what determines a cars turning circle?

[edwardh1]

my 99 maxima turns about like a school bus, but Toyotas I have owned, a camry and a highlander you can really u turn in a lot of places that the maxima needs a 3 point turn.
is it laziness on the designers of the steering, they don't put in enough angle or related to the wheel base or what?

in london years ago and a cabbie driving one of the black sedan cabs said the front wheels would almost turn sideways to let the cab turn better on small streets.

 

[SatinSilver]

When I drove a Sequoia I couldn't believe how easy it was to maneuver such a large truck. The steering made it feel like a Corolla when parking.

 

[Tomioka]

Part of it is the CV joint angle limitations. A CV joint can only turn so far before it starts binding when rotating. I had a 1990 Toyota 4Runner 4x4 (w/ auto disconnecting front diff) and the CV joints would bind when trying to turn at full lock.

Other factors like wheelbase length, spindle design, etc.

 

[mclasser]

My I35 has a terrible turning radius, like all 5th gen Maximas. I don't even bother making U-turns since it needs 3 lanes. My Pilot turns on a dime and it's an SUV.

 

[MinamiKotaro]

My '98 S10 had a startlingly tight turning radius. It would turn in a smaller space than my '67 Bug, the '84 Caravan, or Dad's '97 Taurus.

I kind of regret trading it in. The tranny was shot and the 2.2 was pitiful, but a 5.7/4.8/5.3/6.0/6.2 LSx V8 and 4L80E can be had for cheap, nowadays.

 

[Silk]

Fwd have a poor turning circle, a rear wheel drive car nearly always has a better turn radius. My Mercedes has the best turning circle in our fleet, the others are fwd, regardless of wheelbase. The London Cab was rwd. Best turning circle was the Triumph Herald, it turned so much you couldn't actually move forward, the wheels would slip sideways.

 

[spk2000]

Can't just be RWD as my Grand Marquis is RWD and has a very poor turning radius. Wheelbase plays some part in this as well. Shorter wheelbase seems to almost always turn sharper.

 

[Hokiefyd]

Wheelbase plays a large factor. The two vehicles in my signature have front suspension geometry that is, for all intents and purposes, "the same". The biggest difference between our two vehicles, under the skin, is the wheelbase. The MDX has a much tighter turning radius than the Ridgeline does. It also feels more nimble on the road, despite the MDX having a softer suspension. Wheelbase plays a role in a lot of how a vehicle behaves.

 

[eljefino]

The turning circle is a spec london cabs have to meet. 25 feet, to turn around in "Savoy court", whatever that is.

My w123 mercedes (midsize, RWD) does an amazing job.

Saturn s-series are the worst compact FWD I've ever dealt with.

 

[Toaster_Jer]

I noticed that with our former 02' Prius,very tight turning radius. The 2010 we now have has more of a normal turning radius. Wonder if it was to save on the CV joints.

 

[Chris142]

My ford truck needs acres to turn. Im always having to back up and straighten it out.

 

[RooflessVW]

It's a function of total steering angle, front wheel caster, and wheelbase.

My '96 E220 had the best turning circle out of any car I've ever owned.

 

[y_p_w]

There were a few cars with 4-wheel steering that had a really tight turning radius.

I think GM had it in some of their bigger vehicles. It might have been a GMC commercial where a woman is parking her SUV in a tight space hemmed in by a bunch of motorcycles watched over by several hardcore bikers.

 

[expat]

Originally Posted By: eljefino
The turning circle is a spec london cabs have to meet. 25 feet, to turn around in "Savoy court", whatever that is.

My w123 mercedes (midsize, RWD) does an amazing job.

Saturn s-series are the worst compact FWD I've ever dealt with.


That was the turning circle in front of the Savoy hotel in London.
the latest edition Taxi cabs emply 4 wheel steering to make those turns.

The Triumph Herald had a turning circle of 23'

 

[d00df00d]

Few things, no particular order:

1. Suspension design
2. How much room there is in the front wheel wells
3. How far the steering rack will move
4. Whether there are front driveshafts (FWD/AWD/4WD), and if so, what angles they can operate at
5. Wheelbase length

Wheelbase length also affects how much room the car needs within the turning circle. E.g., say you're in one of those tightly curved driving lanes between levels in a parking garage. A car with a long wheelbase might have enough steering angle to stay within the outer wall, but either way it'll be more likely to scrape the inner wall.

 

[veryHeavy]

Originally Posted By: Hokiefyd
Wheelbase plays a large factor.

Absolutely. My tiny two-seater with 5 foot wheelbase can do a U-turn on a narrow road. None of my other/longer cars can.

 

[mjoekingz28]

Originally Posted By: eljefino


Saturn s-series are the worst compact FWD I've ever dealt with.



No joke! I thought it was just my 98 coupe since the wheelbase was shorter for s-series earlier on. This ~2400lb coupe took low speed 90 degree turns like a barge. Great ride otherwise.


What do y'all think about section width/aspect ratio of the tire having any relation?

 

[asiancivicmaniac]

I usually need at least a very wide 2 lane road to a u-turn in my Maxima and it would just barely make it without hitting the curb.

 

[d00df00d]

Originally Posted By: mjoekingz28
What do y'all think about section width/aspect ratio of the tire having any relation?

That'd affect steering effort, but not turning circle.

If you try to make the turn by turning the steering wheel while the vehicle is moving, wider tires might make it feel like you have a bigger turning circle because the extra resistance in the steering wheel would limit how quickly you steer. Instead, if you turn the steering wheel all the way and then start moving, wider tires will make it take more effort, but your turning circle will be unaffected.

 

[eljefino]

Originally Posted By: mjoekingz28


What do y'all think about section width/aspect ratio of the tire having any relation?


It would only matter if the wide tire were hitting the tie rod or other parts of the steering mechanism.

I have access to a forklift with an amazing turning circle.