Leaf Springs - 2018 Ford Ranger

I looked on the Ironman4X4 website. It wasn't very helpful - I guess you tried that.

My guess is that it means suitable for up to 300kg constant load. Hopefully someone can confirm

I agree with Frank's guess.

My interpretation is that compared to the original springs, it should be capable of holding up the level to 300 kgs more.

Original springs appear to be suitable to make the vehicle ride nicely when empty but load them up and they sag.

Cheers, Duncan

Scruffy
The auto parts industry isn't necessarily staffed with people from the auto industry, rare in fact.
I see it as the SET of the spring holds the vehicle in the same ride height position with an additional 300kg loaded onto vehicle. However it may be higher ride height when unloaded as a result and tail "up" compared to std spring. Where the load is positioned also has a large bearing on the ride height position with any vehicle. At the tail the worst of course. Ask where the load is positioned for the rating of their springs and see their eyes glaze over.
Some springs are able to withstand the additional 300 and still be at the same dropped height which std springs would be at.
Where they are actually set initially varies and so any desired ride height has to be worked out what you want/tolerate for when unloaded, so it is ok when loaded with that additional load.

Not sure almost anyone in the sales depts analyse springing for the above, they simply sell to what the book says for a load value, they know nothing more than that. Best, by prior negotiation, to check and ensure any fitment "can and will be", altered to see you happy with what you wanted.
Now, straight answers is something bordering on the hens teeth concept!.

If seriously considering such springs, you WILL load your vehicle with 300kg of "bricks" or similar, ie, before and after, so a known loss of height is measured at the axle clearances and then you are armed with knowledge what you want to prevent and the situation you want to achieve. If not done, you are at their mercy when trying to get what you want because you have no background or base to negotiate from.

Its the amount of load that the spring pack is designed to carry and maintain the nominal ride height. The stock springs may be able to carry 600kg, but the back end will sag and you will be intimate with the bump stops over lumps and undulations as the spring pack isn't up to it.
Springs are manufactured and given a 'rate', which is how much they will deflect with a given force applied. A spring pack that is made to carry more load will have more leaves and/or heavier leaves to support the weight without deflecting as much as a thinner leaf, but will be a horrible, bone rattling ride with no load onboard.

A replacement pack that is designed to give 50mm lift (pretty much the industry standard) and 0- 300kg will sit 50mm higher when empty and probably close to factory unladen height with the 300kg on board. The 300+ will be stiffer, so will sit 50mm higher than stock with no load and won't settle much with 300kg onboard, but will be much happier carrying that load over bumps and undulations without compressing to the bump stops as once they compress there are more leaves to bear the load and resist compression.

I have Tough Dog 0-300kg comfort springs in the back of my BT50 (same vehicle, but different) under an alloy tray. The ally tray is around 100/150kg lighter than the style side body, so I'm a bit ahead there. My camping set up is around 450-500kg fully loaded and with that on the back it sits bang on the height it left the factory.


I find them much better than the factory springs as they are a bit taller, so when empty they have more flex to soak up the bumps, but then load carrying leaves can then come into play and it is rare that I hit the bump stops, even when fully loaded. Its not passenger car smooth, but pretty good. Before I fitted the springs and had the same load on it was often nudging the bump stops, even on reasonably good roads and the back end felt like it was wallowing around as the springs just weren't up to the job.

The big question is how much 'stuff' do you constantly have in the back? If you motor around basically empty, then the 300+kg will probably be too much and the 500+kg will probably rattle your teeth loose as they will be very stiff. We have them under a Patrol fire truck and with less than a full water tank, you just about need a kidney belt.

It might also be worth going and seeing a suspension specialist (not Pedders), I had a bit of an idea what I wanted, so went and saw Climax Suspension in Berresfield (bit of a drive for you), He listened to what I had to say, put me straight and got me exactly what I actually needed.

Scruffy : if considering up grade of springs i personally wouldn't look at Irion man from past experiences :(((
King spring QLD give a life time warranty & from past experiences are made & engineered well.. IMO
( note : NOT the super store mob !! )
The 300kg is Constant load carrying I.E loaded over standard weight .

Ain’t it great most of the people selling this stuff can’t actually give the proper information.!!

G'day Scruffy,
As others on this thread have pointed out, changings springs and shockers won't change your legal GVM. Only an authorised engineer's inspection AND (in WA at least) a roadworthy inspection is required to have the GYM upgrade recorded on your vehicle's registration (if you just get the engineer's report and plaque showing the new GVM fixed to the car, it's not necessarily automatically recorded on you rego).
The other factor you will need to consider if loading up and considering upgraded springs to better carry the load, is the rear axle housing will also have a maximum load rating. It should be listed in the technical specifications for your vehicle.
Some mine spec vehicles have their front/rear/or both axle housings strengthened from brand new .
We travel at maximum weight for extended outback touring and had +400kg rear springs packs (as others explained 0-300kg is a spring pack designed to carry that load in the back all the time) which were great, but we broke a spring (fault in the metal we have been told and it does happen). We then had +600s fitted which were ok, given that there is always a load in the back and usually a camper trailer on behind. Unfortunately, we cracked our Isuzu's axle housing ( hence my reference to axle housing rating) and the suggestion is the +600s were too stiff and contributed to the metal-fatigue flexing failure of the rear housing.
Good luck with whatever you choose.
Mal & Naomi Gill