For this project I have chosen to design a wheel and tire assembly for an MX5 participating in the 5Club Racing MX5 Cup. To ensure the compliance of my design with the race series requirements, I have thoroughly reviewed the pertinent rules and regulations. When looking into the design of the of the wheel I have compiled key information that I have used for the design.  

The purpose of this study is to look further into the wheel design created for an MX-5 competing in “5Club Racing MX5 Cup”, this requires the wheel to deal with the working loads of a high performance/motorsport environment. The design of the wheel is very important as can improve the vehicles performance by; increasing the wheels strength, lower the wheels weight, increase the wheels safety and reduce rolling resistance, thus saving time on and off track. 

In this study we are going to look at the FEA (Finite element analysis) data from the design of the wheel. The material of the wheel is Aluminium alloy 6061, however, in this study we will look at Aluminium alloy 6061 which has been heat treated (such as 6061-T4 and 6061-T6), these allow for a greater yield strength and tensile strength.    

In this study we will be looking at two different tests, these being a Radial Load test and a Inner Flange test this will allow us to look into the safety and performance aspects of the wheels design and further look into any areas which could be improved. Below I have included a table maximum yield and tensile strength of Aluminium Alloy 6061 after being heat treated to different stages, this data is used within the design of wheel and has applied to the FEA tests.  

The first test that we are going to look at is the Radial Load test. This is where the rear lip of the wheel is fix and a rotational load is applied to the centre bore of the wheel, in the case the load applied is 5000 N mm. This test is designed to simulate forces and conditions which the wheel could experience.

In figure 1 we are looking at the displacement created by the rotational load (using 6061 – T6). As we can see the maximum load (5.461e-05 mm) is applied on the inter section of the wheel’s spokes, with little amounts of displacement.  

Figure 2 shows the safety factor of the wheel design, when using Aluminium Alloy 6061-T6. Looking at this data we can see that the wheel is reaching a safety rating of 15 throughout the wheel, thus ensuring the safety of the design, however, this could also imply that the design is over engineered. 

The second test that we are going to look at is the Inner Flange test. This is wheel is fix in position using the wheels bolt wholes and a force is applied to a point on the lip of the wheel, in this case a force of 3000 N is applied. Simmerly to the Radial Load test this test is designed to simulate forces and conditions which the wheel could experience while on track.

 In Figure 3 we see the displacement that occurs when the force (3500 N) is applied to the lip of the wheel. Here we can see a displacement of 0.9613mm occurs at the point of the applied force. Due to the force applied we can also see that some displacement also appears around the left and right of the wheel. 

Figure 4 shows the safety factor of the wheel, here we can see that the minimum safety factor is 1.55 in the area the the force is applied. Looking further into the safety factors the recommended safety factor for a component is above 2. 

In concusion the wheel design need further looked at to improve the safety factor when completing a Inner Flange test. As well as this the wheel overall safet factor could be reduce as currently in the Radial Load test the whole wheel has a safety factor of 15, thus making the wheel over enginnered for its application. This could be due to an exess of materal, which could be making the wheel heaveyer that is needed, this materal could be moved to solve the displacement which occurs with the Inner Flange test.