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:blink:

Righty ho then........

Me 90

I am going to have to fit a new rear casing as I have managed to seriously damage the old one (nuther story) and am having a wonder......... :huh:

Basically I have long and very soft springs in there - yep - poss a tad too soft, but for twisters and off road at slow speed loverleey...but I was thinking

I have 2x forward facing rear shock (lon un's too) what would be the effect if I took this opportunity to weld on the casing the same mounts for the base of the shocks and then fitted 2x extar shocks facing backwards via shome additional mounts on the chassis. Thuis way I would have long travel shocks facing both front and rear.

I think this would obvuioulsy add extar damping and maybe means that it may solve the problem I have now of a tad to soft springs when too quick moving off road, can anyone who knows about these things point out the pros cons and is this a worthwhile avenue to persue ?

Nige :huh:

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Why not solve the problem with a pair of Airshox?

They are spring, damper, bump stop and check strap all in one, which gives you a clean uncluttered undercarriage (oh er) :moglite:

plus they are adjustable for ride height, damping and spring stiffness

Image072.jpg

However you may need to check the weight of your vehicle as they are designed to be used in leightweight applications, I cannot speak for Chris Abel but this has not been a problem on the vehicle above, but I will bet it weighs substantially less than your 90

Lewis :)

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Why not solve the problem with a pair of Airshox?

They are spring, damper, bump stop and check strap all in one, which gives you a clean uncluttered undercarriage (oh er) :moglite:

plus they are adjustable for ride height, damping and spring stiffness

Image072.jpg

However you may need to check the weight of your vehicle as they are designed to be used in leightweight applications, I cannot speak for Chris Abel but this has not been a problem on the vehicle above, but I will bet it weighs substantially less than your 90

Lewis :)

No reason why you can't double up air shocks....

Nige, Simon Buck did the same mod on both his RRC and his 110. Oh, and do tell, he you killed your Uber strong laminated casing :lol:

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Sorry Nigel - don't want to do any firework pissing - but.....

Increasing the damping will not make much difference to the suspension bottoming out or wallowing on the road. It will slow it down which will help on a slalom, but little else.

Air shocks seem a great idea, but take a lot of setting up. The spring rate increases with compression - which in general is a good thing, but many have found that for the first part of the travel it is doing naff-all. It does however allow you to 'tune' the suspension characteristics - but it takes a lot of work.

Fox recommend them for light trucks - partly because they are easier to set up. They can be used on heavy 2 ton plus trucks - it's just a bit more tricky to get right.

Ultimately, the simplest way to solve the problem is with stiffer springs! This will give you better handling on the road, better side slope performance and better stability. You will also be able to nail it across bumpy ground without it bottoming out.

Si

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Sorry Nigel - don't want to do any firework pissing - but.....

Si

Firework P*ssing is fine by me.........hence why I asked.

Ok

lets put it another way

What would I gain with twin shocks over single shocks, ??

I spoke to a knowledable mate tonight - who I respect - he says ...

yes it will help 'damping' and 'crashing' about a tad too quick maybe .... but up the poundages too :huh:

His logic is even with the right pounages go too quick and Mr Bumpstop gets an early vsit, 2x shocks helps this

Discuss ?

? :huh:

Nige

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People generally run twin shocks for two reasons.

1. Redundancy - you can bust one and the handling won't be too bad.

2. Heat dissipation - the heat loading is spread between two dampers so you get less suspension fade when racing.

For soft springs, for critical damping, you actually need less damping not more. It is true that it will make it hit the bump stops less often and less hard, but at the expense of your wheels being in contact with the ground less often! One of the main job of a damper is to stop the wheels 'skipping' as the mass / spring go into resonance. You can sometimes see this, particularly on hill climbs where the wheel appears to jump up & down on the slope loosing contact inbetween.

Shock absorbers have a number of pressure sensitive valves which are used at different compression & rebound rates to try to achieve critical damping. Multiple valves allow a single shock to be OK with a number of different rates of spring and mass of vehicle.

Doubling up will push you to the outside of the bandwidth of the shocks and will degrade handling in the extremes (which is often when you need it the most!).

The answer is, I'm afraid, to increase the rate of the springs or the length of the travel. The thing people forget when they fit soft springs is that you have to increase the separation of the axle and bump stop at rest pro-rata.

E.g. If on hitting a bump a 250 lb/in spring compresses 4", a 170 lb/in spring will compress 6". Therefore, to cope with the same terrain at the same speed, you need 50% more travel.

Buggies with coil-overs can usually achieve this, but on a Land Rover, you probably don't want a 4" or 6" lift!

This is where the idea of dual rate springs comes in. You can have a soft spring for the flexibility when you need it and a hard spring for the bump response when you are going fast. However, it's difficult to make a dual rate spring with more than about 20% difference between the hard and soft bits. For most road-going applications that's plenty but off road it's not really enough to give you the best of both worlds. For a vehicle used on as well as Off road, a few hundred % would be really useful so the soft part is fully compressed most of the time and you get stiff suspension and good bump response at speed while getting the extension and over-damping when you need it.

You can probably see what I'm leading up to with this. That's where the idea came from!

Si

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Fit some D44 OME rear springs and X-Eng X-Flex.

Would that cost more than Airshox at £160 ea?

I'm not trying to push Airshox (I dont have them), just curious as I run conventional gen parts springs & pro-comp dampers

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Would that cost more than Airshox at £160 ea?

I'm not trying to push Airshox (I dont have them), just curious as I run conventional gen parts springs & pro-comp dampers

Per corner, OME springs are about £60 and the x-springs are £65 - so you would save £35 per corner over air springs.

Si

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People generally run twin shocks for two reasons.

1. Redundancy - you can bust one and the handling won't be too bad.

2. Heat dissipation - the heat loading is spread between two dampers so you get less suspension fade when racing.

For soft springs, for critical damping, you actually need less damping not more. It is true that it will make it hit the bump stops less often and less hard, but at the expense of your wheels being in contact with the ground less often! One of the main job of a damper is to stop the wheels 'skipping' as the mass / spring go into resonance. You can sometimes see this, particularly on hill climbs where the wheel appears to jump up & down on the slope loosing contact inbetween.

Shock absorbers have a number of pressure sensitive valves which are used at different compression & rebound rates to try to achieve critical damping. Multiple valves allow a single shock to be OK with a number of different rates of spring and mass of vehicle.

Doubling up will push you to the outside of the bandwidth of the shocks and will degrade handling in the extremes (which is often when you need it the most!).

The answer is, I'm afraid, to increase the rate of the springs or the length of the travel. The thing people forget when they fit soft springs is that you have to increase the separation of the axle and bump stop at rest pro-rata.

E.g. If on hitting a bump a 250 lb/in spring compresses 4", a 170 lb/in spring will compress 6". Therefore, to cope with the same terrain at the same speed, you need 50% more travel.

Buggies with coil-overs can usually achieve this, but on a Land Rover, you probably don't want a 4" or 6" lift!

This is where the idea of dual rate springs comes in. You can have a soft spring for the flexibility when you need it and a hard spring for the bump response when you are going fast. However, it's difficult to make a dual rate spring with more than about 20% difference between the hard and soft bits. For most road-going applications that's plenty but off road it's not really enough to give you the best of both worlds. For a vehicle used on as well as Off road, a few hundred % would be really useful so the soft part is fully compressed most of the time and you get stiff suspension and good bump response at speed while getting the extension and over-damping when you need it.

You can probably see what I'm leading up to with this. That's where the idea came from!

Si

What about fitting a central air spring, like the Boge units on the classic's but use an air spring, my thinking is if the air spring is carrying some weight then it effectively makes the vehicle lighter in respect to the rear coils and therefore stiffer. Its another thing I'm planning on the Disco :lol: , its adjustable so it can be inflated for heavy loads or towing.

Andy

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Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmm :ph34r:

Interesting stuff thanks Si.

My thoughts on this were that I remembered when I had a set of Koni shocks, they were adjustable, and didn't half damp !.....just can't get them in the length I need, so I have the procomps +5, and they don't seem to have half the dmaping the Konis did - hence my thoughts of doubling up.

Yep there is the attraction of having stability if one breaks, but thats a bonus rather than a reason, my exoperiences of double shocks comes from comp safaris and yes boiling shockers was normal !

I'm still thinking around this, can see what you mean by the edge of bandwidth, shame I can't get a "Tougher" shocker, the 9000s are good, but I do wonder....

Springs it may be though,

Much to think through

Nige

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I'm still thinking around this, can see what you mean by the edge of bandwidth, shame I can't get a "Tougher" shocker, the 9000s are good, but I do wonder....

Going by use of Rough Country +5" shocks they don't have as much damping as the +2" deCarbon's that I had on before, so they won't be an option. Gwyn Lewis has used OME Nitrochargers with his suspension and I understand they are more heavily damped so this may be an option. Hopefully someone with experience of these shocks will be able to comment.

Steve

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Going by use of Rough Country +5" shocks they don't have as much damping as the +2" deCarbon's that I had on before, so they won't be an option. Gwyn Lewis has used OME Nitrochargers with his suspension and I understand they are more heavily damped so this may be an option. Hopefully someone with experience of these shocks will be able to comment.

Steve

Hi Steve,

Yep

If I could find a decent shock with the right lengths that would be good :)

I spent HOURS on the www and website etc trawling through manufactuers dtat sheets, but Procomp where virtally all I could find without having custom valving and shocks built to suit (a la mates racer at £600 per corner :o each !), so thats why I have the Procomps.

Ho hum

Rough countrys are out, anyone any ideas for other long travel shocks "Off the shelf(ish) with more damping etc than procomps ?

Nige

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If you want advice Ohlins are based in Alton

aurok

Having stuff valved / set up is not as hard as you may think.

I had +4" pro-comps and 190 Bearmach springs cranked rear arms and it would score 1190 on a twist off ramp.

it could climb over most things but it was carp for handling but it could get across brickiln farm open ground up to about 80mph and still be controllable but it would drift nicely but had loads of body roll.

the RRC has just had OME shocks and spring fitted all round and handles very well and has a carp twist off due to the shock only being +2 but I am impressed with it.

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Going by use of Rough Country +5" shocks they don't have as much damping as the +2" deCarbon's that I had on before, so they won't be an option. Gwyn Lewis has used OME Nitrochargers with his suspension and I understand they are more heavily damped so this may be an option. Hopefully someone with experience of these shocks will be able to comment.

Steve

I have Gwyns kit on my 110 with the +5 procomps. It works well.

Hi Steve,

Yep

If I could find a decent shock with the right lengths that would be good :)

I spent HOURS on the www and website etc trawling through manufactuers dtat sheets, but Procomp where virtally all I could find without having custom valving and shocks built to suit (a la mates racer at £600 per corner :o each !), so thats why I have the Procomps.

Ho hum

Rough countrys are out, anyone any ideas for other long travel shocks "Off the shelf(ish) with more damping etc than procomps ?

Nige

Procomps go up to +8, but pin to ring. I take it you need pin2pin?

What I have through of doing is moving the shocks inside the chassis rail. Yes I know I will not get as much damping. But I am not sure how much damping I will lose and how much more travel I will gain. Not sure what to do with the front yet?

Paul

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Nige, have you calculated what spring poundage you'll need to hit / sit on the bumpstops on articulation?

OME shocks are good but travel is limited (11" IIRC) FYI they do a road and an off road rated damper for the reasons Si mentioned. Procomp seem to be cheap and lightly damped and seem to do a reasonable job off road. Are you happy with the way it handles off road at the moment or is it both on and off road handling you don't like? Have a search around, you can get nice shocks for not that much money. I chose 12" Procomp MX6R's as they're adjustable, high quality and I got them at a very good price. You could probably get hold of a full set for about £600. Not cheap but equally not silly money. The shame is they only go up to 12" travel at the moment....

P.S. you still haven't told us what you've done to your axle :D

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You can sometimes see this, particularly on hill climbs where the wheel appears to jump up & down on the slope loosing contact inbetween.

That hopping is usually because you are running high anti squat values in your rear suspension. Lift a vehicle but keep all the original suspension mounting points (trailing arms and A-frame) and you dramatically increase the anti squat.

FB

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What about fitting a central air spring, like the Boge units on the classic's but use an air spring, my thinking is if the air spring is carrying some weight then it effectively makes the vehicle lighter in respect to the rear coils and therefore stiffer. Its another thing I'm planning on the Disco :lol: , its adjustable so it can be inflated for heavy loads or towing.

Andy

I agree with you Andy. It's a shame that Rover didn't persevere with refining the centrally pivoted load compensator concept, as IMO the difference in crosscountry performance between this system and heavier coils on the sides is very noticable. Also, having dislocating springs makes much more sense when the axle has a central spring or load leveller to apply downforce to the wheel on the extended side. My experience with a hybrid I built some years ago with 130 lb in springs at rear required twin concentric 16'' long opposite wound coils of a combined rate of 400lbs in to adequately replace the Boge unit.

Bill.

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That hopping is usually because you are running high anti squat values in your rear suspension. Lift a vehicle but keep all the original suspension mounting points (trailing arms and A-frame) and you dramatically increase the anti squat.

I agree that's where the force comes from, but the oscillation is allowed to happen by inadequate damping.

There was a hill climb I watched at Mike Wolf and the only truck I saw (out of 5) which did not skip belonged to Tony (White90). They all had the same tyres and similar amounts of lift. Tony's climbed the hill with ease where the others struggled.

I'd be interested to see what springs & shocks he's running.

Si

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OME 764 springs on the front-OME N45F front shocks

OME 781 springs on the rear-OME N44 Rear shocks

the 764s were fitted 07-02

the 781s were fitted 06-05

the front shocks were also fitted 07-02 the rears are a year newer after one was damaged and I replaced both.

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