Sway bar functions

I think this is one of those US misnomers. In the UK we call this an "anti roll bar".

Its main purpose is to keep the [front] wheels vertical when you go round corners, so that all the tread of the tyres is on the road. This improves handling, and IIRC also reduces body roll on the car. They form a second attachment the hubs and increase rigidity in the vertical plane.

Yes, but "sway bar" is the commonly used term in the USA.

Camber control is up to the suspension geometry and wheel rate, not the sway bar. The primary purpose of a sway bar is to transfer load from a wheel on one side of the car to the other one on the same end.

JRE

No. I've never wondered that at all.

So going back to a beam axle would be better since the wheels are always 'vertical? ;-)

Are there anti-roll bars on F1 cars?

On one of my cars, it's also the only location in the horizontal 'plane'.

True; unfortunately, 'antiroll bar' is a more correct term.

*OR* to keep the whole car more level so that a tire *at the other end* will stay planted. In the end, it all has to do with influencing over- and understeer characteristics. Since I already know that, someone else will have to visit the spammer's website.

-- C.R. (BT, DT)

Last time I checked, yes. Along with adjustable aerodynamics, it's one of the most valuable suspension adjustments they have available. What I don't know is if they can currently (legally!) be adjusted while underway ...

-- C.R.

No they are not, they are always normal to the axle, which may or may not be parallel to the road surface .

Maybe, but F1 cars have very little suspension, and in many ways are like (500kW) roller skates!

No bottom link or track control arms then, or did one snap (like on my Triumph 2500TC in ~1980)?

The rules exclude adjustable suspension or aerodynamics when on track. Any adjustments must be made in the pits. To get round this, some rear wings were designed to bend, and alter their profile at speed. As soon as it was discovered, such wings were banned. Mike.

Let me think... Nope, I already know. It's a length of metal attached between the left and rght wheels across there the front/rear of the vehicle that uses it's tortional stiffness to resist suspension movement on one side without the other. Designed to allow softer suspension to be used to absorb bumps on the road, but still have respectable corner handling.

Known as an Anti-roll bar in the UK.

Often the bushes the bar goes through that are attached to the vehicle body are the source of odd clonks and creaks when the bushes wear.

Did I miss anything?

Dodgy.

The one on your Triumph snapped because the inboard mounting bush was shot. In time, it causes the arm to fracture. I learned the hard way how important bushes are, so to speak.

Here's a little story. When I bought my 94 Volvo turbo wagon (estate), it came without a rear stabilizer bar. In hard, tight corners, it had a bad habit of lifting the inside front wheel, losing traction, and sometimes letting the wheel spin. =20

About a year later, I installed a rear bar, with the intent of reducing overall body roll. When I took it out for a test drive, the bar had so dramatically reduced understeer that I nearly ran off the inside of a familiar fast sweeper. =20 One reason for this is that it kept the rear of the car from rolling to the outside of the turn, which kept the opposite (inside front) corner more firmly planted. I now had two tires guiding me through the corners instead of just one. (Think of a table with one short leg. Push down on that corner, and the opposite corner lifts.)

I suspect this effect was more dramatic due the higher rear C.G. of the wagon body.. =20

I'm still upset that Volvo left the rear bar off on this model, leaving me with lousy handling until I discovered the fix.

-- Email reply: please remove one letter from each side of "@" Spammers are VERMIN. Please kill them all.

Not quite true. The arm appeared to be drop forged and consequently rather brittle.

Fortunately for me it broke when I was trickling up behind a bus at lights doing about 25mph about 1km from home.

The previous day I had been carved up by a Porsche near the start of the M62 in Liverpool, and had kerbed the OSF wheel. I initially assumed that this had caused the damage, however on extraction of the arm what I actually discovered was an absolutely classic fatigue crack accross the base of the [badly designed] lug. It had little waves where the crack had propagated, corrosion worsening towards its origin, and then some rather large advances before total failure (one no doubt caused the previous day).

I was I guess pretty lucky that the failure did not occur when I was doing

70mph on a busy motorway!

The progressive fatigue cracking in the place you describe is also what happens when the inboard bush is no longer performing its function.

It was a common failure mode.

If it wasn't that, then I'm not sure what it was that caused the fatigue cracking in yours.

Started at the one side of the lug, where there was a right angle corner and no stress relief.

May the bush was bushed, but I would have probably noticed any handling deterioration.

Which means 'vertical' (or nearly depending on camber angle on undriven wheels) until one wheel leaves the ground?

I'm not sure what you mean by 'little' suspension. To me, they appear to have *very* sophisticated suspension. Roller skates have pretty well non.

On many *basic* strut designs, the anti-roll bar provides the only front-back location, as the bottom link isn't a wishbone.

Modern BMWs are rather more sophisticated. ;-)

Apparently a good thing you didn't know the proper primary way to accomplish that is with stiffer springs.

Yup. Stiffer rear = less understeer. Exactly what you should expect.

BMW made the same mistake with the NA-spec. '77 320i, which lifted the inside rear (drive) wheel and yelped like a whipped puppy in hard cornering. The following year, they removed the rear bar, installed a stiffer front one, and the problem went away.

-- C.R. Krieger