Intermittent vibration at constant speed???

[T4RMatt]

I have noticed that my truck has developed a bit of a weird vibe. If I am going say 80 with the cruise control on or off, I will get an out of balance tire sensation intermittently. This happens with no visible change in road condition and no change in speed. I do not notice this problem on poured concrete road surfaces, but noticed it on asphalt roads all around knoxville, and all the way to winston-salem yesterday. Any thoughts? I am taking it to the dealership tomorrow morning but I am doubting they will be of much help.
Thanks
Matt

 

[biglatka]

I have noticed that my truck has developed a bit of a weird vibe. If I am going say 80 with the cruise control on or off, I will get an out of balance tire sensation intermittently. This happens with no visible change in road condition and no change in speed. I do not notice this problem on poured concrete road surfaces, but noticed it on asphalt roads all around knoxville, and all the way to winston-salem yesterday. Any thoughts? I am taking it to the dealership tomorrow morning but I am doubting they will be of much help.
Thanks
Matt

Take your foot off the gas at 80 and see if it goes away when coasting. This has been discussed before, do searches on helicopter sound and resonant vibration. I think it was finally agreed upon that it was a resonance problem, probably exhaust system. I had it, and it disappeared some time later. If it isn't gone when coasting, then it

 

[T4RMatt]

This is a slower vibration than the fast harmonic vibration we have discussed before. It does not seam to make a difference whether the truck is accelerating or holding a speed. It is very odd....you can be driving eighty with the cruise on and it will be smooth as can be and then all of the sudden it will shudder a bit. I am doubting that every paved asphalt road from here to NC has intermittent bumps spaced apart every fifteen seconds. I really feel that it must be the tires and be related to weight shifting etc, but I have not been able to isolate any circumstances it does this.

 

[T4RMatt]

Well the dealer of course would not drive it past the speed limit, which I can understand. I talked with the mechanic and he said that if it was driveline related that it would usually manifest itself at slower speeds than 80. He road force tested my tires (Dunlops) and said the most force they put out was 12lbs, which is very low. (Dunlops specs 34 as the acceptable limit) . He also said the tires were in good balance, but he tried balancing them all on a Hunter balancer to confirm. He was out of ideas......so am I. Anyone else have anything to throw out that I can check??? The truck has 29k on it and the tires are relatively new.

 

[lasallen]

I have driven two new Sports w/ V8 and they both did the same thing. The wheel viabrated at speeds from 40mph up.