Fender Design - Wheel Arch Challenge

Fender Wheel Arch Calculation

Wheel Arch is the semi-circular part of the fender located above the wheel of the vehicle. The wheel arch area of the fender is usually designed as cover over the tyre to stop any stones or debris, dirt, and sand from getting thrown into the vehicle. Different regions have different wheel arch regulations to comply with, to be marketed in that region.

                                           

European Standard

The European standard requires a clearance (L) of more than 10mm between the outer-most tyre face and the fender inner face at specific points i.e., at SA-SA, SB-SB, SC-SC, SD-SD, SE-SE on the fender as shown.

Wheel guard reqiurement: The value of 'a' should be more than 5 mm at a line 30* forward and 50* rearward from the central vertical axis of axis of wheel.

                                                            

Japanese Standard

A clearance (L) of minimum 5mm between the outer-most tyre face and the fender inner face at specific area K as shown in the figure.

Wheel guard requirement: The value of ‘a’ should be more than 10mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel.

                                                     

USA standard:

Make clearance check details on all positions from -100* to 100* & make the clearance check table. All values should be greater than 5 mm to satisfy the regulations. The value of 'a' should be more than 5 mm at a line 30* forward and 50* rearward from the central vertical axis of the wheel. 

Procedure

• A horizontal and vertical Axis is drawn from the centre of the wheel.
• The vertical axis intersection point is labelled as SA.
• Similar references are drawn at 30 degree to the left and 50 degree to the right of the section SA and are named SB and SC respectively.
• A line of 150mm is drawn perpendicular to the horizontal axis and the normal from that point on the fender gives us SE.
• The midpoint of the arc cut by the sections SC and SE results in a new section SD.
• The value of 'L' at each section and the value of 'a' are found out to determine whether the fender satisfies the European standards as shown below. 
  
  

MEASUREMENTS:

• The clearance value 'L' was measured and found to be as follows:

• Section	Required Clearance (mm)	Measured Clearance ‘L’ (mm)	Remarks
  SB	10	10	Pass
  SA	10	9.94	Fail
  SC	10	0.11	Fail
  SD	10	2.84	Fail
  SE	10	5.90	Fail

As per the European standards, the value of 'L' should be greater than 10mm. But at Section SB, the value of L is equal to 10mm and at other sections the value of 'L' is less than 10mm. So, it does not satisfy the condition L > 10mm to meet the European standards in any of the sections.

The value of 'a' at the sections SB and SC are greater than 5mm. So, it satisfies the criteria for wheel guard requirement.