10" Rims For W126 500sec

[NEIL MAWDSLEY]

Does any one know the ET,for fitting a 10j rim to the rear of my w126 500sec
1987 ,I have seen them fitted to the 500sec and they are the ones for me !!!
The man selling the wheels thinks its et25 but i dont want to take just his
word for it.???

many thanks Neil.

 

[davidsl500]

You should be able to calculate it from your present setup. So what is the ET and present wheel width?

The ET dimension is the measurement from wheel centreline to mounting face. So if for instance you increased the rim width by 2" that would be effectively adding an inch to each side of the rim and thus the ET would have to increase by 25mm to stop the inner edge of the wheel rim from fouling the body/suspension etc.

 

[Bolide]

Wider wheels

The ET dimension is the measurement from wheel centreline to mounting face. So if for instance you increased the rim width by 2" that would be effectively adding an inch to each side of the rim and thus the ET would have to increase by 25mm to stop the inner edge of the wheel rim from fouling the body/suspension etc.

Succinctly (and accurately) put. The only caveat is that there is usually a limited amount of additional clearance in the inner arch for wider wheels. A 15" wide rim probably wouldn't fit with offset calculated as above but I would imagine a 10 probably would

Best way to check at the rear is to put the car on a ramp and measure the clearance between the inner face of the rear tyre and the inner arch. Guesstimate the inward movement of the wheel & tyre on maximum compression and see if the rim will fit

At the front the problem is exacerbated by the steering. With the existing wheels on full lock you'll probably find the tyres are pretty close to the inner wing at the rear and the chassis at the front. You may need to use spacers or calculate a different offset to prevent the tyre rubbing on full lock, or you may need to adjust the rack lockstops and accept a larger turning circle

If you're going to run into problems I think it'll be at the front with some lock on over bumps. I expect the tyre edge will foul the inner arch at times. A square-shouldered tyre will make this worse

You might be wise to check what rim width & ET the AMG cars of the period ran and stick to that. They would have done the calculations & the tests. Inevitably it's not quite as easy as it sounds!


Nick Froome
www.w124.co.uk