Choosing the Right Rock Sliders for Your Rivian Electric Truck: DOM vs HREW Steel

Choosing the Right Rock Sliders for Your Rivian Electric Truck: DOM vs HREW Steel

When it comes to protecting an electric truck like the Rivian R1T or R1S from off-road hazards, rock sliders are an essential accessory. Rock sliders, not to be confused with running boards, provide added protection to the undercarriage and sides of your vehicle, keeping it safe from rocks, debris, and other obstacles you might encounter on your adventures.

When it comes to choosing the best rock sliders for your Rivian, it's important to understand the difference between DOM (Drawn Over Mandrel) and HREW (Hot Rolled Electric Welded) steel. While both are types of steel tubing, they have distinct differences in their manufacturing process and properties that affect their strength and durability - factors that are incredibly important when dealing with a tech-heavy (literally) platform like the Rivian.

HREW tubing is made by taking a steel strip, hot rolling it into a tube, and welding it together without any further drawing. This results in a tubing with a rougher surface finish, and less uniformity when compared to DOM tubing. What kind of non-uniformity? The first is a visible weld seam, which runs the entire length and is visible on the uncoated tube. More importantly, HREW steel is less uniform at the molecular level. This lack of molecular uniformity is, all other parts being equal, what makes HREW weaker than DOM steel.

Just because it is less uniform, that does not mean HREW is always a bad choice. HREW steel is often a cost-effective solution. When building sliders for a lighter vehicle, or for light off-roading, high-quality HREW can be an acceptable choice.

HREW (Hot Rolled Electric Welded): 

  • Yield strength: 40,000 psi
  • Good for: light trail use

Pro: Cheaper

Con: Weaker

DOM tubing actually describes a process vs the steel itself. This type of tube also starts off by being hot- or cold-rolled and electrically welded. It then goes through the extra step of being drawn through dies and over a mandrel. This smooths out any wrinkles, seams, or deformities that may have occurred during the welding process. It also ensures tight tolerances and an excellent finish. When combined with the use of high-quality steel, the uniformity of DOM tubing provides superior surface strength to HREW, albeit at a cost premium.

DOM (Drawn Over Mandrel): 

  • Yield strength: 70,000 psi
  • Good for: More serious off-roading and heavier vehicles

Pro: Stronger
Pro: More precise
Pro: No welded seam

Con: More expensive

Many online will argue that HREW steel can be used just fine in many applications. This is true when the correct steel is used and when applied to the right application. Unfortunately, though, we have found that when rock slider manufacturers start to cut costs, it can also result in the use of foreign steel.

Why does that matter? Plenty of good things come from abroad, but steel mills in the United States have to follow regulations set by ASTM (American Society for Testing and Materials) and AISI (American Iron and Steel Institute), which are the governing bodies that set standards for steel production, ensuring that the steel produced is of high quality and consistent in properties. As a result, a high quality HREW tube made of domestically produced steel might be sufficient for light off-roading when compared to imported DOM steel used in a heavy duty application.

When it comes to developing rock sliders for an electric truck like the Rivian R1T and R1S, the Megawatt team has chosen to only use DOM steel. Its resistance to impact and abrasion make it the ideal choice for developing rock sliders for a heavy electric truck like the Rivian. When looking for Rivian rock sliders, we strongly recommend doing your homework and going with a manufacturer who uses heavy gauge, high-quality DOM steel to ensure the best protection for your vehicle while off-roading. Doing so will help reduce the risk of damage to your Rivian, keeping you happy and your truck on the trail.

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