Good vibrations or bad 60+mph harmonics
09-07-2013, 09:03 PM
#21
Rotors rarely warp. What is generally called warped rotors is uneven pad material transfer onto the rotors causing the pulsing while braking. No way is the uneven pad transfer enough to cause an imbalance in the rotor. Maybe if you have a sticky caliper you could feel it. If turning rotors helps it look at the parking brake or calipers sticking.
09-07-2013, 09:20 PM
#22
One Bad MoFoMoCo Owner
Rotors rarely warp. What is generally called warped rotors is uneven pad material transfer onto the rotors causing the pulsing while braking. No way is the uneven pad transfer enough to cause an imbalance in the rotor. Maybe if you have a sticky caliper you could feel it. If turning rotors helps it look at the parking brake or calipers sticking.
Did I say Dodge trucks suck?
09-09-2013, 02:05 PM
#24
09-09-2013, 04:29 PM
#26
Ford Customer Service
Hi all,
New member of the forum and new owner of a 2013 FX4 F-150 Supercrew 145" 3.55 gears Ecoboost 1000Km. Unfortunately I am one of the unlucky when it comes to highway speed vibration. Good news is the dealer is doing their best a trying to solve the problem.
Reading another forum (can't remember which one) I read about a technique to determine the harmonics at which your vehicle is vibrating. It involves downloading an application called "vibration" onto your Iphone or Ipad. Placing it on a surface in your vehicle (I used center console) and taking a sample. I did this to try and be a little more informed when taking it to the dealer. Although I never mentioned anything about doing it to them. They actually have their own vibration analyzer that probably does a way better job (MTS 4000?). Anyway attached is one of the samples I took.
I believe the culprit is the frequency the vertical cursor is on at 765 rpm or 12Hz. The other large spike on the right in the Y axis is at 2703 rpm or 45Hz. Now what is rotating at 765 rpm at highway speed? I have 20" scorpions, they rotate 652 rev/mile or 652rpm at 60mph. Doing one of those solve for x equations (60mph x 765rpm)/652rpm = 70.3mph was my speed or 112kph. As for the other spike at 2703 rpm, 2703rpm/3.55gears = 761 rpm. Close enough to the tire rpm so that spike seems to be the drive shaft. So I thought awesome it's the tires and drive shaft. I was wrong.
Dealer confirmed vibration:
balanced tires - still vibrated
rotated tires - still vibrated
swap out known good drive shaft and tires - still vibrated
further diagnosis required.
Am I screwed? Is it expected these trucks vibrate this much? Definitely not comfortable for a long road trip like this. Well at least that vibration application is pretty cool for showing me how my truck is vibrating.
New member of the forum and new owner of a 2013 FX4 F-150 Supercrew 145" 3.55 gears Ecoboost 1000Km. Unfortunately I am one of the unlucky when it comes to highway speed vibration. Good news is the dealer is doing their best a trying to solve the problem.
Reading another forum (can't remember which one) I read about a technique to determine the harmonics at which your vehicle is vibrating. It involves downloading an application called "vibration" onto your Iphone or Ipad. Placing it on a surface in your vehicle (I used center console) and taking a sample. I did this to try and be a little more informed when taking it to the dealer. Although I never mentioned anything about doing it to them. They actually have their own vibration analyzer that probably does a way better job (MTS 4000?). Anyway attached is one of the samples I took.
I believe the culprit is the frequency the vertical cursor is on at 765 rpm or 12Hz. The other large spike on the right in the Y axis is at 2703 rpm or 45Hz. Now what is rotating at 765 rpm at highway speed? I have 20" scorpions, they rotate 652 rev/mile or 652rpm at 60mph. Doing one of those solve for x equations (60mph x 765rpm)/652rpm = 70.3mph was my speed or 112kph. As for the other spike at 2703 rpm, 2703rpm/3.55gears = 761 rpm. Close enough to the tire rpm so that spike seems to be the drive shaft. So I thought awesome it's the tires and drive shaft. I was wrong.
Dealer confirmed vibration:
balanced tires - still vibrated
rotated tires - still vibrated
swap out known good drive shaft and tires - still vibrated
further diagnosis required.
Am I screwed? Is it expected these trucks vibrate this much? Definitely not comfortable for a long road trip like this. Well at least that vibration application is pretty cool for showing me how my truck is vibrating.
I replied to your PM and requested some information in order to assess what the next step is. I'll see what I can do.
Bianca
09-10-2013, 01:20 AM
#27
OP update - test drive new samples
I had the truck for a test drive today after the dealer replaced a bad tire. The vibration is better but it is still there. The vibration now comes and goes in waves, quite frequently. Below is a vibration analysis from before on the left and after on the right. To me it doesn't really say much has changed. The sweet speed is no longer 110kph its a little higher at 120 - 127kph. The sample on the right has more resolution as I increased the sampling frequency. The actual values of the spikes just beside the vertical cursor on the right are.
x = 0.024
y = 0.017
z = 0.020
I test drove another truck from a different dealer (same road) and it did not vibrate.
x = 0.024
y = 0.017
z = 0.020
I test drove another truck from a different dealer (same road) and it did not vibrate.
09-12-2013, 09:27 AM
#29
I will be taking the truck in next Thursday. I will make sure to mention tire balancing and warped rotors. Anything else i should mention for this issue? I will let everyone know my results.
Matt
Matt