Vibration 70-80mph after balancing numerous times and getting an alignment

[GIjoe]

Thanks, let me take a look to see if I see anything like this. You think low air pressure could cause an issue? I have tires set at exactly 35psi in all corners.

I have the same size on 18” methods at 35psi and I’m as smooth as can be.

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[kishorejoseph]

Jack the truck up so tire is just barely off the ground and spin it. If it’s out of round you’ll see it and it’ll get hung up on the ground. I had a similar issue and after several balancings at DT I did this and found 2 were out of round. They replaced them and now I’m smooth as silk. I would’ve thought they would have checked this but obviously they did not.

Oh perfect, I can definitely try this.

 

[Big Dog Daddy]

Are the wheels your using hub centric or are you using the plastic centering spacers? I ask this because the plastic centering rings wear out and have a tendency to leave the wheel in a position slightly out of concentricity to the hub. Thus causing in inbalance at speed even though the wheel / tire assembly is balanced perfectly,

 

[kishorejoseph]

Did you measure your rear driveshaft u-joint angles after installing the Deaver rear leaf springs to see if your pinion angle needs to be adjusted?

I just checked this, I’m seeing 6.5 degrees at the u-joint connecting to the transfer case and 5.9 degrees where it connects to the rear differential. Safe to say this is not the issue since the difference is 0.6 degrees?

 

[kishorejoseph]

Jack the truck up so tire is just barely off the ground and spin it. If it’s out of round you’ll see it and it’ll get hung up on the ground. I had a similar issue and after several balancings at DT I did this and found 2 were out of round. They replaced them and now I’m smooth as silk. I would’ve thought they would have checked this but obviously they did not.

Tried this as well and they all seemed to be even.

 

[kishorejoseph]

Not always obvious. Just go take a look at them, and if one has a lot of wheel weights on it, more than the others, it could well be bent or have a flatspot.

All 4 wheels actually seem to have a lot of weights on them. I even found one wheel with a weight from a previous balance done at a different shop (it’s black compared to the new silver ones). Did they forgot to take off, should I try taking that one off? I figured they just balanced with that weight there so it should be fine.

 

[RickBullotta]

All 4 wheels actually seem to have a lot of weights on them. I even found one wheel with a weight from a previous balance done at a different shop (it’s black compared to the new silver ones). Did they forgot to take off, should I try taking that one off? I figured they just balanced with that weight there so it should be fine.

Sounds like they tried to do their best. Does one wheel have noticeably more than any of the others?

 

[kishorejoseph]

Are the wheels your using hub centric or are you using the plastic centering spacers? I ask this because the plastic centering rings wear out and have a tendency to leave the wheel in a position slightly out of concentricity to the hub. Thus causing in inbalance at speed even though the wheel / tire assembly is balanced perfectly,

They are hubcentric!

 

[Antimatter22]

My Limited has a noticeable vibration around 80mph. It's very small at 75. My truck isn't modified. I plan on getting the stock wheel road force balanced when I take it to the dealership in a couple weeks.

Interested to see if you find anything. I don't recall having the vibration when I first got the truck. I have had a couple weird situations when performing aggressive braking caused a couple of "slam" noises under the cab during ownership. Never figured out what it was from but I'm wonder if it's related to the vibration I'm having. Truck drives fine under 80.

 

[kishorejoseph]

My Limited has a noticeable vibration around 80mph. It's very small at 75. My truck isn't modified. I plan on getting the stock wheel road force balanced when I take it to the dealership in a couple weeks.

Interested to see if you find anything. I don't recall having the vibration when I first got the truck. I have had a couple weird situations when performing aggressive braking caused a couple of "slam" noises under the cab during ownership. Never figured out what it was from but I'm wonder if it's related to the noise I'm having. Truck drives fine under 80.

I had the same slam noise a couple times in the middle of this but it has not come back since. I’m not sure if that’s got anything to do with the vibration either.

 

[SALEEN961]

I just checked this, I’m seeing 6.5 degrees at the u-joint connecting to the transfer case and 5.9 degrees where it connects to the rear differential. Safe to say this is not the issue since the difference is 0.6 degrees?

I normally aim for having the rear diff nose down 1° from perfectly even operating angles when measuring the driveline at rest and it sounds like your pinion is 0.6° nose up, correct?

The idea behind putting the pinion 1° nose down is that as the pinion climbs up under load the angles should be close to even.

If I'm interpreting your measurements correctly and your pinion is slightly nose high, you could improve the angles by getting a 1.5° shim to set your resting u-joints angles to roughly 7.4° at the pinion and 6.6° at the transfer case output.

If you have someone you really trust, you can measure the angles again while your truck is running in gear. Have your helper load your driveline by hitting the throttle and brake at the same time to simulate the load your driveline would see at 70-80mph, 1500RPM in drive should be a good target for this. This will help you by showing exactly how much your pinion climbs under load with your aftermarket leaf springs.

 

[kishorejoseph]

Sounds like they tried to do their best. Does one wheel have noticeably more than any of the others?

So went to take a look closer, I can’t tell the actual weight but this is what I saw.

FR - ~20 weights
FL - ~20 weights
RR - ~10 weights
RL - ~30 weights

 

[RickBullotta]

So went to take a look closer, I can’t tell the actual weight but this is what I saw.

FR - ~20 weights
FL - ~20 weights
RR - ~10 weights
RL - ~30 weights

30 individual stick on weights???Thats a lot.

 

[RickBullotta]

So went to take a look closer, I can’t tell the actual weight but this is what I saw.

FR - ~20 weights
FL - ~20 weights
RR - ~10 weights
RL - ~30 weights

Maybe a pic of the worst one?

 

[kishorejoseph]

30 individual stick on weights???Thats a lot.

Yeah, 30 or so individual but stuck on together in like 2 rows.

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