Thread: Parabolic leaf springs

After reading your posts here and on outerlimits4x4 I decided that I had too many leafs in my rear packs (7mm x 8) when my car is a cab chassis with an alloy tray! Waaay oversprung. So at 9pm last night I got underneath and pulled out the 3rd leaf... took me a couple of hours to do both sides. I should have taken out the second leaf to maintain the even stepping of the individual leafs but it had the military wraps and I didn't want to pull out the bolts in the bushes.

I'm gonna have to take a good look at my suspension, pull out some leaves from the front and get them all reset a little higher and tempered and see how that all goes.

So in the current config it isn't ideal but oh my god did it soften the rear a lot, I can now compress the rear by pushing down with my weight! And I did originally want to take out two leaves but found that my centering bolt was too long!

Anyway I took a look at that Leaf spring design manual by SAE in the library, pretty comprehensive and pretty much tells you how to design the packs from the ground up! It was interesting to note that having leaves with blunt ends is the worst configuration. Chamfering is next best and then there was two other cofigurations that looked like the tips of a flat bladed screwdriver.

Anyway I'm heading out to do some offroad work tomorrow with some of the other guys on the forum, it will be interesting to see how it goes now as before it was the rear which was sorta letting me down in the articulation deparment.

Also, on the rear I have these two big rubber bump stops about 150mm long, are these after market or original items? Does anyone know? Was tempted to pull them out also but I figure I better check how close the tyre comes to making contact with the bottom of the tray (running 33" tyres) and If my shocks can compress all that way also.

The official count is 7 in each side front and 8 in each rear.

Originally Posted by Ruski73

The official count is 7 in each side front and 8 in each rear.

Which model landie?


Stirlsilver, there should be a couple of big rubber bump stops in there front and rear - would have to see a pic of yours to see if they are factory or not.

Glad youa re happy. I would never remove the 2nd leaf, it is a great safety factor in case the main leaf dies.

I'm now actually eyeing off parabolics... $1,600, geez they are expensive... hmm maybe in a couple of months... It's always hard to justify purchase for the car that is the same or greater value than the car!

Originally Posted by isuzurover

Which model landie?

Bog standard Series 3 88"

Originally Posted by Ruski73

Bog standard Series 3 88"

Not quite. See the page from the SIII manual on p3. 9 leaf front and 11 leaf rear is factory.


Stirlsilver NOOOOOOOOOOOOOOOOOOOOO Don't do it - not now you have started with custom springs. Paras may be (a bit) more comfortable, but with custom semi elliptics you can get exactly what you want.

Originally Posted by stirlsilver

....... I should have taken out the second leaf to maintain the even stepping of the individual leafs but it had the military wraps and I didn't want to pull out the bolts in the bushes.

...........

Not quite sure why you call them military wraps - as far as I know they are standard on all leaf spring Landrovers.

John

The 101 landy has a parabolic set up from the factory and they are set up for carrying a payload.
The interesting thing is these springs work best at small defections like corrigations because of the little interleaf friction,but they dont have the off road flex of normal springs.
I personally would rework the leaf pack and reset the original leafs if they are in good nick.
If you have a ex army 2a one of the best things you can do is take a few leafs out (experiment) to reduce the spring rate as the miltiary always set the springs up for over load.
I found some landys like the stage one V8 wagons are very good from the factory.