Different Shock Types

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Categories: Product Info

There are many brands out there now with a wider variety of shocks than ever before. People are asking us all the time “why should I choose this shock instead of this other one?”, and it can be difficult to answer sometimes. But sometimes it’s very straight forward. I’ve recently come up with a simple analogy for comparing the 3 different types of shocks and struts that Dobinsons Suspension offer in the market today. It’s obviously just a quick and simple analogy, but it may help you to decide which level of shock you may want to choose.

  1. Twin Tube struts and shocks (sometimes called GS by Dobinsons for Gas Shocks) are your standard aftermarket replacement bolt-on and maintenance free shocks that give excellent ride quality, performance, and longevity in pretty much all road conditions. They’re fully sealed and can’t be rebuilt. I consider these to be like a standard road tire.
  2. IMS struts and shocks (Internal reservoir Monotube Shocks) are a bigger body and bigger piston monotube shock with a floating piston that separates the oil and nitrogen gas inside the shock so that cavitation (“A phenomenon in which rapid changes of pressure in a liquid lead to the formation of small vapor-filled cavities in places where the pressure is relatively low.” – aka bubbles in the oil) pretty much cannot ever happen. They’re fully rebuildable, although they DO NOT have a rebuild cycle, unlike some other brands of rebuildable shocks. They have more travel, displace heat better, and can perform significantly better offroad at higher speeds than a twin tube shock can. I consider these to be like an all-terrain tire – the best option for all around use and someone who offroads quite often.
  3. MRA struts and shocks (Monotube Remote reservoir Adjustable) are 3-way adjustable remote reservoir versions of the IMS shocks. They have all the same features, but more oil due to the reservoir, and also you can adjust high and low speed compression as well as rebound with the simple turn of some dials. These are like mud terrains, you wouldn’t run mud terrains unless you’re going for a specific look, or if you go offroad a lot and need something that can stand up to a lot of abuse and harsh conditions. To put these on a street-only vehicle would be overkill in my opinion, even though they will ride as soft of firm as you like, since you’re in control of adjusting the valving.

Now, onto some other brands, and a quick, short comparison.

OME NitroSport Shocks (aka Nitrocharger Sport) are similar in build to the Dobinsons Twin Tubes, although the Dobinsons valving stack is usually more on the comfort side, whilst OME are on the firmer side. OME doesn’t offer an IMS or MRA equivalent. They have the BP-51 shocks, which are an internal bypass shock which operates differently than a 3-way adjustable monotube shock. The MRA’s adjustment range is significantly greater than the BP-51, and BP-51’s can only adjust high speed compression and rebound, not low speed compression.

Ironman NitroGas shocks – these are similar to OME and Dobinsons Twin Tubes. Ironman Foam Cell and Foam Cell Pro (FCP) are essentially the same as each other, just different sizes with different piston and rod sizes, body diameter, and oil volume. They’re a twin tube shock with a layer of foam in the outer tube embedded with nitrogen to reduce cavitation. Some FCP’s have an adjustable height front collar for the coil seat. The pistons in these are still not as large as the IMS or MRA from Dobinsons due to their twin tube design (not enough room), and they don’t offer any valving adjustment in any of their range currently. A nice talk-through of their shocks with internal details can be seen here: https://youtu.be/_8kIfYLmpv4

If you want an outside perspective on different types of shocks, this page here gives an excellent reference to each type of shock you could use on your 4×4, and they explain it super simple and easy to understand.

https://www.shocksurplus.com/pages/shock-absorber-design-differences

If you have any questions about any type of shock, or are looking for a comparison between the shocks we sell at Exit Offroad and any other shocks you’re looking at, please shoot us an email or give us a call!!