Double shocks. Any unintended concequences

[wolley]

Hi forumites

My 130 carries a fair load when I go out and standard shock fade soon after my daily trip. I fitted and expensive brand that is adjustable and works perfect, bht the replacement cost contains a fear factor (for me). I am thinking to do a coversion and fit a double rear set, each side. Are there any cons?

Pros
* Easily available and less expensive (each)
* I have broken shocks in thr past and this option gives me a backup
* I can take ons out (each side) when driving with no load for a more 'conv' drive

Why shall I not do this?

Load I carry on thr rear axle is close to max spec

KR

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[BushWacker]

HC 130s have double springs each side at
the back and I would think they are
matched with the spec shocks ?

You must be doing heavy stuff to
warrant upgrading a HC 130 s suspension...
payloads about 1.5tons

[wolley]

I do carry the full load...
Comparing heat om my shocks with a friends 110 with limute load has a significant temp diff, and I mentioned them fading after some work

Keen to learn more about the pros and cons of double shocks

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[wolley]

HC 130s have double springs each side at
the back and I would think they are
matched with the spec shocks ?

You must be doing heavy stuff to
warrant upgrading a HC 130 s suspension...
payloads about 1.5tons

I do carry the full load...
Comparing heat om my shocks with a friends 110 with limute load has a significant temp diff, and I mentioned them fading after some work

Keen to learn more about the pros and cons of double shocks

Sent from my SM-G955F using Tapatalk

[Mad Manny]

This is why leaf Springs are better.

But surely your problems is the coils, not the shocks?

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[wolley]

This is why leaf Springs are better.

But surely your problems is the coils, not the shocks?

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Have added to the double coils air bags (do you call the inner bags "air bags"?)
Vehicle runs level. Leaf springs versus coils is a diff discussion

Experince on double shocks?

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[BushWacker]

There s a couple who are members of
the Land Rovers Owners Club :
Di and Nigel Hardres-Williams ..
who have/or had a 130 with a very
heavy canopy setup ...
... and I think they upgraded
their back suspension ...
... suggest you try and get hold of them.

[Johannes]

Manny , leaf springs are not better !! But keep on believing what you want !!

[Mad Manny]

I don't think giving advice on double shocks is the correct approach.
Something is wrong. Shocks don' t carry loads, suspension (Coils or leafs) do.
I'd be interested to know why this vehicle is so heavily laden.
I run a small fleet of bakkies which always have 400kg to 1200kg loads.
I've never had shock issues & I fit the cheaper brands.

I do STRONGLY suggest the OP goes to the Club Events section & reads the Weighbridge Thread & then SERIOUSLY considers joining us that day.

[grips]

First what is the brand of your current shocks?

[Hedgehog]

I think a double shock layout would be more expensive to install, than just getting a proper shock that will not over heat or fade.

Just by adding another shock to each end does not mean it will work less or better... It will still have to move up and down the same distance and the same amount of times, thus it will create the same heat.

Sometimes you will even gain benefit by fitting a shock with a larger diameter fluid chamber/cylinder and piston thus having a larger area to disperse or absorb the heat...

But in effect, a proper foam cell shock will remove your heat fade problems. And this will probably work out cheaper in the end...

Oh, and you need to maybe lower your tyre pressures more.

[XJ Junkie]

Defender owners have been running heavy loads on their coils since the 80’s.

It’s the coils that might be worn. Shocks don’t carry load.

[ThysleRoux]

I agree with Manny - shocks do not aid load carrying. Shocks damp and control the suspension to slow down the axle/wheel up and down movement. Would Coilover shocks not provide a better solution to your problem?

[Ty@autoventure]

Hi there.

I would recommend a heavy duty spring set with a decent foam cell pro shock.
I would need to understand how much heavier than the GVM you actually are to advise you better.
The right springs and shocks should sort you amd then if you want to add the air springs to level additional load then you can always use that option.
Give me a call
If you need help.

[Apocalypse]

you need to understand what shocks and springs do before deciding on the double route.

I am personally well against those airbag helpers. if you use them it should really only be for a couple of inches of height adjustment , not for keeping excessive loads off the bumpstops. they are often abused.


So, first of all - springs. Springs are rated in weight over compression - e.g 30N/mm which is about equal to 30kgf/cm - the yanks and poms use the arcahic lbs/inch

it's easy to measure - you put a weight on the coil and when it's compressed by 1cm you have your rating.

It's linear too until the coil is coil bound - if you put 90kg on a 30N/mm coil, it will compress by 3cm (for the pedants, for the purpose of this discussion we are on earth and we are rounding 1kg to 10N ...)

'progressive' coils have closely spaced coils at one end which become coil bound when heavily loaded, effectively shortening the wire length and increasing the spring rate on the widely spaced end.

Length of spring - any spring with the same wire and length of wire in it's construction will have the same rate (until coil bound) - so if the coils are spaced further apart, the free length of the spring will be longer than one with closer coils, but still have the same spring rate.

So, there are several ways that changing springs can work.

1. putting in a longer spring with the same spring rate means the vehicle will sit higher, but the suspension will still compress at the same rate.
2. putting in a stiffer spring of the same length will also make the car sit higher (as it won't compress as much) but the suspension will take more effort to compress.
3. A stiffer but shorter spring will keep the vehicle at the same height but it will take more effort to compress the suspension.

One other thing to note - on a 4 wheeled vehicle one spring works against it's diagonally opposite mate, thats what keeps control. A particularly hard rear spring will push the diagonally opposite front spring into compression if the rear won't compress. thus you can't just stick stiffer rears in the back and hope for the best - you need to balance it out to the front.

Pretty simple and we'll keep it there - there is a catch on any spring suspension and that is there is always a lever attached to it, so the rate at the spring is not the same as the rate at the wheel - and that lever varies according to compression and even worse, on a live axle, it varies with axle to chassis angle.

(yes, that does mean that fitting wider tyres / wheel spacers softens your suspension on independent vehicles but not on live axles when they are level ....)

this nice catalogue gives us the spring rates of some common Land Rover springs:


http://www.acc16.com/gammefrontrunner/c ... mance-.pdf

they are listed in ibs/iinch - multiply by ,18 to get to kg/cm

as you can see - a set of heavy duty upgraded rear springs for a defender / disco 1 / RRS is 90kg/cm (510lbs) - off the top of my head, stock HCAP is around 65kg/cm and 90s and Disco 1s are around 35kg/cm