NO AIR BAGS replacing the cone rubber springs

[old Jack]

I have been looking at this for sometime. "stevemc181" on the Gen4 & "Ent" on the PB/PC Challenger subforums have just started looking so I thought lets start a thread, more brains thinking about this the more options.

When I was doing why rear suspension the aim was to get a coil spring to work well with 200kg in the rear through to 600kg and maintain ride heights of +40mm at 200kg and back to +10mm at 600kg from standard unladen ride height. Having used airbags for 15 years and had a few issues I was determined not to use them if possible.

After 3 sets of aftermarket off the shelf coils I finally got a set of custom extra heavy duty variable rate coils ."stevemc181" has just done the same and "Ent" has his on order, all springs are a little different but the principle is similar.

Mounted inside the rear coil is a factory fitted rubber cone spring, the purpose of this is to add progressive spring rate under deep compression and reduce shock loads on the final bump stops. The standard cones work ok with an unladen car but once you are fully loaded they are way too soft and come in too late in the spring compression. The length and rate of increase of load for deflection is important to get correct.

So far I have found these possible untested options;

1. Toyota 80/100 series bump stop either original or aftermarket from http://www.roadrunneroffroad.com.au/...---Rubber.html
these maybe too long and too firm.

2. Mackay M190, specs are at the bottom of this PDF:

http://www.mackayrubber.com.au/pdf/vibration-isolators/conical-buffers.pdf

these may be too short and too light.

3, Aeon Springs from Hardy Spicer, PDF of range;

http://www.hardyspicer.com.au/rubber_springs.asp

a better range so maybe there is a solution here.

What I really need from someone in Adelaide, that has fitted airbags, if I can borrow the original cone spring. I have found someone that will test progressive load rates, therefore I can tackle this from a mathematical angle rather than the expensive in time and money, trial and error method of R & D.

Can someone loan/give me their old rubber cone spring lying around in their shed?

Edit: Aussie Dan has PM'ed me to say these rubber cones are not fitted to IRS Pajeros, he is correct I have just checked the Service Manual. However the system may still be able to be used in Pajero's subject to being able to attach them.

cheers, old Jack.

[Kingbrown]

My cones (as new) are gathering dust and cobwebs in the shed (somewhat north of you Col), so if you don't have any luck in Adel then I can get them down to you.

[stevemc181]

I'll be interested to see how this all pans out. I haven't had a chance to get offroad with the new King coils yet, but I did notice when using the Lovells CRR-92’s on my last trip down to Yeagarup that she did bottom out fairly hard a couple of times.

[PBding]

OJ, I've been following the posts about springs as I'm not sure I'm completely happy with what I've had fitted,it's fine without the van but.

Anyway I have a pair of the rubber bumpers out of my PB challenger, but they are here in the ACT if other offers don't come to the fore.

Cheers

[old Jack]

Thanks Kingbrown and PBding for the offer but at this stage I wait a while and see what comes up in Adelaide. I have PM'ed a couple of the Adelaide members who have airbags listed on their signature so hopefully that might help me.

cheers, old Jack.

[kbahus]

I would think that if you used an actual bump stop, like the 80 series, it would be way too firm and bounce down the road because there would be no travel. I have been thinking about trying something like this: http://www.prothanesuspensionparts.c...sp?prod=191705

Here is a lengthy thread about using the inserts on Jeeps: http://www.jeepforum.com/forum/f9/pr...te-up-1150862/

Another option is high end rear shocks like King or Radflo and adjusting nitrogen pressures to compensate for the load.

I would have tennis balls jammed in my springs right now but fear they will get snowy, wet, and freeze solid creating problems. The large bolt sticking down also creates some challenges and a reason why I have not tried airbags yet. There has to be more options......

[old Jack]

I would think that if you used an actual bump stop, like the 80 series, it would be way too firm and bounce down the road because there would be no travel. I have been thinking about trying something like this: http://www.prothanesuspensionparts.c...sp?prod=191705

Here is a lengthy thread about using the inserts on Jeeps: http://www.jeepforum.com/forum/f9/pr...te-up-1150862/

Another option is high end rear shocks like King or Radflo and adjusting nitrogen pressures to compenate for the load.

I would have tennis balls jammed in my springs right now but fear they will get snowy, wet, and freeze solid creating problems. The large bolt sticking down also creates some challenges and a reason why I have not tried airbags yet. There has to be more options......

Thanks Kbahus,

I haven't seen these before so I have emailed Protean for load vs compression graphs.

Do you have a Mitsubishi Montero Sport ?
What year?
Do you have a photo or more information about the bolt you have sticking down?

cheers, old Jack.

Edit: I just checked your details a Montero 2003, so I presume coil spring rear, if that is the case then the large bolt which the rubber cone springs locates on is removable, normally done up very tight, once removed there is a threaded nut plate at the top of the coil top pad.

[kbahus]

Jack, mine is an 03 Montero Limited which is like the Pajero NM with independent rear suspension. The bolt on this model that I referenced I believe is one of the sub frame mounting points.

Let us know what Prothane has to say.

[old Jack]

Update on this thread;

No response from Prophane.

I had a rear coil out to check some suspension measurements so I took the opportunity to remove the rubber cone helper spring and do some tests.

It is 110mm long and 90mm in diameter.
Makes contact at EBH of 490mm and within 35mm of compression reaches it maximum compression load of 85kg, further compression does not increase load until the cone is fully bottomed out which is well after the axle/chassis bump stop contacts and compresses at a EBH of 430mm with the coil removed but in real life the coil winds bottom out at EBH 467mm. So the maximum assistance is 85kg per side so 170kg total.

Alternatives?

The Mackay M190 (103mm x 79mm) with a 15mm spacer will contact 7mm earlier (EBH 497mm) and with 25mm of compression apply 150kg per cone (300kg in total) the coils winds bottom out at EBH 467mm so that is about 200kg per cone. These might do the job particularly if I add more spacers (20 mm so EBH 510mm is first contact) so they come in earlier and I estimate they would be close to 300kg per cone at coil bottoming.

I will also check Landcruiser bump stops.

The quest continues!

cheers, old Jack.

[old Jack]

A quick update from some more research.
Peddars do a pair of bumpstops that are 40mm longer and 10mm larger in diameter PN 5899 $122 inc a pair. They are 20% softer than Toyota 80 series and 30% softer than Roadrunners, they are made by Aeon and are progressive rate so I think they could be suitable for the PB PC Challenger. Peddars listed them as replacement for 88-01 Pajero, PA Challenger and 80/100 series Landcruiser.

I will pick up at set to bench test and fit to the Challenger this weekend.

cheers, old Jack.

[Toddyh]

Very interested to hear how you go with that OJ.

[old Jack]

I have not had a reply from the USA Aeon Springs, so I picked up a pair of Peddars PN5899 bump stops and did so compression tests whilst having a Friday afternoon Coopers ale.

I only have a scale that goes to 130kg but here are the compression figures;
150mm - 0kg.
120mm - 50kg, this is when the flutes on the bump stop are fully closed up.
115mm - 90kg.
110mm - 110kg.
105mm - 130kg.

With my EBH of 590mm, the existing bump stop has 85mm before it contacts so that is EBH 505mm then within 30mm of travel it reaches its 85kg at EBH 475mm.

The Peddars bump stop is 40mm longer so it will contact earlier at EBH of 535mm, at EBH 505mm 50kg (this is when the factory bump stop first contacts). At EBH 495 it is 110kg and at EBH 490mm 13Okg, this 150% more load and 25mm earlier in the spring compression than factory!

Full spring scrag/bind is EBH 464mm based on calculations, so I still have 25mm of compression travel left in the Peddars bump stops. I was getting 20kg for 5mm of travel so I will at least get another 100kg per bumpstop before the spring binds, thats 230kg per side minimum!

Ideally I would like a more gradual increase in load rating but since I have not found anything any better and based on the above I am happy to pull the coils out again and change the rubber cone springs bump stops over.

I will also update my thread on rear suspension calculations once they are fitted and tested.

Peddars PN 5899 no load.


Peddars PN 5899 30mm compression, 130kg load.



cheers, old Jack.

[old Jack]

Fitted this afternoon, a straight bolt in job but with aftermarket springs the coils must be removed to get the rubber cone springs in and out. No clearance issues.
Unfortunately it will be several months before I get a chance to get away and test at GVM+ on unsealed roads.

Peddars cone spring compared to standard.


Standard cone spring at EBH 590mm.


Peddars cone spring at EBH 590mm.



cheers, old Jack.

[Toddyh]

Looks good OJ. Might have to consider a pair of these.

[old Jack]

I had a chance to test the Peddars cone springs today. A quick run out of Burra via Mt Bryant to Carrona Creek Conservation Park. The western access track is 26km of very undulating dirt/gravel roads with many creek crossings, floodways and jump ups, most are not sign posted so they can sneak up on you and really test the suspension compression and control. Though not at full touring weight, only about 2650kg, I was very happy with the results. Deep compression is now very progressive and when the cone springs reach full compression there is not the harshness that the soft/short factory cone springs exhibited.

So for $122 plus an hour of my time to fit them, they have been successful mod.

cheers, old Jack.