ModelC

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Yup must be a defect. Felt exactly like brake fade at the track but the cruising at 70mph on the highway is no track.

I know what brakes should feel like on high performance cars and trucks. Had em all. Ferrari’s to 3500 dualy trucks.
My other current car is a Landcruiser i built for taking off road. Full steel under armor, rock sliders, steel full roof rack, roof tent, steel swing out tire carrier. Basically It weighs as much or more than the CT and would have made the necessary stop.

I love the CT so far. No false narratives being created. Im just concerned that my CT may be defective. I pushed the brakes and not much braking was happening. Pushed harder and harder and nothing. Couldnt even make the wheels skid or ABS go off.

Maybe it was my driving position idk. I was pretty relaxed. But Im not new to driving. Probably the reason i was able to steer away before hitting.
Thanks for the detail and thoroughness. If you think they are defective can you set up an appointment for Tesla to check it and get their feedback, then come back here and inform us of what they say? That would be beneficial for all, so it eliminates wondering either way. Thanks
 


TwilightHan

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I tracked my Mercedes AMG GLE 63S Coupe. I also tracked the Mercedes AMG GT 4 Door Coupe at Laguna Seca raceway. They are both extremely heavy vehicles.

The GLE had normal steel brake rotors. The brake pads were a specific formula that only Mercedes uses under their brand name. I used OEM brake pads and they were not the same.

The GT 4 Door had carbon ceramic brake rotors and pads.

Both vehicles had stick summer tires on them.

Brake fade on normal rotors won't necessarily Fade on one stop. When you are going 140 in such a heavy machine and stomp on the brakes so you can hit the corner under 40mph, even the steel rotors can handle it. But if you don't let the brakes cool down properly before the next turn, including on the ceramic brakes, then you will feel the brakes fading or getting mushy. If you overdo it, your brake rotors and pads will be so hot that they are hotter than a volcano and nothing will engage. My OEM steel rotors typically turn orange after just 20 minutes on the track.

If you are brake properly, then a lot depends on the tires. With ATR tires, you will not be able to stop like you want because of the weight of the vehicle. The brakes will do their job, but the tires, all things being equal will be the limiting factor.

My recommendation from cheapest solution to expensive. 1. Plan ahead if you will be driving faster than normal. Look ahead down the road while being aware of your surroundings and expect the unexpected. 2. Change your tires to street tires. 3. Upgrade the rotors and brakes in case you do take it on the track or drive like a BMW driver on the roads.


My next recommendation is to go to the AMG Academy across the world and learn how to drive a vehicle. If it's raining on your track days, the better. You will really understand how to drive a vehicle and see its limitations, but mostly you will learn how to drive and learn the amazing capabilities vehicles actually have if you drive it correctly.
 
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Propernice

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I tracked my Mercedes AMG GLE 63S Coupe. I also tracked the Mercedes AMG GT 4 Door Coupe at Laguna Seca raceway. They are both extremely heavy vehicles.

The GLE had normal steel brake rotors. The brake pads were a specific formula that only Mercedes uses under their brand name. I used OEM brake pads and they were not the same.

The GT 4 Door had carbon ceramic brake rotors and pads.

Both vehicles had stick summer tires on them.

Brake fade on normal rotors won't necessarily Fade on one stop. When you are going 140 in such a heavy machine and stomp on the brakes so you can hit the corner under 40mph, even the steel rotors can handle it. But if you don't let the brakes cool down properly before the next turn, including on the ceramic brakes, then you will feel the brakes fading or getting mushy. If you overdo it, your brake rotors and pads will be so hot that they are hotter than a volcano and nothing will engage. My OEM steel rotors typically turn orange after just 20 minutes on the track.

If you are brake properly, then a lot depends on the tires. With ATR tires, you will not be able to stop like you want because of the weight of the vehicle. The brakes will do their job, but the tires, all things being equal will be the limiting factor.

My recommendation from cheapest solution to expensive. 1. Plan ahead if you will be driving faster than normal. Look ahead down the road while being aware of your surroundings and expect the unexpected. 2. Change your tires to street tires. 3. Upgrade the rotors and brakes in case you do take it on the track or drive like a BMW driver on the roads.


My next recommendation is to go to the AMG Academy across the world and learn how to drive a vehicle. If it's raining on your track days, the better. You will really understand how to drive a vehicle and see its limitations, but mostly you will learn how to drive and learn the amazing capabilities vehicles actually have if you drive it correctly.
lol. You dont think one of those recommendations should be go to Tesla and ask them to check It out because I think any car, whether its an AMG or a Toyota Prius should be able to lock up the tires when braking. However, in the described instance. My CT did not feel like it had any power to lock up the brakes or trigger ABS.

I should not have brake fade from cruising on the highway. Im not saying brake fade is the cause, im saying thats what it felt like.
 

TwilightHan

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lol. You dont think one of those recommendations should be go to Tesla and ask them to check It out because I think any car, whether its an AMG or a Toyota Prius should be able to lock up the tires when braking. However, in the described instance. My CT did not feel like it had any power to lock up the brakes or trigger ABS.

I should not have brake fade from cruising on the highway. Im not saying brake fade is the cause, im saying thats what it felt like.
I was sharing information that is not predominantly known with large vehicles and more extreme usage of the vehicle. Obviously if you feel it is out of the ordinary, yes, please don't let me stop you from doing the extremely obvious thing.

If it felt like brake fade, it's also possible you have issues in your brake lines. I am looking forward to the results as this is quite an issue.

Folks on the track who also do not use the right brake fluid will have their brake fluid boil and prevent their brakes from working, but I doubt this is the case in normal circumstances.

I had a Lincoln Navigator that would also feel like it's not stopping This was before I really understood vehicles and started doing all the maintenance work myself on the AMG for off-road and track usage. It may have been because the fluid was never replaced in 10 years. I had recurring nightmares I couldn't stop the vehicle and crash. Turned out those dreams were just what I was living through in real life.
 

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Anyone have to do an emergency stop yet? Had to push the brakes fairly hard yesterday when a large object flew onto the highway causing traffic in front of me to suddenly stop and swerve. I had good follow distance at 70mph but did not have enough stopping power to avoid the car in slowing front of me that any of my previous cars would’ve easily avoided.

Luckily i was able to switch lanes before impact.

I will try to purposely make some hard stops later and see whats going on.
On my first day with the truck, I had an experience that served as a valuable lesson. While attempting to demonstrate the vehicle's acceleration to my wife and son (by engaging in BEAST mode): we were already traveling at a moderate speed of 10-20 mph when a motorcyclist approached from behind (in the other lane). In the excitement of the moment, I accelerated as the motorcyclist was getting close. We definitely were ahead, but there was stopped trafic ahead. As we neared stopped traffic, I became acutely aware of the extended stopping distance. Despite applying full pressure to the brakes, the truck took noticeably longer to come to a complete stop. Fortunately, I managed to stop in time, albeit very close to the vehicle ahead. Needless to say, the motorcyclist was impressed and gave a thumbs up multiple times... lots of mixed emotions in that single moment. But it definitely served as a stark reminder of responsible driving. While I doubt that I will have this in the dashcam, I will review the footage nonetheless.

This incident also highlighted the importance of getting acquainted with a new vehicle's dynamics. Compared to my previous electric vehicles (Tesla Model 3/Model Y), this truck's increased weight necessitated a more cautious driving approach.

On another occasion, I did experiment with the truck's regenerative braking system, which I appreciate for its one-pedal driving capability in my TM3/TMY. It definitely takes longer for the vehicle to come to a stop.
 

Kuiper__Belt

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Yeah, but Urus weights 2000lbs less, has performance summer tires, and is also a Lamborghini, with brakes likely inspired by its siblings.

So I mean in comparison, not too bad for the CT.
lol yup good point. I have a buddy with a raptor and another buddy with I don’t know what it’s called but it’s at 700hp (I think) Ram we might have to do a breaking comparison once I get my cybertruck!
 


scottyah

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lol software was probably set up to go light when they weren't sure on the brakes and all the engineers knew to be safe while testing. Watch it be fixed in a software update about 'adjusting for better brake scaling' or something like that
 

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Yeah, but Urus weights 2000lbs less, has performance summer tires, and is also a Lamborghini, with brakes likely inspired by its siblings.

So I mean in comparison, not too bad for the CT.
I have actually suggested to Kyle Connor at Out of Spec that brake tests should be part of what he does. His subjective comments about the CT's disk brakes are concerning. It would be nice to see objective data.

The other concern he raised was the CT loosing regen on long downgrades, even when not towing. The Rivian had some issues but not as bad. The Lighting and Silverado EV had no issues with regen.
 

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Some interesting features of the Cybertruck brakes.


Brake Disc Wiping
When cold and wet weather is detected, brake disc wiping repeatedly applies an imperceptible amount of brake force to remove water from the surface of the brake discs.

Hydraulic Boost Compensation
Cybertruck is equipped with a brake booster that activates the brakes when the brake pedal is pressed. Hydraulic boost compensation provides mechanical assistance if the brake booster fails. If a brake booster failure is detected, the brake pedal feels stiffer to press and you may hear a sound when you press the brake pedal. To stop Cybertruck, apply steady force to the brake pedal without releasing or pumping. Drive cautiously and maintain a safe distance from other road users—brake pedal responsiveness and braking performance may be degraded.

Hydraulic Fade Compensation
Hydraulic fade compensation assists in monitoring brake system pressure and ABS activity for instances of reduced brake performance. If reduced brake performance is detected (for example, as a result of brake fade, or cold or wet conditions), you may hear a sound, feel the brake pedal pull away from your foot, and notice a strong increase in braking. Brake as you normally would and continue to press the brake pedal without releasing or pumping the brakes.
Warning
Always maintain a safe driving distance from the vehicle in front of you and exercise caution when driving conditions are hazardous. Brake disc wiping and hydraulic fade compensation are NOT substitutes for adequately applying the brakes.

Regenerative Braking
Whenever Cybertruck is moving and your foot is off the accelerator, regenerative braking slows down the vehicle and feeds any surplus power back to the Battery. By anticipating your stops and reducing or relieving pressure from the accelerator pedal to slow down, you can take advantage of regenerative braking to increase driving range.
Vehicle deceleration due to regenerative braking may vary depending on the current state of the Battery. For example, regenerative braking may be limited if the Battery is cold or is already fully charged.
To experience the same amount of deceleration whenever you release the accelerator pedal, regardless of the state of the Battery, you can choose to have the regular braking system automatically engage whenever regenerative braking is limited. Touch Controls > Dynamics > Apply Brakes When Regenerative Braking is Limited. When enabled, the brake pedal may move or feel stiffer when pressed. This is expected and does not change your ability to slow down Cybertruck.

Source:
https://www.tesla.com/ownersmanual/cybertruck/en_us/GUID-6DD1AA33-2FE0-44B0-93EA-17CF5BB80F76.html
 

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Thx for the heads up, like I do with my motorcycles I will take the CT and bed in the breaks with a few 60-0 stops - seat the pads, etc...and learn the stopping distances at the same time!

I have a 2500 with 35x12.5 AT Tires and it's never let me down towing 13k or stopping from 90mph, etc....so not like it's impossible to have a well sorted braking system on a heavy (8300lbs) vehicle!
 

truck

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I think the issue that everyone in this thread is facing is that they're pressing brake and accelerate at the same time. I have a huge issue with fat footing both, which is coded to reduce braking power.
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