Fender Design - Wheel Arch Challenge

Wheel Arch is an arch shaped cavity in the fender body, which houses a wheel. The main intention for the calculation of wheel arc radius is to position the wheel inside the fender body , because during motion the car tyres will tend to throw particles present on the road like sand, mudrocks, liquids etc. into the air which may harm the pedestrians and cause problems

There are different standards of wheel arch designs

1) Japan Standard

As per the Japan Standard, the Clearence value L i.e. the gap between the tyre and the fender wheel arch should not be less than 5 mm for all the 3 points B, A & C.

2) U.S Standard

Lines are drawn from the centre of the wheel for every 10 degrees from -20 to 180 deg as shown in the figure 1.2. So as per U.S standard the clearence gap distance between the wheel and the fender wheel arch should not be less than 5 mm at every 10 degree angle

3) European Standard

As per European Standard, The clearence L should not be less than 10 mm at all the 5 points SB, SA, SC, SD, SE

Now let us see if the given Fender & wheel model will pass the European standard or not.

Procedure

1) Take a plane on the face of the wheel and create a certical straight line SA from the centre of the wheel

2) Create two similar lines SB & SC at 30 degree and 50 degree angle respectively from the line SA taken from the centre

3) Create a horizontal line passing from the centre on the wheel and offset it to 150 mm upwards, and mark its point of intersection with the edge of the wheel

4) Draw a line passing throgh centre of the wheel and intersection point. Create angle bisector using bisecting lines and name the two new lines created as SD & SE

5) Exit the sketch and measure the distance between the Fender outer edge and the lines drawn on the wheel.

According to the European Standards, 5 points in particular positions at the outer surface of the wheel should be at a minimum distance of 10mm from the inner surface of the fender.

The below table represents the position of the points, the clearance condition and if those points satisfy the condition.

Clearance Check Table:

Points	Angle from vertical	Clearance according to standard	Available Clearance	PASS/FAIL
AA	0	10	9.9489	FAIL
BB	50	10	2.9653	FAIL
CC	-30	10	10.000	PASS
DD(150mm)	63.10	10	2.0777	FAIL
EE( b/w BB & DD)	56.60	10	0.6735	FAIL

From the above results, we can conclude that the Fender does not pass the European Regulations, as the minimum clearance ‘L’ between the Fender wheel arch and wheel for vehicle should be 10mm and this design does not meet the European Regulation requirements.