The Strength Difference Between Cast, Flow Formed and Forged Wheels
It may sound absurdly obvious but it is pretty tough to enjoy an automobile if said automobile doesn’t have wheels on it. Simply stated the possession of wheels is not optional when it comes to cars. Cars just don’t move around very well without wheels. You do still have some options though, as in “What type of wheels do you want?” If you answered “round wheels” you are on the right track. However, there are more specific questions when it comes to wheel choices. What are you going to do with your car? Race it? Put larger brakes on it? Show it and occasionally take it to a track day? Go to the store to pick up groceries? We are going to examine the differences between cast, flow formed and forged wheels.To get more news about Alloy wheels
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If all you want to do is drive to the store to pick up beer then save yourself some money and get some stamped steel wheels with plastic hub caps. But, if you have a performance oriented vehicle then you will quickly want to move beyond the stamped steel wheel option and get some alloy wheels. Alloy wheels are lighter than steel (which means less rotating mass) and do a much better job of dissipating heat from brakes. But, not all alloy wheels are created equally. Depending on how the wheel was manufactured can determine how light the wheel is and how strong it is.
Alloy wheels are commonly manufactured through three different processes: Cast, Flow Formed, and Forged. We will go through how each of the manufacturing processes is conducted and some of the pros and cons of each finalized wheel.
Casting aluminum wheels is the most common manufacturing process for alloy wheels on the market. How these wheels are made is molten aluminum is poured (or drawn in with a vacuum) into a mold which forms the material into the desired wheel shape. The aluminum cools and then it is machined, drilled and trimmed into the final wheel. This processing of casting a wheel is easy and less expensive than other methods however the process of allowing the molten aluminum to solidify can lead to porosity. Porosity is inconsistencies in the material structure which can lead to cracking and the overall reduction in the wheel’s integrity. Because of porosity, in order to ensure a cast wheel can be stronger manufacturers have to use more material which leads to heavier wheels.
The advantage of a cast wheel is they are relatively inexpensive. The disadvantage of a cast wheel is their failure point. Cast wheels tend to crack under stress and have spectacular failures on track. The porosity of the alloy allows for opportunities for the casting to break away. This is a bad thing when you are driving and can cause a lot of damage, not just to the wheel but to the rest of the car or even worse, it can cause a collision that will damage you.
Cast wheels are designed for a lower load rating and are built to have 500 treadwear tires on them. If you put a slick tire on a cast wheel (or even a 200 treadwear tire, like used in Optima Search For the Ultimate Street Car) with a heavy car you can actually break a cast wheel. Buyer beware.
The flow forming process can create some very lightweight wheels. Racers who compete in small cars like Spec Miata or Honda Challenge use these wheels for their advantage with reducing rotating mass. Less rotating mass helps with acceleration and breaking efficiency. There is some risk involved with flow formed wheels because with all of their lightness comes some issues with failures. The center of the wheel is still cast (with granular aluminum) and thus still has porosity in it which makes the hub section of the wheel brittle.