Corner weighting confusion

[Martin S.]

I’m trying to get my head around corner weighting (flat flooring). Just when I think I’ve got it clear some thing comes along to confuse things! Roger Swifts guide in Komp Korner says that because of the added weight of the driver, the weight on the 2 drivers side wheels should be set to be more than of the passenger side…..I thought the idea was to get the fronts equal weight and let the rear take the uneven load. Or is he talking about diagonal corner weighting to get the 2 diagonal weights matching?

[Revin Kevin]

Martin,

To start with flat flooring and corner weighting are not the same thing. For the best explanations try reading any of Alan Staniforths books on suspension set up, Fred Puhn's book How to make your car handle is a good read also.

Be very careful who you listen to as their are alot of people who claim to know what they are talking about but I'm afraid they don't.

 

Knowledge is Power

 

Cheers

Chris

[oldbutnotslow]

Very True!

Don’t start mucking about by screwing adjustable platformus up and down and hoping!

 

Are you looking for general handling improvements or specifically to help on track days? Either way my advice is to take it to a specialist who

A) has the right kit

B) understands what they are doing

 

 

It has to be be done as an all up weight. ie the weight of the driver with the car set as you would have it if you were either going on track or for normal driving. If you have it set up for track with just you in it and then take a passenger out it makes a difference.

 

To give you some practical figures to look at: -

 

I set mine up with equal fronts.(By the way I am part owner of a set of computer scales)

In his way I should stop in a straight-line Well that’s the theory

 

FYI my car fueled and with me in it weighs 635kg. 🙆🏻 😳 This is distributed 138kg to each of the front wheels and 168kg to the passenger side rear wheel and 190kg to the driver’s side wheel. I use about 6mm of rake fore and aft

 

Alter the rake and the weight distribution changes of course.

 

The easiest analogy to help explain what happens is to sit a 4 legged table on 4 scales.

With no weight placed on the table all 4 corners should be the same.

Now put some weight (the engine) in the middle of one side and call that the front. The weight goes up in total on all 4 scales by the amount of weight that you have added as you would expect.

The weight on the front 2 corners should increase by the same amount if the weight id in the middle of that side but not necessarily by the total weight that you have added as some weight may still be distributed to the rear.

Moving the weight more toward the centre of the table will show that even more markedly.

 

In just the same way if you were to add weight representing the driver over the rear right side the total weight on all 4 scales will increase by the total weight of the driver but its distribution not only affects the side to side weight over the rear two legs but also affect the weight exerted on the front near side and the front off side as well. This diagonal shift also needs to be taken into account.

 

It’s very easy to get your existing settings mucked up in double quick time and is why you should take it to a specialist!

 

The Scales Owners Club have a pc whizz who took a basic idea and turned it into a fool proof means of inputting the numbers on a pc prog that you start with and then by 4 easy stages of ajustments you can get Equal fronts Equal dioganal or Equal overall balance in % terms.

 

I hope that this makes sense. Dont worry if it dosent just let the specialist work it out for you !!

 

 

Grant Taylor

OBNS Motorsport

 

😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here

 

[TopQ1967]

oldbutnotslow,

 

Good simplified information.

I have the books, and a set of Intercomp Pro scales, but don’t know “The scales Owners club”. I can’t find them on the internet.

 

I an also looking for software to keep my data. (Intercomp software or alike).

 

 

Cheers,

 

Quirin

 

 

 

[Tony C]

So, what's the objective of corner weighing if not to flat floor the car - I thought the terms were synonymous.

[oldbutnotslow]

Quirin

Sorry to confuse you. Sales Owners Club is just what the 10 of us call our Association. There is nothing on the Internet about it.

Mine was the first car that we messed up! (Yes we really did!)

There were about 6 of us the inaugural setting up afternoon / evening BBQ. This was before we had the computer programme. It was not made any better by the consumption of beer! One good thing was by the end of the night it did not seem to matter all that much.

 

The PC programme (Excel) has been the key that and setting the rake up before you do the corner weighting.

 

the programme tells you what you should do ie "tighten wheel A until the scale reads XYZ" It then tells you what the other 3 scales will show so that you know that you are on the right track.

3 further adjustments and you get the desired results.

 

Dead easy - NOT

 

Screwing springs up and down with the wheels in situ is not easy and there is a set process to ensure "binding" is kept to a minimum.

 

Its very satisfying when it comes out right though.

 

 

Grant Taylor

OBNS Motorsport

 

😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here

 

[TopQ1967]

Hi,

 

Is it possible for me to get the program?

 

Cheers,

 

Quirin

 

 

[oldbutnotslow]

I Just knew that this would be your next question 😬

 

I will ask the other members as it belongs to the SOC and in particular I will need to ask the chap that developed it.

It may take me a week or so to get back to you but I will come back to you

 

Grant Taylor

OBNS Motorsport

 

😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here

 

[Revin Kevin]

Hi

I agree and disagree, Flat flooring a car takes very few tools (that can be made very cheaply) and is relatively easy with good knowledge (all this knowledge is readily avaliable) and will achieve a very large percentage of what most people want to achieve ( what most of us are able to make any use of, we are not all F1 drivers). Corner weighting is really the icing on the cake and if to achieve the correct weights you push the flat flooring out you will cause more problems than you rectify. The only way to achieve true equal corner weights and accurate flat floor measurements is to have a symetrical car (IE a single seater ) and be prepared to move weight around in the car, like batteries etc. For instance if you artificially balance the front wheel weights of a non symetrical car this can cause oversteer on the limit in either power off or power on situations asymetrically ( IE different in left and right hand turns). It can also cause a very loose rear end in braking and inconsistent rear wheel locking under heavy braking.

As I say, do the reading, make your own mind. Knowledge is power!

 

Cheers

Chris

 

Cheers

Chris

[Tony C]

With an asymmetric car like ours flat flooring/corner weighing is only ever going to optimise the set-up; it's simply not possible to achieve a true "Flat Floor", as you say, without redistributing the mass.

 

I still consider corner weighing is carried out to achieve, in our case, as flat a floor as is possible under the circumstances.

[Revin Kevin]

Tony,

You can achieve a "flat floor", but the likely hood of this being equal weights on the diagonals ( which is what you should be aiming for ) is very unlikely and virtually impossible on an asymetric car. To artificially achieve equal weights on any one end of the car by pushing the ride heights up and down you will cause an imbalance at the other end as previously stated.

 

Cheers

Chris

[Jason Plato]

set the front spring platforms at equal thread heights

 

set a 15mm rake in the rear ride height

 

set the rear springs at equal thread heights

 

add 4 threads in height to the drivers rear spring platform

 

bet you wont be mroe than a few Kg off equal front wheel weights

 

My thoughts are that unless you start moving physical weight around the chassis you will always have about 25Kg extra weight over the drivers side rear wheel - with the driver sat in the car .

 

Dave

 

here is C7 TOP

Powered by Special K, Tweeked by this lunatic here

South Wales AO

[Martin S.]

Thanks to all for the excellent feedback it’s a lot clearer now *thumbup* . I just wanted to fully understand what I was doing before having a go at the Peter Charmichael method. Maybe my headache will go away now!

 

I'll be going for equal fronts with my weight in the drivers seat to get maximum braking.

 

Grant I hear what you’re saying but it’s new suspension that needs setting up from scratch so leaving alone isn’t really an option!

 

Love the simplified version Dave 😬

 

 

BRG De-dion, 2Ltr Dunnel Zetec 165 (now with added track and looking for 15 inch wheels)

[daveley]

thanks to Dave Jackson i now dont have to spend (A) lots of time working on setting up my suspension or (B) lots of money having someone else do the work for me.

for me thats the best post there has ever been on the subject 😬 😬

[Brucey]

Anybody want the 6 x 25kg bags of sand I've just aquired!

 

Seriously, I like Dave Jacksons method, but will modify it slightly.

 

I have recently fitted adjustable platforms to raise my sump ground clearance for 100% road use after changing from 16" wheels to 14" wheels.

 

I intend to set my desired sump clearance (90mm) by adjusting the front platforms equally with 4 bags of sand in the drivers seat (100kg), 2 bags of sand in the passangers seat (50kg) and 1/2 a tank of fuel.

 

I'll then adjust the rear platforms until the back is 15mm higher than the front both sides (keeping the same ballast in place).

 

Then I'm going to build a huge sand castle!

 

Bruce.

[Martin S.]

Personally I'll be using spuds!

 

If you're adjusting ride height at the front it might be worth bearing in mind that for 'ideal' geometry the bottom wishbones should be parrallel with the ground. I would guess to minimise bump steer effects 🤔

[Martin S.]

Just to close the loop on this..............This weekend I set up my corner weights using the Peter C method to acheive equal front weight and adjusting the rear to offset for the bags of sand in the drivers seat. After lots of balancing the car on blocks of wood and general fiddling around it turned out that I had to screw the offside rear platform up exactly 4 turns. So It's a big to the Dave Jackson simplified method

[David Lynch]

Nice job Martin, car looks great. Big for the Freestyle ARB. Got to get me one of those.

Fronts now on (could only put them on upside down to avoid lower wishbone fouling spring C collar ). Rears this week hopefully. Hoping for ride height improvements for road use, softer ARB will be next step.

 

David

 

1.4K SS 😬 Saving for the next trackday

[elie boone]

You also find more " stick " with the Metalistic bushes than with balljoints, making it more difficult to set it up.

[Dobuy]

I used to apply the four threads on my old CC billies and it worked a treat, however the freestyle springs and dampers I now have are completely different lengths to each other. I have used the parallel wishbone for the front and this seems to get me close, but I am confused as well.

 

Correct me if I am wrong, but you add preload (wind up) to put more weight on a specific corner to equalise corner weights. But if you also add preload to compensate for the extra weight of a driver to achieve a flat floor, is that not contradicting the corner weight philosophy

 

Duratec SV, built in Dubai