Tuning, handling offset of wheels

Offset of wheels

The offset, or commonly refered to as 'ET'-value is a measure for the distance bewteen the inner face of contact and the centre line of the wheel.'ET' comes for the German abbreviations for Einpress Tiefe, or in English: the amount in which your wheel protudes from the wheel-arch, or much it is 'sunk' in. The centre-line can be perceived as the virtual........ of all the forces acting on the wheelbearings. With our Peugeots, the offset is positive, as shown on below drawing. Negative offset obviously would be the case where the face of contact would be on the right of the virtual centre-lijn. The Maxi-versions sometimes need a negative offset.

Example:
The 106 GTi requires an offset of 16 to 18 mm. The alloywheels of a 206 have an offset of 28 mm. To actually create a smaller offset or ET, we need to bring the face of contact closer to the centreline. Using so-called spacers, this can be achieved (in this case, it would not work the other way around: you should not use 106 wheels on a 206 - the wheel would stick out too much!).

You can choose to use spacers for 2 reasons: 1. For compensating the offset, or better yet, to achieve the correct (!) offset - this is NOT harmfull to your car! 2. To make your wheels stick out more.

This last reason is used for looks only (e.g. Gulf Mk 1 and 2 often found in Germany), but is deadly for the handling (unless you actually know what you are doing and (thus) are working for a rally-team ;-) ) and more so for the wheelbearings. When using the correct offset, the bearings are loaded as they in accordance with the design - the engineers at Peugeot have designed the bearings taking in account the dimensions of the brakes, the trackwidth, wheelarches etcetera. If you were to deviate from the proper offset too much, you will be applying a 'momentum'on your bearings - a lever effect, if you will. This will increase the pressure on the bearings anc chances are, they will die an early death. And to make it worse: if your wheels are catching on any part of the wheelarch, this coudl result in a MOT failure.

Try and keep the offset or ET-value within a 3 mm tolerance.

Important:
Don't go fiddling about with cheap plain spacers, get so-called 'hub-centric' ones. These are fitted with a hub, making sure the wheel and spacer are alwars aligned. OZ for instance fits their wheels as standard with their wheels - these click inside the (OZ) wheels. H&R carries spacers in their program which you can bolt onto the hub - the wheel is in turn bolted onto the spacer. Shop around for the spacers and take in account that they may add around Ł130 to the bill.

Make sure - even more so when using spacers - that you use the correct bolts!! Length and type (flat or conical) should be the correct one for your application.

With regards to your wheels, you should always be dead-serious - being taken over by your own wheel on the M1 will be not be that amusing.

Standard Peugeot wheels with offset.

Article written by Sidney Nijeboer.