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Old 18 Aug 2008, 20:27 (Ref:2271175)   #5
GordonG
Racer
 
Join Date: May 2004
Posts: 155
GordonG should be qualifying in the top 10 on the grid
Mumford Beam

There was an article a few years ago in Racecar Engineering (Might have been Race-Tec) about the Mumford Beam. I have used this exclusively for cornerweighting ever since.

All the ideas about using bathroom scales just arent worth bothering with. There isnt the accuracy or repeatability on them, even if you use 2 on a corner.

The mumford beam is just a see saw that you place the wheels of one axle on so that the pivot is halfway between the 2 wheels. I made mine in 2 hours from 2 lengths of scaffold tube (for my lightweight car I could have used much lighter tube) welded about 4" apart with a bit of angle iron for the pivot. This can if necessary be taken to the race/test day strapped to the trailer.

To use, you place the beam under the front wheels, with the rear wheels on a level piece of floor (you only need 2 level patches - use ply or old copies of Race Tec to level the patches if necessary). Pick a horizontal surface on the chassis, and adjust the rear spring platforms so that that surface is truly horizontal (use a spirit level). Then place the level on the mumford beam, and adjust the front spring platforms until that too is level.

Now, when the car sits on a flat surface it will be level, and there will be equal weight on the front wheels. If the car has even left/right weights, there will also by definition be equal weights on the rear wheels and equal diagonals. Even if your car has uneven side-side weights, you still ahve equal front weights, which is arguably as good as equal diagonals as braking is where corner weights have most effect. At worst, it is better than guessing or using even spring platform positions, and your settings are 100% repeatable which ensures consistency.

Enjoy.

G
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