Come on. The only significant difference between off-the-mill Bilstein shock and a Nimbus strut is the rod diameter. Both of them have N2 between 150 and 400 psi - but a 12-mm rod on a Bilstein shock provides ~50 lbs of lifting capacity (as a byproduct of having pressurized can), while ~2" of Nimbus inner body (don't know what the real diameter is) can give up to 800 lbs or so. This is hardly a difference between low/medium and high pressure.
Main point - if you break a regular shock, you still have a coil to support the body. If you break a strut, you're hosed - badly, since the replacement is not available off the shelf in your neighborhood AutoZone (neither is a proper Grenadier factory shock, but you can improvise).
It applies to ANY modification of a vehicle - whenever you use an exotic part, you trade serviceability for performance. Again, in my extensive Land Rover life, I happily used half-ton GM truck shocks whenever Bilstein or OME broke (I never, ever, broke a factory Land Rover shock - however shitty they may have been).
For me, a far more meaningful upgrade would be a combo of lowest-load-rated springs and air shocks. I could bump the pressure for a little lift - no more than 2" - for a rocky waterfall climb and lower it back to keep the driveline together. I'd love to adapt some of Delphi struts to Grenadier, but it will definitely involve hacking of the axle and/or frame brackets.
oh I'll bite... and i've had a nice dinner with some wine, spelling errors and too long text is entirely mine... (and i mean this not to be a fighting war of words, but i think there is more to nimbus than just marketing or superficial similarities with conventional shocks).
The logic of your argument, reducing it to pressure and physics is that the difference between a bicycle pump and an offroad jack is rod diameter?
Have you tried to jack up your grenadier with a bicycle pump - it is impossible....
The physics is similar but the argument of application by simplification of physics is flawed.
The Science: Both use Nitrogen (N2) to prevent oil foaming (cavitation). The "lifting force" of a gas shock is calculated by multiplying the internal pressure by the surface area of the piston rod.
Bilstein: Small rod (≈12-14mm) = Small surface area = Low lifting force (≈50-70 lbs).
It’s a damper, not a spring.
Nimbus (Oleo-Pneumatic): Large internal diameter = Massive surface area = High lifting force (≈800+ lbs).
It acts as both a spring and the damper simultaneously.
The Flaw in the Logic: The basis of the claim is that the only "significant difference" is the rod diameter. While the pressure might be similar, the function is entirely different.
A Nimbus strut replaces the coil spring; a Bilstein works with a spring.
You make a second point which actually has merit but only if your value
field repairability above all other values in the world.
i submit there is more to picking a suspension architecture beyond just field repairability, you should also consider integrated failure points as much as other values.
I guess i'm in the mood to type a lot... here is a few points worth considering besides field repairability:
Point A: Variable Rate vs. Linear Rate
A coil spring (doesn't really matter if its branded as linear or dual rate) has a mostly a linear rate in most of the areas you care for. An oleo-pneumatic strut (Nimbus) has a naturally progressive rate across the entire length of compression. As it compresses, the gas volume decreases, and the "spring" gets exponentially stiffer.
This prevents bottoming out in ways a standard Bilstein/Coil combo (or any other classic oil shocks with steel springs) combo cannot match without complex bump stops and other methods to handle near end of travel compression.
.
Point B: Unsprung Weight and Space
By combining the spring and shock into one unit, you significantly reduce unsprung weight. By reducing unsprung weight you gain a tremendous benefit in that is now able to to react faster to terrain, improving traction. Furthermore, you eliminate the bulk of a heavy coil spring, which allows for better cooling and more room for tires or steering components.
The science equivalent is to put a pen in the palm of your spread out hand, hit it from below with a soft hammer, the pen stays with the hand as it moves upward. Now put a 10lbs sledge hammer on your hand, do the same thing and observe you hand and the bones in it being crushed. Inertia is a real force and the part that sits between your vehicle and the surface of the road/terrain is what need to have a low moment of inertia - low unsprung weight - to handle these movements really well.
IF that was too crude of an example, here is another one: unsprung weight sis the same physics that makes it easy to dribble a basketball but impossible to dribble a medicine ball. These shocks, and especially with lighter tires, tackle that problem quite nicely.
why does unsprung weight matter?
Traction: On a washboard road, a light wheel can "dance" over the ripples, keeping the rubber on the ground. A heavy wheel will "skip" off the peaks of the bumps, meaning you have zero braking or steering for fractions of a second.
Ride Quality: Because a heavy wheel resists moving, the energy of the bump isn't absorbed by the suspension—it’s transferred directly into the chassis, which you feel as a violent jolt.
Every report i've read about these oleo-pneumatic systems and how they are tuned to vehicle suggests that they find that magic balance between traction and quality. Graeme's report from his landy experience (and i think he crossed africa in it) goes straight to this point altough he expresses it in driver experience and not strictly in physics - the joy i had when i read his report is that i could close my eyes and see the physics translated to experience in his words. I'm no stakeholder here btw. i just like this kind of stuff (and i tend to think of the world in terms of physics and first principles).
Point C: The "Air Shock" Fallacy
Air shocks (like the old Monroe or Delphi styles) are notoriously poor dampers. i had them in my ford expedition before i hacked them up and made it into a more conventional suspension but for offroad they are pointless imho. For the most part these designs are designed to level a load, not to provide high-speed damping control. By "hacking" these onto a Grenadier, they are actually reducing the vehicle’s performance envelope to gain a marginal, manually-adjusted lift. i worked a bit on my friends disco's air suspension and i just didn't think thqt was the pinnacle of good engineering, not that i claim to be the master of the universe... But that car drove exactly the way i thought it would.
i have magntic dampeners on my daily driver and that works surprisingly well. but i don't think its nerly in the same league as oleo-pneumatic dampeners nor would i take this on a highspeed rattle road in africa or back country southwestern united states without going pretty slow. My grenny on the other hand has been pretty well tuned, i'd go faster in that if it wasn't for the fact that i put on heavy and cool looking rims that screws with my suspension by adding a lot of unsprung weight. But they look cool and they are strong so i think i'm keeping them...
Point D: Reliability is Relative
Modern high-end struts are engineered for desert racing and aerospace. While a "local AutoZone" won't have a Nimbus, a properly maintained exotic system like a nimbus seems to work well in the real world based on the reports i've read. But yes, if you want the simplest possible system back to as conventional and mainstream suspension as possible to maximize access to parts in faraway place. Don't get a diesel, def doesn't exists in many parts of the world.
final thoughts.
The point you made or implied was that nimbus was a dishonest marketing machine. i don't think that is true and i hope i've made a decent argument about it based on the science and not based on the company.
I think Nimbus are the real deal and that the science is proven that its a different system than your fox/king/sachs/bilstein although it shares some common fundamentals in physics but use that for different purposed.
I think objectively its a more expensive system and i do not know first hand how reliable it is. I'm certain that if it breaks when you are out adventuring there is going to be more work to get a temporary fix in place vs anything more conventional. But i have no evidence from anywhere that it is not a well designed product that is fit for purpose. If anything i haven't read many reports of them failing at all.
i don't have them because i think they are a touch too expensive for me, altough i would love to play with them if given the chance. they certaily apear to be an interesting solution to suspension. Its what all heavy aircraft use so there is that. At $3k i would be interested enough to switch out my fox/eibach setup.
And finally, they have the science on their side.
