Uprated Shocks

[VerMonsterRV]

Hey all, so while doing our parabolic spring swap I took the quick, dirty and inexpensive route in replacing our worn out shocks with standard Monroe truck shocks. I knew at the time that they were not the right or best option but trying to get the truck going and livable helped make the decision. Now fast forward to now, DFF has told me (after I inquired) that given the new springs have more travel I need shocks that allow for more down travel. So I have started to look into the various alternatives.

1. Marquart in Germany makes a shock for this truck/spring combination. Sort of a blind faith purchase as their website does not have any details about the shocks. I have also directly inquired and still not much info. Price 700 euros plus shipping for all 4.

2. Fox has a commercial truck line of shocks, not a whole lot of info on those either (but I can likely get it when I call). They use them on LMTV's so maybe they are ok. Looks to be about $1k USD for 4 without any discounting. Still need to find a spec chart for length/size as they do not list an LN2. Not sure if these are really intended for rough roads or mainly highway.

3. Fox or King "Smooth Body" shocks with external reservoirs. All the details about these shocks available on the respective websites. Can possibly get them "tuned" for our truck as part of the purchase price. Looks to be between $2-2.5k USD. Bit more than I would like to spend on shocks but will do it they are the best long term most durable option.

4. Fox/King top of the line shocks, well they look really nice but out of our budget.

We just drove about 30 miles on pretty serious washboard. We can travel at 30-35mph in 4th gear pretty dang well, without airing down. Next test is to air down and give it a whirl (still have yet to connect the truck compressor into our DC air tank circuit, airing up will take a long time). On the airing down bit, looking into some auto deflators as doing one tire at a time manually is tiring.

 

[DiploStrat]

I would go with the German option, if only 'cause they'll fit and the price is right.

Had Fox external reservoir shocks on the Tiger and they were great, but probably way overkill. We are simply never going to drive this kind of truck, on that much washboard, at that high a speed, for that long, to induce shock fade. (Now that the Sahara is closed the two big exceptions might be Australia and, perhaps, the Yukon.)

I have an air jack plumbed into the air system. Lets me use a standard inflator hose. Works, but very slow.

 

[VerMonsterRV]

I would go with the German option, if only 'cause they'll fit and the price is right.

Had Fox external reservoir shocks on the Tiger and they were great, but probably way overkill. We are simply never going to drive this kind of truck, on that much washboard, at that high a speed, for that long, to induce shock fade. (Now that the Sahara is closed the two big exceptions might be Australia and, perhaps, the Yukon.)

I have an air jack plumbed into the air system. Lets me use a standard inflator hose. Works, but very slow.

Thanks, and you a most likely correct about the shocks. The "commercial" Fox shocks would sorta be nice as they are rebuildable, but gotta make sure they are the right fit. Also, the King "Smoothy" shocks are not terribly much more expensive and they have an external reservoir. Our plan is to eventually drive to the Yukon and ship to Australia so want to build to that spec. Problem is I really know very little about 4WD trucks and suspensions, so a steep learning curve.

My plan with the air system to to tie the truck compressor into the 24v DC compressor system so they work together. Just need to take a bit of time and screw in a couple of fittings and a hose. I also have seen on the German LN2 forum someone has adapted a modern Iveco pump to our engines. Way more capacity, but I am not likely to make that change unless something drastic happens.

 

[Geo.Lander]

Hey all, so while doing our parabolic spring swap I took the quick, dirty and inexpensive route in replacing our worn out shocks with standard Monroe truck shocks. I knew at the time that they were not the right or best option but trying to get the truck going and livable helped make the decision. Now fast forward to now, DFF has told me (after I inquired) that given the new springs have more travel I need shocks that allow for more down travel. So I have started to look into the various alternatives.

1. Marquart in Germany makes a shock for this truck/spring combination. Sort of a blind faith purchase as their website does not have any details about the shocks. I have also directly inquired and still not much info. Price 700 euros plus shipping for all 4.

2. Fox has a commercial truck line of shocks, not a whole lot of info on those either (but I can likely get it when I call). They use them on LMTV's so maybe they are ok. Looks to be about $1k USD for 4 without any discounting. Still need to find a spec chart for length/size as they do not list an LN2. Not sure if these are really intended for rough roads or mainly highway.

3. Fox or King "Smooth Body" shocks with external reservoirs. All the details about these shocks available on the respective websites. Can possibly get them "tuned" for our truck as part of the purchase price. Looks to be between $2-2.5k USD. Bit more than I would like to spend on shocks but will do it they are the best long term most durable option.

4. Fox/King top of the line shocks, well they look really nice but out of our budget.

We just drove about 30 miles on pretty serious washboard. We can travel at 30-35mph in 4th gear pretty dang well, without airing down. Next test is to air down and give it a whirl (still have yet to connect the truck compressor into our DC air tank circuit, airing up will take a long time). On the airing down bit, looking into some auto deflators as doing one tire at a time manually is tiring.

What was the focus on external reservoirs? The amount of servicing you will have to apply to them is daunting if they are anything like MTB damper units. shim stacks, seals have to be serviced regularly as the external reservoirs facilitate adjustment in the form of high and low speed on both rebound and compression (via adjustable stacks). If you don't need this adjustability just plain avoid external reservoir shocks.

What do we need on these trucks is a fairly constant damping, rebound and compression speed I assume. With a heavy focus on rebound speed. Looking briefly at Koni website it seems the standard LN2 shocks have defined eye to eye measurements for the LN2 series (min455 - max753) with one adjustment (I assume rebound). I got the same offer from Marquart (DFF), seems a bit pricey if you compare it to these prices...

 

[VerMonsterRV]

What was the focus on external reservoirs? The amount of servicing you will have to apply to them is daunting if they are anything like MTB damper units. shim stacks, seals have to be serviced regularly as the external reservoirs facilitate adjustment in the form of high and low speed on both rebound and compression (via adjustable stacks). If you don't need this adjustability just plain avoid external reservoir shocks.

What do we need on these trucks is a fairly constant damping, rebound and compression speed I assume. With a heavy focus on rebound speed. Looking briefly at Koni website it seems the standard LN2 shocks have defined eye to eye measurements for the LN2 series (min455 - max753) with one adjustment (I assume rebound). I got the same offer from Marquart (DFF), seems a bit pricey if you compare it to these prices...

The only issue I have with the Marquart shocks is there is very little info available on their website to what you are actually buying. Wish they had the technical details so I could do a side by side comparison with other brands. I think I may have stumbled (and stumble is the key as Fox shocks support for the commercial division is absolutely terrible, "Inbox Full" I mean come on, and no info online...) onto that we would use the commercial Fox front shocks similar to an 4x4 military LMTV and a 6x6 LMTV rear shock. Trying to get more info from a aftermarket supplier now.

 

[DiploStrat]

Shock absorbers 001.

Most shocks are valved at about 40/60. That is 40% resistance to compression and 60% resistance to expansion. Basically, this means that when you hit a bump, the shock absorber compresses easily and then controls the rebound, thus "absorbing" the shock. This is ideal at lower cyclic speeds, e.g. driving out of the gas station, hitting a pot hole, dip in the highway, etc. This is the valving that 90% of us want.

A racing shock is valved closer to 50/50. As you might imagine, this produces a very stiff, harsh ride.

The issue is cyclic speed or frequency. All of the events in the first examples happen relatively slowly, that is, you hit a bump, the shock cycles - compression/rebound, and then there is at least a moment before it happens again. This means that the shock resets to its normal, mid position. Again, perfect.

Now consider washboard, tole ondulee, corrugations - pick your language. Most folks have never really seen much of the bad stuff as it is now rather rare. Really bad washboard, as opposed to mere potholes and washouts, requires a dry road with lots of heavy traffic. There is even a wikipedia entry on the stuff: https://en.wikipedia.org/wiki/Washboarding Used to be very common on African laterite roads - those big Mercedes trucks and fleets of Peugeot bush taxis ground the roads into miles and miles of killing vibration. (If you don't know laterite, see here: https://en.wikipedia.org/wiki/Laterite)

It is hard to photograph, but this section of road was so bad that the Blazer simply spun out a few times when trying to get up to speed.

The vibration could be so bad that every bolt would loosen.

The good news is that most dirt roads in the world don't suffer this because they don't have the volume of traffic. It was interesting that while the roads in the CAR were worse than the roads in Cameroon, they lacked the washboard because the traffic was so much lower.

So why the 50/50 valving? Imagine, if you will, a 40/60 shock. You hit the first ridge, shock compresses, then expands (rebound), but before it can return to the mid point, you hit the next ridge, and the shock compresses again. Starts to rebound, and you hit the next ridge. So basically the shock will try to compress all of the travel out of your suspension. Can't do this, of course, but it makes the ride rougher and passes more impact to the frame. And the shock gets hot, and the oil thins, etc. This is related to the old off roaders adage that you always take your foot off the brake before you hit an obstacle - you don't want the front suspension compressed.

So, for a Baja Bomber, Paris-Dakar cruiser, you want a huge shock valved closer to 50/50. Each manufacturer will have its own take on the ideal valving. One way to make a shock "larger" is to add an external reservoir so that you have more oil and a greater cooling surface.

Worth it? My old Blazer had the original Rough Country racing shocks and a relatively soft, long travel suspension with big tires. I could drive washboard all day and so fast that I had to watch the speedometer. The penalty was a stiff ride around town.

The larger and heavier your truck, especially a camper where you are NOT trying to get air with each whoop de do, the more you want a more conventional valving - you simply ain't gonna be driving that fast.

Believe all of this to be accurate, hope it helps.

EDITED to Add: The Marquart site is short on technobabble, at least in English, but I am encouraged that they list "Expedition Vehicles" separately from "Camper Vans" and they show a MB on their page. I suspect that they make a good and appropriate shock for LN2 trucks.

Now with new EDITS.

 

[DiploStrat]

Shocks 002.

Springs matter. Or rather the internal damping or resistance of the spring matters. In order:

-- Elliptical Springs (technically semi-elliptical): As used on the MB NL2, Blazers, and the back end, at least, of lots of pickups. The friction between the leaves damps the spring action in both directions and this means that you need less shock.

-- Coil Springs: These guys have lots to recommend them, especially if they are progressive coils - that is they become stiffer the more they are compressed. But they have next to no internal damping (no rubbing surfaces) and thus need bigger shocks. The first Range Rover was simply amazing - soft, progressive coils, big shocks, and a ride that left all the Land Rover drivers amazed. (Land Rovers have springs? Never felt 'em!)

-- Air Bag Suspension (e.g. Keldermann): These beasts have no damping at all and need really big and/or double shocks if worked hard. But properly set up are probably the best ride around.

Big, high floatation tires can contribute to a softer ride and this may require a softer shock. Trick is, size does not necessarily equate to soft. In my case, I am running load range "L". I could probably run them deflated and they would still support the light weight of my truck. Back in the day, ******** Cepek made his business by selling bigger (10,11,12x5) tires in load range "B", so called "four ply." The problem was that all of the big tires on the market, e.g. 12.00x16.5 were eight to ten ply and very stiff. As an aside, most of the early Land Rover tires in 6.50x16, were high ply beasts to prevent flats, but they rode like rocks and did not air down well.

 

[LikeABoss]

Kind of a odd approach most likely and maybe wouldn’t work for your heavy application but I was finding a bunch of new take off Raptor shocks on eBay at one point (2017 and 18, after that they have some electronics involved). You could revalve them and have yourself a massive 3” Fox for cheaper than any other source I have seen. Maybe I am missing something and seals wouldn’t handle that weight. I put some on my duramax with deavers and they work great.

 

[charlesrg]

@VerMonsterRV what Shocks did you end up using ? I've been waiting for Fox for almost a year and at this moment giving up. I will reach to King do they have. Have you found an optioin for yourself ? If yes, how is it riding ?

 

[VerMonsterRV]

@VerMonsterRV what Shocks did you end up using ? I've been waiting for Fox for almost a year and at this moment giving up. I will reach to King do they have. Have you found an optioin for yourself ? If yes, how is it riding ?

We ended up with Reinforced Shock Absorbers - Marquart Shockabsorbers shocks. Combined with the DFF. THE FEATHER EXPERT. - START (federfachmann.de) springs our ride and handling are much improved. We did though run into an issue with our rear shocks leaking oil, but Marquart not only is replacing them but also paying for the shipping. They really stand behind their product, which is a bit refreshing. I tried for about a year to get shocks from one of the American suppliers, but ran into problems with the size of the eyes. The rear shocks have a top bolt of 16mm and a bottom of 20mm and no one would do that. Spent about the same amount of time looking for springs in the USA. Both DFF and Marquart knew the truck and could supply their "reinforced" shocks/springs.