Series 2a - Parabolic Springs?

I was advised to use gas shocks with para's because they work more than standard springs and if you go on the rough stuff for long periods of time the standard oil filled shocks can overheat and fail,can't confirm that as I've only ever had gas shocks with my parabolics.

Sounds like I'll be going for the GB springs then.

This was the advice Paul at GB springs gave me when i emailed him, might be of use..

For a SWB Land Rover Series II or III vehicle, we offer a two-leaf front and
a three-leaf rear spring (true three leaf spring not a 2+1 spring with a
loose helper) - £295.00. The kit includes the springs (handed and clearly
marked Off side and Near side), "U" bolts, nuts and rubber to metal bonded
bushes (standard Landrover sizes). In some instances the leaning issue comes
from springs not being handed. The load capacity for the two leaf fronts is
930kg per axle and for our three leaf rears is 1190kgs per axle. We do not
recommend fitting two leaf front and two leaf rear springs since in our
experience they have caused problems if any reasonable load is carried in
the back of the vehicle. In our experience with a standard set up these
springs should not raise the vehicle more than 1" at most.
Please look at our website to see the spring ends. Our springs are painted
blue.

Our packages are usually available ex stock and are quoted inclusive of VAT
(at 20%) and include 2-3 day carrier delivery to addresses in England and
Wales.

Re your question "I also have a couple of other questions regarding the
change from multi leaf springs, are the standard chassis bushes and oil
filled dampers ok for use with the new springs." The answer is yes to the
chassis bushes and re the dampers we would suggest that if your existing oil
filled dampers are in good condition then refit them and drive your vehicle
with the paras on a normal long run and get out and feel the dampers, if
they are too hot to comfortably touch (don’t be a hero) then you need to
either fit bigger bore oil dampers or gas dampers.

If you compare like with like then I think you will find our pricing for
Land Rover parabolic springs to be the very competitive, but if you want to
give us a ring (07970105775) then we can discuss any other issues you may
want to bring up.

For your information we do not sell shock absorbers but we would offer the
following advice:- If your driving is mainly on Highway with the occasional
sorties off road, but even then the off road work is at slow speeds over
relatively minor undulations we believe you can get away with using ordinary
shock absorbers.
The longer stroking shocks on the market are required for applications where
the increased articulation possible through parabolic springs comes into
play. Then it is possible that you can over stroke the standard shock and
hence the need for a longer stoking shock.
Re the bigger bore shocks available. Here you only need the bigger bore for
when the shock is being excited rapidly i.e.. Belgian Pave type work. That
is in a normal size shock bore the oil starts to heat up when being excited
in this way and ultimately starts to boil since it is impossible to loose
the heat generated. As a result you can fit a larger bore shock to cope with
higher driving speed driving for long distances over ground where the shock
is very active (i.e. Off-road regularly and for long distances).

We also do not fit polybushes as we feel from our development work that they
will not give a noticeable improvement in suspension performance, we will
supply springs without bushes for you to fit your own polybushes. We do feel
that whilst polybushes last longer than rubber to metal bonded bushes there
is no such thing as a "free lunch", hence the forces that normally wear out
the rubber to metal bonded bush must go somewhere and normally with poly
bushes they go into the chassis and the chassis will show wear (i.e. Oval
holes) at the linkage.

We hope you will buy GB Springs Parabolic's for your vehicle and look
forward to hearing from you!!! Please contact us if we can be of assistance.

Interesting letter....that guy sounds like he know what he is talking about.

Decent honest email

Paul is a top bloke and the springs are good quality. However, I would disagree with him on one thing. The standard shocks don't suit the paras, especially if you fit the LWB springs on a SWB as Paul recommended for heavier loads. They felt ok most of the time but were a nightmare over speed bumps and need to provide more damping. I used to have to drive round with a hundredweight of sand or risk having the load jump into the cab. I tried new standard ones but still was too bouncy.

The trouble is the back kicks out too much over bumps and can be a bit giddy. I fitted some de Carbon (Paddocks DA4163, DA4162) and the ride is transformed it turns in nice and speed bumps that used to cause me to bite me tongue off at 10mph can be taken at 30 without even having to make an appointment with the Chiropractor first.

I didn't have problems with the standard shocks overheating or anything like that they were just a little too easy for the springs. The de Carbon ones aren't super hard and not extreme articulation but seemed a good price for something that suited the springs better.

I could never get my head around shocks and paras....I would have thought the soft the shock to softer the ride...or am I arse about face,

Never had the oppertunity to experiment as I just fitted std and they have been on ever since...would be interested in trying a better set....mine will take off going over speed bumps if I dont slow down.

Nick.

Nah, doesn't really work like that. The spring moves due to instantaneous force i.e. the _harder_ its pushed the further it moves. The shock absorber is different the _faster_ you push it the harder it becomes to push.

If you had no shock absorber (damper) then when you go over a bump the car would bounce up and down for ever, the shock absorber because it doesn't like moving fast slow that down to a stop.

The aim is to balance the weight of the car, the springiness of the spring and the damping factor of the damper so that if you push the car down and let go it pops back up to exactly where it was but doesn't over shoot. If the shockers are too "hard" (i.e. too much friction) the car won't come back to its original position at all, if too soft (not enough friction) it will pop up go past where it started the come back etc. etc.

The reason for needing to change the springs is two fold, firstly parabolic leaves don't rub against each other as much as normal springs, that rubbing action on normal springs is friction and therefore provides some damping. Plus the GB springs I got were the ones for a LWB fitted to a SWB which means they're a bit too hard and when you go over a bump empty the back ones don't really compress far enough quickly enough so more of the "bump" gets transmitted to the car making it a bit worse.

Anyway I just had a search and the simulator on this page might make it clearer http://www.shockabsorbersport.co.nz/wawcs0141481/bounce-o-meter.html

dominicbeesley said:

Nah, doesn't really work like that. The spring moves due to instantaneous force i.e. the _harder_ its pushed the further it moves. The shock absorber is different the _faster_ you push it the harder it becomes to push.

If you had no shock absorber (damper) then when you go over a bump the car would bounce up and down for ever, the shock absorber because it doesn't like moving fast slow that down to a stop.

The aim is to balance the weight of the car, the springiness of the spring and the damping factor of the damper so that if you push the car down and let go it pops back up to exactly where it was but doesn't over shoot. If the shockers are too "hard" (i.e. too much friction) the car won't come back to its original position at all, if too soft (not enough friction) it will pop up go past where it started the come back etc. etc.

The reason for needing to change the springs is two fold, firstly parabolic leaves don't rub against each other as much as normal springs, that rubbing action on normal springs is friction and therefore provides some damping. Plus the GB springs I got were the ones for a LWB fitted to a SWB which means they're a bit too hard and when you go over a bump empty the back ones don't really compress far enough quickly enough so more of the "bump" gets transmitted to the car making it a bit worse.

Anyway I just had a search and the simulator on this page might make it clearer http://www.shockabsorbersport.co.nz/wawcs0141481/bounce-o-meter.html

Click to expand...

That link was very informative, must save it.

Mmmmm the link didnt work...think its gone tits up,

I will try again later when the double vision subsides,

Imformative words thanks....I have an idea that my std shocks maybe to still...any easy way to tell???

Nick.