Turning Circle Calculator

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We’ve added a Turning Circle Calculator to our Axle Weight Calculator this month.  Many jurisdictions now impose manoeuvrability criteria to the vehicle approval process, so calculating Turning Circle is a big deal.

Where to find Turning Circle?

Use the buttons on the right of the Axle Weight Calculator to switch to the turning circle view.

What is Turning Circle?

The turning radius or turning circle of a vehicle is the radius of the smallest circular turn (U-turn) that the vehicle is capable of making.

Smallest Turning Radius

The Smallest Turning Circle is used to determine the smallest U-turn that the vehicle is capable of making.

Regulation Turning Radius

The Regulation Turning Circle is used to ensure that the combination is able to turn within a swept circle having a maximum outer radius and a minimum inner radius as stipulated by the relevant regulation.

We calculate both Smallest and Regulation Turning Circle.

Why calculate Turning Circle?

You may know the Turning Circle of a standard vehicle, and want to see the effect of modifying the wheelbase. Or you may know the Turning Circle for a truck tractor, but want to see how much more space that vehicle will need to turn when you add a trailer.

Modify Wheelbase

You may wish to extend (or shorten) the wheelbase of a truck for which you already know the Turning Radius. In this case, open the vehicle, make the desired adjustment to the wheelbase, then switch views to review the effect of the change on the Turning Circle.

Add a trailer

If you have a spec sheet for a vehicle, and you’re adding a trailer to the vehicle, our Calculator will calculate the turning radius of the vehicle combination. This is especially relevant in Europe, where streets are often little more than a gap between two buildings!

How to calculate Turning Circle

To calculate Turning Circle, you will need to provide one of the following values.  You should find one or more of these on the vehicle specification sheet.

  • Curb to Curb Radius (Kerb to Kerb Radius)
  • Wall to Wall Radius
  • Inner Steering Angle

The Results

Various measurements are used when quoting Turning Circle. The Turning Ability of the combination can be expressed as Curb to Curb Radius, Wall to Wall Radius, or Inner Radius.

Curb to Curb Radius

The name “curb-to-curb” indicates that a street would have to be this wide before the vehicle combination can make a u-turn and not hit a street curb with a wheel.

In the example pictured directly below, the outer arc represents the Wall to Wall Radius, and the inner arc the Curb to Curb Radius.

Wall to Wall Radius

If you were to build a wall on top of the above street curb, which were as high as the vehicle, and tried to make a u-turn in the street, parts of the vehicle might hit the wall. The name wall or wall-to-wall turning circle denotes how far apart the two walls would have to be to allow a u-turn without scraping the walls.

Inner Radius

The difference between Outer and Inner radius indicates the Swept Path. The minimum Inner Radius in Europe is 5.3m, therefore the maximum Swept Path is 7.2m. The purpose of the Inner Radius measurement is to ensure that, for example, pedestrians on the passenger side of the vehicle are not struck when the vehicle is going around a corner on that side.

More on Turning Circle

EU Commission Regulation No 1230/2012 governs the manoeuvrability requirements for new vehicles at Type Approval.

What Else Is New?

This month, we also dedicated more time to improving the usability of the app.

Drag and Drop

You’re going to love this!  Simply hold down your mouse button and pull your mouse along to move bodies and equipment backwards or forwards along the chassis, or indeed above or below the chassis, in the case of equipment.

Rear Overhang

We now display Rear Overhang as a percentage of regulation wheelbase.  In many jurisdictions, Rear Overhang (the distance between the centre of the rear axle unit and the rearmost point of the vehicle) must not exceed 60% of regulation wheelbase (the distance between the centre of the front wheel and the centre of the rear axle unit).  In some jurisdictions, for example in New Zealand, the rear overhang may be up to 70%.

Fifth Wheel height

Fifth Wheel height is now measured from the ground. This change was also implemented in response to user requests.

Vehicles and Equipment added

This month, we added vehicles from Eicher, Freightliner, Hyundai, Isuzu, Iveco, Kenworth, MACK, Peterbilt, RAM, Volvo and Western Star, Dhollandia taillifts and Palfinger cranes. These were requested by users in United States, Canada, Ireland, New Zealand and South Africa. Remember that you can request vehicles, bodies and equipment to be added to our library at no cost.

Make your voice heard!

If you’ve got ideas for making the app more relevant to you, we want to hear them too! Now that you have Turning Circle, do you also need Rear Swing Out (or Tail Swing, the amount that the rear of a vehicle moves to the left if the vehicle turns to the right)?

Have a go!

Click ‘GET STARTED’ above to try out the Axle Weight Calculator for yourself now.  No credit card or complicated installation…  Just provide your name and email address, and you’ll be straight into the app.

Don’t Try This At Home

We previously shared a video on LinkedIn showing a combination carrying a 60-metre turbine blade going round a corner.  If you haven’t seen it yet, you might like to watch it now.

For more on the world’s skinniest streets, check out this post from the Huffington Post.

 

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