Contact US

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.

Students Click Here

Passenger vehicle Bumpy ride.

Passenger vehicle Bumpy ride.

Passenger vehicle Bumpy ride.

Hi all

When a vehicle ride is said to be bumpy in a very good road condition, can i say that shock absorber damping co-eff to be increased to reduce it? But the Damping of the Shock absorber theoretically matched to give a comfortable ride.
Wat else could cause this in general?

Thanx in advance


RE: Passenger vehicle Bumpy ride.

Tyres or wheels being non concentric with axle.

Tyre walls having hard and soft spots.

Tyres or wheels being out of balance.

pat   pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Passenger vehicle Bumpy ride.

Many of the problems indicated by Pat can be the result of poor inflation.  My 4Runner's tires got VERY lumpy after running underinflated for a while


RE: Passenger vehicle Bumpy ride.


Depends what you mean by 'bumpy'. What sort of vehicle is it, and might it have been 'modified' by some previous owner who thinks that rock hard suspension makes you go round corners quicker?

Harsh, jarring ride (even on a good surface) can be caused by seized dampers, or over-firm adjustment of dampers or hard springs. Low profile tyres increase harshness, too.

Could be any of the tyre problems Pat mentions but the bump will be very regular (every 2 metres or so, depending on the rolling circumference of the tyres).

Increasing damper forces will help if the 'bumps' are long, slow, high amplitude inputs from a wavy surface. Otherwise, in my opinion, it will make things worse.

Cheers - John

RE: Passenger vehicle Bumpy ride.

Thanx all..
Well, the vehicle is a minibus (7.5Ton GVW) brand new vehicle.
By bumpy ride i mean the vehicle oscillates up & down once it crosses a bump..
Should i increase the shock absorber damping.. if so is there any rule to relate suspension stiffness & damping?/ (Its a rigid axle suspension-Shackle ended)


RE: Passenger vehicle Bumpy ride.

That is not, typically, described as a bumpy ride.

Anyway, yes, you should look at the shock absorber tuning, but you might also find a mismatch between the front and rear axle spring rates as well.

Check out Olney's book on ride and handling for a description of the 'flat ridw' criterion and related subjects.


Greg Locock

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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