Adjusting the adjustable suspension

[Palpatine]

I switched my Roadster Sport back to the factory settings when I got new tires. I like the more quiet and softer ride.

My rear Sport tires were bald at 6,000 miles. So I replaced them with the standard Tesla tires. The tire roll noise is much more quiet now.

I left my two front Sport tires at the Seattle store in case someone needs replacements. They still have plenty of life in them.

 

[Tdave]

I left my two front Sport tires at the Seattle store in case someone needs replacements. They still have plenty of life in them.

Ooo, I'll take them. Seattle, eh? That's far away.

 

[Tdave]

Just got finished with the suspension settings. Front shocks now at 6 (were at 4), rears at 7 (were at 5). Both sway bars have been set to 3 (were at 2). Ride is a little harsh which doesn't bother me. Dramatic difference. Turn in is much smoother and more predictable. Balance is much better. Feels very flat and settled.
I recommend this if handling is more important to you than ride.

What's the sway bar 3 setting? Is that looser (outside hole) for both front and rear? Or something different?

Also, do we yet have confirmation whether the a setting of 1 or 10 is the firmest setting?

 

[Webbie]

What are the two tires you mentioned?
I have the shocks cranked on all my cars, and set the tires a few pounds above normal, too. I just like a harder ride, no sway, better steering and handling,and I figure most roads are pretty smooth anyway. I doubt this makes any difference in tire wear. You are not likely to get more than 10-15K on Yokohama AD07s, especially if you autocross as I do. They sure are sticky, though.

 

[Webbie]

Sway bar setting three is wider, but I wouldn't call it looser. Shock settings go from soft at 1 to hard at 10. I confirmed that with the Tech here, and I can certainly feel that it's true, too.

 

[Tdave]

While I have my car in for repair, I'm having the following settings done:

1) Shocks all on 10, as they currently are.
2) Front sway bar loose (outside hole), as it currently is.
3) Rear sway bar back to middle position, was on outside hole.
4) One full degree negative camber front, half degree in rear.

I considered increasing positive caster, but without power steering, I really don't want to increase steering effort.

 

[Webbie]

I'm seeing even tire wear for now, so I elected not to change camber.
May do it later after a coupe of autocross competitions.
Let us know how you like it, now or after trying it awhile.
We are lucky to have such an adjustable car with such a
simple power and drive train, eh?

 

[Webbie]

And, why did you move the rear bar back to the middle notch?

 

[Tdave]

And, why did you move the rear bar back to the middle notch?

I'm scared of oversteer. That's what caused my accident. Granted, the rear tires were brand new with only 10 miles on them when it happened, so they were slick, but still. That scared the hell out of me.

 

[Webbie]

OK, I will watch out for it. Felt some understeer and front tire scrubbing before the change. Driving on too much dirt and snow so far to push hard and be sure. Will definitely test it in autocross in April --better there than on the road anyway ( Ooooops! .... No problem). ;-)

 

[Roger Reid]

Well it it is finally warm enough to get my Sport out of the garage.

I attended the local SCCA autocross driving school yesterday. I am new to the sport, having only one event (last October) under my belt. Last October I reported understear and weak brakes.

Since last October there were three things I changed.

First I didn't charge the system to full performance mode. This allowed room in the battery for regenerative braking. At the end of the event I still showed 130 miles remaining.

Second I switched to Hawk H4 brake pads from Sector 111. A good change but still need heavy pressure to activate the ABS Chatter. The brake squeal of the stock pads is now gone.

Third I changed the front sway bar to the outer (soft) hole setting. The rear sway bar to the Inner (firm) setting. The shocks were set to position 9 (I only counted 9).

The results were great. There is still understeer in the skid pad (with traction control on) and by turning off the traction control I can finally induce some oversteer at full throttle. A welcome change (for track conditions).

I had a blast. Everyone there was amazed at the quickness and response between the cones. It was still the second time ever driving 4 wheels on a track (cones). My times were respectable and should get better.

I concentrated on smooth throttle input and had no power interuptions.

Autocross will teach you things that you can not (re: should not) do on the street. The if someone pulls out in front of you you have a better chance of staying out of an accident.

Roger

 

[TEG]

Thanks for that report! Sounds like great fun.

...I concentrated on smooth throttle input...

You might want to experiment with more dramatic inputs and try pushing your limits.
Someone once told me that you aren't trying hard enough unless you spinout once and a while.
In autocross you have nothing but cones to run into so you can take chances you wouldn't want to do on the track or street.

 

[Webbie]

"aren't trying hard enough unless you spinout"
True enough. But smooth curves and smooth inputs are still the rule -- you just push them further.
Some good rules: Slow hands make fast times. You have to know where to go slow to go fast. The fastest way around any corner that's more than 120 degrees is the shortest way. Brake before you turn.

With the kind of torque these cars have, you need to roll on the power when you are coming out of a turn, not floor it.

Here's a rule for clutch cars that we would have to modify: In a spin, both feet in. ;-)

Anyone with a roadster-- if you haven't been to an autocross, find one. It's the most fun you can have in a car safely. And that includes ... well ... never mind.

Question for y'all. What about charging in standard mode, then switching to performance mode just when you are running the autocross course? Maybe get the best of both?

 

[Webbie]

tdave got me thinking about oversteer spinouts.
Obviously, making an abrupt turn while on full acceleration is likely to cause a spin (that's not a criticism of you in any way, tdave -- just fact - you did well to steer around the idiot). Not so obviously, especially with our severe regenerative braking, abrupt steering while quickly lifting the foot from the accelerator can also cause a spin. the regen acts like a brake on the rear wheels only, like pulling the emergency brake. I learned that first hand at 90 mph in my m-coupe at the very top of third gear and wound up going backwards through the infield. Something for us all to remember, perhaps.

 

[Tdave]

Anyone use left foot braking during an autocross? Allows quick brake input without having to totally lift the accelerator, or for so long. That's standard in kart racing, which our Roadsters sort of ar .. nevermind, not going to say it.

 

[Webbie]

Left foot braking in autocross.
We have a married couple in our area that have 27 National Championships between them.
She left-foot brakes. He does not. I think it is generally considered more useful for cars that have to keep their engine spinning in order to keep the torque up. Like karts. ;-)

 

[Roger Reid]

...smooth curves and smooth inputs are still the rule -- you just push them further.
Some good rules: Slow hands make fast times. You have to know where to go slow to go fast. The fastest way around any corner that's more than 120 degrees is the shortest way. Brake before you turn.

With the kind of torque these cars have, you need to roll on the power when you are coming out of a turn, not floor it....

Question for y'all. What about charging in standard mode, then switching to performance mode just when you are running the autocross course? Maybe get the best of both?

Agreed 100%. I did charge in standard mode and ran in performance mode. The only way for me to induce oversteer or spinout was full throttle without traction control. At no time did the car oversteer without my input and I could back out anytime.

It was great fun
Roger

 

[Webbie]

Seventeen days until my first autox with the Roadster. Gee, that's a long time.

A

 

[Tdave]

Got my car back yesterday, with some new suspension adjustments. So of course I had to go out during the evening for a 1+ hour drive. Wow, another great improvement. The car is just getting better and better with each tweak I do.

This latest big change was with camber. To adjust the camber you need to use shims, which is a bit more of a pain than just switching a bolt on the sway bar, or turning a ring on the adjustable shocks.

Stock spec camber settings from Tesla are:

Front: 0.0 degrees
Rear: -1.8 degrees

The spec range is:

Front: +0.01 to -0.03
Rear: -1.6 to -2.0

I wanted to dial in quite a bit more negative camber in the front, to improve cornering grip and get rid of more of the understeer without sacrificing rear grip with a tighter sway bar setting in the rear. To that end I moved the rear sway bar back to the middle hole, put more negative camber in the rear, and quite a bit of negative camber in the front. I was more confident with this change given the tire temperature readings that was posted above by DaveF, which proved the front definitely needed negative camber.

So this is where I'm at now with all my settings.

Adjustable Shocks: 7 in the front, 10 in the rear
Sway Bars: outside (loose) hole in the front, middle (stock setting) hole in the rear
Camber: -1.0 degrees in the front, -2.0 degrees in the rear

This was another significant improvement over only the front sway bar setting change, which was the previous big win. So this is big win #2, in my opinion. There's still some understeer, especially at very low speeds. And if I used the car only for performance driving, it could probably use 1.5 or 2.0 degrees of negative camber in the front. For now I'm happy with the -1.0 I have dialed in now.

I'm looking forward to more data and tire temp readings from autocrossers, especially if you also add as much or more negative camber in the front as I did.

 

[Tdave]

Drove over 100 miles today just for fun. More experience with my recently changed settings...

I don't know. I think it may have been a mistake to return the rear sway bar back to the middle hole. Leaving it tight, on the inside hole, may be better. I'm still not entirely sure though. The thing is that the understeer is still too much at low speeds (20-30), but not so much at 40-50. At those medium speeds the car corners pretty damn good. That's why I'm uncertain. Where I have it now may be a good choice, as higher speed handling is more important for safety.