MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Suspension settings (Again !)

I know this has been a subject of much discussion but I don't recall seeing any threads comment on what is considered a 'safe' minimum setting. By safe I mean without causing damage to the car as opposed to comfort level. My MGF is currently running a 345 mm and am thinking of getting this pumped up although I do not seem to have any grounding problems on speed humps etc. I also don't really want to end up driving around in 'off road' mode either; it looks good low but I certainly do not want to cause any damage.
andrew northcott

Hi Andrew

If you mean "at what height do I run the risk of damaging the underside of my car" then in my experience the lowest practical ride height is about 340mm. Lower than this, one runs the risk of losing the catalytic converter and damaging the toe eye on the front subframe (mine is already hopelessly bent when the ride height was 320mm).

At what height do you risk suspension damage- I don't know, and I don't care to find out!!! Total decompreesion leaves a ride height of 280mm. Therefore the lower the car, the less suspension movement available, and the increased risk of damage... 320mm is probably okay with lowering knuckles, but with decompression of hydragas pressure, I'd *speculate* that this would be bad - as it represents a pressure at least 12.5% under manufacture's specification.

If you haven't got tyre wear with 345mm suspension height, then I'd be tempted to leave well alone. The old saying applies- "if it aint broke, don't fix it"!

R
HTH

Rob
Rob Bell

Thanks, maybe I should leave it well alone. I am not unhappy about the ride hight and handling seems fine. I am just perhaps paranoid about causing damage to the car if running it outside manufacturers specifications
andrew northcott

Andrew, don't worry too much - I ran round with my VVC set at 335 for a long time with the only damage being the towing eye on sleeping policemen. I have now raised it to 350 for the comfort of my girlfriend - she found the ride too harsh at 335 and was beginning to refuse to go in the F!
Jason
jason harris

With the car any lower than 345 just on the Hydragas without lowering knuckles could cause damage to the Hydragas units IMO. Please note the word COULD.

If your car has been lowered with Knuckles you can ignore this point and lower it to 340mm without any problems. My F is at 355 at the moment and I can take speed bumps easy at 40kmh, it was at 330mm one time and it couldnt take them at 10kmh (my K&N pipes kept grounding :-)

Watch out for the inside of your tyres at this height though (assuming you are using standard Rover settings that is).
Tony Smith

Hi,
sorry for breaking in here, but I'd like to add some new pressure measures from a last weekends pump assessment with my homemade hydragas pump.
I stated already several month ago the measures of two standard MGF.
If you recall it was about 29...30 bar (420..430 psi) to reach the hight of 368mm and about 25 bar for the hight 335mm
http://mgf.purespace.de/pumpjob/guidopump.html

On Saturday I helped a friend with a 'lowered by Knuckles' MGF. It was set to app 345 mm, but got a bit to low on the drivers side (335mm).

I will not bore you with to much values. Only the reffering pressure for 368 mm with and without knuckle bolts would be interesting for your knowledge.
With standard knuckles 368mm it where 29 to 30 bar (420..430 psi)
With short knuckles and equal hight it was 40 bars (forty!!) 580 psi for the highlander hight of 368mm

For comparison the hight of 345 mm we got at the standard with 25 bars (350 psi)
and at the lowered by short bolts car at about 30 bars, so the 30 bars (420 psi)

result is an approximate difference of 5 bars (70..80 psi) if you use the short lowering bolts.

Important also is that I got the measures from a RHD MGF and there is a remarkable difference between the drivers side and the co-drivers side pressure of about 20psi.

As Tony said, IMO also any hight below 345 mm (or 360 .. 370 psi will surely shorten the life of your 100 GBP per piece Hydragasunit. Not at the inner valves, but surely at the below located metal mesh armed rubber diaphragma.
This one needs IMO a kind of centered hight working average or it gets stressed to much. The mesh breaks then and grinds at the rubber.
*Pufff*, and off goes the fluid.

http://mg-f.purespace.de/pump/
explains it a bit more detailed for experts, but forgive me, it remains still under construction.

That all isn't proved and I'm also sure that not all cars are build equal. Alone the tolerances of the individual postion of the HG-unit to the wishbones can result in different pressure ranges.

HTH
Dieter
Dieter

This thread was discussed between 24/07/2000 and 27/07/2000

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.