Suspension options for 70 series? (1 Viewer)

[Black94Prado]

I'm at a point with the truck where it is accumulating a fair amount of weight (roof top tent, drawer system with tools in the back, water storage, etc.) and it's starting to bottom out on me at higher speed off road sections plus the lean to the right is a bit more noticeable. It has a 2.5 or 3" lift with Procomp shocks and unknown springs from Japan, but the setup is pretty old and can definitely use an update. Would the standard 2.5" dobinsons lift kit be enough to keep the rear from sagging and to reduce the lean to the right side? Or are there better alternatives for these rigs? Thanks.

 

[Rigster]

You can get different rated coils from Dobinson's based on static load. I went for the heavier ones for my front, for static extra load of 100KG for heavy duty bumper and winch. I imagine you could look into the same for the rears... not sure if they have heavier than that but you could check it out. I have been told by a supplier that deal mostly with Land Cruisers that the Japanese lifts are not that great... but I have no personal experience with that, so it is just hearsay at this point.

The other option, which may be cheaper in the long run would be to add adjustable airbags on the rears... but that may not rectify the lean.

 

[Felde]

Plenty of options out there. Dobson, OME ...
All have in common: you need to have a sound idea on what your permanent and max weights are.
So: First (!) equip your vehicle with anything to permanently stay on it: Roofrags, bumpers, swingouts, winch, secondary battery, aux tanks for fuel and water...
Weight the vehicle then front & rear.
Calculate additional load that might vary: Fuel, water, flexible gear, food, passengers...
Come up with figures min, average (daily use), max.
Utilize the customer service of the suspension supplier of your choice.
With those figures available they can point you to the optimal setup.

Airbags imho are suitable if you have a heavily changing load of a few hundred pounds e.g. a removable camper cabin on a pickup or very big aux tanks. One should consider it's complexity and cost, too.
Airbags should not be taken as a mitigation to poor requirement assessment or poor estimation on the weights.
Good luck
Ralf

 

[Black94Prado]

Plenty of options out there. Dobson, OME ...
All have in common: you need to have a sound idea on what your permanent and max weights are.
So: First (!) equip your vehicle with anything to permanently stay on it: Roofrags, bumpers, swingouts, winch, secondary battery, aux tanks for fuel and water...
Weight the vehicle then front & rear.
Calculate additional load that might vary: Fuel, water, flexible gear, food, passengers...
Come up with figures min, average (daily use), max.
Utilize the customer service of the suspension supplier of your choice.
With those figures available they can point you to the optimal setup.

Airbags imho are suitable if you have a heavily changing load of a few hundred pounds e.g. a removable camper cabin on a pickup or very big aux tanks. One should consider it's complexity and cost, too.
Airbags should not be taken as a mitigation to poor requirement assessment or poor estimation on the weights.
Good luck
Ralf

You can get different rated coils from Dobinson's based on static load. I went for the heavier ones for my front, for static extra load of 100KG for heavy duty bumper and winch. I imagine you could look into the same for the rears... not sure if they have heavier than that but you could check it out. I have been told by a supplier that deal mostly with Land Cruisers that the Japanese lifts are not that great... but I have no personal experience with that, so it is just hearsay at this point.

The other option, which may be cheaper in the long run would be to add adjustable airbags on the rears... but that may not rectify the lean.

Ok yeah thanks guys I'll do that, contact the supplier and give them a rough idea of the weight of the truck fully loaded and have the appropriate springs sent. I'm thinking Dobinson's because they're a bit more available in Canada here it seems. Soon she'll be a new truck... Just a few more things (and more, and more, and more....)

 

[Omrib]

Plenty of options out there. Dobson, OME ...
All have in common: you need to have a sound idea on what your permanent and max weights are.
So: First (!) equip your vehicle with anything to permanently stay on it: Roofrags, bumpers, swingouts, winch, secondary battery, aux tanks for fuel and water...
Weight the vehicle then front & rear.
Calculate additional load that might vary: Fuel, water, flexible gear, food, passengers...
Come up with figures min, average (daily use), max.
Utilize the customer service of the suspension supplier of your choice.
With those figures available they can point you to the optimal setup.

Airbags imho are suitable if you have a heavily changing load of a few hundred pounds e.g. a removable camper cabin on a pickup or very big aux tanks. One should consider it's complexity and cost, too.
Airbags should not be taken as a mitigation to poor requirement assessment or poor estimation on the weights.
Good luck
Ralf

To emphasize @Felde's point of view, I am usually taking this even one step further (with very heavy vehicles) and remove the load leaves completely.
Instead of the severe, almost indefinite, spring-rate thick flat leaves (sometimes more than one, depending on type and brand of vehicle), I add additional stepped down leaves graduates proceeding towards the welded spring purch length.
This actually decreases the sudden spike in spring rate towards the end of the travel and is more appropriately fitting the type of loading.
To the best of my experience, when standard (daily) to fully loaded deviation is around 20 to 25 percent of RAWR this works really good.

There are a lot of legitimate ways to approach this, and can compensate for lower spring rates with higher compression valving for the shocks (at least from stability point of view) and aur bags are very nice for higher valued differences (between loaded and curb weight), but for simplicity and reliability, the graduated leaf stack had always performed very well for me.

Good luck with your setup

 

[malteser]

So first of all, I'm assuming your vehicle is a KZJ/LJ/77/78/79 from your username. I am saying that just to clarify what suspension system we're talking about. If its a heavy duty leaf sprung follow these fellow members advice and you'll be sorted. If its a coil sprung Prado I can give my 2cents cos I've been through this more then once

First off, definitely don't go for the 65mm Dobinsons lift. They only offer that in medium duty and its way too soft (was my second suspension set). The 40mm lift comes in HD, that might be better. I've read users, mostly Aussies, got custom rated springs done from Dobinsons but outside of Australia I doubt if that would be possible. OME's HD springs are also 40mm lift. The only brand I know of that make higher HD springs is Ironman, which are 50mm but when installed look exactly like a Dobinsons 65mm lift.

My third (and hopefully final) spring set is rear Ironman HD springs and on the front chopped King progressive 76 series springs (you need to cut the last coil which has a smaller OD). I went this route since I think from factory the front is way too soft and all the suspension manufacturers didnt increase their springs' rate enough for it not to bottom out, and keep some proper lift (any kit you'll buy you'll find the front sits much lower then the rear).

 

[malteser]

Oh bdw I'm also running heavy (front/rear steel bumpers, rock sliders, drawers, rtt, fridge, tanks, etc), if you want the following is my build, I had recently posted about this suspension change, theres a couple photos and info you might be interested;

Builds - 1993 LJ79 from Malta

Just came across this thread. Not many times do you find a Land Cruiser owner on Malta. I live on the island for a few months in-between a stint in Sicily. Beautiful country. I lived in some apartments across the highway to the east of the university of Malta.

forum.ih8mud.com

 

[GTSSportCoupe]

So first of all, I'm assuming your vehicle is a KZJ/LJ/77/78/79 from your username. I am saying that just to clarify what suspension system we're talking about. If its a heavy duty leaf sprung follow these fellow members advice and you'll be sorted. If its a coil sprung Prado I can give my 2cents cos I've been through this more then once

First off, definitely don't go for the 65mm Dobinsons lift. They only offer that in medium duty and its way too soft (was my second suspension set). The 40mm lift comes in HD, that might be better. I've read users, mostly Aussies, got custom rated springs done from Dobinsons but outside of Australia I doubt if that would be possible. OME's HD springs are also 40mm lift. The only brand I know of that make higher HD springs is Ironman, which are 50mm but when installed look exactly like a Dobinsons 65mm lift.

My third (and hopefully final) spring set is rear Ironman HD springs and on the front chopped King progressive 76 series springs (you need to cut the last coil which has a smaller OD). I went this route since I think from factory the front is way too soft and all the suspension manufacturers didnt increase their springs' rate enough for it not to bottom out, and keep some proper lift (any kit you'll buy you'll find the front sits much lower then the rear).

I've been through three suspensions myself, and couldn't agree more with malteser ^^ Listening to his advice will save you lots of money trying different things.