Rock Crawlers On Propane: What Are The Benefits?

For the uninitiated, a rock crawler is a vehicle, customized or purpose-built for the sport of rock crawling. Many drivers convert their rock crawlers to use propane as fuel, either exclusively, or in conjunction with gasoline. The question is, why would rock crawler drivers perform this modification on their vehicles? What are the benefits that make propane a better alternative fuel to gasoline for rock crawlers?

Running your rock crawler on propane has several advantages. There are no fuel starvation problems on steep angels with propane, and it burns cleaner, less engine maintenance is required, it is safer, and, as a bonus, it is better for the environment!

If you are a rock crawler owner and considering converting to using propane in your vehicle, then you may find the details below will help you decide one way or another. We will detail the benefits of using this fuel in your rock crawler, some other questions you may have around using it as fuel, and some disadvantages that may be relevant to your situation.

Rock crawling is an extreme 4×4 off-road driving activity that puts unusual demands on a vehicle. Essentially rock crawling is driving over very rocky ground, and here I am talking boulders rather than rocks and traversing steep angles in hilly terrain. It is a test of both the driver’s skill and the vehicle’s abilities in the difficult terrain.

The vehicles used in rock crawling are either purpose-built vehicles that have been built from scratch or heavily modified production 4×4 vehicles such as Hummers, Jeeps, pickup trucks, and the like. The suspensions have to be dramatically improved to handle the terrain, roll cages installed, and often fuel systems modified. This is where a propane conversion comes in to play.

The Benefits Of Running A Rock Crawler On Propane

Converting gasoline combustion engines to run on propane is not a new concept. The equipment and expertise to perform these conversions have been around for over 40 years and are approved by the EPA. Running a vehicle on propane has a number of advantages, some of which are specific to rock crawling, while others are general advantages for any vehicle.

We will start by focusing on the benefits specific to rock crawling and then continue to benefits that anyone would experience from the conversion.

  • No Fuel Starvation. The steep angles that rock crawlers drive on a regular basis can be a problem for traditional gasoline-fueled engines. These steep angles can cause carburetor bowls to flood, or drain out. The fuel in the gas tank can also change the level on a steep angle, so it no longer flows out of the tank and into the fuel system. With propane, the fuel in the fuel lines is in a gas form, and the pressure forces the gas forward, so no fuel starvation occurs. Likewise, in the tank, the propane, although in liquid form, is under pressure, and the outlet is, therefore, at the top of the tank. This allows the fuel to exit the tank and flow into the fuel lines, even on steep angles. The liquid propane will only block the outlet in the event of a roll-over, in which case you don’t want your engine running anyway!
  • Propane is safer than gasoline. This is probably a surprising point to most people, but LPG, or propane, is less flammable than gasoline. Not only this, but the fuel system for propane is completely sealed. Where this is an advantage in rock crawling is that there is no fuel spillage or leaking when driving at steep angles. No fuel spillage means less risk of an accidental fire, which could be life-threatening for the driver.
  • Less maintenance required with propane. Propane burns cleaner than gasoline, which creates fewer carbon deposits. The consequence of this is cleaner spark plugs, cleaner oil, and overall, less wear-and-tear on the engine. Studies have shown that propane can increase engine life by up to three times that of a gasoline-powered engine! While this benefit is not strictly related to rock crawling, it saves on maintenance costs for anyone, and who doesn’t want to save money?
  • Propane is better for the environment. While saving the planet may not be high on the agenda motivating rock crawlers to convert to propane fuel, it is nonetheless a useful advantage. Propane does not have lead, carbon, or sulfur, making it a clean-burning fuel that does not have as many harmful emissions as standard gasoline!

If propane has these advantages over gasoline, why are there not more conversions, or production vehicles running on this fuel? There are some disadvantages to running propane, which has restricted it from becoming a popular conversion or fuel of choice for combustion engines in general.

What Are The Disadvantages Of Propane Fuel?

Most of the disadvantages of using propane as fuel for your vehicle pertain to where you live. The laws in Europe regarding using propane in cars are much more progressive in comparison to those in the USA. As a result, Europe has much more support for propane-fueled vehicles and more of them on the road.

  • Fuel availability. Not all gas stations cater for refilling propane-powered vehicles. As a result, this may be a restriction for you in your area.
  • The legality of propane. In certain regions, you are allowed to modify vehicles to use propane for recreational purposes, but these vehicles are then not deemed to be street legal. So if you use your road crawler on normal roads as well as off-road, you may want to check this legal issue in your location before you convert.
  • A drop in power. Propane does not deliver as much power in its combustion as gasoline, so there will be a slight drop in power in a motor converted to use propane. Modern tuning techniques have largely overcome this issue, but don’t expect propane to give you a nitrous-like power boost.
  • Added weight. The pressurized canisters that house the fuel supply have to be heavy-duty steel to handle the additional pressure safely. This increases the weight of the tanks, making them significantly heavier than standard gasoline tanks.

While these drawbacks may not be huge, they may be enough to be a problem for you, depending on your situation.

How To Convert Your Rock Crawler To Propane

The method to convert a vehicle to using propane is usually achieved by installing a kit which will be purchased from specialist suppliers of this kind of equipment.

It is not recommended to attempt converting your engine to using propane as a DIY garage project. The installation requires a specific skillset and adherence to strict safety protocols and the use of good quality parts.

Even if propane is not street-legal where you live, you will be able to find a mechanic in your area with the necessary skills to do the conversion for recreation purposes.

While it is possible to find conversion kits online, it is better to speak to a professional installer to get advice on the correct kit for your particular engine. Some engines require cam and manifold conversions to efficiently use propane and handle the additional heat that is generated during combustion.

Is Propane Cheaper Than Gasoline?

The price of propane fluctuates seasonally in most locations. During wintertime, there is an increased demand for propane for heating in households. This increased demand pushes the price of propane up during this season.

Buying propane from a gas station that is selling it for the purpose of vehicle fuel will usually have a more stable price than buying from other suppliers.

Propane is usually cheaper than gasoline, but propane does not go as far as gasoline does. Propane will not give you as many miles per gallon as gasoline. The lower price of propane, however, equalizes the shortfall. It makes the cost per mile similar to that of gasoline, even though you will use more propane for the same distance traveled.


While the benefits of using propane as fuel for your rock crawler far outweigh the disadvantages, the downsides may be significant enough for you to persuade you to stick with gasoline. On the other hand, if the restrictions are not significant in your situation, propane is a great choice of fuel to power your rock crawler. Many drivers who have converted to propane state that there is no way they would go back to gasoline for their rock crawler!

Happy rock crawling!

Louis Pretorius

As an amateur off-road enthusiast, I have always been drawn to outdoor adventure. I have decided to share all of my learning experiences with you as I dig a little deeper into my new-found passion and wonderful world of off-roading. My mission is to create the Ultimate Off-roading space on the internet in the process. Stay safe and happy Off-Roading!

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