Aluminum vs Steel Axle Shims

I needed some 3 degree axle shims from my truck. Ordered some from Toytec. When they arrived I immediately noticed how lightweight they were…aluminum.

I have used their shims for another application before and they were steel, very hefty…not sure why they switched but it was very misleading because I expected the steel shims again. Their website made no indication of the material these are made of.

Will these aluminum axle shims hold up over time? Does anyone have experience with these? For the life of me, I cannot find 3 degree steel shims for a Tacoma anywhere else…

 

Aluminum is just as strong as steel. It's also rust proof. It's what most engine blocks are made out of so you know it's going to last.

 

In general steel is stronger than aluminum... but in this application aluminum is plenty strong enough for the application

 

"Strength" is a relative term. Are you talking tensile strength, torsional strength, bending strength, etc.? Generally speaking, aluminum and steel are pretty close in strength, but aluminum provides the same strength with less weight. (That's why airplanes use aluminum instead of steel.)

As for corrosion, both steel and aluminum oxidize / corrode. With steel you get classic "rust" as the result of the oxidation / corrosion process. With aluminum you get what's called "white salt corrosion" where the oxidation / corrosion process turns aluminum into a white powder. If you don't think aluminum corrodes, you've never seen an outboard motor that's been used in salt water.

What does all of this mean? You should be just fine with aluminum shims.

 

I feel better about it now, I just read online that a lot of people have had trouble with aluminum shims flattening out or cracking. I don’t know the validity of those stories but it seemed to be a common problem. I know aluminum is very strong but I wasn’t sure how practical it is for a load bearing application with the entire rear weight of my truck resting on a quarter inch to half inch thick block of aluminum.

I would sincerely hope that a company such as Toytec would not sell me a part that is of inadequate strength that is going to break or warp easily. And of course I will probably paint it to prevent corrosion

 

Even in the rust belt where road chemicals are applied, aluminum turns into a white powder when exposed. It's why I scrapped my OEM aluminum wheels. The wheels were so badly corroded that they wouldn't hold air and looked awful.

 

I'd butter them up with a thin coat of grease when you install them, especially where they mate to steel.

 

I was going to hit em with a couple coats of rustoleum to prevent direct contact, what do you think?

 

That would be fine but I'd still put some grease in the interface. It will help keep water and salt from wicking in.