New chapter to my driveline vibrations

[Skandocious]

With regard to the wheels/tires...

Have you tried rotating your tires, to see if that changes the vibration any?

Obviously not a solution, but it may help narrow down the problem somewhat, and if not- hey, you've got your tires rotated.

Yeah they've been rotated several times, never seemed to show any changes but its tough to tell. The vibration doesnt seem to come from a specific place...

 

[john112deere]

Neither does mine...but if you put the rear tires on the front, it all of a sudden comes up straight through the steering wheel.

But I already kinda knew those tires weren't balanced right. Good thing I get to take 'em off in another few weeks when it's done snowing.

 

[Skandocious]

Neither does mine...but if you put the rear tires on the front, it all of a sudden comes up straight through the steering wheel.

But I already kinda knew those tires weren't balanced right. Good thing I get to take 'em off in another few weeks when it's done snowing.

Yeah I'm not worried too much about it. I'm going to have the tires balanced and rotated next weekend so until then I'm not going to be doing anything to the truck.

 

[Old_Paint]

Vibration above 40 will be more wheel balance related than anything else. Below 40, they're just not rotating fast enough for balance to be an issue. On smooth new pavement at < 40mph, if there is a roundness issue, and it's significant enough, you'll feel a slow loping more like a vertical wobble. You might even feel some vibration from the tread if it's an aggressive tread. Get it above 40, though, and yes, it'll have a harmonic associated with it, i.e., it will fade at some speeds, and be more prominent at other speeds, but typically at some fixed speed interval. Notice the speeds where you feel the vibrations. Sometimes an eccentric tire will throw off balance if it's severe enough, and the balancer is run fast enough. The problem is, the heavy weight is on the low side of the tire to offset the high side of the tire.

Been there, done that with OE tires on my old 'Bird which shook like a wet dog at 30 mph on smooth pavement. That's when I found out from Firestone (sorry for my language) that there are different tolerances for OE tires versus retail tires. I.E. the OE tires are basically seconds. The eccentricity tolerances for an OE Firestone (again, sorry for using the F word) tire are nearly .100 greater than those for retail tires. Long story longer, Firestone only warranted 1 out of 4 tires, despite all 4 were right at OE limits. Odds are, if they're bargain tires, they won't be very round, especially large tires. You get what you pay for. That said, in the "old days" when a new tire was mounted by a tire shop, they would TRUE them first by slicing off the high spots, THEN balance them. What you had then was a ROUND rolling surface, and a well balanced tire/wheel assembly. Smooth as silk. Those machines have gone the way of the dodo, however, and nowhere have I found any tire shops that still do that. They all claim tires are perfectly round. Well, maybe they were when they came outta the mold. But air them up the first time, and stretch the plies in them a little, and who knows what shape they take. Tires are pressurized in the molds, but the molds prevent them from distorting. There would be no way to mount and pressure test every tire coming off a tire assembly line. I've done service work for Michelin/BF Goodrich/Uniroyal (all in the same plant) and i've SEEN how tires are made. It ain't as precise a science as I would prefer considering my life depends on that rubber between me and the road. But, faced with the alternative of different rubber (shoe soles), I'll live with what tire manufacturers make.

A bit o trivia to conclude this. Know what the TA means in BF Goodrich Radial TA? Tuscaloosa, Alabama. The tire was designed there.

 

[Skandocious]

Tim, you're always a wealth of info. What do you think my best plan of attack is if I want to get these tires analyzed to the minutia? I'm not sure telling Les Schwab "make sure to check these for roundness" is going to be that effective... Is there a specific procedure I should request or watch for?

 

[blacksnapon]

Theres a piece of electronic equipment available called "EVA" (electronic vibration analyzer). Any shop that has one of these will be able to pinpoint the vibration for you. One of our classes for Ford, is NVH class (noise, vibration, and harshness). We used an eva to diagnose vehicles that were bugged. The eva, used in conjunction with a program called "vibrate", is what we used.

 

[Blue Goose]

Theres a piece of electronic equipment available called "EVA" (electronic vibration analyzer). Any shop that has one of these will be able to pinpoint the vibration for you. One of our classes for Ford, is NVH class (noise, vibration, and harshness). We used an eva to diagnose vehicles that were bugged. The eva, used in conjunction with a program called "vibrate", is what we used.

Eva, hell that's the same unit Ryan had trouble with...

 

[john112deere]

For those of us who don't got fancy toys...

Find a buddy with a truck that's got the same bolt pattern on the wheels, and doesn't shake.

Swap wheels and give 'er hell. Tell you for sure whether it's in the tires.

 

[blacksnapon]

Eva, hell that's the same unit Ryan had trouble with...

Its probably just as expensive!

 

[surewhynot]

Did eva find Ryans vibration?

 

[Skandocious]

Theres a piece of electronic equipment available called "EVA" (electronic vibration analyzer). Any shop that has one of these will be able to pinpoint the vibration for you. One of our classes for Ford, is NVH class (noise, vibration, and harshness). We used an eva to diagnose vehicles that were bugged. The eva, used in conjunction with a program called "vibrate", is what we used.

Funny you mention that Vince. I was following a Rotella EVA on ebay a couple weeks ago. It sat at around $15 for a while and I was ready to nab it, then it jumped up over $100

What kinda shop would have an EVA at hand?



Oh and Brad.... Now I know why your parents named you Brad... They were thinking about how BAD you were while in a snow storm...

"This....brrrr... kid is gonna be ... buh buh buh brrrrrr.... ad. BRAD!"

 

[Blue Goose]

Did eva find Ryans vibrator?

Corrected for accuracy...

 

[O'Rattlecan]

reps for the original funny brad made, and a banning for post 72.

Ryan

 

[surewhynot]

BURN!

And from an admin, no less.

 

[Skandocious]

Lol, I second that notion. Reps. Brad made a funny!!!

 

[TheRoadVirus]

I second that!!

 

[blacksnapon]

I would say, any high end shop (an EVA can cost upwards of $1000). Many places wont spend that kind of money on one (our dealership included). It measures the frequency of the vibration. Then with that figure, the program "vibrate" narrows it down. You input tire diameter, diameter of harmonic balancer, w/p pulley, alt pulley, a/c pulley. Diameter of driveshaft, rear end gear ratio, and vehicle speed. The program then tells you where the vibration is.

 

[surewhynot]

Did you notice that Brad is a splendid one to behold?
(hover your pointer over his rep dots)

I feel bad for whoever be holding him...

 

[Skandocious]

I would say, any high end shop (an EVA can cost upwards of $1000). Many places wont spend that kind of money on one (our dealership included). It measures the frequency of the vibration. Then with that figure, the program "vibrate" narrows it down. You input tire diameter, diameter of harmonic balancer, w/p pulley, alt pulley, a/c pulley. Diameter of driveshaft, rear end gear ratio, and vehicle speed. The program then tells you where the vibration is.

Yeah I know all about it. I was actually reading up a lot about the whole process of using an EVA to get the data then entering it into a computer program. The website I was reading it from is the Vibrate Software website, which I believe is the company that manufactures the Vibrate software that you're talking about. Sure wish I could afford it all

http://www.vibratesoftware.com/

 

[blacksnapon]

The instructors would do things like, putting stick on weights inside the water pump pulley, use hose clamps to attach weight to the driveshaft, they even had one that they removed the weight from a flywheel, then reinstalled it.