Should I install underbody protection on my Toyota LandCruiser?
QUESTION
Hi John,
During lockdown I have been preparing my beard, gut and 2021 Toyota LandCruiser 200 to go take on the Creek with my fat wife, annoying kid and a two-tonne bucket of shit.
After looking at all the accessories you told me not to get (that I’m getting anyway), a question was raised regarding galvanic corrosion when choosing accessories.
Harry Fisher from ‘Fire to Fork’ mentioned this specifically when he was deciding on under body protection for his Toyota Prado. He settled with steel to minimise the likelihood of corrosion occurring in this way.
I am looking at underbody protection made from what is apparently ‘'5052 Marine Grade Aluminium’. According to the description it “resists corrosion”.
Is it necessary to consider the potential for galvanic corrosion to occur as the result of material combinations when choosing off-road accessories?
Is there a relationship between how resistant one metal is to corrosion and what extent the other is impacted?
All the best,
Brad
My AutoExpert AFFORDABLE ROADSIDE ASSISTANCE PACKAGE
If you’re sick of paying through the neck for roadside assistance I’ve teamed up with 24/7 to offer AutoExpert readers nationwide roadside assistance from just $69 annually, plus there’s NO JOINING FEE
Full details here >>
ANSWER
Brad,
If only you’d remained awake at school…
Pretty clearly, aluminium resists corrosion. Aluminium cans don’t rust away, for example. (The corrosion forms an airtight barrier. So they self-protect.)
Zinc is used in galvanisation. It’s more active than steel, and therefore sacrifices itself so the steel may live longer, in a process called ‘cathodic protection’.
More active metals protect less active metals in this way, when they are in close contact. Aluminium is more active than steel. (Hence ‘Zincalume’ is used to protect roofs.)
You know these plates are a joke, right? What, exactly, are you protecting your shitbox from? (Answer: the idea that the underbody might get damaged. Meanwhile, actual risk of underbody damage: Zero.)
Does Harry Fisher look like he has a single engineering bone in his body? As far as I can see, the guy’s a chef with a 4WD. Getting corrosion advice from this guy is like getting medical advice from a priest.
Aluminium is half the weight of steel for an equivalent structural performance. That’s its only advantage. (In your case, it’s all just unnecessary heavy shit.)
There is no ‘corrosion’ dimension to this choice, any more than there is for a bullbar (which is also quite useless).
JC
TOWING, LOADING AND MODIFYING UTES & 4WDs
CRACKED! Hi-tensile bolts Vs chassis Vs dealer incompetence >>
The Applied Physics of Heavy Towing >>
When can I use '4H' in my new 4X4? >>
The heavyweight problem with Ford Everest Basecamp >>
What's the best 4X4 dual cab ute for families and towing in 2021 >>
LIVESTREAMS
Don't forget to join me for my 'Ask Me Anything' Q&A livestreams on YouTube (Sydney time).
Subscribe to my YouTube channel and hit the bell icon to get an alert you every time I go live.
More reports
The all-new Kia Tasman 4X4 dual-cab ute is finally coming to Australia in mid-2025. The covers are off, too. Here’s everything we know so far