Henry Ford
Well-known member
I was calling me a fancy boy.
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Jake24
Well-known member
- First Name
- Jake
- Joined
- Jul 4, 2024
- Threads
- 9
- Messages
- 146
- Reaction score
- 155
- Location
- Sicamous BC
- Vehicles
- '24 XLT Avalanche 9.6kW
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Whammy Bar
Well-known member
Lariat ER
The eibach kit totally fixes both of your pain points OP. I have the kit. 100% love it.
Behemoth60
Member
Ohh... suspension discussion. Now you are in my wheelhouse! Building off-road suspensions is my hobby. I have gone very deep into the world of suspension frequency, roll axis, instant centers, squat and dive, anti-sway, compression and rebound damping, and center of gravity. I literally do hands on design, build and tune suspensions for my personal 4x4's.
The speed at which the vehicle 'bounces' up and down is called Suspension Frequency. It is the most important factor in determining what feels like a 'smooth' ride. A Frequency of about 0.8 to 1 Hz is usually associated with a 'smooth' ride. Lower number, .5 or below, feels more jarring, like a race car. too high, like 1.4 or higher, and you feel like you are on a ship riding swells at sea. There is a sweet spot that humans call 'comfortable'. Not too surprisingly, it's about the frequency up and down motion while walking or jogging.
When you go fast, you want your wheels to respond fast so they stay in contact with the road. Hence sports cars tend to have high suspension frequency, at the expense of a 'harsh' ride.
Now, the secret is that suspension frequency is determined by the natural spring rate (i.e. how many newtons of force the spring exerts for every cm that it is compressed), and the total weight applying force on those springs. More weight = lower suspension frequency = smoother ride.
My Ram 5500 when driving around empty, is absolutely jarring. Put a 8,000lb Toyota Land Cruiser on the back, and she rides smooth as silk. Weight/SpringRate=Suspension Frequency. Easy.
Bu then there is the damping. Generally, you initially want small amount of compression damping, to allow springs to absorb bumps without the shocks pushing back too hard, and just enough rebound damping to let the wheel 'fall' back fast enough so the wheel stays in contact with the ground, but not so fast that it doesn't resist a second cycling of the suspension from the previous bump. It's a delicate balance, and the art is to 'Tune' the rebound and compression damping to a specific ride scenario (terrain and speed), but at the compromise of imperfect tuning at every other scenario.
So, knowing what I know, here's my evaluation of the F150 suspension. Clearly, the engineers have the suspension tuned to a 'smooth' feeling suspension frequency (about 0.8Hz I think - Perfect) , when the truck is riding empty, on paved city streets with speeds up to about 80kmph. Probably 90% of the driving that most people use their trucks for. Certainly, that's me. In that scenario, the ride is excellent.
The compromise is that when loaded, and at highway speeds (i.e. when towing my boat) , the tuning is now off, and the frequency is actually too long (almost 1 or 1.1) , and there is not enough rebound damping to prevent multiple cycles of the suspension. Those two things are what cause that "floating" feeling.
How do you fix that. Some companies sell 'tunable' shocks that allow you to dial in the compression and/or rebound damping. Increase the load, Increase the damping.
But that does not help with the frequency. You need air bags to change spring rate to compensate for changing load/weight. That's why Semi trucks use them everywhere. Massive changes in load.
I need to stop, this is way too long.
The speed at which the vehicle 'bounces' up and down is called Suspension Frequency. It is the most important factor in determining what feels like a 'smooth' ride. A Frequency of about 0.8 to 1 Hz is usually associated with a 'smooth' ride. Lower number, .5 or below, feels more jarring, like a race car. too high, like 1.4 or higher, and you feel like you are on a ship riding swells at sea. There is a sweet spot that humans call 'comfortable'. Not too surprisingly, it's about the frequency up and down motion while walking or jogging.
When you go fast, you want your wheels to respond fast so they stay in contact with the road. Hence sports cars tend to have high suspension frequency, at the expense of a 'harsh' ride.
Now, the secret is that suspension frequency is determined by the natural spring rate (i.e. how many newtons of force the spring exerts for every cm that it is compressed), and the total weight applying force on those springs. More weight = lower suspension frequency = smoother ride.
My Ram 5500 when driving around empty, is absolutely jarring. Put a 8,000lb Toyota Land Cruiser on the back, and she rides smooth as silk. Weight/SpringRate=Suspension Frequency. Easy.
Bu then there is the damping. Generally, you initially want small amount of compression damping, to allow springs to absorb bumps without the shocks pushing back too hard, and just enough rebound damping to let the wheel 'fall' back fast enough so the wheel stays in contact with the ground, but not so fast that it doesn't resist a second cycling of the suspension from the previous bump. It's a delicate balance, and the art is to 'Tune' the rebound and compression damping to a specific ride scenario (terrain and speed), but at the compromise of imperfect tuning at every other scenario.
So, knowing what I know, here's my evaluation of the F150 suspension. Clearly, the engineers have the suspension tuned to a 'smooth' feeling suspension frequency (about 0.8Hz I think - Perfect) , when the truck is riding empty, on paved city streets with speeds up to about 80kmph. Probably 90% of the driving that most people use their trucks for. Certainly, that's me. In that scenario, the ride is excellent.
The compromise is that when loaded, and at highway speeds (i.e. when towing my boat) , the tuning is now off, and the frequency is actually too long (almost 1 or 1.1) , and there is not enough rebound damping to prevent multiple cycles of the suspension. Those two things are what cause that "floating" feeling.
How do you fix that. Some companies sell 'tunable' shocks that allow you to dial in the compression and/or rebound damping. Increase the load, Increase the damping.
But that does not help with the frequency. You need air bags to change spring rate to compensate for changing load/weight. That's why Semi trucks use them everywhere. Massive changes in load.
I need to stop, this is way too long.
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