Suspension Thoughts after 2000 Kilometer Alpine Tour + 10 hrs of intense twisties

[Norm Peterson]

You can also loosen, then equally re-torque all of your lug nuts to spec, ensuring you do so in the “star-shape” order.

Do this in stages, with at least the first stage with the tire off the ground and subsequent stage(s) with the tire having less than full weight on it.

It really can make a difference.


Norm

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[TheLion]

I always use a calibrated torque wrench and torque to 149~150 ft-lbs as per the spec. I also go in a star shape first, then I do around the world once as final check. After 100 miles I re-torque in a star just in case things settle a bit. So I'm not sure it's related to any run out variations due to improper torquing. My bet's on the balancing and 115~120 mph is a resonant frequency, either that or the tires are slightly out of round. Those Pirellies flat spot very easily if I let the car sit for a few days. Takes a couple miles for them to loosen up again.

I will say this however, I think from a handling standpoint the BMR Minimum Ride height springs would have been a better choice. I wasn't aware they existed when I got my SP080's and the SP083's were too much for stock PP struts. I think the front could use just a little bit more height as on really bumpy roads the front gets a tad un-settled as I think it's reaching it's travel limits too quickly.

Back is fine as it's only a 1/2" drop with SP080's. Front drop however is aggressive at 1.2". Visually it has just a slight rake to it. It had more of a rake before I clocked all the rear bushings under load, but the rear dropped a bit more after clocking as to be expected. Nothing to clock in the front as it's all spherical except the single inner rear arm end that's solid rubber.

 

[BmacIL]

Do this in stages, with at least the first stage with the tire off the ground and subsequent stage(s) with the tire having less than full weight on it.

It really can make a difference.


Norm

This. I torque the rears off the ground and then drop the front just enough so that the wheels don't spin when I torque them (and snug them up while fully in the air).

 

[TheLion]

Maybe I"ll give that a try. I've always just snugged them first with a 1/2 drive ratchet. Then dropped the car. Then torqued it all. The threads are not rusty and the lugs move freely, so I shouldn't need added torque to compensate for thread friction and I don't want to add to much pre-load to the wheel bearings.

 

[Norm Peterson]

The bearing itself isn't in the load path of the studs. And as long as all of the mating surfaces (hub flange, both sides of the rotor, back side of wheel) are flat, I'm not expecting the hub flange to bend and indirectly affect the bearings that way. Though it doesn't hurt to be careful about not overtorquing the studs for their own sake.


Norm.

 

[TheLion]

Right on, i'm thinking of some older designs where the wheel torque adds pre-load to the hub bearing like a few drum brake rear's. My bad.

 

[Roadway 5.0]

Update:

Sway Bar

I took the advice of many and adjusted my rear sway bar from the stiffest setting to the softest setting. After a week or two of driving my overall impression is: it is INCREDIBLE how much sway bars affect a car's suspension and driving dynamic. My once telepathic/sharp turn-in at slower "daily driving" speeds with the full-stiff bar has been reduced, sadly, but at the beneficial trade-off of gaining MUCH more feedback in turns at speed.

The largest surprise is that I can now break the rear tires loose on-demand easier in a turn, and I find myself "steering" with the gas much more too; this counters what I've read on suspension workings, which leaves me puzzled a bit. I suppose the more predictable feeling of the car allows me to better gauge the breaking point of the tires, and thus gives me "green light" on when to finesse the gas to get the results I want. Anyway, I REALLY like how the car reacts to my driving style now.

Springs

I absolutely love my setup...it is very refined and much like a performance BMW (from their glory years). Of course, there is still room for improvement, and with that said I now have Steeda Dual-Rate springs in my garage awaiting install. I can't wait to get these on and see how they do!

UPDATE SEP 6th, 2019: I installed the Steeda bumpsteer and roll center correction kit before swapping to the Dual Rates; I liked the feel so much I decided to stay with the Ultralites

Wheels

I pulled the trigger on lighter wheels (24ish lbs each) and will grab a set of Michelins in the spring to see just how good I can get my stang to handle. I'll keep you all in suspense on which wheels I scooped-up ;)

-----------------------------------------------

If you all are interested to see how my car handled on the trip, here are two new videos of my Mustang driving on Austria's Grossglockner High Alpine Road. Enjoy, and thanks for all of the help navigating through my feedback post and getting me the handling I was looking for.

- Mike

 

[Norm Peterson]

Update:

Sway Bar

I took the advice of many and adjusted my rear sway bar from the stiffest setting to the softest setting. After a week or two of driving my overall impression is: it is INCREDIBLE how much sway bars affect a car's suspension and driving dynamic. My once telepathic/sharp turn-in at slower "daily driving" speeds with the full-stiff bar has been reduced, sadly, but at the beneficial trade-off of gaining MUCH more feedback in turns at speed.

The largest surprise is that I can now break the rear tires loose on-demand easier in a turn, and I find myself "steering" with the gas much more too; this counters what I've read on suspension workings, which leaves me puzzled a bit. I suppose the more predictable feeling of the car allows me to better gauge the breaking point of the tires, and thus gives me "green light" on when to finesse the gas to get the results I want. Anyway, I REALLY like how the car reacts to my driving style now.

Perhaps when the rear bar was full-stiff your sense of self-preservation was kicking in . . . telling you that since you don't like big surprises that happen too abruptly or too soon, don't make them happen. It'd certainly be a factor on that Alpine road.


Norm

 

[Bluemustang]

Your discovery about softening the rear bar stiffness doesn’t surprise me. Glad you are enjoying the setup! Curious as to why you are changing springs though if you’re happy with your setup. Ultimately I think the dual rate springs may be better. Higher rate, less geometry change from lowering as you have with the Ultralites now.

 

[Roadway 5.0]

Your discovery about softening the rear bar stiffness doesn’t surprise me. Glad you are enjoying the setup! Curious as to why you are changing springs though if you’re happy with your setup. Ultimately I think the dual rate springs may be better. Higher rate, less geometry change from lowering as you have with the Ultralites now.

You mentioned my reason to change: higher rate. I do love my Ultralites, and the look is killer, but I am hungry for even more aggressive handling for my road trips. These dual rate springs stack-up some insane numbers -- 350/1200 when compressed and are supposedly smooth on the street. With the initial rates slightly softer than my Ultralites, maybe these are truly the best of both worlds. I will certainly try and find out

Either way, if I do find myself unhappy with the switch I can always revert back; it's just an afternoon install and an alignment away

 

[Bluemustang]

You mentioned my reason to change: higher rate. I do love my Ultralites, and the look is killer, but I am hungry for even more aggressive handling for my road trips. These dual rate springs stack-up some insane numbers -- 350/1200 when compressed and are supposedly smooth on the street. With the initial rates slightly softer than my Ultralites, maybe these are truly the best of both worlds. I will certainly try and find out

Either way, if I do find myself unhappy with the switch I can always revert back; it's just an afternoon install and an alignment away

That's good! I was a bit wary of the extra harshness when I planned to switch to the BMR SP083s because of the high rate. I was surprised and @BMR Tech was right - I was surprised how docile they were. My ride quality actually got better. So I assume with your planned changes, you might be surprised how well they ride. I do not know much about the Steeda Dual Rate and how the spring rate transitions

I also found that I needed less bar with the higher spring rates. My theory is big spring/small bar. The high rate keeps the body flat and stable in corners and softer bars allows some independence of the suspension. Too much bar and you loose the independence of each wheel to react to road impacts/bumps. It also keeps it I think from being "razor edge" where it feels like it could lose it at any moment. I think you discovered that once you softened up your rear bar.

 

[Roadway 5.0]

It also keeps it I think from being "razor edge" where it feels like it could lose it at any moment. I think you discovered that once you softened up your rear bar.

Absolutely true on this. I think keeping the bars tame keeps the suspension "playful" feeling, in a stunt driver sort of way

I do not know much about the Steeda Dual Rate and how the spring rate transitions

This is something I'm excited to find out for myself. The science behind the springs leads me to think that I'll receive even more "feel" from the suspension during weight transfer, which I'm a huge fan of, and a more controlled transfer as well.

 

[NightmareMoon]

In my experience. A softer rear bar setting isn't a recipe for being able to just mash it whenever. The car will still power-oversteer pretty much on demand, there is just a bit more margin for error if you get on it. Shock settings make a difference too.

 

[BmacIL]

Update:

Sway Bar

I took the advice of many and adjusted my rear sway bar from the stiffest setting to the softest setting. After a week or two of driving my overall impression is: it is INCREDIBLE how much sway bars affect a car's suspension and driving dynamic. My once telepathic/sharp turn-in at slower "daily driving" speeds with the full-stiff bar has been reduced, sadly, but at the beneficial trade-off of gaining MUCH more feedback in turns at speed.

The largest surprise is that I can now break the rear tires loose on-demand easier in a turn, and I find myself "steering" with the gas much more too; this counters what I've read on suspension workings, which leaves me puzzled a bit. I suppose the more predictable feeling of the car allows me to better gauge the breaking point of the tires, and thus gives me "green light" on when to finesse the gas to get the results I want. Anyway, I REALLY like how the car reacts to my driving style now.

Springs

I absolutely love my setup...it is very refined and much like a performance BMW (from their glory years). Of course, there is still room for improvement, and with that said I now have Steeda Dual-Rate springs in my garage awaiting install. I can't wait to get these on and see how they do!

I think your ability to break the tires loose and throttle steer is as much to do with the ability to make the differential work better as anything. Your torsen will not be able to bias torque well or at all if the inside tire gets light, and softening the rear bar allows it to do that. Big spring/soft bar is best on the back of these cars for getting the power down. Having the midcorner balance be a little less oversteery helps too.

 

[Bluemustang]

I think your ability to break the tires loose and throttle steer is as much to do with the ability to make the differential work better as anything. Your torsen will not be able to bias torque well or at all if the inside tire gets light, and softening the rear bar allows it to do that. Big spring/soft bar is best on the back of these cars for getting the power down. Having the midcorner balance be a little less oversteery helps too.

Yeah I agree on the midcorner balance thing. I want to see how my car handles high speed corners as often times the handling behavior can be very different from low, mid to high speed corners. I’d like to it have a slight understeer in the high speed sweepers for a little safety net. Definitely don’t want the back end coming out on you at 100+ mph.

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