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Author: Subject: Bit of corner weighting.....
Nickp

posted on 18/2/18 at 03:02 PM Reply With Quote
Bit of corner weighting.....

Thought I'd have a go at this today after reading a method the other day that made sense to me. I managed to get 90kg of ballast into the drivers seat and was aiming to get the rear ride heights the same and then get the front wheel weights the same.
A problem I had was that my '200kg' scales actually top out at 180kg!! This was fine when I was just weighing the car as each wheel was about 150-160kg for a total of 630kg but the extra 90kg tipped it over the edge.
The only wheel I could accurately measure was the NSF at 163kg. The OSR was 10mm lower than the NSR, so I wound up that spring platform until they were even. This had the added bonus of transferring weight onto the light NSF, which was now 170kg but the OSF was still maxing out.
So I then wound up the NSF platform about 10mm until I was at 178kg. When I then checked the OSF that was 178kg too, winner winner chicken dinner
I think it's always a compromise with a single occupant in our cars but will see how this feels on the next track day

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40inches

posted on 18/2/18 at 03:12 PM Reply With Quote
I used a spreadsheet, makes the whole process so much easier. I used one from here
https://robrobinette.com/corner_weight.htm

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se7ensport

posted on 19/2/18 at 09:53 AM Reply With Quote
I just checked my setup notes, Im running 5kg extra on the passenger front, this should be enough to accommodate the weight transfer; it still feels neutral in corners.

Alex

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SPYDER

posted on 19/2/18 at 11:44 AM Reply With Quote
If you were to weigh all four wheels and use one of the many calculators available to optimise your corner weights it would be highly unlikely that your front wheels would end up with the same weight. On a single seater, yes, but with an offset driver,no.
To get your front weights equal you will have made your rear crossweight worse.
Whether this outweighs the perceived advantage of the fronts being the same I've no idea.
Proof of the pudding... etc.
Let us know how you get on. Im intrigued.

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Nickp

posted on 19/2/18 at 03:04 PM Reply With Quote
quote:
Originally posted by SPYDER
If you were to weigh all four wheels and use one of the many calculators available to optimise your corner weights it would be highly unlikely that your front wheels would end up with the same weight. On a single seater, yes, but with an offset driver,no.
To get your front weights equal you will have made your rear crossweight worse.
Whether this outweighs the perceived advantage of the fronts being the same I've no idea.
Proof of the pudding... etc.
Let us know how you get on. Im intrigued.


Yeah it's always a compromise in such a car I guess and I'm no expert as to what works and what doesn't, so I'll see how it feels on track in a couple of weeks (if we get a dry day!!). I need to get some 300kg scales so I can see what's actually happening at the back end too.

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se7ensport

posted on 19/2/18 at 10:21 PM Reply With Quote
8x5 Asda scales and a bit of 7inch timber across a pair gives a pretty good starting point. But you need all 8 level before you add the car.
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Nickp

posted on 20/2/18 at 06:29 AM Reply With Quote
quote:
Originally posted by se7ensport
8x5 Asda scales and a bit of 7inch timber across a pair gives a pretty good starting point. But you need all 8 level before you add the car.


Ta but I think I'm going to get one (or two) of these - https://www.ebay.co.uk/itm/NEW-Heavy-Duty-Digital-Postal-Parcel-Scales-Weighing-150kg-300kg/202191837067?hash=item2f1392978b:g:1gEAAOSwD39aaLEx

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peter030371

posted on 20/2/18 at 08:52 AM Reply With Quote
quote:
Originally posted by Nickp

Ta but I think I'm going to get one (or two) of these - https://www.ebay.co.uk/itm/NEW-Heavy-Duty-Digital-Postal-Parcel-Scales-Weighing-150kg-300kg/202191837067?hash=item2f1392978b:g:1gEAAOSwD39aaLEx


I got one of them to try and they are 'OK'. Repeating the readings gave plus or minus 1/2kg accuracy. Possibly that could be improved on with better pads to sit them on (and keep them level on my garage floor) but I have not had time to do that yet. The actual readings my not be that accurate but so long as they are repeatable then the number is what matters to get a good setup

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CTLeeds

posted on 20/2/18 at 10:42 AM Reply With Quote
I'm keen to see the results Nick. I would assume my 2.8 is almost identical in weight to your 2.5.

Chris

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jtskips

posted on 20/2/18 at 08:05 PM Reply With Quote
Them scales are very poor bought two , sent one back the others going in the skip ,the reading was miles out, think they worked ok for about a day,save your money
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alfas

posted on 20/2/18 at 08:54 PM Reply With Quote
https://www.ebay.de/itm/DIGITALE-WAAGE-INDUSTRIEWAAGE-BIS-200-KG-IN-KILOGRAMM-ODER-PFUND-EDELSTAHL/202231840515?hash=item2f15f4ff03:g:9poAAOSwd1laiHYw

i used 4 of those....this said: their max is 200kg and the "heaviest" corner is "only" 167kg... im only 65kg

maybe time for you starting a diet?

[Edited on 20/2/18 by alfas]

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Myke 2463

posted on 22/2/18 at 09:55 AM Reply With Quote
postal scales.

I bought 2 of these, Large Digital 300Kg 660lb Heavy Duty Postal Parcel Platform Scales 34 posted ebay no 381710698868. weighed myself and only 50g difference between them.





Be Lucky Mike.

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CTLeeds

posted on 4/4/18 at 07:57 PM Reply With Quote
Hi Nick, did you manage to get any further with this?

Regards,

Chris

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Nickp

posted on 13/6/18 at 07:03 PM Reply With Quote
Just got some 250kg Salter bathroom scales to have another go after changing the rear spring rates.
Bit of tweaking saw the fronts matched up again and the rear ride heights level too.
However, I can now weigh the rears too and have a huge difference between them with driver ballast in place. Drivers side rear is nearly 60kg heavier than the passenger side!! I guess there'll always be quite a difference with just a driver on board but I don't think I was expecting quite that much tbh. Maybe I need to compromise the front weights to bring this difference down? Or set it up with a passenger on board? I wanted the car to be at its best when I'm on my own and at 10/10ths on track.

[Edited on 13/6/18 by Nickp]

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