Turning circle

[Jerome P.]

Dumb but maybe not so dumb of a question. My car has a 39 foot turning circle; is that the diameter of the inside wheel track or the outside wheel track?

My car is in a garage 28 miles away. I would measure the actual turning circle, but I thought maybe someone could save me the trip.

Thanks

[Jim S.]

Re: Turning circle

Typically when you refer to a car's turning circle, you are refering to the outside track diameter. There is also a wall to wall circle which takes into account the car body. It is somewhat larger.
Jim

[Jerome P.]

Re: Turning circle

Jim,

That is what thought, but after looking at the website at this link I am confused.

http://en.wikipedia.org/wiki/Turning_radius

Any comments? Your thoughts are appreciated. Is there anyone else who has thoughts/ideas on the definition of a turning circle?

Jerry

[Terry M.]

Re: Turning circle

Jim,

That is what thought, but after looking at the website at this link I am confused.

http://en.wikipedia.org/wiki/Turning_radius

Any comments? Your thoughts are appreciated. Is there anyone else who has thoughts/ideas on the definition of a turning circle?

Jerry

I am curious why this is an issue for you? I don't think you can change it, short of major modification of the car. I have heard of cars that due to physical damage had different turning circle one direction than the other, and I suppose NASCAR cars would have side to side differences, if allowed by their rules.

Unless you are designing a parking garage with ramps, and if you are I can send you to a test garage in downtown Chicago, why does it matter?

[Jim S.]

Re: Turning circle

Just refer to either the curb to curb (footprint of the outside tire on the ground). Or the wall to wall (taking into account the body and bumper structure.) Both refer to the car being driven in a circle with the curbs or the walls dictating the diameter of the turning circle.
Jim

[Jerome P.]

Re: Turning circle

I am adding another garage onto my house and the approach/entrance to the garage door will be tight.

The other thing I need is to find out/draw the turning path track of both the front and rear tires.

Any ideas?

Thanks for your help.

[Terry M.]

Re: Turning circle

I am adding another garage onto my house and the approach/entrance to the garage door will be tight.

The other thing I need is to find out/draw the turning path track of both the front and rear tires.

Any ideas?

Thanks for your help.

Want pictures or measurements of the tight ramps in the garage in Chicago? I would think those ramps would be a piece of cake for a vintage Corvette. They are real tight for our 1995 "full-size" Caprices. I can't imagine a Suburban or the like, but that is probably where the "wall rash" comes from.

For the turning path -- on a open parking lot put down a puddle of water and drive through it. The wet tires will make a path. The path will last longer on an overcast day on concrete. A sunny day on blacktop will give the shortest measurement time. If water doesn't last long enough for measurements some oil will do the same thing, but the parking lot owner may not appreciate the residue -- and you and your car may not either.

[Jerome P.]

Re: Turning circle

Want pictures or measurements of the tight ramps in the garage in Chicago? I would think those ramps would be a piece of cake for a vintage Corvette. They are real tight for our 1995 "full-size" Caprices. I can't imagine a Suburban or the like, but that is probably where the "wall rash" comes from.

For the turning path -- on a open parking lot put down a puddle of water and drive through it. The wet tires will make a path. The path will last longer on an overcast day on concrete. A sunny day on blacktop will give the shortest measurement time. If water doesn't last long enough for measurements some oil will do the same thing, but the parking lot owner may not appreciate the residue -- and you and your car may not either.

Terry,

My intent is to incorporate the info derived from the turning path track into a drawing. I understand there maybe some free download software that well actually do a schematic basis on the turning circle, width and length of the car.

Your idea about wet tires and converting actual to a scale drawing would be difficult, particularly in the Phoenix, AZ area. It is very seldom not sunny and the temperature is already approaching the 80's

[John H.]

Re: Turning circle

Is there anyone else who has thoughts/ideas on the definition of a turning circle?

Jerry

Yup - Chevrolet Engineering specifications define it very clearly; these numbers are for a '67, but the chassis is identical to the C3's:

Turning Diameters (feet):

Outside front, wall-to-wall = 41.6
Outside front, curb-to-curb = 39.9
Inside rear, wall-to-wall = 25.6
Inside rear, curb-to-curb = 25.6
Outside front wheel angle with inside wheel at 34* turn limit = 27.37* (result of Ackerman geometry)

Note: Wall-to-wall numbers will differ somewhat on a C3 due to different front overhang; it's 31.9" on a midyear, don't have that spec for a C3.

[Jerome P.]

Re: Turning circle

Yup - Chevrolet Engineering specifications define it very clearly; these numbers are for a '67, but the chassis is identical to the C3's:

Turning Diameters (feet):

Outside front, wall-to-wall = 41.6
Outside front, curb-to-curb = 39.9
Inside rear, wall-to-wall = 25.6
Inside rear, curb-to-curb = 25.6
Outside front wheel angle with inside wheel at 34* turn limit = 27.37* (result of Ackerman geometry)

Note: Wall-to-wall numbers will differ somewhat on a C3 due to different front overhang; it's 31.9" on a midyear, don't have that spec for a C3.

What does this mean:

Outside front wheel angle with inside wheel at 34* turn limit = 27.37* (result of Ackerman geometry)

[John H.]

Re: Turning circle

What does this mean:

Outside front wheel angle with inside wheel at 34* turn limit = 27.37* (result of Ackerman geometry)

Jerome -

All cars have Ackerman geometry designed into the steering linkage, so the inside and outside front wheels (in a turn) are at different angles, as they are located at different distances from the center of the turning circle. Without that geometry, the front tires would "scrub" during a turn.

[Jerome P.]

Re: Turning circle

Thanks alot.