Outer Limits 4x4 Board

Hi i have built a lwb suzuki based truggy and i have a problem getting the front end to flex.It runs a long leaf front in spoa setup with shackle reversal and the rear is an a frame with coils which are only captured on the bottom.The car is front heavy as it runs a commo v6 and the rear only has the weight of the radiator and a 35inch spare.I have been thinking that a swaybar on the rear might force the front to work more or would it be better to make the coils captured top and bottom.Any suggestions or ideas would be much appreciated

if all the weight is up front then it will be flexing to its fullest right now (providing shocks are set up right)... coils in the back are likely to flex more than the front leaves regardless - perhaps limit the flex on the rear to balance the ride rather than increasing the front?

I know yours is leaf front, but check out Jafa's NZ build:

http://www.pirate4x4.com/forum/showthre ... 64&page=10

Looks like he found the front to flex better when the coils were captured both ends.

longer shackles and soft leafs how many in the pack?

Troopy94 - you're on the right track.

You've currently got higher roll stiffness in the front than the rear, so, basically, the rear will have to go to full flex before the front does anything.

This is very common with coil rear conversions and especially GQ patrols.

adding roll stiffness to the rear with a swaybar will sort it. Capturing the coils both ends will help, but you'll still have to heavilty flex the rear before the front starts to work.

Ideally, with a front wheel on a ramp/jack etc, you want the front to do around 50% of the flexing. You'll be surprised how much swaybar it will take in the rear to achieve this.

Factory leaf cars, and well designed factory coil cars, have higher roll stiffness in the rear than the front. Nissan and toyota effectively "converted" a leaf chassis design to coil with the GQ and 80 series, which resulted in inadequate rear roll stiffness.

Range rovers, Gwagens, (hell, even suzuki vitaras) don't use a tapered chassis like nissan and toyota, and the rear springs are as far outboard as possible to improve roll stiffness for a given spring rate.

sorry, that's a bit off topic, but it should help you understand the problem a bit.

Steve.

Gwagensteve wrote:Troopy94 - you're on the right track.

You've currently got higher roll stiffness in the front than the rear, so, basically, the rear will have to go to full flex before the front does anything.

This is very common with coil rear conversions and especially GQ patrols.

adding roll stiffness to the rear with a swaybar will sort it. Capturing the coils both ends will help, but you'll still have to heavilty flex the rear before the front starts to work.

Ideally, with a front wheel on a ramp/jack etc, you want the front to do around 50% of the flexing. You'll be surprised how much swaybar it will take in the rear to achieve this.

Factory leaf cars, and well designed factory coil cars, have higher roll stiffness in the rear than the front. Nissan and toyota effectively "converted" a leaf chassis design to coil with the GQ and 80 series, which resulted in inadequate rear roll stiffness.

Range rovers, Gwagens, (hell, even suzuki vitaras) don't use a tapered chassis like nissan and toyota, and the rear springs are as far outboard as possible to improve roll stiffness for a given spring rate.

sorry, that's a bit off topic, but it should help you understand the problem a bit.

Steve.

THANKYOU VERY MUCH - TOP INFO

Serious lightbulb moment for my understanding of flex.

cheers
Leeham

put in an X-LINK

put in an X-LINK

HOW when it is leaf spring

I think it was a joke Stressed.

Steve.

Thank you everyone for your help i was hoping the swaybar idea was on the right track.Do you think it would be worth trying a front swaybar from a sierra fitted to the rear or would a heavier swaybar be needed.The front leaves are rears out of a mq patrol and there are 3 leaves in each pack which sit nearly flat.

I reckon you'll need more than that, but it's a start.

Steve.

Thanks steve ive got access to a few different swaybars to experiment with i thought id start small and work my way up and try it with the coils captured and free and also would it be better to remove the shocks or leave them in when trying the different setups.

Leave the shocks in and capture the coils both ends.

There's a reason why the factory makes sure the coils don't go loose and part of the reason is what you're currently experiencing.

Steve.

Hi everyone just a little update on progress,I have fitted a front swaybar from a sierra to the rear and it has improved the car alot.I have lost only 50mm droop in the rear but have gained around 250mm more in the front so very happy with that.It has also made the car feel much more stable when driving the ramp as it felt quite floppy before and at the moment i can drive to the top of a 1200mm high ramp without lifting a tyre front or rear.

Nice! Pics?

troopy94 wrote:Hi everyone just a little update on progress,I have fitted a front swaybar from a sierra to the rear and it has improved the car alot.I have lost only 50mm droop in the rear but have gained around 250mm more in the front so very happy with that.It has also made the car feel much more stable when driving the ramp as it felt quite floppy before and at the moment i can drive to the top of a 1200mm high ramp without lifting a tyre front or rear.

Couldn't ask for a better outcome than that! - you've just picked up 200mm of articulation, made your car nicer to drive, and improved your balance - by fitting a swaybar.

Many people will struggle to believe that's possible.

Steve.