Originally Posted by Ron AKA

The dirty dark secrets that Ford is not talking about is that the Young's modulus (E value) for aluminum is about 1/3 that of steel. In other words for the same stress aluminum deflects three times as much. Aluminum can be made strong, so it can take the stress, but you have to live with the E value and extra flex. That is why they are making the aluminum thicker. They pretty much have to. And they still can't match steel for stiffness. Steel is about double the weight of aluminum, but has three times the E value. Bottom line is that if you want weight reduction you have to give up some flex, or you have to reduce spans of open material. Have not looked at the new F150 close enough, but I suspect they will have done that. Put reinforcing behind the large span panels, or reduced the panel span. To me the attraction of aluminum is more the corrosion resistance than the weight saving.


And on the high tensile strength steel frame for weight savings, you have a similar issue. Yes, you can increase the tensile strength of steel to make it stronger, run stresses higher, save weight, BUT, the high strength steel E value is the same as the lower strength. That means to utilize the higher strength you have to put up with more flex. Again there are some ways around it to change the design, but the thing to watch is how flexible the frame may be. As it is with a supercab long box when I park on uneven ground it is not hard to see frame flex, and the whole truck twists from front to back. Will be interesting to see how these new high strength frames react, especially the longer wheelbase models...

Originally Posted by Ron AKA

The dirty dark secrets that Ford is not talking about is that the Young's modulus (E value) for aluminum is about 1/3 that of steel. In other words for the same stress aluminum deflects three times as much. Aluminum can be made strong, so it can take the stress, but you have to live with the E value and extra flex. That is why they are making the aluminum thicker. They pretty much have to. And they still can't match steel for stiffness. Steel is about double the weight of aluminum, but has three times the E value. Bottom line is that if you want weight reduction you have to give up some flex, or you have to reduce spans of open material. Have not looked at the new F150 close enough, but I suspect they will have done that. Put reinforcing behind the large span panels, or reduced the panel span. To me the attraction of aluminum is more the corrosion resistance than the weight saving.


And on the high tensile strength steel frame for weight savings, you have a similar issue. Yes, you can increase the tensile strength of steel to make it stronger, run stresses higher, save weight, BUT, the high strength steel E value is the same as the lower strength. That means to utilize the higher strength you have to put up with more flex. Again there are some ways around it to change the design, but the thing to watch is how flexible the frame may be. As it is with a supercab long box when I park on uneven ground it is not hard to see frame flex, and the whole truck twists from front to back. Will be interesting to see how these new high strength frames react, especially the longer wheelbase models...

Originally Posted by dannofx4

You had my attention right up until this point...frame flex on uneven ground?


Some people on here talk like they know more than Ford engineers.

Originally Posted by MT-Ford

Are you saying you don't believe the frame will flex? Have you had any trucks off road on uneven ground. They will Flex.

Originally Posted by dannofx4

Ya, when you're supremely off roading...not when parking on uneven ground...gimme a break.


Here, I just yanked this off the web and even its "flexing" to look like less than a 1/4 inch

Originally Posted by Mike FX4

The new Mustang IS aluminum. It didn't shed any weight though.

Originally Posted by dannofx4

You had my attention right up until this point...frame flex on uneven ground?

Some people on here talk like they know more than Ford engineers.

Originally Posted by 11screw50

You act as though nothing has changed except the material being used and that simply is not the case.

Originally Posted by Ron AKA

Absolutely, and I do happen to be a mechanical engineer, so I could have that chat if necessary.