What is it that gives the Volvo such a great(small) turn radius? Just wondering.

In cooperation with the University of Linköping, Volvo has the last three years been working on four-wheel steering. It's the new "by wire" technology that makes this interesting. At the present configuration, all wheels can be angled in the same direction if you want to move the car sideways. But you can also angle the fronts opposite from the rears if you want to reduce the turn radius. Or you can angle the wheels for better stability on the highway. What they trying now, is to incorporate some kind of anti-drift system. Source: Last issue of Teknikens Värld.
Note the rear wheel:



Erling.
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My 240 Page

My 1969 144 (145K miles) had a turning radius that was one foot more the VW beetle. That was listed in the Volvo published specs. My 1983 242 (340K miles) has a bit larger radius but I still love it. I can U-turn in the tightest places and parallel park like a son of a gun.

No facts to back this up—but I think a Road & Track test of the 140 (different steering than 240 but similar dimensions) compared the Volvo turning radius most favorably to the VW Beetle. (I almost want to say it was better then the bug.)
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Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

For a given wheelbase, RWD cars are not limited by the front CV joints, as other posters noted. But also, engine width relative to the width of the car is another factor. FWD cars typically have the engine mounted sideways. This takes up more of the car's width and impinges into the space where the wheels would go when turned at full crank. Volvo's new offerings with a transverse mounted inline 6 really cuts into the available space. Some cars and long wheelbase trucks compensate by adding a bit of steer to the rear wheels but that adds expense and more stuff to break.

BTW, the number of turns of the steering wheel lock to lock is not a reliable indicator of turning circle since the gear ratios vary a lot.

I vaguely recall a car from the 40's that had it's spare tire mounted 'Continental' style vertically across the back end of the car. It was on some hydraulics that could be lowered and the car could be pivoted around. Neat. Just drive front first into a parallel parking spot, lower the spare and pivot the rear into the spot with only inches of clearance between the cars.

Bill
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Volvo Info Site 1990 745GLE 16valve

simply put, it's because the front wheels turn a lot more.

this probably isn't a very good way of measuring it, but just try turning the steering wheel on your volvo all the way to one side and count the number of revolutions it takes. then try it on another car. you'll find you have a good 180 degrees extra rotation. or maybe it was 90.

of course the ratio of turns to the actual wheels turning may be different on each car, but still.

or you can just go outside and take a non-volvo and turn it all the way and take your volvo and turn it all the way, and you'll see. it's obvious our wheels turn sharper :)
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Kenric Tam
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

It is 9,8 meters. (!)

Very short diameter, comparing it to other even smaller cars.

The reason for this:design etc, monstruous wheel arcs,

The turning of the front wheels is actually so sharp, that the inner wheel sometimes slides in stead of only rolling (when applying too much gas for example)

turning radius for a S60 +- 11 meters!!

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240 '88 B200K 260+kkm virgo,Phoenix Gold ampli, Focal door speakers, debadged, 6 rear red lights

yeah, i've noticed this too. go a little too fast and you hear your front tires scraping against the ground :)
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Kenric Tam
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

Mostly it's the freedom of RWD. In the "old" days, the Volvo turning radius wasn't as noteworthy as today, because cars were typically RWD -- today things are very different. How many RWD cars are left (Mercedes?)?
With RWD, there is no driveshaft (I can't remember the special name, "halfshafts"?) that goes into the front wheels to make them turn.
Attaching such a shaft, in a FWD or 4WD/AWD car, to the inside (or backside) of the hub prevents the wheel from turning as far around as it could without it -- even with universal joints, there is just so much that the wheel can turn before the joint is jammed and can't rotate the hub anymore. Yes, some short wheelbase FWD cars have a tight turning radius, but not as tight as they would have if they were RWD.
Free of that shaft, a RWD car's front wheel can turn (steer) until it's close to a right angle to the long axis of the car (or the plane of the rear wheels), and the front of the car can swing around in a tight arc with the rear wheels hardly advancing (especially if you've built up some rotational momentum by turning the steering wheel gradually from straight ahead -- but don't try this on ice or snow, or the front wheels will merely slide forward and act as a plow to stop the car).
Other factors that tighten a turning radius include wheelbase (a shorter wheelbase has a smaller turning radius), but Volvo 240's aren't particularly long or short wheelbase cars -- sort of in-between -- so it's almost all due to not having to accommodate room for, or limit turning because of, the shafts.
Regards,

It's not just FWD versus RWD. My friend's Pug 505 has nowhere near the turning circle of my 240T, which in turn feels like it turns in a bigger circle than his former 764T.

All in all, it probably comes down to how the car was designed more than anything. Supposedly the 850s had a pretty tight turning radius.

- alex

'85 244 Turbo

Then how come my '89 Lesabre (FWD, about 14' long) had a better turn radius than my '89 Horizon (FWD, about 11' long)?

There's more to it than just the RWD. My 945T turns much more sharply than several other RWD's that I own or have owned, including our current 1988 Grand Marquis. That car has a short wheel base for its overall size, and still requires careful planning in close quarters doe to large turning radius.