There are plenty of suspension options on the market these days. Lots of brands, lots of options and lots of price points. You can spend anywhere from $3,000 to $18,000 on suspension for a 300-series.

I've run various twin tube shocks on my 4WDs for over 30 years and never had an issue with them. In most situations, they are a perfectly acceptable shock and you'd never reach their limits. The thing about the suspension industry is that manufacturers will often claim that the option they offer is the only one to have. This is particularly true for companies offering only one type of shock. There's a particular retailer of twin tube shocks out there claiming that their twin tube foam cell shock outperforms a remote reservoir monotube. Conversely, there are retailers of $15,000 remotes implying that anything less is hopeless. Neither claim is true.

So, what are the pros and cons of different shock absorber types?

Twin tube (Eg XGS Roamer):

Twin tube shocks -as the name implies- have an inner cylinder which contains the piston, and an outer cylinder which acts as an oil reservoir and contains some nitrogen gas. A foam cell shock is a variation on the design, where the outer cylinder contains a closed cell foam rather than gas. Twin tubes are the most common and affordable type of shock absorber installed on vehicles today.

Their primary advantages are cost and durability. The twin tube design means they are less susceptible to impact damage, and they also run lower gas pressures, reducing stress on seals. Foam cell shocks often have no gas pressure at all. Twin tube shocks typically offer more piston travel than monotube (non remote) shocks.

Their primary disadvantages are that they are more susceptible to performance degradation from heat. They rarely offer any form of adjustability, so must be valved well to suit the vehicle, although this will always be a compromise depending on operating weight and conditions.

Monotube (eg XGS Rugged):

Monotube shocks are a single cylinder construction, with a high pressure gas charge. They are commonly found in high performance sports cars and in premium aftermarket brands. Their larger piston allows for more precise damping and the single tube improves heat dissipation, reducing fade under extreme conditions compared to most twin tube shocks. The larger piston means potentially higher damping force can be applied.

Their primary disadvantage is that the single wall increases susceptibility to impact damage. Some monotubes (such as the Rugged) have thicker walls to allow for this, but particularly in a vehicle such as the LandCruiser (which has its rear shocks in front of the axle), it's important that they are protected from stone impacts. Another downside is that high gas pressure in monotubes puts seals under more stress than twin tubes.

Monotube Remote Reservoir (eg: XGS Remote):

The remote reservoir version of the monotube design improves on the advantages of the monotube, and adds a few more. The biggest advantage from my perspective is the addition of full damping adjustability. For a vehicle operating at various weights and in different conditions like mine, the adjustability is what sealed the deal on choosing remotes for this build.

The reservoir increases total oil volume and surface area, reducing fade. It also increases gas volume, reducing stress on seals. Compression adjusters like those on the XGS Remote shocks allow for a further reduction in gas pressure, reducing stress on seals.

The main drawback of remote reservoir monotube shocks is typically the cost. Some systems for the 300-series can top $18,000. I honestly would never consider spending that sort of money on suspension, unless I had a sudden desire to enter the next Finke Desert Race! The XGS Remote system costs around $5,900 at the time of writing That's fully installed with a pre-rego GVM upgrade. This makes them excellent value. For about double the cost of a twin tube system, they offer substantial feature and performance advantages.

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