Out of Spec - Gravity vs Escalade

[xponents]

Apropos of almost nothing in your typically very informative post, I think Eric Bach is the hot daddy of the Lucid engineering team.

Wait a second... almost?

 

[hmp10]

As it stands, no one does this. Lucid didn’t do it for the Air either

Tires have their own spring rates arising from both inflation pressure and sidewall characteristics, including their height. Racing teams do, in fact, account for the spring rate of sidewalls in setting up suspensions. Also, sidewall height affects camber angle during cornering, another factor that precision suspension tuners take into account.

I'd like to know the source of your certainty that Gravity chassis tuning doesn't take sidewall height into account.

 

[momo3605]

I did not say definitely that Lucid tuned for different wheel sizes. I simply said that because they went with split diameters for cosmetic reasons doesn't necessarily mean they didn't tune for it.

Whether they did or not, I don't know. And neither, I doubt, do you.

I mean they don’t. They allow you to switch between different sets. I don’t see them selling you different springs and suspension components.

I agree with you on offsets though. That can have an affect on handling, steering, etc…but that’s simple enough. Wheels come with many offset choices. When picking aftermarket wheels you can pick the one with the right offset.

Also in many cases, downsizing wheels has a positive impact on not only range but performance as well. Due to marketing reasons, a lot of OEMs including Lucid will put huge wheels like 22s and 23s on cars because they look better. But smaller/lighter wheels with equal performance rubber will usually provide better comfort AND handle better. You see this commonly across sports cars like M, AMG, RS lines etc…

 

[hmp10]

Apropos of almost nothing in your typically very informative post, I think Eric Bach is the hot daddy of the Lucid engineering team.

The German accent, maybe?

 

[hmp10]

I mean they don’t. They allow you to switch between different sets. I don’t see them selling you different springs and suspension components.

If you have watched any videos of Sapphire and Gravity suspension tuning exercises, you will see that a lot of the suspension behavior is in the computer programming, not the hardware. And those engineers pore over the most minute details of chassis behavior under as many conditions as they can generate, constantly tweaking the computer program(s) as they go.

It may well be that there are separate computer programs for each wheel option or that the computer program for all three wheel options has different front and rear settings to account for the different spring rates of the front and rear tires.

The fact is that, unless we have some inside knowledge of the Gravity suspension tuning, we just don't know.

 

[hmp10]

I mean they don’t. They allow you to switch between different sets. I don’t see them selling you different springs and suspension components.

I just checked the Lucid Owners Manual. When you switch between different sets of wheels you do, in fact, have to reset the computer for the different wheels (page 208):

 

[momo3605]

I just checked the Lucid Owners Manual. When you switch between different sets of wheels you do, in fact, have to reset the computer for the different wheels (page 208):

View attachment 26128

That’s for the range estimates

 

[hmp10]

That’s for the range estimates

And you know that how?

The manual says "several vehicle systems rely on knowing the wheel size . . . ." I suspect the traction control system and the brake torque vectoring system might be among those several systems that need to know of a wheel change.

Also, the Air does not have an adjustable suspension system except for the damping in the Bilstein shock absorbers. The Gravity has a considerably more complex, computer-controlled suspension system.

 

[joec]

I think the way they’ve done it on Gravity is better. Stealth/black trim is generally more popular these days. The “old at heart” crowd that likes shiny chrome will pay more for platinum regardless.

I resemble this mark.

But I totally agree. I'd pay extra for platinum. Depending on the color of the car.

Stealth looks sick with Fathom Blue. It looks good on Gravity with the green.

But if I were to go white again, I'd totally pay extra for platinum.

 

[hmp10]

But if I were to go white again, I'd totally pay extra for platinum.

I'm on the fence, too. I ordered Stealth for the Aurora Green, but if I end up changing to Lunar Titanium, I might go with Platinum. That was the combo I saw at a Design Studio, and it looked great.

 

[Bobby]

If the 22/23's weren't Pirelli I'd consider them but I got burnt with the Pirelli's on the Air so going to opt for the mid-wheel.

There was a while there we were seeing this issue all the time. Lately, hardly at all. It seems they redesigned the tires for better sidewall strength, and it seems to have worked.

 

[HC_79]

There was a while there we were seeing this issue all the time. Lately, hardly at all. It seems they redesigned the tires for better sidewall strength, and it seems to have worked.

Interesting! I’m not so worried about the tire as much as the rim. Yes, it’s still costly to replace but I copped the double whammy of bubble in the side wall and rim damage which set me back about $1600 from memory. Wasn’t prepared to be potentially having to spend that money every time a bad pothole was struck.

Not gonna lie, the 21’s & 22’s do look good though on the Lucid’s

 

[momo3605]

There was a while there we were seeing this issue all the time. Lately, hardly at all. It seems they redesigned the tires for better sidewall strength, and it seems to have worked.

Either that or you’ve gotten more cautious around potholes lol

 

[illopp00]

That's the point I was trying to make on another thread about tires. By going with both staggered widths and diameters on all three wheel options, there are precious few options for summer performance tires on the Gravity.

According to Tire Rack, probably with the most comprehensive tire selection in the U.S., there are NO summer performance tires that will fit the 20/21" wheel package, and there is only one summer performance tire -- the Pirelli P Zero -- that will fit the 21/22" wheel size, at least if you want the "Y" speed rating on both axles. (You can go with the Michelin Pilot Sports if you'll accept a lower speed rating on the front axle.). Same with the 22/23" wheel size, but again with a speed rating mismatch on the axles. And the Pirellis for the rear axle cost almost $800 per tire for the 22" wheel and over $1000 per tire for the 23" wheel.

There are many fine performance tires on the market, but the Gravity's odd staggering makes only two of them usable, and even then not on the smallest wheel package.

To be honest; there is some moot point here. I think the Gravity GT might be electronically limited to below 150 mph....

 

[hmp10]

To be honest; there is some moot point here. I think the Gravity GT might be electronically limited to below 150 mph....

That may well be. But there are probably some differences in the tire structure and/or rubber compound that yield different speed ratings within the same model tire, and I wonder what role they might play. I talked to Tire Rack, and that's why their search engine doesn't show a 4-wheel set of tires as available if the front and rear speed ratings don't match. They'll still sell you such a set, but you have to accept an invoice that carries a warning of the speed rating mismatch and a liability disclaimer.

The Gravity is a heavy vehicle with very high torque. Driving it aggressively -- which is kind of the point of the top wheel/tire option -- will put huge load forces on the tires.