Cheap way to measure corner weights?

[Guest]

I was researching about suspension set up and came across this

on youtube! Seemed an interesting idea, all you need is a couple of pieces of cardboard, a tyre pressure gauge and a pencil!

 

Ian

 

[6speedmanual]

Nope!

"If you come within 10% you've done a great job."

The measuring technique is fraught with inaccuracies:

How to get the papers exactly parallel and measured patch rectangular?

Contact patch is more oval shaped?

Tyre wall stiffness supports some of the weight.

Tread pattern? Compare a knobbly rally tyre with a slick.

 

Even if the measuring method is not accurate, could it just be used as a comparator?

For this high levels of repeatability would be required which I doubt the measurement method achieves.

 

In corner weighting a car adjustments could be in the region of sub 5% . Eg with 150Kg on a wheel, a tweak could move it to 155Kg,

 

When using corner weight scales and taking precautions to eliminate sticktion/settle car properly, repeatability is around 1%.

 

Is the method useful? I don't believe it can be regarded as anywhere near accurate enough to set up a suspension system.

 

Peter

[Guest]

Peter

 

I kind of thought as much, but I liked the concept using the pound per square inch and the area of contact directly. I suppose the only way it would work if the car was standing on inflated inner-tubes and the oval shape of the contact patch could be accurately measured! Not practical… ☹️

 

Ian

 

[Surreptitious]

Can't you just use 4 x bathroom scales?

 

[6speedmanual]

You can! Very hard to fing wirh big enough capacity.

Some have used a pair on each corner.

It's a lot of faffing about.

I built my flatfloor in my garage, considering various budget options all with their drawbacks and complications. Eventually almost a year later I bit the bullet and bought a set of motorsport scales which are dead simple and consistent to use.

 

Peter

[Jonathan Kay]

Quoting 6speedmanual: 

Very hard to fing wirh big enough capacity.

I don't understand that: 200kg bathroom scales are widely available. Is more than that needed?

 

Thanks

 

Jonathan

[Neil66]

Quoting Jonathan Kay: 

Quoting 6speedmanual: 

Very hard to fing wirh big enough capacity.

I don't understand that: 200kg bathroom scales are widely available. Is more than that needed?

 

Thanks

 

Jonathan

 

Not that easy - I looked at this a couple of years ago, so maybe things have changed... Yes plenty 200kg scales available but they're digital, so they need a tap to switch on and usually go off if no one steps on them quick enough.. I didn't want to make an investment in 4 to find out I was running around in circles...

 

I went with Simon (Meteor) set up instructions and with a little tweaking found a really good balance in handling and perfect braking... Good enough for spirited road driving anyway ;)

[Jonathan Kay]

*arrowup*Thanks.

 

Has anyone found scales that hold the display?

 

Jonathan

[Mankee]

I tried using £4 Argos scales. They were pretty naff and wildly inconsistant though. But you get what you pay for! Would be interested in finding some digital scales that don't have an auto off function, if they exist. Can you modify the electronics inside them so that they stay permanently switched on, until you remove the batteries perhaps? £1000 on some proper motorsport scales isn't high on the agenda!