Wheel spacers, who has fitted them? before and after pics?

[S8QUATTRO]

Morning, I had never considered using wheel spacers before until this week, someone told me about them...so i googled some before and after pictures and cant believe what difference it makes to the look of a car..

Has anyone used them on here?
Do you have before and after pics?
Do they cause any extra wear or issues?

Car is a 2006 CLS with 19 inch AMG wheels, they are wider at the rear

There seem to be 10mm 15mm and 20mm variations, so not the comedy stuff

[S8QUATTRO]

Not sure now then, the Audi S5 looks a lot better with them on..

lostkiwi said:

Here's something to think about when using spacers (from another forum):

Another forum said:

The purpose of tightening a bolt is to elastically (and in some cases plastically) deform the bolt, to stretch it. For equilibrium, the stretch in the bolt is matched by the compression across the faces of the joint.

In the case of a gasket joint, this compression is needed to make the gasket seal.

In the case of a wheel to hub joint, this compression is needed to transmit the drive and brake torque. In this respect, the hub face and inner face of the wheel are acting as the two faces of a clutch. The bolts themselves should not be transmitting the drive and brake torque.

So, applying torque to stretch and preload the fastener is how it tends to be done, but, it's a rubbish method. It's poor because there is so much variation in the levels of inter-thread friction, and friction between the bolt head and clamped part (in our case on the radius under the bolt head).

During some tests I did on a rail vehicle, with instrumented M16 bolts, after torquing using a calibrated torque wrench, wielded by a highly trained fitter, there was of the order of 25% scatter between the bolt which was stretched the most, and the bolt which was stretched the least.

Using grease anywhere on the bolt is a bad idea, becasue you then get more stretch of the bolt for your torque, and you are over-stressing the bolt. However, as the under head (or radius) section is at a larger radius from the centre line of the bolt, changing the friction here has a larger effect on the torque to preload conversion.

Using grease on the wheel to hub joint face is also a bad idea, because this face transmits the drive and braking torque. Some calculations I did demonstrate that you would get slip across such a grease joint under hard braking conditions.

Slip across the wheel and hub interface is bad because this loads the bolts in a way they were not designed for.

If you are concerned about alloy to hub corrosion, it's better to remove wheels frequently, perhaps as part of a rotation regime, and clean thoroughly.

It happens that manufacturers have long known about the abuse meted out to wheel bolts, and they tend to be designed with a large margin of safety or margin for bodging!, and so people tend to get away with it.

On commercial vehicles, the design margins are not so large, and wheel loss is much more common.

With bolt through spacers the original stretch design spec is no longer valid as the bolt is now longer hence can deform more along its length. This results in less compressive force being applied to the mating surfaces hence adding more stress to the bolts. Coupled to the extra stress added to the bolts as a result of the leverage effect of moving the wheel outwards off the hub it can seriously stress the bolts.

In addition to this spacers will affect steering geometry. Most mnodern vehicles have negative scrub radius - i.e. the contact point of the centre of the tread is inboard of the imaginary line drawn through the steering axis (the point about which the tyre will pivot). Negative scrub is highly desirable for ABS braked cars to prevent snatching of the steering as one wheel brakes and releases under the influence of the ABS system. On a positive scrub setup this would cause a lot of feedback through the wheel.
Scrub radius is also important for feedback through the steering. A zero scrub setup would have poor feel. High scrub radiuses will have a lot of feel (and potentially kickback through the wheel if positive.
Negative scrub also automatically compensates when wheel hits a bump by applying a force in the opposite direction to the force generated by the bump (another reason negative scrub is common on modern vehicles).
Fitting spacers will therefore reduce the amount of negative scrub (or increase positive scrub on some vehicles). This may have undesirable effects on the vehicles steering feel - especially on bumpy roads or when ABS is operating.
Moving the contact patch outwards also stresses (and can wear) wheel bearings more (loads are now away from the design centre of the bearings and load suspension ball joints more by acting as a larger lever on the joints.
Finally the spacers can also reduce effective spring rates. In simple terms the spacer acts as an extension to the lever (suspension arm) operating the spring hence softening it and increasing wheel travel (which may cause bodywork issues).

So in summary:
1. Increases loadings on wheel bearings.
2. Increases loadings on suspension pivots
3. Reduces effective spring rates
4. Alters steering geometry which can cause stability issues (esp under braking).
5. Reduces the safety margins inherent in the wheel retention system (for bolt through spacers as opposed to bolt on spacers).
6. They are banned in many forms of motorsport.
7. They are banned in some countries for road use.

[S8QUATTRO]

Think I might leave it for now

[S8QUATTRO]