Corner Balancing

[Brightonuk]

I posted this on FB and have had some responses but maybe here someone with the time an patience to explain the art of corner balancing the car.

Attached are the numbers, have now, I was going for that 50% cross which I seem to have come close to for a first attempt (yes I am in the car)

My concern is the numbers themselves the front left and right have a huge difference as do the rear, should I be trying to get these closer? (And keep that 50% cross)

Then we have the Left and Rear what does this relate to?  

I have a 56% vs 52% +/- variance here, but a 50.8% cross (which is a better number than when I started)

If anyone has a corner balancing print out from a shop It would help me out to see roughly what I should be aiming for, or someone who knows the secret of setting up the car 

I was told why not just take it to a pro? But the point is to educate myself about how to set up the car (and justifying the 600 bucks I spent on the scales) 

 

Thanks for any help 

 

[John Vine]

I had my R400D flatfloored last year at Millwoods.  These were the figures:

Driver weight was 90.5 kg.

Hope that helps.  I don't claim to understand the science!

JV

[Brightonuk]

Thanks

[Tazio]

On FB you mention what you have set the ride heights to, from memory you have a height difference , ie. the rake, of 30 mm, this is so very wrong, as it should be 15 mm. With a 30mm rake you are piling on oversteer.

My concerns are you don't know what you are doing and are currently making the car dangerous. To start with disconnect the anti roll bars, and ideally loosen all of the bolts holding the front and rear suspension, so that you unload the bushes, and do not put preload into them.

Ballast the car, if you typically drive solo, put the equivalent of the drivers weight into the cockpit, dispersed to mimic weight distribution. Fuel, say half a tank, and if you carry tools keep them where you normally do

Now set the rideheight at the front such that ground clearance under the lowest point of the sump, is 75mm.

Now set the front to rear rake, the rear should be 15mm higher than the front, by adjusting the collars on the shockers

Now check the corner weights, again by slight alterations of the collars, aiming to get the sum totals of the diagonals LF and RR, to be equal to the RF and LR ( Left Front Wheel LF, and Right Rear Wheel etc), all looking from the drivers seat.

Put weight on the wheels, and re-torque all suspension bolts again, reconnect the anti roll bars. Check camber and front end alignment toe etc., adjust as necessary. Or take it to someone who knows what they are doing, watch and learn, get a printout, then you have a set up you can replicate.

Remember your rake at 30mm is dangerous!

[elie boone]

Don't you have a screen where you can see the weights of each wheel ? i have a button for each scale so i can activate or deactivate and see the weight in diagonal or even by side or in total.

Linear springs demand a different rake than progressive springs BTW the rake for progressive springs is 35mm

and another myth is that you can use a bag of sand to replicate the human body weight and that is not mine statement but it was a engineer at Van Amerfoort Racing claiming that it was a pity they need te driver in the seat as otherwise they could set up the chassis without even the need of the driver.

place the screen close enough to you so you can read the numbers and take note

[p.mole1]

You do not need all this fancy equipment. All you need is a very flat floor a tape measure and someone who is roughly your weight. Decide how much ground clearance you require and adjust accordingly with a rake of around 10 to 15mm.

If you change your ride height by a significant amount re-check the the toe. Corner weighting is for race cars. You can get good results just with a tape measure. It is often worth checking rear toe and camber, although the level of adjustment is limited to shims. Westfields are far superior in this respect.

Also it's worth checking the front suspension for bump steer, this can be horrendous on some cars  

[Brightonuk]

Tazio I set the ride hight per this information 

Caterham chassis set up 001_0.pdf

Taking the measurements from the chassis tube 

[StevehS3]

#6 that's how I did mine

#4 cars without adjustable platforms eg standard S pack cars are unlikely to have 15mm of rake. From memory mine had well over 30mm until I fitted adjustable platforms. 
 

The diagrams above result in a rake of 35mm for progressive springs. I have always thought 15 was the norm.

I have wondered whether setting the corner weights correctly results in a level car in respect of L to R sides, or put another way if my car is level from L to R what would the weights be like.

[Brightonuk]

OK thanks to all for the education, at this point I am going to invest in a pro watch and learn then come home and place the car back on the scales to see where I went wrong.

Anyone in the market for a set of very lightly used scales (-: 

[aerobod - near CYYC]

My car is level L to R with a near perfect 49.9/50.1% LF/RR diagonal balance. The main noticeable difference is the platform position on the front left (LHD car) is set for about 6mm more coil-over extension than on the front right, leading to an even front ride height with lower wishbones parallel to the ground with me in the driver's seat.

[Brightonuk]

I booked her in for an alignment and corner balancing next week and I will get back to this thread on how much I screwed up and how much I I have yet to learn.

Hopefully helping inexperienced others who wish to attempt this procedure avoiding my pitfalls