eastcoastdrifter
18th September 2007, 10:09 PM
Fitting a set of negative offset or dished wheels that may also be wider than standard requires you keep a number of things in mind. These are discussed below. You must not however, that this information has been described for a rear drive car. And that front-weel drive cars often have amplified problems when fitting varied offset or wider wheels to the driving axles.
So what to keep in mind? Firstly, since the offset, and size of a wheel will determine the stress that is placed on your cars bearings and wheel studs, the massively dished negative offset wheels that have become quite popular may result in increased wear on your car. Also, with modern cars using larger braking hardware. It will be necessary to specify a precise calliper overhang area before choosing some wheels for your car.
Additionally, it is important to note that altering your wheel offset of your front wheels will affect the way in which your car behaves on the road. This may make your car more prone to bump steering or torque steer when considering a front drive vehicle.
So why do manufacturers specify a particular wheel offset for a car? Currently the majority of new cars on the market both rear and front drive designs - feature a positive offset. The reasons for this are many, however of most importance is the fact that manufacturers aim to locate the centreline of the wheel as close to the centreline of the hub bearings as possible. As well as this, a positive offset offers a number of benefits relating to: appearance better handling (particularly in front drives) and for allowing room to fit components such as brakes and CV joints.
To understand why wheel-to-Bearings alignment is desirable, you have to realise that the bulk of physical forces acting on a wheel will transfer to the hub through an axis that runs straight down the vertical centre of the rim, The best way to minimise the effect of this force being transferred through to your car. Is to line the centre of the wheel up with the centre axis of your cars wheel bearings.
Now, to move the centreline of the wheel away from the centreline of the hub's bearings will create a situation where the forces from the wheel act with a type of leverage against your cars bearing and wheel studs. For anyone that doesn't already know. Utilising a situation of leverage allows more acting force to be distributed to a smaller portion of space. This means that the force coming from the wheel acts on a smaller portion of the hub materials and therefore increases the risk of causing damage to the hub's components.
So. To fit some extended dish wheels without massively altering your cars reliability. Or handling. It is important to increase the backspacing area (the area between the mounting face and inside rim of the wheel) by the same amount that you add on to the wheel's lip. For instance if you had a seven inch wide wheel as standard, you could opt for half an inch more dish. With another half inch added to the inside of the rim (space permitting). This however, is not the ultimate answer to fitting wider rims: under cornering loads there will be increased instances of leverage. Thanks to the extra half-inch on either side of the wheel.
That being said, there is a certain extent to which you can work outside of the optimum centre alignment. Porsche vehicles are one example of cars that commonly have wider wheels fitted to the rear. These fitments quite often alter the centreline-of-wheel to centreline-of-hub alignment. To overcome the problems associated with increasing stress on the bearings and wheel studs. It is possible to buy stronger wheel studs and bearings. This would be a good option for anyone that does alter their centreline alignment from standard by fitting dished rims.
To Sum everything up, although massively negative-offset. Wide rims will definitely lead to increased wear on your car's wheel mounting components. There are things you can do to counteract this. While for the rear of a car this strength is the only real problem. Changing offsets at the front of the car may see you bump steering off the road, Basically don't Opt for excessive dish up front. Strengthen your components in the rear and you should be able to use some decently dished wheel.
So what to keep in mind? Firstly, since the offset, and size of a wheel will determine the stress that is placed on your cars bearings and wheel studs, the massively dished negative offset wheels that have become quite popular may result in increased wear on your car. Also, with modern cars using larger braking hardware. It will be necessary to specify a precise calliper overhang area before choosing some wheels for your car.
Additionally, it is important to note that altering your wheel offset of your front wheels will affect the way in which your car behaves on the road. This may make your car more prone to bump steering or torque steer when considering a front drive vehicle.
So why do manufacturers specify a particular wheel offset for a car? Currently the majority of new cars on the market both rear and front drive designs - feature a positive offset. The reasons for this are many, however of most importance is the fact that manufacturers aim to locate the centreline of the wheel as close to the centreline of the hub bearings as possible. As well as this, a positive offset offers a number of benefits relating to: appearance better handling (particularly in front drives) and for allowing room to fit components such as brakes and CV joints.
To understand why wheel-to-Bearings alignment is desirable, you have to realise that the bulk of physical forces acting on a wheel will transfer to the hub through an axis that runs straight down the vertical centre of the rim, The best way to minimise the effect of this force being transferred through to your car. Is to line the centre of the wheel up with the centre axis of your cars wheel bearings.
Now, to move the centreline of the wheel away from the centreline of the hub's bearings will create a situation where the forces from the wheel act with a type of leverage against your cars bearing and wheel studs. For anyone that doesn't already know. Utilising a situation of leverage allows more acting force to be distributed to a smaller portion of space. This means that the force coming from the wheel acts on a smaller portion of the hub materials and therefore increases the risk of causing damage to the hub's components.
So. To fit some extended dish wheels without massively altering your cars reliability. Or handling. It is important to increase the backspacing area (the area between the mounting face and inside rim of the wheel) by the same amount that you add on to the wheel's lip. For instance if you had a seven inch wide wheel as standard, you could opt for half an inch more dish. With another half inch added to the inside of the rim (space permitting). This however, is not the ultimate answer to fitting wider rims: under cornering loads there will be increased instances of leverage. Thanks to the extra half-inch on either side of the wheel.
That being said, there is a certain extent to which you can work outside of the optimum centre alignment. Porsche vehicles are one example of cars that commonly have wider wheels fitted to the rear. These fitments quite often alter the centreline-of-wheel to centreline-of-hub alignment. To overcome the problems associated with increasing stress on the bearings and wheel studs. It is possible to buy stronger wheel studs and bearings. This would be a good option for anyone that does alter their centreline alignment from standard by fitting dished rims.
To Sum everything up, although massively negative-offset. Wide rims will definitely lead to increased wear on your car's wheel mounting components. There are things you can do to counteract this. While for the rear of a car this strength is the only real problem. Changing offsets at the front of the car may see you bump steering off the road, Basically don't Opt for excessive dish up front. Strengthen your components in the rear and you should be able to use some decently dished wheel.