Originally Posted by 1010tires.com

The main differences between alloy and steel wheels lie in their durability and strength. Most high-performance wheels are made of an alloy and composed of aluminum, and other metallic substances. By using alloy wheels, you not only improve the looks of your vehicle but also the performance. The extra strength provides longevity as well as effecting tire wear in a positive manner. The weight reduction will improve steering response and handling, as well as help improve acceleration and braking.

Originally Posted by tirerack.com

Alloy Wheels
· Enhance the look of your vehicle
· Are manufactured to precise standards to meet exact fitment and performance needs
· Weigh less than steel wheels and have superior strength
· May be the preferred option for your vehicle based on fitment requirements
· Will allow for better brake clearance (depending on wheel style and brake components installed)
· Require proper maintenance as finish damage may result in the harshest winter climates where salt and sand are routinely used

Steel Wheels
· Meet the basic needs of drivers who want the convenience of a winter tire package without the additional cost of an alloy wheel
· Typically available in black or silver finish depending on the application
· Basic styling can often be updated with wheel covers
· Cost less than alloy wheels due to ease of manufacturing and lower material costs

Originally Posted by difflock.com, a 4x4 magazine

What's the difference in choosing wheels?

Choosing wheels seems very easy, look at all those brainless yuppies who run on alloys. This doesn't mean however that alloy is bad. But more on this later. There are literally hundreds of wheels on the market that suit Land Rovers. Most differences are cosmetically but some are also practical. Which material is best is a hotly debated topic.

Most common are steel and aluminium alloy, exotic materials like carbon fibres being way out of financial reach of most ofroaders. You simply can't compare them as they are completely different by construction.

Steel

Most genuine wheels are made of steel. An stamped inner part is junctioned to a rolled outer rim and nowadays welded together. If you look at older rims on Willys of Toyotas you can still se that they were riveted together. The setup is strong, easy to repair but most important, cheap to fabricate. They can be painted over and over again if years of off roading take their toll. Many manufacturers use the same production method but take stronger and/or thicker materials to increase load capacity and they also make them in sizes better suited to aftermarket tires. The biggest disadvantage of steel is it's weight or better it's lack of performance. An alloy wheel will accelerate faster and stop quicker as well as reducing load on shocks and steering linkages. How can such a rather small weight difference make up for a drastic change you may ask. After all the difference will rarely exceed 8 pounds peer wheel. This would be true in a static situation.

But the wheel is a dynamic part on the car. It's weight must be accelarated and braked, it's movements must be tamed. And everyone familiar with physical laws can tell you that a moving parts inertia is completely different from a static part as the rest of the axle is (in this example).

Just to give you an idea of how much energy is stored in an tire wheel combo let me tell you something I saw myself: One day I was driving on the motorway to work when I was overtaken by an Alfa Romeo, you know, these small italian sports cars. The guy was doing about 110 Km/h when I noticed his left front wheel wobble and suddenly coming loose. The wheel slowly run along the car, then drifted to the middle when it hit the separation. Although it hit the wall at a very flat angle it immediately changed direction, jumped over the Alfa in windscreen height and only landed some 50 yards away in a meadow where it still went on for about 300 yards. Imagine how much force this took- and it was only a very small wheel, about 13inches with an equal small tire. Had it hit a car it would have smashed through the windscreen and killed everybody inside. Luckily the guy brought his car to a standstill with nothing more than a damaged brake disc.

So what does this show us? There's a tremdous amount of force stored in a rotating wheel. You need much energy to get it up to speed and you need also good brakes to bring it down. The steering linkages will wear faster too.The heavier a wheel/tire combo the more energy is needed. Similar for shock absorbers. If you have a heavy wheel they will take a beating. So aim for the lowest possible weight.

A steel wheel will also bend much earlier than an alloy wheel. But you can hammer an steel wheel back in shape while an alloy wheel will usually break. So if you intend to do many miles far away from civilization keep the steel. If shopping for used rims you can test them by mounting them and holding a pencil or similar against the edge and rotating the wheel. This runout can be of up to 2-3mm even on new wheels but I'd keep off if it exceeds more than this.

Old miltary wheels are mostly bent so keep that in mind. This is less of a problem on cars seldom exceeding 80 Km/h. Also it's not uncommon for steel to rust to a point where structural integrity is affected.

Aluminium alloys

One piece cast alloys

Those are the usual rims offered on the market for 4x4 applications. Up to 1/3th lighter than steel, restant to bending and not too expensive they are good for almost all applications. Beware however of rims marked 'not for off road use'. Their disadvantage is that they can break. However this is very rare and only caused by violent encounters of the sort that would also ruin the tire and bend a steel rim They do get scratches and dents on the trail and don't support winter roads well without special care. If corroded they take more work to refurbish. Corrosion however rarely affects their structure to a point rendering them dangerous.

Two piece alloys

Also called modulars they have a cast center and a spun rim, held together by welds, rivets or even nuts and bolts (not legal in many states). Their construction makes for a very strong and lightweight wheel but they are easily bent and hard to repair. They are also cheap to produce so they make up the majority of alloys for street going cars.

Forged alluminium alloys

Those are the best and most expensive wheels for our applications. They are way stronger than steel and lighter than most cast alloys. They are also the most expensive to buy.

Carbon fiber

Those wheels are very rarely seen on 4x4's. They are extremely light, less than half that of a steel rim of the same capacity. However they are prone to breakage if not constructed for off road use- and I know of none produced in greater quantities. They are also extremely expensive due to initial cost of raw material and the lot of manual work involved. Count about 10 times the price of a forged alloy wheel.