INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

new vehicle - how much vibration is acceptable?

new vehicle - how much vibration is acceptable?

(OP)
I noticed on my new SUV that there is a bit of vibration between 55 and 60 mph. I feel it both in the steering wheel and the seat. Is there a maximum vibration level that the manufacturers deem to be allowable at wheel hop frequency? I'm tempted to mount an accelerometer to the steering wheel just for fun.

RE: new vehicle - how much vibration is acceptable?

Not really. . I don't know how other manufacturers currently set targets, 20 years ago it would have been a case of somebody like me (NVH engineer) or a manager saying that's no good, fix it, whether on a prototype or a production car.

Most likely is one of your wheelweights has fallen off

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: new vehicle - how much vibration is acceptable?

(OP)
Thanks Greg - kind of nice know there's still subjective feel that's being used. A bit surprising though. I'd of thought that these days dealers would be required to road test each vehicle to some objective standard before letting the vehicle out the door.

RE: new vehicle - how much vibration is acceptable?

If you can feel it in the steering wheel, it is not acceptable of a new vehicle.

RE: new vehicle - how much vibration is acceptable?

(OP)
It is an SUV and the tires are low profile so I don't expect it to ride as smooth as a car. I haven't brought it back to the dealer yet. I suspect their mechanic will say the vibration level is "normal". I'd love to go in with accelerometer data and tell them it's above the "limit". That's why I was hoping there was some sort of quantifiable vibration limit.

My fault though. When I test rode the vehicle I mentioned the vibration to the salesman sitting in the passenger seat. He said "...we just had a memo on that. For these vehicles, the sitting around not being driven for awhile is causing flat spots on the tires. They'll go away...".

RE: new vehicle - how much vibration is acceptable?

Was just expressing my own expectations smile

RE: new vehicle - how much vibration is acceptable?



Can you double integrate and throw the signal thru a frequency seive?

Maybe something along the line of curve b in Fig 2 here?

http://www.indofork.com/environment.htm

Probably have to measure pith accel point tangent to the wheel rim, vertical and ???.

RE: new vehicle - how much vibration is acceptable?

Greg,

In response to your comment, "People's sensitivity varies by about 5 dB, the goal of the manufacturer is to satisfy some percentage of the buyers, not all of them.". I would like to ask:

In your experience, would you say people's sensitivities can change over time, depending on what they are exposed to? For example, someone who has driven premium cars all his life will be more likely to notice the OP's noise issue than someone who has only ever driven beetles. Or is this variance bio-mechanical, depending on the different states of the ears of the people driving?

RE: new vehicle - how much vibration is acceptable?

Both. People's innate sensitivity varies, just as hearing acuity varies, and then there is a learned response, and then there are expectations. It's a complex field, papers by MJ Griffin are a good place to start.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: new vehicle - how much vibration is acceptable?

Rotate the tires front to rear and see if you still get the same vibration. If not, then one (or both) of the front wheel/tires is out of balance and/or out of round.

RE: new vehicle - how much vibration is acceptable?

(OP)
I finally brought the vehicle in. I figured I'd wait for the first recall and get everything fixed. The mechanic said both the right side tires were out of balance. The ride is much better now.

The alarming thing for me was that the mechanic said it's not unusual for the new cars to need to have the tires/wheels balanced. Yikes, that might be it for me buying American made SUVs.

RE: new vehicle - how much vibration is acceptable?

Dealer service is paid for by the dealer's markup. Less service = more profit.

RE: new vehicle - how much vibration is acceptable?

We had a CRV in storage for almost a year, and it was bumpy for a LONG time; I think we actually wound up getting all new tires to get rid of the bumpiness.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close