Suspension Geometry

[Bluemustang]

There's been some talk on this forum here and there about suspension geometry and how bad the bumpsteer is on these cars, etc.. But it seems like the whole suspension geometry is an oft overlooked piece of the puzzle.

When I started my suspension modding journey, it had not occurred to me that lowering the car would hinder the suspension geometry in such a significant way. I wish somebody had told me these things when I was searching for suspension mods. I feel like I would have made different choices and given this much more thought than I have. When you read lowering spring descriptios that say things like - increases cornering ability, decreases body roll, etc...etc.. and then you find out that by changing the roll center of the car, you car now will have more body roll and less grip? That doesn't make sense and sounds disingenuous.

With the release of Steeda's new front control arms, which are supposed to correct the front roll center from the effects of lowering, is there any plans from aftermarket suspension companies to release products to correct the rear suspension geometry? I assume that adjusting the front roll center will correct the geometry of the front suspension, is this correct? I am given to understand that the rear is much more sensitive to lowering the ride height than the front is.

SO.. This is making me wonder, are there plans to help correct rear suspension geometry changes from lowering spring kits? I am considering those Steeda front control arms but it doesn't seem to make sense to correct the front end geometry while the rear is still out of whack. BMR/Steeda, etc. must be working on this, no?

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[BmacIL]

There's been some talk on this forum here and there about suspension geometry and how bad the bumpsteer is on these cars, etc.. But it seems like the whole suspension geometry is an oft overlooked piece of the puzzle.

When I started my suspension modding journey, it had not occurred to me that lowering the car would hinder the suspension geometry in such a significant way. I wish somebody had told me these things when I was searching for suspension mods. I feel like I would have made different choices and given this much more thought than I have. When you read lowering spring descriptios that say things like - increases cornering ability, decreases body roll, etc...etc.. and then you find out that by changing the roll center of the car, you car now will have more body roll and less grip? That doesn't make sense and sounds disingenuous.

With the release of Steeda's new front control arms, which are supposed to correct the front roll center from the effects of lowering, is there any plans from aftermarket suspension companies to release products to correct the rear suspension geometry? I assume that adjusting the front roll center will correct the geometry of the front suspension, is this correct? I am given to understand that the rear is much more sensitive to lowering the ride height than the front is.

SO.. This is making me wonder, are there plans to help correct rear suspension geometry changes from lowering spring kits? I am considering those Steeda front control arms but it doesn't seem to make sense to correct the front end geometry while the rear is still out of whack. BMR/Steeda, etc. must be working on this, no?

There's no real way to do that without different control arms and knuckles. Those are expensive things to develop and replace compared to the front arms.

Don't drop the rear so much and it doesn't get hurt so much. Staying to near a half inch drop or less keeps things in the range of where they should be (confirmed this with Ford VDE friend).

 

[Roadway 5.0]

Take in a good deep breath and relax.

I truly doubt you have much, if any, adverse geometry effects with your setup. The FRPP kit is mild on drop, has stiffer springs, stiffer swaybars, and your negative camber has increased; all of these forces counteract the ill effects brought on by lowering your car (not to mention the FRPP Track Pack was tested and put down fantastic improved numbers).

Save your money and leave these new bits to the track stars hunting tenths.

 

[Bluemustang]

I'm considering a lot of things but keep coming back to your suggestion Bmac of the SP089/SP082 spring combo. Should help the compliance and a little bit of suspension geometry.

 

[wildcatgoal]

I don't have bumpsteer issues and haven't with any of my spring combos (Steeda Ultralite, Swift Spec R, and now Steeda Dual Rate Comps). I do have the bump steer kit from Steeda but I only eyeballed the spacers. The new Steeda control arm is in the mail so I'll see what affect that has. Frankly I'm very happy with how my car handles and I don't get much body roll at all, which can be seen in many of my track photos where the car behind me (whatever it is, as long as it's not a super-stiff Miata or something) is leaning a lot. My issue now is I basically am slung out of my premium (non-Recaro) seats which don't hold me in enough any more... ug.

As long as you adjust the alignment appropriately in the rear, I think you're fine there. I quote like my Dual Rate Comp springs because they are only .75" drop which gives me nice suspension/wheel travel which has been helpful when it's time to cut a curb. These cars look wonderful with .5-.75" drops, IMO.

I'll report if I feel any difference with the new Steeda control arm thingy.

But to think that lowering a car isn't going to affect (negatively) suspension geometry that Ford spend a gazillion dollars to engineer and spec parts for is lunacy...

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