Some interesting lessons on getting rid of front end vibration
#1
11-23-2010, 09:53 PM
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Some interesting lessons on getting rid of front end vibration
Well, I seem to have licked 95% of the front end shake. It took a couple of months, many new parts, and numerous alignments. But I learned some interesting things, so figured I'd share. Also some lessons on larger tires and wheels
I have an 05, that came with the stock 16" wheels and 245 tires on them. When I bought it, it had 17x8 wheels and 265/65-17 tires, which are a stock size also. It had a bit more than 90,000 miles when I bought it.
There were a variety of different vibrations in the front end, and it turned out that I had to peel them away, one at a time, fix them one at a time, and then go back for more. It also had what I could describe as warbling, where the steering wheel was always moving side to side, especially on the highway.
Wheel Balance: I did this several times, and each time, it changed the behavior, but never really got rid of the shakes. I ultimately asked the guys at Firestone in town to do the entire RoadForce balance, to see if the tire/wheel was either out of round, or mismatched. Turns out they were fine, but the weights needed to be adjusted (after the 4th time doing it)
Ball Joints: Turned out that I had 1 lower that had to be replaced, the others were still tight and silent.
Shocks: This made a SEMINAL change in the truck. It turns out that a majority of the noises and instability in the chassis were radically improved by changing the shocks/struts and the upper strut mount. It also nearly wiped out the warbling of the steering, and finally returned stability to the steering wheel. (I used the Monroe shocks BTW)
Alignment: This step was pretty important. I had it aligned 5 times in the past 2 months. I watched most times, as I was curious what effects it had. This is important, as the Dakota has a sensitive front end as we all know. Most alignment machines have a tolerance range for what is "acceptable alignment". This range does not seem to be good for our trucks, especially with oversized tires. There needs to be some precision.
On my truck in particular, Caster settings needed to be absolutely precise to the factory numbers. Caster is supposed to be 3.5 degrees with a .05 degree variance. Not only is caster a challenge to set correctly on our trucks, but the machines don't necessarily measure it correctly. Camber also needs to be pretty precise, but not as tight as caster. Caster also needed to be exactly symmetrical for the warbling to stop (the machines don't tell the tech to make them symmetrical!)
Also, if you've ever either done an alignment or watched it being done on an upper/lower control arm vehicle, it takes time, and you need to go back and forth over and over again, while adjusting caster, then camber, then back and do it again.
Toe needs to be set last most of the time, and if caster and camber were off, then toe will be out substantially in most cases. The steering wheel needs to be centered and the car rolled and bounced before the toe is set.
The last time I had it aligned, the tech was patient, and we went back and forth 5 times before caster and camber were correct. Caster was set to exactly 3.5 degrees on both wheels ( the machine incorrectly gave asymmetrical caster settings, which I asked him to ignore.) The truck now goes straight down the road, with no wander, warbling, or shaking. The steering wheel is straight, and the front end is stable.
Conclusion:
After 2 months of working on the front end, it is nearly perfect, with no vibration, wandering, warbling or bouncing in normal driving. There is a very very mild vibration in the high 70s, and I believe this is because the alloy wheels need spacers to align them correctly around the brake rotor hub circle. Just relying on the lug nuts to align the wheel assembly correctly is not sufficient in my estimation.
I have an 05, that came with the stock 16" wheels and 245 tires on them. When I bought it, it had 17x8 wheels and 265/65-17 tires, which are a stock size also. It had a bit more than 90,000 miles when I bought it.
There were a variety of different vibrations in the front end, and it turned out that I had to peel them away, one at a time, fix them one at a time, and then go back for more. It also had what I could describe as warbling, where the steering wheel was always moving side to side, especially on the highway.
Wheel Balance: I did this several times, and each time, it changed the behavior, but never really got rid of the shakes. I ultimately asked the guys at Firestone in town to do the entire RoadForce balance, to see if the tire/wheel was either out of round, or mismatched. Turns out they were fine, but the weights needed to be adjusted (after the 4th time doing it)
Ball Joints: Turned out that I had 1 lower that had to be replaced, the others were still tight and silent.
Shocks: This made a SEMINAL change in the truck. It turns out that a majority of the noises and instability in the chassis were radically improved by changing the shocks/struts and the upper strut mount. It also nearly wiped out the warbling of the steering, and finally returned stability to the steering wheel. (I used the Monroe shocks BTW)
Alignment: This step was pretty important. I had it aligned 5 times in the past 2 months. I watched most times, as I was curious what effects it had. This is important, as the Dakota has a sensitive front end as we all know. Most alignment machines have a tolerance range for what is "acceptable alignment". This range does not seem to be good for our trucks, especially with oversized tires. There needs to be some precision.
On my truck in particular, Caster settings needed to be absolutely precise to the factory numbers. Caster is supposed to be 3.5 degrees with a .05 degree variance. Not only is caster a challenge to set correctly on our trucks, but the machines don't necessarily measure it correctly. Camber also needs to be pretty precise, but not as tight as caster. Caster also needed to be exactly symmetrical for the warbling to stop (the machines don't tell the tech to make them symmetrical!)
Also, if you've ever either done an alignment or watched it being done on an upper/lower control arm vehicle, it takes time, and you need to go back and forth over and over again, while adjusting caster, then camber, then back and do it again.
Toe needs to be set last most of the time, and if caster and camber were off, then toe will be out substantially in most cases. The steering wheel needs to be centered and the car rolled and bounced before the toe is set.
The last time I had it aligned, the tech was patient, and we went back and forth 5 times before caster and camber were correct. Caster was set to exactly 3.5 degrees on both wheels ( the machine incorrectly gave asymmetrical caster settings, which I asked him to ignore.) The truck now goes straight down the road, with no wander, warbling, or shaking. The steering wheel is straight, and the front end is stable.
Conclusion:
After 2 months of working on the front end, it is nearly perfect, with no vibration, wandering, warbling or bouncing in normal driving. There is a very very mild vibration in the high 70s, and I believe this is because the alloy wheels need spacers to align them correctly around the brake rotor hub circle. Just relying on the lug nuts to align the wheel assembly correctly is not sufficient in my estimation.
Last edited by nanohead; 11-23-2010 at 09:56 PM.
#6
12-02-2010, 08:19 AM
Join Date: Sep 2010
Location: New Jersey
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I should have the spacers installed some time in the next week. Hopefully, this will fix the final tiny bit of vibration.
FYI, the spacers do something fairly important. Aftermarket Alloy wheels have a center hole cut very large in most cases, so they can fit around most rotor/hub assemblies, with a center protruding hub. In most cases, we rely on the tapered lug nuts to align our wheels to the center of the hub/bearing assembly. Well, that is probably a lousy assumption, as the lug nuts and wheels are not precise.
The OEM wheels are manufactured with the precise inner diameter hole so it lines up precisely with the rotor/drum center protruding hub, or plinth. What happens if you don't have precise center alignment is the wheel mounts concentric to the center-line and therefore vibrates. I believe this is whats happening to my truck.
Most wheel balance machines will balance the wheel/tire assembly based on the centerliine mounting (ie the little cone shaped thing that they put through the center of the wheel). Alternatively, you can use the lug nut stud hole mounting flange for the balancing machine, but this won't necessarily solve the problem, as it still doesn't know the center-line and it still doesn't guarantee that the lug nut/studs are in the proper place.
Even if you use a sophisticated RoadForce protocol when balancing your tire/wheel assembly, it still doesn't guarantee it will behave properly on the truck, if you have an aftermarket wheel that has a larger center circle.
FYI, the spacers do something fairly important. Aftermarket Alloy wheels have a center hole cut very large in most cases, so they can fit around most rotor/hub assemblies, with a center protruding hub. In most cases, we rely on the tapered lug nuts to align our wheels to the center of the hub/bearing assembly. Well, that is probably a lousy assumption, as the lug nuts and wheels are not precise.
The OEM wheels are manufactured with the precise inner diameter hole so it lines up precisely with the rotor/drum center protruding hub, or plinth. What happens if you don't have precise center alignment is the wheel mounts concentric to the center-line and therefore vibrates. I believe this is whats happening to my truck.
Most wheel balance machines will balance the wheel/tire assembly based on the centerliine mounting (ie the little cone shaped thing that they put through the center of the wheel). Alternatively, you can use the lug nut stud hole mounting flange for the balancing machine, but this won't necessarily solve the problem, as it still doesn't know the center-line and it still doesn't guarantee that the lug nut/studs are in the proper place.
Even if you use a sophisticated RoadForce protocol when balancing your tire/wheel assembly, it still doesn't guarantee it will behave properly on the truck, if you have an aftermarket wheel that has a larger center circle.
#7
12-02-2010, 09:20 AM
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#8
12-02-2010, 08:23 PM
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I should have the spacers installed some time in the next week. Hopefully, this will fix the final tiny bit of vibration.
FYI, the spacers do something fairly important. Aftermarket Alloy wheels have a center hole cut very large in most cases, so they can fit around most rotor/hub assemblies, with a center protruding hub. In most cases, we rely on the tapered lug nuts to align our wheels to the center of the hub/bearing assembly. Well, that is probably a lousy assumption, as the lug nuts and wheels are not precise.
The OEM wheels are manufactured with the precise inner diameter hole so it lines up precisely with the rotor/drum center protruding hub, or plinth. What happens if you don't have precise center alignment is the wheel mounts concentric to the center-line and therefore vibrates. I believe this is whats happening to my truck.
Most wheel balance machines will balance the wheel/tire assembly based on the centerliine mounting (ie the little cone shaped thing that they put through the center of the wheel). Alternatively, you can use the lug nut stud hole mounting flange for the balancing machine, but this won't necessarily solve the problem, as it still doesn't know the center-line and it still doesn't guarantee that the lug nut/studs are in the proper place.
Even if you use a sophisticated RoadForce protocol when balancing your tire/wheel assembly, it still doesn't guarantee it will behave properly on the truck, if you have an aftermarket wheel that has a larger center circle.
FYI, the spacers do something fairly important. Aftermarket Alloy wheels have a center hole cut very large in most cases, so they can fit around most rotor/hub assemblies, with a center protruding hub. In most cases, we rely on the tapered lug nuts to align our wheels to the center of the hub/bearing assembly. Well, that is probably a lousy assumption, as the lug nuts and wheels are not precise.
The OEM wheels are manufactured with the precise inner diameter hole so it lines up precisely with the rotor/drum center protruding hub, or plinth. What happens if you don't have precise center alignment is the wheel mounts concentric to the center-line and therefore vibrates. I believe this is whats happening to my truck.
Most wheel balance machines will balance the wheel/tire assembly based on the centerliine mounting (ie the little cone shaped thing that they put through the center of the wheel). Alternatively, you can use the lug nut stud hole mounting flange for the balancing machine, but this won't necessarily solve the problem, as it still doesn't know the center-line and it still doesn't guarantee that the lug nut/studs are in the proper place.
Even if you use a sophisticated RoadForce protocol when balancing your tire/wheel assembly, it still doesn't guarantee it will behave properly on the truck, if you have an aftermarket wheel that has a larger center circle.
The rims should have included alignment rings to prevent this. It eats up the space and ensures the wheel is aligned.