Jacking Rails Improve Stiffness???

[EFI]

When I ask about increased stiffness, I'm thinking about lifting a wheel when exiting a driveway at an angle kind of stiffness.

That already happens. Go lift the car by the front pinch weld and the rear goes up almost in unison.

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[Cobra Jet]

Just to add more to the discussion, this image has been posted here a few times for those needing it for determining jacking points OR placement of jack stands for when a lift is not available. This image is unaltered and already has these areas noted as you see:

Adding to and editing that initial pic, the area in ORANGE I have circled is the L & R factory pinch weld/jack rail locations directly under the rocker:

Again, adding to and editing the initial image, the area I have highlighted in GREEN is the factory unibody subframe that is integrated to/under the floor pan:

With the above S550 visuals, one can see that on the modern S550, the factory subframe rail starts up at the firewall (as initially discussed on my other post), but is now "full length" of the floor pan, where it terminates on the floor pan under the rear seat and just before the rear IRS.

On prior Mustangs to the S550, the front subframe rails would have terminated just after the end of the trans mount. Also to note, on all Mustangs with the live rear axle, BUT EXCLUDING the 1999-2004 SVT Cobras w/IRS, the rear subframe rails would have terminated just in the proximity of where you see the S550 resonator in the above pics. Using the image as a reference, the rear subframe rails on prior Mustangs would have ended where the back of the S550 resonator begins. Thus there would be a large gap between the front and rear subframe rails. That gap is where the aftermarket created sub-frame connectors.

Could an off-shoot of a prior subframe connector design be utilized under the S550? Possibly, but keep in mind we also now see that Ford has "filled the gap" with more steel boxing/stamping on the S550.

This is why my prior comment is that placing jacking rails under/near the pinch weld has no magical impact to structural rigidity. That specific area is already "boxed" and rigid by the design of not only the rocker, but how the floor pan is welded to the rocker from the underside AND the inside of the cabin. That area on either side of the unibody is the strongest area of the entire body shell.

The "weakness" is the area you see where the rear of the floor pan ends and the IRS begins - that is the "new gap" for any S550. The above images are also a prime example of how STEEDA has filled that gap with their rear chassis braces. STEEDA is the only Company to date that has (IMO) properly connected the front and rear unibody structure together to form that necessary rigidity an S550 needs WHEN under duress or being used during extreme timed events for competition purposes.

IMO, the factory subframe rails could be improved upon as well. That steel is just hollow boxed. While strong, a better aftermarket design could be implemented to make that area of the subframe/floor pan much stronger and more rigid for S550's used for and in competition.

Discuss.

 

[SH!FT]

What is the benefit of exposing the factory jack points (with the shorter version)?

Mainly just my preference. As @EFI stated, you can lift up from pretty much anywhere on the pinch weld and have both wheels leave the ground. I tend lift towards the mid point on the jacking rail to get two jack stands installed based on the CJ pony diagram.

The full length rails run the risk of crushing the end caps if your careless with choosing 4-point lift locations as shown from what I accidently did here:

Steeda's shorter version should reduces risk/temptation to pick up at the endcap. Plus, that L-bracket should offer endcap rigidity if you do by mistake or... bring the car to a shop that doesn't give a sh!t .

The jack rails work great for quick jobs, but I like having 4 wide support points on pinch rail pucks if I plan to have the car in the air for a while.

 

[Toretto]

I got the BMR jacking rails installed two months after I got the car, and honestly I didn't feel any difference. I got it for the sole purpose of being able to lift the car easily to change wheels, that's it.

 

[derklink]

Mainly just my preference. As @EFI stated, you can lift up from pretty much anywhere on the pinch weld and have both wheels leave the ground. I tend lift towards the mid point on the jacking rail to get two jack stands installed based on the CJ pony diagram.

The full length rails run the risk of crushing the end caps if your careless with choosing 4-point lift locations as shown from what I accidently did here:

Steeda's shorter version should reduces risk/temptation to pick up at the endcap. Plus, that L-bracket should offer endcap rigidity if you do by mistake or... bring the car to a shop that doesn't give a sh!t .

The jack rails work great for quick jobs, but I like having 4 wide support points on pinch rail pucks if I plan to have the car in the air for a while.

Thank you! This is an excellent explanation.

 

[BlackandBlue]

Lol

The placebo effect is real. If a car is flexing where those rails go, it has bigger problems.

 

[ice445]

Just to add more to the discussion, this image has been posted here a few times for those needing it for determining jacking points OR placement of jack stands for when a lift is not available. This image is unaltered and already has these areas noted as you see:

Adding to and editing that initial pic, the area in ORANGE I have circled is the L & R factory pinch weld/jack rail locations directly under the rocker:

Again, adding to and editing the initial image, the area I have highlighted in GREEN is the factory unibody subframe that is integrated to/under the floor pan:

With the above S550 visuals, one can see that on the modern S550, the factory subframe rail starts up at the firewall (as initially discussed on my other post), but is now "full length" of the floor pan, where it terminates on the floor pan under the rear seat and just before the rear IRS.

On prior Mustangs to the S550, the front subframe rails would have terminated just after the end of the trans mount. Also to note, on all Mustangs with the live rear axle, BUT EXCLUDING the 1999-2004 SVT Cobras w/IRS, the rear subframe rails would have terminated just in the proximity of where you see the S550 resonator in the above pics. Using the image as a reference, the rear subframe rails on prior Mustangs would have ended where the back of the S550 resonator begins. Thus there would be a large gap between the front and rear subframe rails. That gap is where the aftermarket created sub-frame connectors.

Could an off-shoot of a prior subframe connector design be utilized under the S550? Possibly, but keep in mind we also now see that Ford has "filled the gap" with more steel boxing/stamping on the S550.

This is why my prior comment is that placing jacking rails under/near the pinch weld has no magical impact to structural rigidity. That specific area is already "boxed" and rigid by the design of not only the rocker, but how the floor pan is welded to the rocker from the underside AND the inside of the cabin. That area on either side of the unibody is the strongest area of the entire body shell.

The "weakness" is the area you see where the rear of the floor pan ends and the IRS begins - that is the "new gap" for any S550. The above images are also a prime example of how STEEDA has filled that gap with their rear chassis braces. STEEDA is the only Company to date that has (IMO) properly connected the front and rear unibody structure together to form that necessary rigidity an S550 needs WHEN under duress or being used during extreme timed events for competition purposes.

IMO, the factory subframe rails could be improved upon as well. That steel is just hollow boxed. While strong, a better aftermarket design could be implemented to make that area of the subframe/floor pan much stronger and more rigid for S550's used for and in competition.

Discuss.

I get what you're saying, but just because something is already strong doesn't mean it can't be made even stronger. If you draw a diagonal line from front left subframe mount to the right rear, there's a twisting force present there in the actual unibody tub due to the weight on both ends of it. In older cars it was a lot more obvious, if you lifted one corner high up, the door wouldn't open/close smoothly. The s550 doesn't have that issue, but it's definitely not entirely "placebo" like some of you are saying. I'm not even saying it improves drivability or anything you'd notice driving down the road, but I'm pretty confident that it will pick up a rear tire sooner and higher than a stock car due to a few mm less droop. I admit the conditions I drive my car on are atypical, but given the only time I noticed something was climbing those weird angles, I'm confident it's not some placebo. But to each their own.

 

[K4fxd]

They add a small amount of additional stiffening. But like Niki Lauda, god gave me a great ass. I can feel a cracked weld on a full chassis car.


The IRS braces from Steeda make a huge improvement. It's like adding subframe connectors in an earlier mustang.

 

[Robottrainer]

Can anyone comment on the improvements in chassis feel/performance from welding in jacking rails?
Is the car stiff enough already that the rails don't make much difference? Way back when, I welded in "subframe connectors" that actually made a difference in my 1990 SHO. Do they make a difference in the S550?
Thanks.

Maybe a little. In order to be effective it needs to be tied side to side

 

[Hoofer]

Just to add more to the discussion, this image has been posted here a few times for those needing it for determining jacking points OR placement of jack stands for when a lift is not available. This image is unaltered and already has these areas noted as you see:

Adding to and editing that initial pic, the area in ORANGE I have circled is the L & R factory pinch weld/jack rail locations directly under the rocker:

Again, adding to and editing the initial image, the area I have highlighted in GREEN is the factory unibody subframe that is integrated to/under the floor pan:

With the above S550 visuals, one can see that on the modern S550, the factory subframe rail starts up at the firewall (as initially discussed on my other post), but is now "full length" of the floor pan, where it terminates on the floor pan under the rear seat and just before the rear IRS.

On prior Mustangs to the S550, the front subframe rails would have terminated just after the end of the trans mount. Also to note, on all Mustangs with the live rear axle, BUT EXCLUDING the 1999-2004 SVT Cobras w/IRS, the rear subframe rails would have terminated just in the proximity of where you see the S550 resonator in the above pics. Using the image as a reference, the rear subframe rails on prior Mustangs would have ended where the back of the S550 resonator begins. Thus there would be a large gap between the front and rear subframe rails. That gap is where the aftermarket created sub-frame connectors.

Could an off-shoot of a prior subframe connector design be utilized under the S550? Possibly, but keep in mind we also now see that Ford has "filled the gap" with more steel boxing/stamping on the S550.

This is why my prior comment is that placing jacking rails under/near the pinch weld has no magical impact to structural rigidity. That specific area is already "boxed" and rigid by the design of not only the rocker, but how the floor pan is welded to the rocker from the underside AND the inside of the cabin. That area on either side of the unibody is the strongest area of the entire body shell.

The "weakness" is the area you see where the rear of the floor pan ends and the IRS begins - that is the "new gap" for any S550. The above images are also a prime example of how STEEDA has filled that gap with their rear chassis braces. STEEDA is the only Company to date that has (IMO) properly connected the front and rear unibody structure together to form that necessary rigidity an S550 needs WHEN under duress or being used during extreme timed events for competition purposes.

IMO, the factory subframe rails could be improved upon as well. That steel is just hollow boxed. While strong, a better aftermarket design could be implemented to make that area of the subframe/floor pan much stronger and more rigid for S550's used for and in competition.

Discuss.

Thank for the pics!

My '20 PP1 vert has some additional structural bracing in the rear.

Would you have access to pics showing those?

 

[WD Pro]

Thank for the pics!

My '20 PP1 vert has some additional structural bracing in the rear.

Would you have access to pics showing those?

WD

 

[Hoofer]

WD

Thank you!

 

[TeeLew]

The twist of the chassis is going to put bending loads in the racking rails, so they'll have an effect, but a couple bolts on a piece of 1x2 tubing isn't going to be life-changing.

 

[DadzMach]

Thanks for all the replies.
When I ask about increased stiffness, I'm thinking about lifting a wheel when exiting a driveway at an angle kind of stiffness. Subframe connectors did that for the SHO. I think I won't see that kind of improvement on an S550. I've already got the Steeda 4pt in the front and semi-solid mounted subframe in the rear. Guess I should be happy with that on the street.

My favorite photo of my SHO plus is when it was pulled into my driveway partially and the rear wheel is about 2.5 inches off the ground. Not the correct photo but figured I would add one anyway. I miss that car.

 

[Rose City R]

These rails helped my jacking and improved my stiffness.

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