DIY scales.

[Tony Hanna]

I remember watching a friend scale a dirt track car years ago. He had some kind of plates made that sat on the ground on one end and on the scale on the other. The scales he used appeared to be ordinary bathroom scales. I'd have to assume that the plates were made in such a way that the scales would only see a certain % of the true weight so as not to excede their capacity.
I'd like to build a set of plates like that, but I need some help with the math. Mostly figuring out how long the "lever" part of the plate would need to be and how far from the ground "pivot" the centerline of the axle would need to be to drop the weight down to a reasonable ammount for the scales. Also, tips on how to convert the reduced weight back to the true weight over each wheel would be handy.
Thanks in advance,
Tony

[cordes]

Just throw a 25lb weight on top of one of the wheels when you have it on the scales and convert. You might have to adjust the amount of weight, but you get the idea.

There is a simple ratio that you can use to figure out how much the scale will see based on the length of the lever relative to the fulcrum, but I will leave that to someone that knows it well, or a good search of google. It might also help to have the car weighed initially so that you know where you are starting.

[Tony Hanna]

Just throw a 25lb weight on top of one of the wheels when you have it on the scales and convert. You might have to adjust the amount of weight, but you get the idea.

There is a simple ratio that you can use to figure out how much the scale will see based on the length of the lever relative to the fulcrum, but I will leave that to someone that knows it well, or a good search of google. It might also help to have the car weighed initially so that you know where you are starting.

I never thought about adding a set ammount of weight like that. Good simple solution, I like it!
As for weighing the whole car, there are a set of scales in the commercial part of Parkersburg that sit on a lot with no fence, and are left on 24/7.:thumb:

[cordes]

I never thought about adding a set ammount of weight like that. Good simple solution, I like it!
As for weighing the whole car, there are a set of scales in the commercial part of Parkersburg that sit on a lot with no fence, and are left on 24/7.:thumb:

It sounds like you are half way there. I would love to see this when you are done. I think it would make for a rather affordable setup. The only thing I can think of is that you will want to test all the scales in the store to make sure that they are fairly close to one another, as the cheap scales usually vary by a good amount.

[Turbodave]

as the cheap scales usually vary by a good amount.


I agree, everytime I get on the cheap scale I've got at home it reads about 30lbs too high.:o

With the method your doing the inaccuracy of the scale will be amplified by the lever method, so if they are way off it will only make it worse. Also it's not going to give a very detailed measurement, so if your goal is to get the weights dialed in to the oz. that won't happen. However for getting it set up give or take 10lbs on either corner it will probably work fine.

[Tony Hanna]

Well, I figure give or take 10 lbs should be fine. I was just wanting to play with the L/R weight bias a little and figured this would be a good inexpensive way to check the results.