SpeedTalk Store - Opinion Columns

SUV ROLL DAMPENING

Open

Moderator: Team

Re: SUV ROLL DAMPENING

Postby Olefud » Thu Oct 06, 2016 11:07 am

Brian, agreed. The subject SUV was maybe a year old unibody Nissan. These have a pretty high CG. With such CG the roll couple between the CG and tires is controlling in terms of rollover but dampening the roll around the suspension roll center will control the buildup of roll oscillation.
Olefud
Pro
Pro
 
Posts: 323
Joined: Thu Feb 21, 2013 11:37 am
Location: Boulder, CO

Re: SUV ROLL DAMPENING

Postby Keith Morganstein » Thu Oct 06, 2016 3:57 pm

Crash statistics show the modern late model SUV to have lowest fatality rate of passenger vehicles.
Keith Morganstein
Guru
Guru
 
Posts: 4821
Joined: Sun Feb 19, 2006 10:19 am
Location: MA

Re: SUV ROLL DAMPENING

Postby Olefud » Thu Oct 06, 2016 4:58 pm

Keith Morganstein wrote:Crash statistics show the modern late model SUV to have lowest fatality rate of passenger vehicles.


That was our experience. Seat belts and airbags do wonders. An experienced driver helps.

What about crash data per se?
Olefud
Pro
Pro
 
Posts: 323
Joined: Thu Feb 21, 2013 11:37 am
Location: Boulder, CO

Re: SUV ROLL DAMPENING

Postby Zmechanic » Thu Oct 06, 2016 9:06 pm

Yes, underdampened suspension can enhance oscillations in driving just like any feedback loop. Only difference is the human is the controller. If the controller is too simple (unexperienced) it cannot handle this. You must train your brain to behave like a PID loop to keep everything going stable if you don't want the oscillations to grow. The PID loop was actually developed by watching experienced seaman pilot ships...
Zmechanic
Member
Member
 
Posts: 196
Joined: Wed Oct 24, 2012 8:33 am
Location: Austin, TX

Re: SUV ROLL DAMPENING

Postby Brian P » Fri Oct 07, 2016 3:05 pm

Keith Morganstein wrote:Crash statistics show the modern late model SUV to have lowest fatality rate of passenger vehicles.


And there are a few factors in that ...

1. Universal application of ESP (stability control). These systems are calibrated to whatever the stock suspension calibration is, and no matter how badly the suspension works, ESP will do whatever it can to keep the rubber side down and the front out front. Result ... fewer fishtails, fewer spins off the road, and thus, fewer roll-overs. This makes a biiiig difference. It doesn't mean the underlying suspension is any better, the ESP just makes it work.

2. Most of them have been transitioning to unibody construction with a designed-for-the-purpose layout as opposed to being based on pickup truck frames. And this is coming hand in hand with much better design for crash protection.

3. Demographics. These are for the most part family vehicles driven by people who, demographically, have the lowest crash risk. Fortysomethings give or take. Same situation as minivans.
Brian P
Guru
Guru
 
Posts: 1137
Joined: Wed Jan 02, 2008 7:35 pm
Location: Toronto, Ontario, Canada

Re: SUV ROLL DAMPENING

Postby pdq67 » Fri Jan 06, 2017 7:41 pm

TTT just for the heck of it..

He, He!!

And once while driving AP Green's Ford LN-7000 diesel powered Gunning Truck through the country coming home from a job, I topped a hill and lo-and behold, there was almost a 90 degree curve at its bottom!

I had that big old truck up on 3 wheels before I got around the curve!!

Scared me almost to death!!

I slowed down after that.

In fact, I turned the BSM Plastic Gunning Machine that I had been using on the job over... 18' box van....

pdq67
pdq67
Guru
Guru
 
Posts: 6678
Joined: Thu Mar 04, 2010 8:05 pm

Previous

Return to General Discussion

Who is online

Users browsing this forum: No registered users and 2 guests