Thread: Sway Bars

Originally Posted by rammypluge

Fitting very thick front anti-roll bars is the main trick for avoiding rollovers, plus these days esp settings. Shame that these can create other undesirable and sometimes dangerous qualities.

Main trick is dont do what that guy done in the video in any car, ever!

Any examples of dangerous ESP interference?

Originally Posted by manic

Main trick is dont do what that guy done in the video in any car, ever!

Any examples of dangerous ESP interference?

Esp slows down the turning process primarily by braking the outer front wheel.

I would rather avoid a truck and then roll over, than hit the truck.

At least one car during evasive testing had such severe esp interference that it temporarily popped the bead on the outside front tyre. Freaky. (Did they avoid the truck?).

I have seen one dashcam vid where a car tries to avoid running into the rear of another car, and just doesnt quite make it, possibly due to esp. It runs up the rear bodywork and tyre of the hatchback in front, which causes it to roll.

I did some repeated handling assessment of my own car around a particular corner (after a suspension tweak). I pushed it harder and harder each time. I found that it started squealing sooner than i expected. A friend then pointed out that the outside front tyre looked to have accelerated and odd wear. I think its likely that esp was the cause.

Esp is not for drivers, for people that have advanced car control skill. You dont appoint two prime ministers, it just creates a very confused and dysfunctional heirarchy of control. In a situation where i am trying to avoid an accident, i want the car to have one master, with a clear plan.

Imagine for example that the car started to skid, but you needed to accelerate to avoid a head on. Esp wont let you do that.

Originally Posted by manic

Main trick is dont do what that guy done in the video in any car, ever!

Any examples of dangerous ESP interference?

Most modern cars will tolerate you doing what that guy did in the video.

Originally Posted by rammypluge

Range Rover Classic rollover - YouTube

Following to close, not paying attention etc. Whos pulling into oncoming traffic to avoid a rear end..... Set up for TV

I had my RRC for 3 years and never rolled it, nore my Defender 110 (18 years) both sans sway bars.

I know people dislike body roll. I know people want their vehicles to "handle" better.... But people also Increase the COG and dont drive within the limits of the selected Vehicle. Buy a 4x4 and its a compromise. I personaly dont want sway bars.

FWIW anti-roll bars were an optional extra on some Porsche models in years gone by....

Some vehicles are positively dangerous without swaybars, whereas others, particularly those designed to be without them, can be not too bad.

The RRC has a number of factors that help it; the raised rear roll centre, alloy body, good front to rear weight balance unladen due to the light engine and rear overhang, the good suspension geometry and tuning, the boge self levelling strut.

Another thing though is that engines have become a lot more powerful, creating greater torque dynamics, acceleration and top speeds. The RRC suspension may be less suitable with more power than what it had from factory.

The Citroen 2CV is a perfect example of a car that worked with a gutless engine, but due to various design factors including leading arm independent front suspension, it was unsuitable for significant power upgrades.

The rear roll centre should be higher than the front, that way as the car rolls into a corner weight is transferred from the rear to the front helping mitigate understeer.

I've driven a car with a low rear roll centre and it was pretty twitchy on the track, it would swap ends in an instant.
Played with roll centres to a more conventional arrangement, much, much nicer.

With a high CofG we need higher roll centres anyway, it can somewhat mitigate body roll.

That RRC roll over was a deliberate provocation with that last jerk back on the steering wheel.

Most cars don't fall over, they need to trip over something.

I've had Defenders sans any anti-roll bars sliding on dry bitumen at stupid speeds and never been in fear of a roll over, ditto with an old Jeep that had more body roll than an RRC, but the Jeep terrified me off road on any side slope.

Anti-roll bars are weigh transfer devices, they transfer load laterally from an inside wheel across an axle, and diagonal to the opposite corner, which is why they are used to balance a cars handling characteristics in terms of under/oversteer.

Of course a car that doesn't roll as much feels nicer, and in sudden transitions they can make a vehicle more responsive to steering inputs, eg. a swerve situation as the weight transfer period is shortened.

Originally Posted by rick130

The rear roll centre should be higher than the front, that way as the car rolls into a corner weight is transferred from the rear to the front helping mitigate understeer.

I've driven a car with a low rear roll centre and it was pretty twitchy on the track, it would swap ends in an instant.
Played with roll centres to a more conventional arrangement, much, much nicer.

With a high CofG we need higher roll centres anyway, it can somewhat mitigate body roll.

That RRC roll over was a deliberate provocation with that last jerk back on the steering wheel.

Most cars don't fall over, they need to trip over something.

I've had Defenders sans any anti-roll bars sliding on dry bitumen at stupid speeds and never been in fear of a roll over, ditto with an old Jeep that had more body roll than an RRC, but the Jeep terrified me off road on any side slope.

Anti-roll bars are weigh transfer devices, they transfer load laterally from an inside wheel across an axle, and diagonal to the opposite corner, which is why they are used to balance a cars handling characteristics in terms of under/oversteer.

Of course a car that doesn't roll as much feels nicer, and in sudden transitions they can make a vehicle more responsive to steering inputs, eg. a swerve situation as the weight transfer period is shortened.

The RRC driver in the video was presumably trying to stay on the 'road' and also avoid any oncoming traffic. The moose test involves swerving back into ones lane.

Most passenger cars need to be tripped to roll over, but many 4wds are a different story. However, most 4wds on showroom floors with esp would be hard to roll without a trip.

Less body roll reduces the risk of simple harmonic motion, where two or more factors combine and compound to create a rollover.

All that being said, many people are now blindly obsessed with minimal body roll, at the expense of many things, including ride comfort, off road ability and off road safety. Its about striking the right balance, and these days swaybars are typically taken too far.