Corner weights

Mark A · April 13, 2021, 16:57

I'm keen to have a go at corner weighting the car, first off I appreciate that I've done this the wrong way around and should have corner weights then alignment. I'm also not keen on spending £1k so I was looking for some cheap 300kgs scales I could use. I've found a set on Amazon with remote display for £22 each so x4 equals £88 total price and then I need to do a bit of maths to complete the task.

Has anybody done this before and what did you use?

1979scotte · April 13, 2021, 19:18

I paid someone a few hundred quid not 1k.
Don't forget your driver ballast.

1979scotte · April 13, 2021, 19:20

Quote from: 1979scotte on April 13, 2021, 19:18I paid someone a few hundred quid not 1k. For a grand you can get yourself a set of proper scales.
Don't forget your driver ballast.

Roj · April 14, 2021, 07:20

I think he meant he wants to scales to do it himself but doesn't want to pay £1k for the proper motorsport ones.

Funnily enough I just read a post elsewhere, where someone had a Mini on some ebay 300kg scales, reckons they do a decent job. £38/ea isn't bad at all!

1979scotte · April 14, 2021, 07:44

Quote from: Roj on April 14, 2021, 07:20I think he meant he wants to scales to do it himself but doesn't want to pay £1k for the proper motorsport ones.

Funnily enough I just read a post elsewhere, where someone had a Mini on some ebay 300kg scales, reckons they do a decent job. £38/ea isn't bad at all!

Seen them for under 30 somewhere.

Petrus · April 14, 2021, 11:15

You only need óne, three about equal hight planks and an extra half hour rotating the scales.
Have one underway btw. 35€ ex 12 shipping. Fingers crosses about customs; is from Switzerland so shoúld sail through but nowadays grrrrrr....
Taking its time but then it is not a perishable so no hurry. Just curiosity.

Dev · April 14, 2021, 13:47

I did something like that a long time ago with an Ebay kit that I split with a friend.
We had a hell of a time adjusting my friend BC coilovers but with my Teins which were set by the factory as far as ride hight it was perfect. Using the scales and then having to make adjustments was tedious. Eventually we got my friends car close as we could and sold the kit but it was worth it because we were able to understand corner balance.

AdamR28 · April 14, 2021, 16:17

From experience:

- The cheapo scales are crap and not worth bothering with. Buy cheap, buy twice.

- Having a proper flat floor is absolutely essential to get a good result. 1mm maximum variation between platforms required.

- Ergo, trying to properly corner weight on the average garage floor with cheapo Amazon / eBay scales is a waste of time.

Sorry!

Mark A · April 14, 2021, 16:49

Thanks for the input everybody.

Hi Adam I'm not doubting your expertise or skills as I know you do this on a regular basis but can I ask why the cheap scales are a waste of time? Is it just that they break or inaccurate?

If its because the readings are inaccurate then surely if I "calibrate" each scale with a 100 or 200kgs so I can see the difference between each scale then I can adjust the figure to take this into account. I had assumed it was important to see the balance between left and right, front and back?

I'm happy to pay for someone to corner weight the car but as with most things until you do it yourself you don't learn and I wanted to understand a little more about setting the car.

Mark

AdamR28 · April 21, 2021, 07:25

Both unfortunately!

The problems I faced were...

- The scales are rated to 300kg. That turns out to be 300 Chinese UDL (uniformly distributed load) kg. So sticking a 200kg point load on them bends the platform.

- You need to bounce and roll the car during the process. The platforms aren't big enough, the screw in feet on the scales suck, and bend the body where they screw in.

- I appreciate it is possible to 'calibrate' the scales, but once the platform has bent and the feet are wonky, readings are all over the place.

MR2 specific issue: the car is nearly a ton alone, with 60% ish rear weight. So that would be over 300kg rear corner weight each side when the car is loaded up correctly. So you need two scales per rear corner and a platform between them to double up. Then you need to raise the front ones by the same amount.

As I said before, there's a reason I have 8x Tesco value bathroom scales and a set of 4 300kg electronic scales sat in my workshop doing sod all, haha.

I do completely get the desire to DIY this and understand more about the process. Perhaps a local car club may have scales you could rent? I know the Nottingham area of the Westfield club has a set, for example.

Petrus · April 21, 2021, 09:40

To do a real good track racing job there is no short cut to pro equipment. Is that nééded?

On my car, for a good aproximation, four scales would be enough*.
It does not matter much if they are accurate as long as they are reasonably consistent. All you need do is compare them. After all you do not need the exact absolute weights but the relative values per corner.

As Adam observes, a flat and level floor is paramount.
Over here I have given up on that.
The only literally level playing fields nearby are the two wheel allignment jigs.

* I have just the one and use it for fun only. ´Calibrated´ it at the coöp.