Driveline vibration with Caltracks?

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dieselduck

New member
Just installed Caltracks on my 06 QCSB Ram. Two days later I put 4 new BFG A/T's (305/65/17 E rated) on the truck. I only drove it maybe 5 miles around town with the Caltracks before the new tires and didn't notice anything, but around town I don't notice anything with the BFG's either. Now I have a vibration, feels like from the rear. It kind of "pulses" off and on at 60-70MPH, you can feel it through the floorboard. I am guessing it's the solid Aluminum front bushing used with the Caltracks? Anyone else have an issue with this? I have been playing with tire PSI and Caltrack adjustment trying to find some thing that works, not much luck so far. Could be tires, but I don't really think so.
 
I have caltracs on mine and have never had any vibration.
Did you adjust them when all fours were on the ground.
 
Blueboy; Yes all 4 were on the ground. I re adjusted them with about .100 air gap, and it vibrates less, but still vibrates.

Supershafts; You talking about the drive shaft? If so why/how would that get out of balance? After 70, I did some runs up to 90 and didn't notice anything, but I just ran it up and coasted back down. It is the worst @ steady speeds, and I do notice it in town now @ 30-40mph as well.

I have sent Calvert an e-mail and am awaiting a response.
I will try to call them monday if I have time.
 
Both of my vehicles have caltracs on them and neither have any out of the ordinary vibrations like your describing.
 
I get that same groaning! pulsation on and off sound on the highway too.. I don't have caltracs... Mine seemed to start after installing my turbo's and MBPR muffler.. I bet its the tires causing your... I have had it for at least 10k miles but, sometimes it does not happen. Seems more like a droning/vibration..
 
dieselduck said:
Supershafts; You talking about the drive shaft? If so why/how would that get out of balance? After 70, I did some runs up to 90 and didn't notice anything, but I just ran it up and coasted back down. It is the worst @ steady speeds, and I do notice it in town now @ 30-40mph as well.
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The vibe you're describing is that of a shaft out of balance. . .

A small weight could have fallen off, many things can cause a shaft to develop a small issue.

If you have a slight vibe at 30 to 40 and it stops and then reintroduces itself again from 60 to 70 and again just vanishes that is in the shaft.
Check for a missing weight or something, maybe a joint.

A caltrac even set on kill shouldn't have any vibe issues and then it would be solving a severe angle vibe that would only be noticed under loads.

Steady cruising harmonic drones are usually always a balance issue, sometimes, very rarely the sign of a joint wanting out.

.
 
I checked the drive shaft and all the weights are still on it, no sign of any change in the driveshaft.
I pulled the Bars off completely, drove it, same thing.
Logically I would expect some "roughness" to transfer though the solid bushings, or why else would the factory use rubber mounts?

Interestingly @ 40-50 the vibe is very light, but steady, and @ 60-70 it pulses.

While I was under the truck I noticed the wheel weights on the rear tires.
There is 2 1.75oz together and a .5oz located about 20 degrees radially from the other 2 weights. Front of the same rim has a 1oz/.75oz/1oz cluster of weights. So 6.75oz all together on that tire, the other rear has a little less total weight, but almost identical setup as far as placement. Both front tires have much less weight, like 3-4oz total.

I am going to take it back to the dealer and have them pull the rear and re-spin them on their balancer, to see if they are balanced correctly.
I will let you know what I find out.
 
Supershafts said:
The vibe you're describing is that of a shaft out of balance. . .

A small weight could have fallen off, many things can cause a shaft to develop a small issue.

If you have a slight vibe at 30 to 40 and it stops and then reintroduces itself again from 60 to 70 and again just vanishes that is in the shaft.
Check for a missing weight or something, maybe a joint.

A caltrac even set on kill shouldn't have any vibe issues and then it would be solving a severe angle vibe that would only be noticed under loads.

Steady cruising harmonic drones are usually always a balance issue, sometimes, very rarely the sign of a joint wanting out.

.
Click to expand...


Damn, the other driveshaft builder in the crowd just stole my thunder. The only thing i have to add, is that the only thing that makes me doubt its the driveshaft is the fact that the problem appeared more or less directly after the tires were installed. Maybe rotate the tires with more weight up front and see if it feels different.

What does the truck have in it for a driveshaft? 2 piece or single piece?
 
1pieceatatime. said:
Damn, the other driveshaft builder in the crowd just stole my thunder. The only thing i have to add, is that the only thing that makes me doubt its the driveshaft is the fact that the problem appeared more or less directly after the tires were installed. Maybe rotate the tires with more weight up front and see if it feels different.

What does the truck have in it for a driveshaft? 2 piece or single piece?
Click to expand...

Single pc driveshaft.

Truck is @ the Dealership right now they are going yo look things over tomorrow. BTW service guy agreed that 7oz was a lot of weight for a Name brand 33" tire. Said they would break the tires down and spin them on the rim to try to balance them out with less weight.
 
Dealer rebalanced the 2 rear tires. Said they were out, they added even MORE weights. The pulsing vibration is gone, but I still have a roughness vibration that you can feel through the floorboard and seat. I would compare it to slightly lugging a manual trans truck, not shaking, but just starting to notice the vibe, if you know what I mean.

The drivers rear tire has weights on it in the shape of a Y. If you drew a big Y offset it a few inches that is how the weights are on this rim. Let me be clear the weights are almost equally spaced in 3 places roughly 120 degrees apart. I have never seen a tire balanced this way. The inside looks the same as the outside. The passenger side rear has more as well and now has a gap between weights on the outside. 6.75oz on one 8 on the other.

The dealership wants me to spend another $60 to have them "Road Forced Balanced", said this would also be able to tell if any of the tires are bad.

I'm kind of mad that they want me to pay for this when they know there is an issue here.

You guys with Caltracks, did you notice any kind of difference with the Caltracks vs. without, as far as road noise or roughness???

I think I have at least 1 bad tire, but I am also thinking that this might be a combo of things, including the solid mount spring bushings.


Your Thoughts?
 
Knoberman said:
Sounds like you need a new tire dealer
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It's the local GMC dealer. I have known several guys there for years now, I don't know what is going on. I am obviously getting the brush off. They don't have this new balancer, so they have to take the tires somewhere to have it done. I am disappointed that they can't make the call that the one tire is bad, or at least contact BFG about things. Seems they want someone else to confirm a problem before they take any action.

My $.02
 
dieselduck said:
Dealer rebalanced the 2 rear tires. Said they were out, they added even MORE weights. The pulsing vibration is gone, but I still have a roughness vibration that you can feel through the floorboard and seat. I would compare it to slightly lugging a manual trans truck, not shaking, but just starting to notice the vibe, if you know what I mean.

The drivers rear tire has weights on it in the shape of a Y. If you drew a big Y offset it a few inches that is how the weights are on this rim. Let me be clear the weights are almost equally spaced in 3 places roughly 120 degrees apart. I have never seen a tire balanced this way. The inside looks the same as the outside. The passenger side rear has more as well and now has a gap between weights on the outside. 6.75oz on one 8 on the other.

The dealership wants me to spend another $60 to have them "Road Forced Balanced", said this would also be able to tell if any of the tires are bad.

I'm kind of mad that they want me to pay for this when they know there is an issue here.

You guys with Caltracks, did you notice any kind of difference with the Caltracks vs. without, as far as road noise or roughness???

edit: The solid bushings are probably just putting you more in touch with the tire problem.

I think I have at least 1 bad tire, but I am also thinking that this might be a combo of things, including the solid mount spring bushings.


Your Thoughts?
Click to expand...

dieselduck said:
Anybody had this Road force balancing done? Results?
Click to expand...
I get none of the issues you describe from my caltracs.

Yes, Road Force balancing is the way to go, but it still won't take care of junk tires. That is a bunch of weight you have on them already.

Quite honestly, it sounds like you have a bad tire or two. BFG has not been known for their quality control the last few years. You likely have one that isn't quite round. The amount of weight you have on those tires already is indicitive of an out of round tire or bent wheel. In your case, I'd put money on a bad tire or two.
 
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No problem with Caltrac's on the road or hwy. I do remember that I went through 5 bad BFG's to get a good set of 4 from the dealer about 4 years ago. They just couldn't get them to eliminate the vibration at hwy speed. I finally ordered a set of Centramatics to relieve the last bit of vibration for good. Best $50 per wheel I've spent and they stay on the hub so each new set of tires get the extra fine tuning.[ame="http://www.youtube.com/watch?v=skY6qvzpNXI&feature=player_embedded"]Centramatics[/ame]
 
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