Vibration question

[Chryco Psycho]

Typically vibrations that ast like that are tire / wheel or driveshaft vibrations
 you could try a hose clamp or 2 at each end of the drive shaft & move the worm gear to different postions around the drive shaft to see if it changes the vibe

[Bearcuda]

Also check for any irregular tire wear patterns caused by lack of rotation or alignment issues. Slight feathering on the tires could even cause a vibe at that speed.

[moper]

Typically vibrations that ast like that are tire / wheel or driveshaft vibrations
 you could try a hose clamp or 2 at each end of the drive shaft & move the worm gear to different postions around the drive shaft to see if it changes the vibe

 
You should be able to make it come and go lower in rpm that way. It sounds like a driveshaft a hair out of balance, but tires can do it too. Also, make sure the tires are high speed balanced. The shop wont spin to 110 I think "normal" speeds are 40mph on a balancer. That may not be good enough for your speeds.

[Bearcuda]

High speed balance is a misnomer. Balanced are balanced as long as they are done right. A lot of our customers try and complain about the speed of our balancer when they see how slow it goes with the road force roller on it. I try and explain the same thing to them.

[moper]

Well, I'd respectfully disagree. A tire that is perfectly in balance, you are right about. Most tire shops I watch (and I have several I deal with all the time) dont have the equipment to spin the tires that fast. It's for safety and efficiency. Most cars will not spend their time cruising with wheel speeds in excess of 100mph. Centrifical force will increase the "felt" weight exponentially as the tire's rpm increases to 3-4 times the tested rpm. A tire in balance at 120mph is in balance at 40. A tire in balance at 40mph may not be in balance at 120. I dont think the pressure exerted on the tread will change the weighting. It might change the way the tire reacts at speed, but the masses involved dont change. Just the shape of that mass.

[Bearcuda]

Well, I have been dealing with balance issues first hand for 15 years and that how the Hunter balancer salesmen explain it too. I had to go to a special class just for our balancer with road force capabilities. We are the only shop in a 200 mile area that has one and many dealers have brought vibe problems to me that I have fixed.

[moper]

Then I defer to you sir  .

We didnt have that fancy stuff when I started dealing with these issues. And I've never seen one either...lol. I've also learned how much a good salesman is worth.

[Bearcuda]

I just reread my post. I didn't mean to come off all superior sounding. It's just that I've dealt with these issues for some time now. Sorry for sounding rude about it.

[moper]

Not rude at all. And I wasnt "typing sacrcastic". I feel you know more than I do about it...lol. I learned something from the thread. That's why we're all here.

[Bullitt-]

Could be a slightly out of balance tire being magnified by harmonics. As the slight deflection of the suspension recovers IF the out of balance point is in phase at that moment the next deflection is increased, as speed is increased it goes back out of phase & becomes less noticeable.

[Bearcuda]

Could be a slightly out of balance tire being magnified by harmonics. As the slight deflection of the suspension recovers IF the out of balance point is in phase at that moment the next deflection is increased, as speed is increased it goes back out of phase & becomes less noticeable.

Your views are intriguing to me and I wish to subscribe to your newsletter.

[Bullitt-]

Your views are intriguing to me and I wish to subscribe to your newsletter.

I'll admit it's a long shot. SEND Dollar &  A SASE to..... 


my concept comes from watching out of balance washing machines as the speed up there is always a point that they shake like crazy (hopefully at very low speed) before smoothing out & the phase thing is the reason.

[Bearcuda]

 

[tactransman]

Your views are intriguing to me and I wish to subscribe to your newsletter.

I'm in too!

[Chryco Psycho]

the other balance problem can be pinion angle , if the nose of the diff is too high it will vibrate