Shake or Vibration Issues

TheFactor · September 19, 2015

5 ounces too much from the factory on one wheel? Are you kidding me? Even 1 ounce out total will cause very noticeable vibration at high speeds. Who balances the wheels at that factory? Looks like someone just slapped on 3 oz worth of weights in the wrong position on the wheel to give it that much imbalance. But I wonder if they balanced those wheels right at the dealership too.

If I saw that a passenger car/truck wheel is out by 5 ounces I would immediately suspect that the tire or the rim is junk or someone really just slapped on some weights to make it look like they balanced the wheels.

Is this a chrome clad wheel? If yes, you should never cone the wheel in the front on the balancer, otherwise the cone will catch the cladding first and not center the wheel properly. Rear cone of collet, plus rubber protected pressure cup wing nut is the least acceptable. Rear mounted spacer, collet plus a flange plate in the front would give the best results. Collets are simply short centering sleeves with very low taper, and they are frequently used on high end cars like Mercedes and BNMW for proper balancing, together with Haweka flange plates that hold the wheel by the lug nut holes.

Here is a COUPLE OF short videos showing use of Haweka flange plates to achieve the best balancing results:

As you may have noticed, the balancers in the video do not have road force variation measurement capability. Zeroing on only on reducing road force variation numbers and using inferior mounting techniques will not produce good balancing results. On the other hands, using good quality tires and properly balancing them will more than likely produce very good results without measuring the road force variation. Unfortunately many techs out there simply think that there is some magic in measuring road force that will be a cure-all for all vibration problems. There is no substitute for proper mounting technique and high quality components used with the balancers. BTW, Haweka products are German made. I do not have any affiliation with that company and I do not sell any wheel balancing products. I am merely recommending what is the best on the market in my opinion. Because of high cost of high end products like these, not too many tire shops carry them. A set of adjustable Haweka plates alone costs about $ 3000. Then about $ 1000 for a decent set of collets. For comparison, a regular cone set is about $ 250 per set of four, plus about $ 250 for a good quality pressure cup wing nut and most tire shops will therefore use the traditional cones only.

Great post BTW !

As far as his wheel being off 5oz I would imagine that could of easily happened if he threw a weight and not necessarily had a bad balance when the tires were installed .

Edited September 20, 2015 by TheFactor

pm26 · September 20, 2015

Great post BTW !

As far as his wheel being off 5oz I would imagine that could of easily happened if he threw a weight and not necessarily had a bad balance when the tires were installed .

Stick on weights do not come off easily and 5 ounce one piece weights are common only on large trucks and buses. 3.5 ounce (100 grams) per side is pretty much a practical limit for a light truck tire . If it needs more weight than that, the tire is probably of very poor quality. I have seen this on cheap imported trailer tires.

TheFactor · September 20, 2015

Stick on weights do not come off easily and 5 ounce one piece weights are common only on large trucks and buses. 3.5 ounce (100 grams) per side is pretty much a practical limit for a light truck tire . If it needs more weight than that, the tire is probably of very poor quality. I have seen this on cheap imported trailer tires.

Interesting didn't realize that and thanks for the insight [emoji106]

Sent from my iPhone 6 using Tapatalk

Edited September 20, 2015 by TheFactor

Wrench589 · September 20, 2015

Engine/Trans angle +4.5 degrees, driveshaft +3.5, and pinion angle was -2.6 degrees. The 2 degree put the angles amost exactly the same but this increased the vibration during the acceleration due to the fact that the pinion rotates up when you hit the gas. I did not expect it would be that much. So rotating the pinion angle up to a +0.0 angle will not help at all.

Lost me on the "Engine/Trans angle". The engine and transmission are bolted together, with 0 deg angle between shaft centrelines. What does your +4.5 deg angle represent?

And, when your refer to "driveshaft" and angle, you mean the working angle between the output of the transmission and the driveshaft? And you mean the "pinion angle" is the working angle between the driveshaft and the pinion, right?

And, refresh my memory on the sign convention: which way is "+" and which way is "-"?

Thx.

taps929 · September 20, 2015

Anyone try adding a fourth bar to the leaf spring assembly yet? Just curious. This forum repeats the same info over and over so haven't seen by skimming.

curver900 · September 21, 2015

well it has been a while sense I posted up. So as a follow up so far about 1000 miles sense they fixed it, it is still fixed. I was over 80 this weekend.. and I was shocked when I looked down.. I really thought I was only going 65 or so... so lucky for me I am all fixed.. I am heading to Utah for a 4wheelin' trip so for sure will get to put on a boatload more highway miles...

I still have the crappy LS/2's on it but so far so good... I hope they can figure out how to fixe the rest of these that are broke...

3 tires, 1 new rearend, RF balanced to less then 10lbs per tire.. i think the threshold is 16 or 15.. but mine vibrated at that balance...

abominable z71 · September 21, 2015

Lost me on the "Engine/Trans angle". The engine and transmission are bolted together, with 0 deg angle between shaft centrelines. What does your +4.5 deg angle represent?

And, when your refer to "driveshaft" and angle, you mean the working angle between the output of the transmission and the driveshaft? And you mean the "pinion angle" is the working angle between the driveshaft and the pinion, right?

And, refresh my memory on the sign convention: which way is "+" and which way is "-"?

Thx.

My understading and anyone that feels different please chime in. A positive angle is when the portion towards the front of the vehicle is higher then the rear. In fires case +4.5 for the engine & tranny means the output shaft on the tranny is pointing down 4.5 degrees (centerline points down towards the rear) +3.5 on the drive line, the driveline pionts down towards the rear at 3.5 degrees creating a working angle of 1 degree between the transmission and driveline with the 1 degree difference being an open angle on the bottom side. Basically a \/ in the side view. A -2.6 angle on the pinion I would think and fire can confirm that the front of the pinion is pointing down at 2.6 degrees. This would create a working angle of 6.1 degrees also in a \/ side view which in theory would vibrate like crazy because the angles compound to 7.1 and don't cancel unless the pinion rotates significantly under power. If he meant 2.6 degrees with the front of the pinion pointing up the working angle would be .9 degrees with a side profile /\ and the two angles would almost cancel each other at .1 degrees.

My measurements were +3 transfer case, +1.4 drive line +.8 pinion with working angles of 1.6 \/ front and .6 \/ rear with a difference of 2.2 degrees . I added 2 degree shims to the rear and the results was +3 tcase +1.3 driveline +2.2 pinion. working angles 1.7 \/ front .9 /\ rear. This just created a worse vibration, so perhaps the static working angles need to be significantly out to compensate for spring wrap and acceleration and so forth. I'm going to pull the shims and possibly flip them around and tip the pinion down and see what that does.

On a different note I pulled the front CV axles and replaced them with outer stub shafts to test and the vibration was not changed, pointing back the rear end and most likely the ring and pinion. Next weekend the rear end is getting opened up and inspected. Probably should have checked there first.

Jesse Davidson · September 21, 2015

has anyone done the water bottle test and noticed the water acts in the sine wave around the edge? I took video today, as my truck goes in again tomorrow. the video was too big to upload here, so here are the links to them on youtube.

76 MPH (8-9 s in)

lighter constant vibe almost always exhibited by the truck (the worst feeling of it is in the steering wheel and the pedals, but it is still felt in the seats and floor to a lesser degree)

As I have mentioned before, I also have rough idle in the 4.3 V6 (I will take and post a video during the day today), and terrible AM & FM radio reception, I basically only listen to XM as that is all that works. neither of these videos take into account the terrible AFM Vibration that the truck has and GM refused to do anything about. Before making this appointment for my truck they specifically said they wouldn't take it if it was related to the AFM because that is "normal".

Edited September 21, 2015 by Jesse D

longhorn_cop · September 21, 2015

So here is my story.

I bought my '15 GMC SLT CC in April 2015. 22" Stock rims. . Little vibration but tolerable. Rotated the tires at 7500 and damn thing vibrated at low speed then shook like crazy st 70-75. Craziest thing I ever saw.

I put whells/tires back to preroation locales and back to mild vibration. Crazy!

Its at the dealership now getting checked out. Any suggestions on what else I need to have the services guys check? Anyone have this issue?

Sent from my iPhone using Tapatalk

Jesse Davidson · September 21, 2015

So here is my story.

I bought my '15 GMC SLT CC in April 2015. 22" Stock rims. . Little vibration but tolerable. Rotated the tires at 7500 and damn thing vibrated at low speed then shook like crazy st 70-75. Craziest thing I ever saw.

I put whells/tires back to preroation locales and back to mild vibration. Crazy!

Its at the dealership now getting checked out. Any suggestions on what else I need to have the services guys check? Anyone have this issue?

Sent from my iPhone using Tapatalk

Sent from my iPhone using Tapatalk

that one actually sounds like excessive road force on the tires. have the roundness checked

EastCoast HD · September 21, 2015

has anyone done the water bottle test and noticed the water acts in the sine wave around the edge? I took video today, as my truck goes in again tomorrow. the video was too big to upload here, so here are the links to them on youtube.

76 MPH (8-9 s in)

lighter constant vibe almost always exhibited by the truck (the worst feeling of it is in the steering wheel and the pedals, but it is still felt in the seats and floor to a lesser degree)

As I have mentioned before, I also have rough idle in the 4.3 V6 (I will take and post a video during the day today), and terrible AM & FM radio reception, I basically only listen to XM as that is all that works. neither of these videos take into account the terrible AFM Vibration that the truck has and GM refused to do anything about. Before making this appointment for my truck they specifically said they wouldn't take it if it was related to the AFM because that is "normal".

Different dealer?

Maybe this time around they will check your rear ring and pinion specs.

fireaxxe · September 21, 2015

My understading and anyone that feels different please chime in. A positive angle is when the portion towards the front of the vehicle is higher then the rear. In fires case +4.5 for the engine & tranny means the output shaft on the tranny is pointing down 4.5 degrees (centerline points down towards the rear) +3.5 on the drive line, the driveline pionts down towards the rear at 3.5 degrees creating a working angle of 1 degree between the transmission and driveline with the 1 degree difference being an open angle on the bottom side. Basically a \/ in the side view. A -2.6 angle on the pinion I would think and fire can confirm that the front of the pinion is pointing down at 2.6 degrees. This would create a working angle of 6.1 degrees also in a \/ side view which in theory would vibrate like crazy because the angles compound to 7.1 and don't cancel unless the pinion rotates significantly under power. If he meant 2.6 degrees with the front of the pinion pointing up the working angle would be .9 degrees with a side profile /\ and the two angles would almost cancel each other at .1 degrees.

My measurements were +3 transfer case, +1.4 drive line +.8 pinion with working angles of 1.6 \/ front and .6 \/ rear with a difference of 2.2 degrees . I added 2 degree shims to the rear and the results was +3 tcase +1.3 driveline +2.2 pinion. working angles 1.7 \/ front .9 /\ rear. This just created a worse vibration, so perhaps the static working angles need to be significantly out to compensate for spring wrap and acceleration and so forth. I'm going to pull the shims and possibly flip them around and tip the pinion down and see what that does.

On a different note I pulled the front CV axles and replaced them with outer stub shafts to test and the vibration was not changed, pointing back the rear end and most likely the ring and pinion. Next weekend the rear end is getting opened up and inspected. Probably should have checked there first.

You explained it correctly and looking at the angles you have you may have to point the pinion down a bit more. Also check the thrust angle.

14silverado4.3 · September 21, 2015

With a driveshaft angle, do the vibrations happen at any speed.

I am good until about 70, anything above that gets "shaky".

Getting better tires cured a lot of the road "noise" I was picking up all over the place. It also took care of the steering wheel vibration, the Wrangler SRA may be too light and thin picking up every imperfection in the rode.

Again above 70 is still a problem, did anyone look at motor or transmission mounts as a problem source?

curver900 · September 21, 2015

So here is my story.

I bought my '15 GMC SLT CC in April 2015. 22" Stock rims. . Little vibration but tolerable. Rotated the tires at 7500 and damn thing vibrated at low speed then shook like crazy st 70-75. Craziest thing I ever saw.

I put whells/tires back to preroation locales and back to mild vibration. Crazy!

Its at the dealership now getting checked out. Any suggestions on what else I need to have the services guys check? Anyone have this issue?

Sent from my iPhone using Tapatalk

Sent from my iPhone using Tapatalk

RF all 4 tires... this seems to be an issue with the tires everytime they get rotated they cause vibrations... Why who knows why ? it is just plain weird... happened to me... even moving from front to rear the vibe stuck around... after they RF'd all 4 tires again then it was good as gold... even the SM was in disbelief that it worked...