The Stovebolt Site Forums The Shop Area Engine Shop Vibration at highway speeds

I have a 57 with stock drivetrain and suspension. I have Firestone radials that have less than 5,000 miles on them. 235 with 3 speed. Truck gets a vibration at 60 miles an hour. Today I passed a car at about 65 -68 she really shook. Up to 58 miles an hour it is just fine. I do have plenty of peddle left at 60. Any ideas? I have bought new u joints as I thought that might be it, just haven't had a chance to replace them yet. I did replace all four shocks, and man does it handle a lot better. Shocks were really worn out.

First thing, did it vibrate before the new tires. Has anything else changed that could cause this. I would start by checking all of the front axle parts. Tie rod ends, drag link, king pins, wheel bearings, shocks. Have the alignment checked. Also check the drive shaft, are the u-joints worn?

57thekid,

I usually go with the law of averages and that means the tires. A lot depends on what you classify as a vibration and where you feel it.

A vibration in the steering wheel usually points the fickle finger of fate at a front tire...or worn steering components.

A seat of the pants vibration would be a rear tire...or a drivline component on its way out.

Physically inspect the tires for splits, bumps or tumors. Jack the front end up and do a wiggle test.

If you have disposable income, take it to a tire shop and say...spin the suckers please! Good luck.

Stuart

It has always done this since I have had this truck. I think it is aligned, shocks are new. No problems at all till I get to 60 or above. My guess is to take a look at the u-joints.

I don't think I have a tire problem. Vibration really feels like the whole truck is shaking. I don't really feel it in the steering wheel.

hello.
i have a 57 also, and all new front suspension parts, king pins, newer tapered style tie rod ends, etc, but i also get a shake at 60mph. i jacked up my front end just until the tires were barely off the ground, and spun each front tire and found my drivers side tire is way out of round, like by 3/8 of an inch. so i suspect this is my problem,a nd will find out when i get my new front rims and tires in about a month.

also, believe it or not, i once had a 1970 mustang, got 4 new tires and had the front end all rebuilt. at about 60mph it would shake very violently,a nd i couldnt figure it out.
well, my dad told me to check the tires as i described above, but found that i had a way out of round BACK tire.
took it to a tire shop that trued tires, (its like a lathe machine that cuts rubber off to true it up), and after that it ran perfect.
so even an out of round rear tire can cause the entire truck to shake.
down here they dont true tires anymore, for some reason. if you have an out of round tire, you will just have to replace it.

hope this helps.

leonard

Bent wheel?

Check the lug nuts for looseness. Could also be a bent wheel or out of round tire. I can tell you that Firestones are bad about having heavy spots in them, especially thir truck tires. Another thing to check is runout of the mounting flanges of the axle shafts and front hubs. If there's too much runout, it will cause a vibration. Alignment has been mentioned, and while it is a good idea for maximum tire life, alignment will not cause or cure a vibration.

Check your U-Joints in the drive shaft.

Put the back tires on the front and see if you can feel a difference.

i have a similar problem in my truck, and am not meaning to hijack the thread, but what exactly should i look for when checking the u-joints?

Changed u-joints, rear was bad. Made guite a difference. Now at higher speeds, I can feel just a little shake,will check tire balance. Man, whoever changed them before beat the heck out of the yokes. We had to do some repair work to do it right.

Jack up the rear end & put stands under the axle. Let the weight down on the axle. Remove the rear wheels. Put nuts back on the drums or pull the drums. Run it up to 60-65 in high gear & see if you still get the vibration. You might check the engine/trans mounts & pinion angle.

What should I look for when checking engine/trans mounts? And being the shade tree mechanic I am, what do you mean by pinion angle.
Thanks!

Pinion angle is a little more complicated to check than most things. You might want to have a shop do it.

Basically, the rear end of the transmission tail shaft is probably not going to be at the same height as the input to the rear end, so the drive shaft has to run down at an angle from transmission to rear axle. Oddly enough the angle of the rear end input shaft is usually not horizontal. It will usually be angled upward 4 or more degrees toward the front of the truck. I've always assumed that this is to reduce torque effects, but maybe someone can give us the real reason.

A big related problem is driveshaft U-joint phasing. For an explanation a lot better than I can give, check http://en.wikipedia.org/wiki/Universal_joint in the Angular Velocity section.

If someone has buggered up your drive shaft, such as replacing yokes, this might be a problem.

Bent wheels have been a problem for me. My 1973 Chevy C-30 had some unusual wear on the tires when I bought it, so I went to the local truck tire place to get some new ones. They noticed that both of my front wheels were bent, quite noticeably. The symptom was a shake in the front end between 47 and 55 mph. It was fine at all other speeds.

I just read the thread on wheels and tires. That is one problem I have had also. I adjusted my steering column to tighten her up a little. I think I am getting a lot closer but am wondering that the fact I have a wider tire than normal in front is affecting the steering and leading to the vibration. Truck has P225/70515's on front and back. Any thoughts?

HMMM, your comment on the beat up yokes leads to a ? of a driveshaft out of balance??? or a yoke on the trans or rear that is bent out of alignment????
that may be your culprit...PREVIOUS OWNER SYNDROME!!!!

Yes, I was wondering that too. Also previous owner had paint the drive shaft very heavy with black paint.

i just replaced my u joints the other day and my vibration is now gone!! man i was so stoked driving down the road. that thing was smooth as butter no matter how fast i was going. its a good thing i just changed them rather than taking the driveshaft to get rebalanced which i was just about to do haha. thanks for the help.