20-ish mile range difference between 5 seat and 7 seat Gravity?

[hmp10]

Definitely they are more slick than other tires, but that is the natural compromise that occurs when you get a low rolling resistance tire. It is a fact that lower rolling resistance is directly proportional to lower wet traction. It is physics. Better wet performance means worse efficiency. Pretty much guaranteed.

I see similar comments occasionally, but I can find no basis for it. The Pirelli EV tires on our Air certainly give up nothing in wet traction. Low rolling resistance is not just about contact rubber but has a lot to do with sidewall construction, so I'm not sure what physics you mean.

The Pirelli high-performance summer tires that were tested against eight other tires were from Pirelli's ELECT EV-specific line. They ranked second in both wet and dry track performance, beating all the non-EV tires save one:

They also ranked second in both wet braking and wet cornering against other non-EV tires:

Yet, given the Pirelli's strong traction performance in wet and dry conditions, it still ranked pretty well in efficiency, being closer to the class-leading Hankooks in efficiency than to the only tire to beat it in wet and dry traction -- the Michelin Pilot Sport 4S.

 

[Knucklehead]

I see similar comments occasionally, but I can find no basis for it. The Pirelli EV tires on our Air certainly give up nothing in wet traction. Low rolling resistance is not just about contact rubber but has a lot to do with sidewall construction, so I'm not sure what physics you mean.

The Pirelli high-performance summer tires that were tested against eight other tires were from Pirelli's ELECT EV-specific line. They ranked second in both wet and dry track performance, beating all the non-EV tires save one:




They also ranked second in both wet braking and wet cornering against other non-EV tires:




Yet, given the Pirelli's strong traction performance in wet and dry conditions, it still ranked pretty well in efficiency, being closer to the class-leading Hankooks in efficiency than to the only tire to beat it in wet and dry traction -- the Michelin Pilot Sport 4S.

Two points:
1. I don't want to convince you to get tires you think could be dangerous. If you get them, and then hate them, then I will feel responsible. All I am saying is personally I don't think they are dangerous, and I like them a lot. I am also very happy Lucid is putting them on the Gravity. It is a huge plus for me.
2. There are many factors that impact rolling resistance and wet traction, but as you have shown in your post, the tire with the best efficiency also has the worst wet traction. The reason I say it is "physics" and pretty much guaranteed that improving traction will reduce efficiency, is due to study I read and is referenced below:

"
2.6 Rolling resistance

2.6.1 Rolling resistance in straight-line driving​

Rolling resistance is a result of energy loss in the tyre, which can be traced back to the deformation of the area of tyre contact and the damping properties of the rubber. These lead to the transformation of mechanical into thermal energy, contributing to warming of the tyre.

Sixty to 70% of the rolling resistance is generated in the running tread (Fig. 2.5) and its level is mainly dependent on the rubber mixture. Low damping running tread mixtures improve the rolling resistance, but at the same time reduce the coefficient of friction on a wet road surface. It can be said that the ratio is approximately 1:1, which means a 10% reduction in the rolling resistance leads to a 10% longer braking distance on a wet road surface. The use of new combinations of materials in the running tread (use of silica) has led to partial reduction of the conflict between these aims.
"

I think what you are seeing in the reviews is improved tire compounds that helps reduce that 1:1 relationship. But the relationship still exists with existing tire technology.

Here is a link to the site where I found the study:

https://www.sciencedirect.com/topics/engineering/rolling-resistance

I have the iONs on my Mustang Mach-e, and I often drive very aggressively. It is a performance-oriented car, and I still am happy with the tires. People who value performance over efficiency will not be as happy with the tires as I am. It is personal preference.

 

[Elfin]

do a lot of driving in heavy rain and don't drive in cold climes. The Hankooks have abysmal wet braking and and wet cornering numbers. And, unfortunately, there are no summer-rated tires available in both the staggered width and staggered diameter of the smallest wheel set.

The Michelin Pilot Sport 4 SUV are. $559 each for the rears is ridiculous though! I guess the fronts are an OEM tire and "only" rated to 168mph.

 

[hmp10]

The Michelin Pilot Sport 4 SUV are.

You're right. I had forgotten about them because they and their all-season stablemate were the two bottom-ranked tires for efficiency, and I'm trying to figure out how to get the range up a bit on the Gravity.

 

[hmp10]

Two points:
1. I don't want to convince you to get tires you think could be dangerous. If you get them, and then hate them, then I will feel responsible. All I am saying is personally I don't think they are dangerous, and I like them a lot. I am also very happy Lucid is putting them on the Gravity. It is a huge plus for me.
2. There are many factors that impact rolling resistance and wet traction, but as you have shown in your post, the tire with the best efficiency also has the worst wet traction. The reason I say it is "physics" and pretty much guaranteed that improving traction will reduce efficiency, is due to study I read and is referenced below . . . .

I think what you are seeing in the reviews is improved tire compounds that helps reduce that 1:1 relationship. But the relationship still exists with existing tire technology.
will not be as happy with the tires as I am. It is personal preference.

First, thanks for the link. It was very interesting. And I think you're right that tire compounds are advancing to reduce the trade-offs in things such as traction and efficiency, which is probably why the Pirellis do so well in wet conditions without giving up too much on the efficiency front.

Also, I have probably gone too far in talking about the Hankooks. They are not the tire for me, but there's no reason they shouldn't be the tire for you if they are meeting your needs.

On a more basic level, what really has me wound up is this question about staggered diameters.

Tire Rack is part of the biggest tire retailer in the U.S. (Discount Tire). In the twenty-five years I've been buying tires from them for all sorts of cars, I have never been unable to find a suitable tire from them. If it's on the market, they almost always have it. Even in the early days of the Air, Tire Rack had the Lucid-specific LM1 EV tire in stock (as I found out with a puncture). So I was taken aback when I got this message when searching for the Gravity 22/23" tires:

The Gravity is aimed at a market segment filled with family users and owners focused on utility. To put wheels on it that drastically reduce the choices of tires seems problematic to me. The Gravity has no accommodation for a spare. What happens if you have a flat with kids in the car or road tripping in lower-population areas? How many tires will be quickly available to meet the unusual fitment requirements of the Gravity?

As I've said, unusual fitment requirements on the largest sport-oriented wheels might make sense for drivers more concerned with handling and willing to accept the compromises such a preference often brings. But not to offer even one wheel option without that unusual staggered width and diameter combo just seems kind of tone deaf when considering the intended market . . . and Lucid has struck me as one of the least tone-deaf automotive companies I've ever seen.

 

[borski]

First, thanks for the link. It was very interesting. And I think you're right that tire compounds are advancing to reduce the trade-offs in things such as traction and efficiency, which is probably why the Pirellis do so well in wet conditions without giving up too much on the efficiency front.

Also, I have probably gone too far in talking about the Hankooks. They are not the tire for me, but there's no reason they shouldn't be the tire for you if they are meeting your needs.

On a more basic level, what really has me wound up is this question about staggered diameters.

Tire Rack is part of the biggest tire retailer in the U.S. (Discount Tire). In the twenty-five years I've been buying tires from them for all sorts of cars, I have never been unable to find a suitable tire from them. If it's on the market, they almost always have it. Even in the early days of the Air, Tire Rack had the Lucid-specific LM1 EV tire in stock (as I found out with a puncture). So I was taken aback when I got this message when searching for the Gravity 22/23" tires:

View attachment 25506

The Gravity is aimed at a market segment filled with family users and owners focused on utility. To put wheels on it that drastically reduce the choices of tires seems problematic to me. The Gravity has no accommodation for a spare. What happens if you have a flat with kids in the car or road tripping in lower-population areas? How many tires will be quickly available to meet the unusual fitment requirements of the Gravity?

As I've said, unusual fitment requirements on the largest sport-oriented wheels might make sense for drivers more concerned with handling and willing to accept the compromises such a preference often brings. But not to offer even one wheel option without that unusual staggered width and diameter combo just seems kind of tone deaf when considering the intended market . . . and Lucid has struck me as one of the least tone-deaf automotive companies I've ever seen.

1) the car does not exist yet; perhaps wait until then to start looking for tires on tire rack.

2) a spare would work regardless of wheel size. EZSpare and similar match none of the sizes for the Air, and it doesn’t matter, because it is only to get you to a service shop, and the overall diameter doesn’t change.

 

[hmp10]

1) the car does not exist yet; perhaps wait until then to start looking for tires on tire rack.

2) a spare would work regardless of wheel size. EZSpare and similar match none of the sizes for the Air, and it doesn’t matter, because it is only to get you to a service shop, and the overall diameter doesn’t change.

The car is in production (or so they say), and people will soon be called upon to decide on the wheel option they want (or so we assume). I doubt if there will be many tires not currently on the market that will suddenly become available soon after the Gravity deliveries start. So, if you don't want the largest wheels and want to put summer tires on the small- or mid-size wheels, you pretty much have to make the decision based on the very few tires currently on the market that will fit.

But, all that aside, I'm still curious about any engineering or performance reasons for offering nothing but staggered width and diameter combos across all three wheel options. However, since Kyle Conner couldn't get an answer from a Lucid chassis engineer when he asked, I'm pretty sure I won't be getting one.

So that's that.

 

[borski]

The car is in production (or so they say), and people will soon be called upon to decide on the wheel option they want (or so we assume). I doubt if there will be many tires not currently on the market that will suddenly become available soon after the Gravity deliveries start. So, if you don't want the largest wheels and want to put summer tires on the small- or mid-size wheels, you pretty much have to make the decision based on the very few tires currently on the market that will fit.

But, all that aside, I'm still curious about any engineering or performance reasons for offering nothing but staggered width and diameter combos across all three wheel options. However, since Kyle Conner couldn't get an answer from a Lucid chassis engineer when he asked, I'm pretty sure I won't be getting one.

So that's that.

Sorry, that’s not what I meant - sorry for being unclear. I meant that it’s likely that more tires will show up (including the OEMs that don’t currently show up on TireRack) more quickly after the Gravity is delivering, not just in production.

For the 21s on the Air, it’s still only the Pirellis or naught for summer tires, but for the 20s and 19s lots more tires showed up post-deliveries, not pre-. That’s all I meant.

I’m also curious why they staggered it. I don’t know, and I am curious.

 

[hmp10]

I meant that it’s likely that more tires will show up (including the OEMs that don’t currently show up on TireRack) more quickly after the Gravity is delivering, not just in production.

Actually, Tire Rack shows Pirelli P Zero tires in sizes for the front and the rear 22/23" combo. However, only the front tire is in the ELECT series and has PNCS foam, and it has a lower speed rating than the rear. That's why Tire Rack doesn't show them as a set when you search by Vehicle. Since the Gravity order configurator photo shows only the front wheel, that's why I wondered if the car Conner, Cammisa, et al., drove had a mixed set of P Zeros (EV / non-EV) on it.

That's similar to the situations with the P Zeros that will fit the mid-size wheel option and with the Michelin Pilot Sports that will fit the smallest wheel option on the Gravity. There is a front/rear mismatch of one kind or another, with no full set available from the same edition of the tire series. I called Tire Rack about it, and they will sell you a set with such mismatches, but you have to accept an invoice that notes they are not represented as a matched set by Tire Rack.

Oh, well, I've given myself a headache again and am going to trundle off to bed. Here's hoping I wake up tomorrow with a whole new dilemma over which to fret, as there's probably no more milk to be had from this cow.