A shocking Rancho report and plea for other shocks (Sachs?)

[DzlToy]

While I am not familiar with Oztech, I would be concerned that any damper not specifically designed to control movement on a #10,000 pound truck, will simply fail just as the Ranchos did. I have heard good things about the RS9000 series and Chris and I talked about this when I was at his shop last year, but if they are designed, built and marketed as rock crawling or off-roading shocks for Jeeps and Toyotas, you are asking for trouble putting ANY light duty shock on a 10k pound truck. They simply are not designed to damp that much mass repeatedly.

Regardless of what you purchase or what vendor you buy from, ensure you know what you are getting and that it is suitable for your application, not just that the eyes and overall length match what Fuso used.

King makes an excellent product that is designed to be tuned and serviced easily. However, it is presumed, at least somewhat, that you have the knowledge to tune and modify your dampers, i.e. race team use. Yes, they make bolt on dampers for Jeeps and Land Cruisers, but nothing for an FG that i could find. So, now you are looking at a custom product that will require tuning in order to excel in your specific application, i.e. a very nose heavy cab over truck.

 

[gait]

I currently have Konis. "Heavy Track". With parabolic springs. Parabolics are known to be hard on shock absorbers as they don't have the inter leaf friction damping of conventional springs. I'm a bit lighter than most FGs at 4.5 tonnes. Also front and rear axle loads about the same - long story about roll centre, front beam axle and roll steer.

Shock absorbers (brand x) first supplied with parabolics leaked oil after 1500km. Monroes lasted about 20,000 km before replacement, should have replaced earlier but circumstances prevented. I now have 82 series Konis - the 50mm Landcruiser lift suited my Canter. So far about 25,000 km on predominantly unsealed roads and tracks with no noticeable deterioration - they still get hot and there's no significant pitching or pogoing. Hundreds of km of continuous corrugations would take their toll on most components regardless of speed. All adjustable. The 82 series are 50-55mm OD with 33 mm piston and hydraulic/gas hydraulic twin tube, 88 series (RAID/Heavy Track) 55 mm OD with 36 mm piston and hydraulic twin tube, 90 series (RAID) 70 mm OD with 42 mm piston and hydraulic twin tube. Of interest to me is the softer bounce harsher rebound which reduced/removed some harshnesss from suspension. I accepted the factory adjustment and haven't been tempted to adjust since.

I'm trying (and failing) to reconcile the Koni models with the discussion in this thread so far. Probably a different planet . My simple understanding is the dampers resist movement with a specified force, and convert kinetic energy (motion) to heat which dissipates through the walls. Simple picture. Too much heat, they fail. Wear and tear, they deteriorate. Too much load either creates too much heat or simple component failure

I've also seen dual shock absorbers (two instead of one) on each corner of Canters. A relatively easy modification. I assume double the reactive force and share the heat load.

Another approach, not an easy option for us, is to install shock absorbers at an angle rather than vertically as in the FGs. The FGs also suffer from the narrow chassis and rear shock absorbers well inboard of the springs which are in turn well inboard of the outer tyre - there's a lot of leverage from tyre to shockie.

I also have about 90 kg of solar on the roof (3.3m) which effects roll - soon to reduce to about 12kg for same power.

 

[Amesz00]

Can I ask roughly what the Konis were worth? And did you get them through atw or koni?
I'm up for some newies on my parabolics, have been looking at kings but dang they are expensive ?

 

[gait]

Can I ask roughly what the Konis were worth? And did you get them through atw or koni?
I'm up for some newies on my parabolics, have been looking at kings but dang they are expensive ?

The advice came from ATW. I struck lucky with the first phone call while passing through Adelaide - around $600 for 4 IIRC. http://www.toperformance.com.au/
Useful that they knew what I was asking about. Generally about $800 seems to be the norm.

So far $/km seems to be panning out ok. Just the up front cost that I didn't enjoy. I'm hopeful that this time I can consider shock absorbers to no longer be consumables.

Dark here now. I'd have to crawl underneath for specific model numbers........

 

[Amesz00]

Did they have options on stroke lengths and/or the heavier raid units? And by the sounds you rate them highly?

 

[DzlToy]

If you are keen to try something a bit outside of the box, and have a place for twin dampers, take a look at ORI struts from the states. They are a bump stop, limit strap, shock/damper and "coil" all in one package. Because they are typically used with a link suspension, you would only need enough "leaf" to locate your axle and prevent unwanted behaviours. They can reduce or even eliminate the need for a sway bar, in some applications.

I have heard good things about the Koni Raid dampers, but have no personal experience. For comparison, check out the Rebel-zilla build and see how massive the dampers are on that truck. Something like 3.5" diameter coils (89mm) and 4" bypass shocks (100mm).

Angling the dampers in could potentially solve some of your problems, but it will also increase body roll, so if that is an issue for you, a larger sway bar (anti-roll bar), may be required. Hellwig makes good stuff.

Good luck.

 

[gait]

Did they have options on stroke lengths and/or the heavier raid units? And by the sounds you rate them highly?

ATW provided Koni model numbers so all the hard work on stroke lengths was done for me. Thus 82-nnnn. I'll crawl underneath and read them when I stop driving today - I need to keep a record.

As far as rating anything highly I'm always loathe. I usually only have "one data point" which makes product comparisons difficult. I also only have my "use case". So all I can really say is they work for me having lasted longer than Monroe and brand X, and are a bit more comfortable. The comfort derives from softer bounce harsher rebound than alternatives. Only rebound is adjustable.

First trip with Konis was Simpson. Had to be careful of speed down some dunes where previous uphill drivers had created alternate scallops as roll could be amplified over successive scallops. I have no comparison. Recent 20,000 km included Tanami, Gibb River, Kalumburu/Mitchell Falls, Old Eyre Highway, etc. which all have reputations for corrugations/rough but in different ways. And a host of desert tracks plus highway. Lots of tyre pressure changes in the Toyos. Broke a rear leaf on Sandy Blight when I got lazy, didn't air down early enough, and hit a very bad patch of corrugations at bad speed - lost concentration and ignored the local by-pass.

To be fair. The previous Monroes took us through Asia on some very rough roads and tracks. Just that they wore out.

I think I drive conservatively. One aspect of driving I pay attention to is "safety". I'm interested in how much control I have when vehicle hits something it shouldn't. Hence reference to pitching and pogoing. All shock absorbers should damp the pitching when front bottoms out in the dip after a cattle grid within one cycle .... tired shock absorbers take more cycles and, for me, a sense of being out of control.

Interesting discussion about control following bush repair to a Landcruiser with front coils and failed panhard rod bracket (a bit wobbly). My Canter doesn't have a steering damper.

I did once find some data on bounce/rebound force specs but can't find again. Historically such data was publicly easily available but tendency these days is to not make it readily available. Toperformance are the Aus distributors for Koni with office in all state capitals.

Long travel coils for beam axle with floppy chassis are a totally different use case to leaves, with very different dynamics.

 

[JohnRogers]

I was quoted $750 for the front pair to suit my NPS 300 the other day in the Koni 88 series. I hesitated as I could find no real reviews on them, so I bought a full set of oztecs from ATW at $175+ gst per corner they approached oztec with their specs to suit parabolic equipped campers and they build them as such. Being that I’m running around under 4500kg I’m hoping it will mean they are running well under their designed duty cycle. Time will tell, if they don’t last I’ll put the Koni 88’s on the front

 

[JohnRogers]

Last time spoke to kings the 2.5 were around $1200 a corner what did you pay?

 

[javajoe79]

My other thought is using 2 Rancho's per corner if necessary. In terms of shaft size and body diameter, the rancho's aren't different than other shocks found on these trucks. Perhaps the failures are ultimately a quality issue. They are very low cost for what they are.

 

[steve4wdaus]

I use Sachs, supplied by SSA Brisbane, best move I have made! Good cost, easily replaceable anywhere in Australia, no questions warranty.

 

[Bris31]

When I got front leaf suspension extended (Carrolls), all 4 shocks were replaced with readily available Fireflex. I think $90 each.
No issue yet after abt 3 years, 35K (6k+ on corrugation). But truck setup is under 4.5T.

 

[PKDreamers]

ATW provided Koni model numbers so all the hard work on stroke lengths was done for me. Thus 82-nnnn. I'll crawl underneath and read them when I stop driving today - I need to keep a record.

Hey Julian ,
How are those Koni shocks going ?
And do you have the part numbers you used?
Thank you.