Aluminum vs. steel lift bar

[racefastnow]

What would be the technical reasoning of having an aluminum lift bar. Is the weight of a steel lift bar create any leverage on the rear end?

[hpmaster]

I can't see the material making a functional difference except for weight and that weight being unsprung. As for cost and benifit, only you and your wallet know that. There are smarter guys on here than me that might know better.

[racefastnow]

Looking for thoughts on unsprung weight also. The 10 pounds of lift bar weight vs. 10lbs on the front of the car?

[FlatTire]

Steel has a better fatigue(cycles of loading/stress) life than aluminum. The rigidity(modulus of elasticity) of steel is 3 times as great as aluminum. So for an aluminum piece to be as rigid as a steel piece, you need a sectional area 3 times as great as a steel one. A steel section for the same stiffness will almost always weigh less than an aluminum section.

Lets say that steel lift arm could support 300lbs and would deflect .5". An identical section made from aluminum would only support 100lbs before it deflected .5". So to get that aluminum piece to support 300lbs at .5" of deflection you would need to increase your section and by the time you do that you have increased the weight.

So if these aluminum lift arms they are selling are as strong as the steel counterparts, then they'll most likely be the same weight.

[hpmaster]

Steel has a better fatigue(cycles of loading/stress) life than aluminum. The rigidity(modulus of elasticity) of steel is 3 times as great as aluminum. So for an aluminum piece to be as rigid as a steel piece, you need a sectional area 3 times as great as a steel one. A steel section for the same stiffness will almost always weigh less than an aluminum section.

Lets say that steel lift arm could support 300lbs and would deflect .5". An identical section made from aluminum would only support 100lbs before it deflected .5". So to get that aluminum piece to support 300lbs at .5" of deflection you would need to increase your section and by the time you do that you have increased the weight.

So if these aluminum lift arms they are selling are as strong as the steel counterparts, then they'll most likely be the same weight.

So the aluminum front bumper is only better and 11 lbs. lighter than a steel one until I use it. LOL

[racefastnow]

Great explanation Flat Tire, that was valuable info. Anyone wanna share thoughts on the difference between placing 50 pounds on the rear end directly versus placing it on the left front persay? Not sure i know how unsprung weight effects car on rear end versus adding weight on the frame but in front left corner?

[Nobody]

Steel has a better fatigue(cycles of loading/stress) life than aluminum. The rigidity(modulus of elasticity) of steel is 3 times as great as aluminum. So for an aluminum piece to be as rigid as a steel piece, you need a sectional area 3 times as great as a steel one. A steel section for the same stiffness will almost always weigh less than an aluminum section. Lets say that steel lift arm could support 300lbs and would deflect .5". An identical section made from aluminum would only support 100lbs before it deflected .5". So to get that aluminum piece to support 300lbs at .5" of deflection you would need to increase your section and by the time you do that you have increased the weight. So if these aluminum lift arms they are selling are as strong as the steel counterparts, then they'll most likely be the same weight. Your math is off, depending on materials used: A general rule of thumb is the 1/3 - 2/3 rule: meaning a good grade of aluminum (6061-T6) is roughly 2/3 the strength of steel but 1/3 the weight. So you need to increase material area by roughly 33% on the aluminum to get the same rough strength and end up around 66% of the weight by the time you get some safety factor in there also. Also design make a big difference: Say you looking at a regular steel T/A of a typical car vs say the berky torque arm that has the aluminum top: The Std T/A top will break way way way before the berky one will and is around the same weight cause it has more then 33% more material. A typical steel T/A should be replaced every year or eventually it will fatigue (usually around the top bend where it is flexing by being straighten out by the force and eventually work hardens and starts to crack and will fail). The berky style one will last almost indefinitely from my experience, least on the top piece but would replace the lower part after a while to be safe. The downfall to the aluminum ones is expense and any place it bolts together or has treads into the aluminum.

[Nobody]

Why does it not make paragraphs? anyone else have this problem? It piles it all as one long run on paragraph, even though I'm making paragraphs annoying as hell?

[MasterSbilt_Racer]

Your math is off, depending on materials used: A general rule of thumb is the 1/3 - 2/3 rule: meaning a good grade of aluminum (6061-T6) is roughly 2/3 the strength of steel but 1/3 the weight. So you need to increase material area by roughly 33% on the aluminum to get the same rough strength and end up around 66% of the weight by the time you get some safety factor in there also. Also design make a big difference: Say you looking at a regular steel T/A of a typical car vs say the berky torque arm that has the aluminum top: The Std T/A top will break way way way before the berky one will and is around the same weight cause it has more then 33% more material. A typical steel T/A should be replaced every year or eventually it will fatigue (usually around the top bend where it is flexing by being straighten out by the force and eventually work hardens and starts to crack and will fail). The berky style one will last almost indefinitely from my experience, least on the top piece but would replace the lower part after a while to be safe. The downfall to the aluminum ones is expense and any place it bolts together or has treads into the aluminum.

You could build a steel unit, with the same design, with the same strength, and it be lighter.

There is no stress where aluminum of any grade has infinite fatigue life. There is such a stress for most steels.

[Garrettshurling]

When I was up at Swartz's for the setup seminar this winter, he had new aluminum lift bars for his stuff. I want one!

[BlackMagic]

Why does it not make paragraphs? anyone else have this problem? It piles it all as one long run on paragraph, even though I'm making paragraphs annoying as hell?

Go to your settings in your profile. I can't remember how I did it, but there are different types of paragraph layouts to choose from. I was having the same issue.

[hucktyson]

The birky model is a POS , on the other hand outpace makes a very nice piece that's aluminum on the top and steel on the bottom like the birky bar. I've had 2 outpace bars and 1 birky bar and there will not be another one

[Matt49]

The birky model is a POS , on the other hand outpace makes a very nice piece that's aluminum on the top and steel on the bottom like the birky bar. I've had 2 outpace bars and 1 birky bar and there will not be another one

What was wrong with the birky bar?

[hucktyson]

It's Crude compared to the outpace bar , it doesn't have the same pinion plate clearance the outpace bar has and the outpace bar curves back up to allow the 6th coil to work properly by not topping out the 5th coil shock first when the car is hiked up. The outpace bar comes already coated black. The outpace bar has additional holes to allow it to replace more oem chassis builder bars . And it's much cooler looking

[andy16]

I ran the red bar from that guy in ca a few years back? he made all aluminum spindles too cant remember his name now but it bent in 5 races. and I ran it on a warrior at 32" pretty short. prob woulda broke at 35 or 36" the birky bar looks better but if you built one out of chrome moly prob could get as light and stronger than the aluminum. I think all these billet alum parts aren't from necessity there for adding bling or just that xtra niceness to your car imo

[zeroracing]

The reason some use billet parts is that it is very easy to ensure that all parts are not weld distorted, and you can easily check parts. Also items like spindles are machined square so you can angle finder caster camber without having to turn wheels.