Forged or Cast

[Dualie]

Think rims are generally classify under these 2 manufacturing method...

 

May I know the advantages/disadvantages of the 2?

Which brand/model uses what method... Pls give example...

[Phochem]

Casted rims are the more common ones. Forged rims are much more expensive (2 to 3 times) but lighter and stronger, e.g rims from RAYS engineering. Not much disadv only the price.

 

http://www.rayswheels.co.jp/emenu/wheel.html

[Phochem]

... got in from the web

Forging uses intense heat and pressure to transform a [solid} slug of alloy material into the final shape of a wheel. Forged aluminium is about 300 per cent stronger than cast aluminium, yet less material is needed to produce the same "cast alloy wheel", which results in a lighter product. Because of the basic limitations inherent in forging, most forged wheels are two or three piece units. In two-piece construction, a centre is forged and welded or bolted into a spun or stamped outer rim. In a three-piece wheel, the centre is bolted to an inner and an outer rim half. This stands as an advantage of being easily customisable for a variety of widths and offsets.

 

Casting is a relatively inexpensive way to produce a high-quality, fairly strong alloy wheel. There are two methods used. One, system is known as gravity casting... whereby the molten material is poured into a mold and allowed to cool. These molds are usually made by machining a piece of material on CNC machine equipments to produce a wheel that only requires minor finishing (like drilling or possibly trimming of some excess metal) to be considered complete. The other and better system used is the low pressure or negative pressure casting. Here instead of pouring the molten material into the mould, the molten alloy is drawn up into the mould using a high-pressure vacuum. This eliminates much of the trapped air found in gravity casting process, producing a stronger wheel that is less porous than a gravity-cast one.

[Ghostrider]

Forged rims you hit a pothole while travelling you will cry ah !! Unless one has a fetish of oval shaped rims ??

 

Forged rims is usually used on the track as there is the weight advantage....casted rims are more for road use. If you want to forge rims...better keep your eyes open for road inperfection...cannot afford to bash thru like most cars do.

[Phochem]

yah, heard about it too. Forged rims more for those with deep pockets too.

[Jetcool]

"Forged rims you hit a pothole while travelling you will cry ah !! Unless one has a fetish of oval shaped rims ??"

 

I thot forged rims are stronger than casted rims? For a situation where the impact on a forged rim bends it out of shape, a casted rim would probably have cracked/broken into pieces?

[Ghostrider]

Forged rims are stronger but they are "soft". How to put it....the metal can be strong but easy to go out of shape.

 

That is a safety feature....in fact for normal rims as well. They will not break resulting in a sudden lost of pressure on the tyres (tyre blow out). The air will leak slowly thru you still have control.

 

Steel rims are the ones that will break as they are not easy to go out of shape...one impact sui sui the rims will break or crack.

[Ghostrider]

I have a friend's Advan went out of shape when he hit a pothole in NS....cry until boh bak sia.

[Dualie]

Thanks for the answer.

 

 

Got another question, What is offset?

if my car is having a 46mm offset, can I use a rim with 48mm offset?

What are the complication?

[Vtim]

Keat,

 

here's some info on offset

 

http://www.tyresave.co.uk/fitment.html#TECH

[Sapience]

stronger but more malleable? not too sure... anyone my new rims delay by one week, sianz.... forged or cast? guess...

[Dualie]

Thank you for the link...

 

So if I understand the pictures correctly.

If I'm going to use a 48 offset rim on my stock 46 offset. I will see my wheels proturding out of the wheels well.

Correct?

[Jetcool]

My Materials Science knowledge had long since been returned to school. But I remember that in the forging process, a piece of metal is shaped by pressing, pounding, or squeezing under very high pressure in a hot or cold state. The "working" process actually strengthens the metal. Forging requires higher capital outlay and is hence more expensive. In casting, metal is melted and then left to cool and solidify. It is less costly, but the tradeoff is there are more imperfections (tiny voids and cavities) in the metal.

 

Casted metal is thus weaker, and is more prone to cracking under impact. Forged metal is stronger, so it would tend to deform first rather than crack. I suppose if one hits a really big pothole at high speed, both forged and casted rims would be goners, but from a layman's perspective, a deformed (but intact) forged rim is structurally safer than a casted rim broken into several pieces.

[Vtim]

if you are using +1 (upsize), it'll still be ok! but +2 will be questionable

[Ghostrider]

You are right. My materials knowledge also give back to Poly liao. ha ha ha ha ha ha....

 

Casted rims are not inferior in anywhere (those good ones like Enkei, Fondmetal etc...) where by good QC and good quality materials are used. Those taiwan rims eg are the old with bad QC where by cracks are acceptable....that is why good brand rims cost more than those cheaper taiwan or m'sia rims.

 

Forge rims are stronger and lighter but they deform easily...they dun break....low tensile strenght. (Correct or not ah ?? Higher tensile strenght breaks easiler rite ?) Metal rims have higher tensile strenght.

 

You are right about a deformed rims is better than a crack rim....they will prevent a tyre blowout which is damn dangerous.

[S2077s]

May i add a little...

 

Forged rims are stronger, thus they dun break like cast rims do, they will bend instead.

HOwver, casted rims are more malleable, meaning theoretically it can be repaired while forged rims cannot be bent back to shape.While over potholes, casted rims have their advantage as they being softer or more malleable can change in shape and back. As for forged rims, they are stronger, which means it is more ideal for hard corners and high speed performance since they dun conform to pressures and "bend" to accomodate stress. But once hit hard beyond its limits, it changes shape altogether and permanently.

 

However, truth is, i dun think there are many shops capable of reparing rims. Even if they are casted. Chances are u need to replace them once damaged, be it forged of casted.

[Sturtles]

I used to have a set of OZ f1 cup, and when i hit kerb at ard expressway speeds, which broke my front lower arm, the wheel became oval, but didn't crack or shatter.. took the chance to change to cheap 17", but now back to f1 cup again, cuz i really trust the reliablilty of their rims...