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Coil over leaf spring
Posted: Wed Aug 06, 2008 1:52 pm
by poppywhite
Has anyone any experience of coil over leaf suspension. I was thinking of using air helpers to assist with sagging but worried about punctures. Home is down mostly unmaintained corrigated forest road and I pick up a bit of shrubbery! and flatten the leaves especially front. Outback susp in Vic do this. Your thoughts and experiences appreciated
Toyota HZJ75
Posted: Wed Aug 06, 2008 3:43 pm
by Gwagensteve
I can see no sound reason for coil over leaves. Most of the claims made by Outback in Vic don't really hold up- i.e It's not possible to have more travel and a better ride and more load carrying...
Airbags are a bit different as at least you can tune the bag to payload.
If you don't carry a very wide range of loads just get the right leaf spring on the car.
Steve.
Posted: Wed Aug 06, 2008 6:15 pm
by joeblow
yes, coils on leaves....rubbish.
Posted: Wed Aug 06, 2008 6:54 pm
by phil94delica
I have air bags in the back of my delica. They are great on road for carrying weight and help with body roll, but they are no good off road so I let them down. Inflated they are to bouncy and limit articulation even more ( not that a delica has much to start with.)
Posted: Wed Aug 06, 2008 8:49 pm
by redv8lux
Ring Bryce at Bairnsdale springworks(vic) he has done his own custom coil over leaf setup on his 4 runner ,has spent a fair bit of time swapping in diffferent combinations to find out what was the best setup
Posted: Wed Aug 06, 2008 9:15 pm
by joeblow
i think the best set-up is putting control arms in place of the leaves...
Posted: Thu Aug 07, 2008 8:50 am
by poppywhite
Gwagensteve wrote:I can see no sound reason for coil over leaves. Most of the claims made by Outback in Vic don't really hold up- i.e It's not possible to have more travel and a better ride and more load carrying...
Airbags are a bit different as at least you can tune the bag to payload.
If you don't carry a very wide range of loads just get the right leaf spring on the car.
Steve.
Yes Steve I also think claims made by Outback in Vic don't really hold up- i.e It's not possible to have more travel and a better ride and more load carrying.
I really just want to extend spring life and maintance.
property owners were getting 12 months from spring set (school bus 2x day) regardless of brand. They changed vehicle to 100 series cruiser and had no further issues, I havn't had much better in HJ47 50mm from bumpstop to axle 15 months. Current HJZ75 has noticable flattened on front in 6 months!
My brother has air bag on rear of 75 series and wants to install on front to reduce spring sagg. He swears by them.
Lump of tree and branch through one is my isssue with air. Is usual to pick up some and have it jammed up underneath on most trips to town.
Thanks

Posted: Thu Aug 07, 2008 9:11 am
by Gwagensteve
IMHO coils over leaves won't extend spring life or maintenance at all without making the ride harsher.
Let's say your current rate is 300lb/"
If you add a soft coil - say 150lb/" you'd need to take 1/2 the rate out of the leaf spring to maintain the same ride. That won't leave many leaves to locate the axle, so axle tramp, spring wrap etc will all get worse - the're just less metal holding the axle in location.
Bags are different because you can tune bag pressure until it's "just enough" but that might be such a low spring rate that a coil spring basically couldn't be used- it would be too light.
Comparing a leaf spring car to a coil spring car isn't a fair comparison. Leaves locate the axles as well as provide springing. 80/100 series also have very well designed progressive bumpstops that help to save the springs (they actually have 2 bumpstops per corner - one progressive one inside the spring and a hard stop on the axle.
I also don't really think airbags or coils are a valid way of reducing "sag" if the car is sagging with normal use, the spring rate is inadequate for the job. I guess it can be "boosted" with a coil, but I really don't think it's going to help spring life much at all. I would only agree with the use of bags to return a car to it's normal ride height once additional load is added.
I'm sure there is a leaf spring out there that can do your job.
Steve.
Posted: Thu Aug 07, 2008 1:35 pm
by poppywhite
Thanks
redv8lux wrote:Ring Bryce at Bairnsdale springworks(vic) he has done his own custom coil over leaf setup on his 4 runner ,has spent a fair bit of time swapping in diffferent combinations to find out what was the best setup
If you know him could you ask him to contribute? I would value his contribution and Possibly I'm not the only person with an interest in this topic.

Posted: Thu Aug 07, 2008 8:52 pm
by redv8lux
poppywhite wrote:Thanks
redv8lux wrote:Ring Bryce at Bairnsdale springworks(vic) he has done his own custom coil over leaf setup on his 4 runner ,has spent a fair bit of time swapping in diffferent combinations to find out what was the best setup
If you know him could you ask him to contribute? I would value his contribution and Possibly I'm not the only person with an interest in this topic.

I work right next door to him ,but i'm not sure if he's online
Will mention it when i see him next
otherwise anyone interested can give him a call
(03) 51525966 ask for Bryce