Aluminum or Steel Front bumper

Finally someone else who understands.

 

I'm not an engineer, not very bright, and haven't stayed in a Holiday Inn. But I don't think that a moment arm force calculation really comes into play here. Adding 140 lbs two feet forward of the hubs creates something like 290 ft lbs of additional static torque and as long as the structural connecations are appropriate all the bumper will do is cause the front end to sag a bit in proportion to the added weight. And there is a relatively minor forward shift in the trucks center of gravity. In a static situation all one would need to do is increase the capacity of each front coil by 70 lbs and walk away. But when hitting a bump it takes much more than 140 lbs of force to accelerate that bumper upward and keep from smashing into the bump stops. So springs heavier than 70 lbs per side are required to maintain ride quality. Or not.

 

^Same here. People who say these trucks can handle weight no problem need to come drive my pig. Long bed with canopy, fridge, RTT, 2 awnings, Pelfry Aluminum front w/winch, dual battery, aluminum front skid and now steel HC rear w/swing out plus my camp gear. Thing drives like a bus. Looking back now I am so happy i went with aluminum. When you start adding this and that the weight adds up quick. I have Icons with #650 coils up front and dakars with icons out back and im going to need to AAL to the rear. I understand most people are not going to be cruising around with near as much weight as I do, but it is something that should be taken in consideration. My point being is that unless you are pretty "hardcore" into wheeling (which if you were, you wouldn't be asking) you don't need steel. Aluminum will do just fine.

 

I'm still weighing my options (see what I did there...) the sole reason I want a plate bumper is because of deer impacts. Anyone have pics\ experience with an aluminum bumper deer hit?

 

I did see some pictures on here of guys with aluminum bumpers who have hit deer and they came out on top

 

This is my 07 , 3x deer at @ around 40mph, minimal damage, since sold. Looking to save some weight when i armor my front end this time around on my '15

 

I'm not quite sure I follow what you're saying. That we need to increase the spring rate by 70 lbs? Or that you think a bumper makes a negligible effect on a truck with stock springs?

 

Neither. It has a significant effect but not for the reason the poster you quoted thinks.

 

Ahhh, gotcha. To be honest I gave no idea what I'm actually talking about. I just know it has an effect, but I'm not sure how to explain what I understand it to be in my head.

 

Bringing up an older thread for a question;

I've searched this forums and many others but what I cannot find is evidence that a "good quality" Aluminum bumper from a reputable manufacturer is any weaker than steel.

There are an absurd amount of posts that echo "Aluminum is weaker" but not one I have read actually shows any hard evidence like photos to back it up the claims. Yes, in theory steel plate of the same thickness compared to aluminum is stronger.

Most of the higher end, more reputable manufactures such as a PELFREY, RELENTLESS, OR DREMELLO(TO NAME A FEW) don't just build an exact copy the steel vs aluminum bumper. In fact, the internal gusseting and overall internal frame designs are completely different from steel to aluminum. More work goes into an aluminum bumper build. Thicker materials are used for aluminum, more gusseting and reinforcement, but externally the end result is the same with a lighter product that is in fact more weather resistant (i.e. Won't RUST).

If you ask me. the weight savings (because every vehicle I own will always double as a daily driver) and weather resistance ( because I live in the great white north) seem like a Win, Win on both accounts.

So the reason for this thread bump, is I'd like for anyone to post of some photos, a link, or evidence of a failed aluminum bumper from any of the current manufactures and the circumstances behind the failure to give this ongoing debate some merit in one direction or another.

 

It depends on how you measure "strength", and what specific type of steel and aluminum you're using.

Engineers usually refer to a material's strength in terms of the force that can be supported by a given cross-sectional area, which is called "stress".

Imagine you had a square bar of steel, and you attach one end to the ceiling. You could hang weights from the other end. Say you measured the cross section of the bar, and found it was 1 inch by 1 inch, or an area of 1 in^2. If you hang 1000 lbs, you'll have a stress of 1000 lb/in^2 (also written as 1000 psi).

Engineers usually consider two types of material strength: yield strength and ultimate strength.

If you just apply a little bit of load by bending a paper clip, it will bend, and spring back to its original shape when you let go. But if you put a little more load on it, it will become permanently deformed. The stress at which this permanent deformation occurs is the yield strength, and it's important because we generally want things to stay in their original shape - a paper clip isn't any good if it's straightened out!

Now, imagine pulling a wire. The wire will reach its yield strength, and become permanently stretched. But if you continue to apply load, you'll eventually break the wire. The stress that this occurs at is the ultimate strength, and it's also important - it's a bad day if your airplane wings get permanently deformed, but it's a REALLY bad day if they snap off the plane!

So, that's how we talk about strength. Now let's talk about materials. Just saying "steel" or "aluminum" isn't very descriptive. There are a lot of different alloys of both (an alloy is the name for a particular mix of elements that make up a metal), and each different alloy has a different set of material properties, including strengths. Then, there are various heat treatments and working processes that change the material properties.

Steel generally has yield strengths ranging from 30,000 - 150,000 psi, and ultimate strengths ranging from 50,000 - 200,000 psi.

Aluminum generally has yield strengths ranging from 15,000 - 70,000 psi, and ultimate strengths ranging from 30,000 - 90,000 psi.

So, there is some overlap, but in general, steel is stronger.

The reason airplanes are built out of aluminum instead of steel is because aluminum is generally 1/2 as strong, but 1/3 as heavy. So the strength-to-weight ratio is higher for aluminum. But to have an aluminum bumper with equal strength as steel the weight savings will not be enough to factor in as a bonus, leaving weather resistance as the only real advantage.

 

I had no idea Relentless offered aluminum, let alone DIY build kits. Did you have to special order this from them?? I see nothing on their site.

 

Neither steel nor aluminum.

The tradeoffs are not worth it IMHO. Longer stopping distance and sever understeer and safety concerns.

Also since these bumpers bolt onto the frame, any minor fender bender will turn into a bent frame. Whether you're at fault or not, neither party's insurance will pay to replace the bent frame. Whereas with the stock bumper which is sacrificial, your frame is more protected from a minor fender bender.

There's also very little crash test done on these bumpers and they could very well come flying through your windshield in case of a crash.

The added weight will make the front sage so you'll have to replace the springs and the shocks to match stiffer springs. And if you think it's a good time to add a lift, factor in the cost of the rear as well.

On the plus side? Bro look, if that's what you're into. Meh...

 

@BaconPower
Slow the roll on the broad generalizations. "Back in the day" when trucks had metal bumpers, installing a plate bumper was generally a waste for all but the hardest working trucks and serious offroaders. But our Tacomas now have an enormous facade of homely, fragile, and very expensive to replace plastic that limits an already poor approach angle. Even a minor encounter with brush, stumps, rocks, or Mother Earth will ruin it. For most Tacoma owners installing a plate winch bumper is just playing expensive dress up and is silly as shit. But for many of us who leave the city, beach, and gravel roads a plate clearance bumper makes total sense.

 

This. And for those of us who live/play in deer and elk country, a plate bumper with a hoop can be the difference between finishing the trip home and being stranded on the side of the road.

And I like the bro look, TYVM

 

You're right, it was too much of a wide generalization. Around here malls abound with spotless Tacomas adorned with bro-bumpers, waxed to a shine, which have obviously never seen mud. The same can be said of Jeeps.

I've actually looked into them for the same practical reason as you (deer etc..) and was tunred off by how they fasten to the frame.

It seems that replacing the plastic while expensive would still be cheaper than dealing with a bent frame.

Do you guys know of a push bumper that fastens in a way that would safeguard the frame yet be functional? Police push bumpers look like they are designed for that purpose.

 

I don't think there is any safeguarding the frame because the only way to attach any bumper is to the frame. While I don't yet have a clearance bumper I don't buy into the idea that installing one will significantly increase my chances of having the truck totaled because of frame damage. In stock form there is very little of substance to absorb an impact between the Tacoma frame and whatever the truck hits. Any frame damage that might occur in a fairly low energy accident that wouldn't have otherwise bent the frame would be easy to repair and wouldn't result in a totaled vehicle.

 

This "police grappler" bumper is pretty cool:

 

ARB bumpers have replaceable crumple zones built in to absorb energy during a collision.

 

Sound like a good design to me.