Ride Height Problem.

[Mr Morse]

When I adjusted the coilovers at the weekend I set the rears so that the bottom ring was 20mm from the base of the thread, and the front to 30mm from the base of the thread.

Now I have noticed that the rear nearside wheel is slightly higher (5mm) in the arch than the offside. The fronts are equal both sides.

The only thing I can think of that could make this difference is an almost full fuel tank - 60 litres of petrol weighs around 45Kg.

Any thoughts or suggestions please?

[MacRS200]

I have mine set to the same overall length on the stut and the same spring length and get about a 5mm difference in height from wheel centre to arch as well.

Couldn't make up my mind if it was worth changing to get the heights the same so just left it as it is.

[Tony-Bones]

Negative camber lowers the car on any given corner.... hows the geo now?

[Mr Morse]

Negative camber lowers the car on any given corner.... hows the geo now?

Yep, I know that Tony, but given that the strut and spring lengths are the same on both rear corners I would have expected the ride height to be the same. I was pretty careful measuring the distance....I could have been 1mm out but no way was I 5mm out.

[Monster-Mat]

dont set the coilovers equal.

the car is not equal weight on each corner, what you are roughly achiving is whats called "corner weighting", where the balance of the car is done on its weight and not on the ride height alone.

its best to make the measurements from a "floating aspect", in this case the car, use for example the top centre of the arches to act as a datum, and adjust the coilovers to suit this measurement

Edited March 20, 2006 by Monster-Mat

[Mr Morse]

dont set the coilovers equal.

the car is not equal weight on each corner, what you are roughly achiving is whats called "corner weighting", where the balance of the car is done on its weight and not on the ride height alone.

its best to make the measurements from a "floating aspect", in this case the car, use for example the top centre of the arches to act as a datum, and adjust the coilovers to suit this measurement

OK, I understand Mat.....so I need to back and for the rear nearside to wind the spring higher?

I guess it's trial and error until it's equal at all corners.

[Monster-Mat]

...so I need to back and for the rear nearside to wind the spring higher?

..erm yeah

you need to adjust the springs so the height of the CAR is equal, not the springs

Edited March 20, 2006 by Monster-Mat

[Robin H]

would be interesting if you could post the difference in mm between the rear coilovers

[Mr Morse]

would be interesting if you could post the difference in mm between the rear coilovers

Yeah, will do.

Looks like a job for next weekend!

[MacRS200]

IIRC the spring rate on my rear coilovers is 10Kg/mm so for a difference of 5mm that would be 50Kg, seems a lot to me :duh:

[Mr Morse]

IIRC the spring rate on my rear coilovers is 10Kg/mm so for a difference of 5mm that would be 50Kg, seems a lot to me :duh:

Almost full tank of fuel @ 45Kg which sits to the nearside?

The spring rate on the HKS rears is 9Kg/mm so 45Kg fuel is 5mm

[MacRS200]

IIRC the spring rate on my rear coilovers is 10Kg/mm so for a difference of 5mm that would be 50Kg, seems a lot to me :duh:

Almost full tank of fuel @ 45Kg which sits to the nearside?

The spring rate on the HKS rears is 9Kg/mm so 45Kg fuel is 5mm

The "appliance of science" :D

I would run the tank down and measure again with the tank emptyish just to be sure.

[Mr Morse]

I agree old bean, it calls for a quantatative analysis

[MacRS200]

I agree old bean, it calls for a quantatative analysis

So after much measuring and head scratching you will have to decide to set for full, 1/2 full, empty or somewhere in between :D

[Noel]

Easy.... move the fuel tank like monster-mat :D

oh just had another inspired thought......

what weight are you?.... Does the car lean the other way with the driver in.... ?

[Mr Morse]

Getting interesting this......been for a 30 mile round trip and the fuel needle is creeping closer to 1/2.

Measuring from the top of the arch vertically to the centre of the wheel cap, I now measure:

Front NS 309mm

Front OS 314mm

Rear NS 316mm

Rear OS 315mm

So....is it a case of the springs settling out or less fuel in the tank......probably a combination of both. I'll try it again with the tank close to empty and when the springs have settled some more and then see what I get.

[lexus boy]

They will take a little time to settle down.

[MacRS200]

Getting interesting this......been for a 30 mile round trip and the fuel needle is creeping closer to 1/2.

Measuring from the top of the arch vertically to the centre of the wheel cap, I now measure:

Front NS 309mm

Front OS 314mm

Rear NS 316mm

Rear OS 315mm

So....is it a case of the springs settling out or less fuel in the tank......probably a combination of both. I'll try it again with the tank close to empty and when the springs have settled some more and then see what I get.

30 miles on half a tank OMG :o

Eggs, Sucks and Granny come to mind but is the car on level ground when you measure?

[Bazza]

in theory it would be best to measure it when the tank is half full or even half empty !

and with you sitting in the drivers seat

as a road going car its never going to be 100% as there are many variables, passenger prisca for one !!