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[Powashiftin]

Originally Posted by ALUFELGEN

ALUFELGEN SF-71:



FORGESTAR F14




Exact same weight, on the same scale. The SF-71 are more concave, have more attention to detail, cost $400-$500 less, are made exclusively for the E90, are hub-centric (require no centering rings) and there is no wait. They are also rated and certified to 690kg by VIA/JWL.

Is this car lowered?

[dozer008]

It doesnt appear to be. The rear rim would be alot more tucked if that was the case. I would be willing to guess its stock. 19's fit perfect on this car thats why you dont see alot of 20's.

[adamsclubs]

Update, a 9 lbs drop at each corner has also increased my mpg by about 2, with the same aggressive driving style and route.

I still want to find out if any F14 owners had the same issue of the clearcoat on the painted surface easily chipped away by road debris?

[Br0]

Originally Posted by ALUFELGEN

1. Manufacturing processes do not define the strength of a wheel. A cast wheel is not weaker than a flow-formed wheel, or a flow-formed wheel weaker than a forged wheel. The manufacturing process makes a stronger metal, and since the metal is stronger, you can use less metal to achieve the same strength, hence making a lighter wheel. Don't confuse the strength of the metal with the strength of the wheel. What defines the strength of a wheel is the load rating. Our wheels are rated between 690kg-707kg per corner which is the above standard for the 3-Series.

2. Our offsets are made to fit the E90 chassis without the need of spacers, adapters or any modifications to the vehicle. While making customs offsets is good for aggressive fitments, unless that specific offset and fitment has been tested and certified for your vehicle, you`ll get a wheel that has not been certified for strength.

3. Our SF-71 wheels come Metallic Silver, Titanium Gunmetal, Sports Gunmetal, Hyperblack, Matte Black, Diamond Cut Black, Diamond Cut Gunmetal and Diamond Cut Silver. Our standard finishes are above the industry standard. For custom finishes, we use the same facility that paints for ADV.1 and most high end companies and the possibilities are endless. If you can think of the color, we can make it.

At the end both are good products and the OP can't go wrong with either one.

1. Load rating has nothing to do with how the wheel will hold up to denting, cracking on impact, etc. And who said anything about me confusing wheel strength with metal strength? Pound for pound, the metal in the forgestars is stronger, or strain-hardened, because of the reorganized and aligned grain structure from flow forming, and the tensile/yield strength and fatigue life in the metal is improved. I would go into grain/crystal structure further but I know you're already aware of this being a wheel manufacturer. As for stress calcs or maybe even stress simulation on a 3d model of the wheel used in the design (if they have one) and thickness of spokes, etc...we dont have that knowledge for the overall strength pinned to a finite number, just a required load rating that is pretty general to the application the wheel is intended for and what the wheel is tested at, but does NOT fail at. So with lack of this knowledge and an educated guess required, I will again take the wheel made with a strain hardend metal with properties similar to that of forged metal, even though the load rating is the same for both. This is my reasoning for stating what I originally did.

And yes, I've heard Forgestar's used to be load rated to 1200lbs and are now 1560lbs or so as recommended by BMW and is what you load rate your wheels at. E92 for example weighs 3600 and even with a load of 1400lbs more of passengers/cargo, that's still only 1250lbs per corner.

2. Another way of putting that your offset options are created to prevent even the slight idea of a problem with fittment on a customers car, thus very conservative, which is fine for those that dont care to choose something more aggressive.

3. Most of your color choices apparently only come in certain wheel widths, and others in other widths. In other words, If you get certain wheel widths you dont have the choice of all of the standard finishes you mention. Correct me if im wrong, this is what i have read.

In the end, yes both are pretty good wheels although I know less about the Alufelgen as far as history, just how they are manufactured. It's all about preferences, and my original post states my preferences for choosing the F14.

Originally Posted by Exzackt

when did you order your rims.. I ordered mine june 8th and they were out of stock of the 8.5x18 10x18

I believe it was like June 21st or so. But i got 19's, not 18's.

[dozer008]

this is a thread just to mention two great products. Not to attack alufulgen. He quoted me fairly and has a great product with tons of satisfied customers. I like the style of his wheels and was very helpful to me. I just have have my eye on the f14 even before i purchased my car so that is what I went with. I have good things to say about what both wheels can offer. Hey Br0 whats your name on the e90 Facebook page?..... shoot me a pm

[Br0]

Originally Posted by dozer008

this is a thread just to mention two great products. Not to attack alufulgen. He quoted me fairly and has a great product with tons of satisfied customers. I like the style of his wheels and was very helpful to me. I just have have my eye on the f14 even before i purchased my car so that is what I went with. I have good things to say about what both wheels can offer. Hey Br0 whats your name on the e90 Facebook page?..... shoot me a pm

Ya, my reply sounded a little aggressive lol so i dumbed it down a bit just now. Nobody is attacking, though, just a healthy debate on the 2 wheels. I never said his wheels were garbage or anything negative at all, ive read many reviews on them...just stating the generally accepted knowledge that a flow formed wheel is stronger than a pressure cast wheel, which he seemed to disagree with, just as a forged wheel is stronger than a pressure cast wheel and still carries better properties than a flow formed. Also wanted to clear up for future readers that load rating does not equate to a stronger wheel in every respect, which how he made it sound. His statement is not inaccurate per say, but is worded so as to favor his wheels.

Ill pm you

[ALUFELGEN]

We are not here to debate which one is a better product since both of them are great products and we prefer that to be something for the customer to determine. The topic of wheel strength and manufacturing process came alive and it is important for the consumer to understand what makes a wheel stronger than other.

Originally Posted by Br0

1. Load rating has nothing to do with how the wheel will hold up to denting, cracking on impact, etc.

Load rating, exclusively, does not determine a wheel tolerance to dents or cracks on impact. There are multiple factors that determine a wheel resistance to damage. Tire size, tire ratio, offset, radial speed, linear velocity, material, load rating, load, vehicle weight, and probably several dozens more. While load rating is not exclusive to a wheel resistance to road hazard, it does play a part on the equation.

Wheel strength and wheel resistance to hazards such as potholes, etc, are two different things and there is no easy way to calculate the resistance of a wheel to hazards. If you would like to get a wheel that is more resistant to wheel hazards, manufacturing process or load rating are not proper indicators of that. Design, dimensions and engineering plays a bigger role.

Originally Posted by Br0

And who said anything about me confusing wheel strength with metal strength? Pound for pound, the metal in the forgestars is stronger, or strain-hardened, because of the reorganized and aligned grain structure from flow forming, and the tensile/yield strength and fatigue life in the metal is improved. I would go into grain/crystal structure further but I know you're already aware of this being a wheel manufacturer.

The metal in a flow-formed wheel is only stronger at the barrel, of course, because of the flow-forming. Now, since the metal is stronger, then to take advantage of this strength, manufacturers reduce the barrel thickness to make a lighter product with the same strength. For example, a flow-formed wheel will have a barrel thickness of approx. 4.5mm, while a low-pressure cast wheel will have a barrel thickness of 5.5-6.0mm. The flow-formed wheel barrel is stronger, so it allows manufacturer to use less material to achieve the same strength. You are correct that pound-per-pound a flow-formed wheel is stronger, but it is not pound per pound, since the flow-formed wheel uses less material and that's the only reason why it's lighter. Both Flow-formed and low-pressure cast aluminum use A356 grade aluminum, and regardless of what it's done to it, flow-forming, forging, casting, it does not change the density of the metal. If it was pound-per-pound and they both used the same amount of material, then of course, the flow-formed wheel would be stronger, but that is rarely the case. That is why load rating is the determining factor of strength.

We have conducted rotating bending fatigue test on several samples to see the effects of flow-forming on fatigue strength. By flow-forming, all that is done is the microestructure of the metal is pushed down and is placed in the direction of the rotation of the forming tool. This cannot be confused with how a forging press re-aligns the crystalline structure of a metal. Completely different processes. In our findings, the increase in fatigue strength was due to a reduction in crack growth and reduction of porosity on the test samples, and not an increase in yield or tensile strength. Yield and tensile strength of a metal is improved via heat treatment, not flow forming. Flow forming will not improve yield/tensile strength. Forged wheels use 6061-T6 which is a totally different monster and the properties and strength of 6061-T6 are due to the heat treatment process and not exclusively due to the metal grade.

Originally Posted by Br0

As for stress calcs or maybe even stress simulation on a 3d model of the wheel used in the design (if they have one) and thickness of spokes, etc...we dont have that knowledge for the overall strength pinned to a finite number, just a required load rating that is pretty general to the application the wheel is intended for and what the wheel is tested at, but does NOT fail at. So with lack of this knowledge and an educated guess required, I will again take the wheel made with a strain hardend metal with properties similar to that of forged metal, even though the load rating is the same for both. This is my reasoning for stating what I originally did.

Please read above. There are no educated guesses in engineering. There are precise calculations and testing done to certify and make sure a wheel load capacity is sufficient for an application. We are also limited to the specs provided by institutions like TUV and VIA/JWL which specify the required load for an specific vehicle.

Flow-forming is a very interesting technology and allows to make very light and strong wheels and at very affordable prices which has caused its to grow in popularity but do it generally makes lighter wheels, not stronger.

Any questions, feel free to ask.

Carlos
Owner
ALUFELGEN Wheels

[Br0]

Carlos,

Great writeup, and I see you know your stuff.

I assume you are also the same Carlos whose article was quoted in thread below. The lead engineer at MORR and owner of Alufelgen? Industrial Engineering with minor in mechanical design? Nice to talk to another mechanical designer, which is also my field.

http://www.6speedonline.com/forums/9...-forged-2.html

I read this article, and I now better understand the differences in grain rearrangement/alignment and structure during the manufacturing processes, however it appears that flow-forming achieves the same, or close to, strength properties in the barrel that forging does (and even many forged wheel's barrels are flow-formed anyway).

Also, from what i understand tensile/yield strength is, in fact, improved via the flow forming process. You are saying this is incorrect?:

http://www.ressourceneffizienzatlas....verfahren.html

"Aluminum wheels are mainly produced via the low-pressure casting process. In the production of larger 16-inch wheels, as they are used for middle- and upper-class cars and trucks, the process involves drawbacks in terms of mechanical properties, which have to be compensated by a high material input. With the flow forming process the company Leifeld Metal Spinning GmbH from Ahlen has developed a manufacturing approach, allowing for a significant weight reduction of larger wheels, in comparison to the low-pressure casting process. The rolling machine ’’WSC 700 / 6 H’’, which has been developed for this process, is specially designed for the spinning and flow forming of the rim contour of aluminum wheels, steel wheels, or wheels made from other high-strength alloys for car and truck design. Here, the source material is a blank or forge form, which is wall ironed by means of radially arranged flow forms on a rotating mold core. Thereby, the independently programmable flow forming paths are of particular advantage. The flow-forming process improves the microstructure of the wheels and increases the tensile strength by up to 10 percent compared to the low-pressure casting process, whereby, a smaller wall thickness can be achieved. "




It's almost too hard to believe that forged wheels will hold up no better to the same denting/cracking/bending as a cast wheels given the much different metallurgical properties of the two. And the fact that most damage occurs in the barrel area (where flow-formed wheels are stronger and closer to forged properties) when you, say, hit a pothole, curb, etc.

If you are correct, then what you say goes against what 98% of the people out there believe as far as wheel strength, or "toughness" to be precise when it comes to impact damage, goes. It has to be the most common misconception in wheels ever.

As you can see later in the posts, some people still believe forged are tougher. I must say, I still have a very hard time believing it myself, when it comes to impact resistance with two radically different metallurgical properties...thinner barrel or not.

Originally Posted by ALUFELGEN

Please read above. There are no educated guesses in engineering. There are precise calculations and testing done to certify and make sure a wheel load capacity is sufficient for an application. We are also limited to the specs provided by institutions like TUV and VIA/JWL which specify the required load for an specific vehicle.

I was referring to an educated guess on the consumer's part, not the engineer's part. I am well aware that there are no educated guesses in engineering...trust me.