Do you need underbody protection?

Before you go out and spend a fortune on 4WD modifications, it pays to consider what you actually need, and what’s not really worth getting. In this post, we are looking at whether you actually need underbody protection, and what the con’s of fitting it are.

Underbody protection on our Isuzu Dmax
Do you need Underbody protection?

What is underbody protection?

Like always, we try and start off with the basics first. Underbody protection is steel, or aluminium, or even stainless steel plates that are designed to protect the undercarriage of your 4WD, particularly where it is vulnerable to bumps and knocks.

This generally means from under the radiator backwards to the sump, and then even further back to the automatic transmission (or manual gearbox), and some even go all the way to the transfer case.

They are designed to take a decent bang off road, so if you slip onto a stray rock, or you come down hard on a tree stump or anything else that could do major damage, it will hit the underbody protection and reduce, or eliminate any damage being done at all.

Underbody protection ending on our Dmax
Our Dmax has 4mm steel underbody protection that ends just after the automatic transmission

How much does underbody protection cost?

Underbody protection varies considerably in price. For some vehicles, you can get away with a couple of hundred dollars for a kit, and then you can go all the way up to about $1800 for an aluminium underbody protection set to suit various vehicles if its done very well.

For the most part though, $500 will get you a decent set.

Dmax underbody protection
You can pay a lot, or a little for underbody protection

What’s the downsides of underbody protection?

There’s no free lunch. Every single accessory you add to your 4WD has a list of downsides, and underbody protection is no different.

It costs money

Whilst underbody protection might not be the most expensive 4WD modification out there, its still not free, and that means you need to commit some money towards it. On the flip side, generally one decent hit pays for the underbody protection, so weigh it up.

It is heavy

Weight on a 4WD is never a good thing, and underbody protection can be obscenely heavy, particularly if its 4mm stainless, or steel. You can comfortably add 40 – 60kg to your vehicle with a set of underbody protection, and a lot of that goes onto the front axle weight, which is one of the easiest ways to make your 4WD overweight.

You can go for aluminium, which is much lighter, but it sticks to the rocks a bit more, and you will pay a LOT more to get it.

Dmax rear axle weight
The weight adds up fast when you build a 4WD, so think carefully about what you really need

It can interfere with cooling

I’ve always been cautious fitting modifications that don’t have a huge amount of engineering behind them. Anyone with a bit of nonce could make plates to fit a 4WD, and protect its fragile bits, but there’s often not a huge amount of engineering that goes into what changes they might make.

By covering the bottom part of your 4WD, you can hugely affect the ability of components to cool themselves, and its important that you consider air flow and how hot things are going to get.

It makes servicing your vehicle more difficult

Mechanics hate underbody protection. At best, it’s extra bolts (and nuts) and weight to play with every single time they want to work on your vehicle. At worst though, the bolts seize, or the underbody protection is covered in sand, mud and grit and they get covered in it when they go to work on your car.

Some places even charge an excess to work on vehicles with underbody protection, and its hardly surprising; it adds more work to the job, and whilst they might make sense to you, many mechanics don’t like them for this very reason.

We’ve had countless broken bolts and lately had some stripped captive nuts, that are never fun to deal with.

So, do you need underbody protection?

I think every vehicle is different, and like always, we go back to what you are using the vehicle for. If you intend on doing a bit of beach work here and there, but no rock crawling, then your need to fit underbody protection is hugely reduced.

If you have a vehicle with a heap of clearance, like an old Land Cruiser or Hilux, then you probably don’t need anything either. Our 80 Series had a heap of clearance, and I had no worries about things getting knocked underneath.

80 Series Land Cruiser
I never had any underbody protection on our 80 Series, but it had a lot more clearance and less vulnerable parts

Our Dmax on the other hand, is much lower to the ground, and has some bits that hang down which are far more fragile; you land on the automatic transmission and its going to hurt the hip pocket, guaranteed. For $400, plus the above cons, it made sense to get a set installed, and we’ve hit them a number of times off road, with limited stress on my part as I know they are there to do a job.

Bash plates on our Dmax
We have less clearance now, and an automatic transmission that needs protection

If you can afford the weight, and you think they will get used, then its probably a good idea; one major knock underneath can cause damage that is far more expensive than a set of underbody protection!

Before you go out and get underbody protection though, there’s a few things you should consider, and we have a more generic post on Underbody Protection that dives into it more, linked at the start of this post.

Do you run underbody protection? Are you happy with it?

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