corner weight figures

[lotusdave]

i have collected 4 sets of bath scales,would someone have the setting figures in kg,& a formula to set the car at,as the weight of the driver & car are all different,dave

[Trevor Newman]

balance the front 2 only

 

all cars with drivers will be different weights

[Richard Price]

As Trevor says, get the fronts the same whilst maintaining the ride hight side to side.

Do you want the car setup for solo low flight, or do you want it set for a passenger?

Which ever, the corner weights should be set with driver (and passenger) normally seated.

[Normans_Ghost]

Dave, I weigh 3 sacks of potato's and 3 cans of Mobil 1.

 

As above concentrate on getting the fronts as equal as possible.

 

Make sure the front suspension isn't binding on the pivot bolts.

 

Unclip the rear anti roll bar (if you have one)

 

Get the tyre pressures equal.

 

I use bits of cardboard cut to correct ride height lengths to check the heights. You won't get all 4 corners weighing the same. Get the fronts the same and the ride height equal all round. This is not as easy as it sounds.

 

But remember you don't have to be 100% accurate for road use as you'll never find a flat peice of road anyway.

 

Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here

You and your seven to The French Blatting Company Limited

[lotusdave]

norman,thanks i will try what out what you said about rear anti roll bar,thanks,dave

[Tony C]

I've used this, the Peter Charmichael's: "Flat floor without a flat floor" and it works fine.

 

*find a flattish piece of tarmac;

*set the spring platforms exactly equal at the front;

 

 

* support the rear of the car with the de Dion tube on

axle stands;

* release the handbrake (just in case the cable tension

does something odd);

* remove driver's side rear wheel and disconnect the

anti-roll bar link;

* make sure that the two anti-roll bar links are adjusted

to the same length, left and right;

* now, jack up the front of the car centrally, underneath

the cross, placing a one inch wide strip of softwood longitudinally

between the jack and the cross to produce a powder coat friendly

knife-edge bearing - the front of the car should be able to rock from

side to side and cannot now transmit any torque into the chassis;

* load up the car with your chosen payload... (driver

only/driver and passenger/driver and half passenger);

* now raise or lower the spring platform at the driver's

side rear corner until the anti-roll bar link is perfectly aligned with

the hole in the anti-roll bar - rocking the rear of the car helps to

settle the suspension;

* re-attach the link, put everything back together, drop

the car down and you're done.

 

Using this method, it will be possible to work out the various settings

of this single spring platform that conform to several load conditions.

You will then be able to switch between optimum settings for

driver-only, passenger and driver or any other chosen setting from one

adjustment. I recommend marking up the threads on the spring platform

so that you can record settings and subsequently replicate them at will.

Tip-ex is very good for this sort of marking.

 

All presuming that your chassis isn't twisted...

 

BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery)

[Normans_Ghost]

Forget to mention that ideally you should have 1/2 tank of fuel.

 

ed - and an empty boot

 

Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here

You and your seven to The French Blatting Company Limited

 

Edited by - nverona on 17 Jul 2006 01:15:19

[Revin Kevin]

Hi all,

If you only balance the fronts you are effectively corner jacking your car, this a technique that Oval racers use to make their cars go roung in circles better. I did realise most people with caterhams were oval racers!

 

Cheers

Chris

[stevefoster]

I don't thing total balance of the fronts is the thing to strive for either.

Do that and the rear will be unstable when braking to the apex.

 

The calculation method / spreadsheet that is in the public domain to help with this does not balance the fronts. It makes them more equal - not balanced.

 

Read Roger Swift's excellent article (I think it is online on this site somewhere) it takes you through the theory.

 

Hants (north) / Berkshire club here

Area meeting pics here

My Racing here

 

[Normans_Ghost]

My BDR cast iron block will not get all four corners equal. There's too much weight on the front. A "K" engined car might. I get front equal to each other and rear equal to each other and maintain the required ride height and forward slope. However the front to rear weights are not equal.

 

Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here

You and your seven to The French Blatting Company Limited

[stevefoster]

Front to rear being equal is not what you are striving for...

You cannot move weight, only affect the way it is distributed across the diagonals.

I bet with you in the car you have something like 51-52% rear weight vs. 49-48% front.

Around this is good for a 7. The K had 52/48 without the driver I believe.

Amount of fuel has a big affect on this as the tank is so far back.

 

 

 

Hants (north) / Berkshire club here

Area meeting pics here

My Racing here

 

[Mike Molloy]

I had a go at the PC FF w/o A FF method.

Got to the stage:

"now raise or lower the spring platform at the driver's

side rear corner until the anti-roll bar link is perfectly aligned with

the hole in the anti-roll bar - rocking the rear of the car helps to

settle the suspension;"

 

Rocking the rear of the car just means it comes to rest in a completely different position each time, up to an inch either way from where it was before. There is far too much stiction in the rear suspension for this to work.

(N.B. All my A-frame bolts were torqued up to the correct values, with weight on wheels.)

I can't see how this method can be accurate unless everything is rose jounted or PTFE coated...

 

 

[Tony C]

It works OK on mine and when I put it on the scales at Millwood it was just about spot-on

 

BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery)

[Normans_Ghost]

Mike, We've discussed this before. I've not "overtightened" the front or rear fulcrum bolts so the car does return to the same point after a bounce. With good nyloc nuts I'm happy and they've never come loose.

 

You have to make the choice.

 

I will probably make steel inserts and shouldered bolts when I next strip the car down so that I can tighten the bolts as much as I want without pinching the arms/bushes.

 

Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here

You and your seven to The French Blatting Company Limited

[Jason Plato]

set the spring / platform heights equal and allow 15 mm rake to rear , then simply add 3 turns onto the drivers rear platform

 

 

 

here is C7 TOP

South Wales AO

[Simon.Rogers1]

Dave - I agree always seems to work well and simple to do.

[Richard Price]

then simply add 3 turns onto the drivers rear platform

Over the last few months, I've seen various different sets of adjustable spring platforms, and 3 different screw thread pitches!

 

Having said that, equal spring length at full droop on the front, and 6-8mm less on the drivers side rear, is likely to get quite close.

[stevefoster]

Yep. 6-10mm more on the drivers damper pretty much covers it.

Corners to withing 5kg's is fine too. No need to strive for the nearest gram perfection.

I like more than 15mm rake. That was the rec for live axle cars in my build manual. Perhaps same for a K? I prefer 20mm for my De dion. Taste / weight dist thing perhaps?

 

Hants (north) / Berkshire club here

Area meeting pics here

My Racing here

 

[Normans_Ghost]

Steve, I think 20mm rake with a Ford or Vx block will be too much. It's probably OK for a "K".

 

I have 15 on the BDR and it seems about right. However the BDR install has the engine almost touching the cruciform at the front.

 

Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here

You and your seven to The French Blatting Company Limited

[stevefoster]

I have to go with what I found out for my car on track.

Piling into the first corner at Lydden hill after a start (and subsquently every lap - all being well), slicks scrabbling for grip, you want good turn in and stable rear under trail braking. This I found at 20mm for my VX. The VX is heavy but is installed farther back than the XF/BD/ straight Zetec conversion set up.

 

Hants (north) / Berkshire club here

Area meeting pics here

My Racing here