Tire/Wheel Discussion

[Elfin]

Are these 20"/21" wheels or will smaller diameter wheels fit over the brakes?

I like the idea of a set of all-terrain (3PMSF) tires for snow/dirt and a set of summer wheels.

 

[037]

Are these 20"/21" wheels or will smaller diameter wheels fit over the brakes?
View attachment 26036
I like the idea of a set of all-terrain (3PMSF) tires for snow/dirt and a set of summer wheels.

I was secretly pondering about 19” wheels but since they switched brake supplier to Brembo no one really knows if 19s would clear

 

[Elfin]

I was secretly pondering about 19” wheels but since they switched brake supplier to Brembo no one really knows if 19s would clear

There aren't any all terrain tires in 265/55R19 (or 19" in general).
However, 265/60R18 is a very common size and 285/60R18 is also a very common size (same diameter as stock rear tires.)
Though now I see that 18" wheels don't fit the Air so it seems very unlikely that they'll clear the brakes on the Gravity.

 

[hmp10]

I was secretly pondering about 19” wheels but since they switched brake supplier to Brembo no one really knows if 19s would clear

I thought they switched to Akebono.

 

[037]

I thought they switched to Akebono.

From Akebono to Brembo, 6 piston front, 4 piston rear, 390/388 discs

 

[037]

There aren't any all terrain tires in 265/55R19 (or 19" in general).
However, 265/60R18 is a very common size and 285/60R18 is also a very common size (same diameter as stock rear tires.)
Though now I see that 18" wheels don't fit the Air so it seems very unlikely that they'll clear the brakes on the Gravity.

You are thinking off road and I was going summer tire but there are 0 options in stock sizing for 19s so back to my original plan of 22s front and back.

 

[CWedge411]

Has anyone found 23" winter tires?

 

[hmp10]

Has anyone found 23" winter tires?

The only thing close I've found that will fit both the front and rear wheels of the 22/23" option is the Pirelli Scorpion Zero All Season. Not a true winter tire, of course.

 

[037]

Has anyone found 23" winter tires?

I think the 20/21 wheel tire option is perfect for the winter set as range drop will be offset with smaller wheel. There are highly rated winter tires on TireRack in stock sizes

 

[WeighingGravity]

I'm really struggling with what to do wheel- and tire-wise.

On one hand, I think the look of the 22/23 is BY FAR the best of the bunch, and I want to minimize the minivan aesthetic.

On the other hand, I have always had terrible luck with big rims and low profile tires. The ride is rough, they get killed in potholes, I tear through tires. And the tires on this puppy are NOT going to be cheap. Plus, I do need to navigate the snow sometimes (I live in the Mid-Atlantic, so we get plenty of rain and a handful of snow events on average each year). Snow tires are usually overkill, so I've done really well in general with all-season tires which are a nice compromise (though I know in a Lucid I should be thinking "compromise nothing!") that don't require me to change rims or tires out in the winter (either is a massive PITA). I'm tempted by the Pirelli Scorpions but holy hell are the rears really $1100+ A TIRE??? Wow. I'll be furious when I slam a pothole, or just rip through the rubber after too much aggressive acceleration out of stoplights etc. I am not going to drive this car anywhere close to its limits most of the time, so the max performance is overkill for me, and besides, it's going to cost me $3K on top of the price to mount the all-seasons, since it comes with just summer tires.

So I'm tempted to go with one of the smaller set-ups, which handily include all-season tires (and I think more tire options at lower cost moving forward), but aesthetically I just don't like the wheels as much. I think it's really weird that the smallest wheel is only available in "Onyx Grey" even when platinum trim is selected, so it just looks off to me in that combo. Plus, although I like grey or dark grey rims in the right circumstances, I almost never like black. It's really hard to tell in any of the photos currently available how "black" the rims are (20/21 or 21/22); that could be a deal breaker for me. The Orion wheel looks a bit silly in the photos in the platinum trim - it's just too plain. But we also have precious few photos available of these smaller rims a) in daylight or from multiple angles and b) without the plastic inserts. So it's just awfully hard to make this call sight unseen. I guess I have to wait until there are some samples available at the showrooms - Gosh I hope they can at least ship a few wheels and tires to the experience centers in the various colors so that we're not making this decision blind even once showroom cars arrive.

I will admit there is a slight tug pulling me back to the biggest rims just to be earlier in the queue.....

Am I the only one struggling with this decision?

 

[037]

I'm really struggling with what to do wheel- and tire-wise.

On one hand, I think the look of the 22/23 is BY FAR the best of the bunch, and I want to minimize the minivan aesthetic.

On the other hand, I have always had terrible luck with big rims and low profile tires. The ride is rough, they get killed in potholes, I tear through tires. And the tires on this puppy are NOT going to be cheap. Plus, I do need to navigate the snow sometimes (I live in the Mid-Atlantic, so we get plenty of rain and a handful of snow events on average each year). Snow tires are usually overkill, so I've done really well in general with all-season tires which are a nice compromise (though I know in a Lucid I should be thinking "compromise nothing!") that don't require me to change rims or tires out in the winter (either is a massive PITA). I'm tempted by the Pirelli Scorpions but holy hell are the rears really $1100+ A TIRE??? Wow. I'll be furious when I slam a pothole, or just rip through the rubber after too much aggressive acceleration out of stoplights etc. I am not going to drive this car anywhere close to its limits most of the time, so the max performance is overkill for me, and besides, it's going to cost me $3K on top of the price to mount the all-seasons, since it comes with just summer tires.

So I'm tempted to go with one of the smaller set-ups, which handily include all-season tires (and I think more tire options at lower cost moving forward), but aesthetically I just don't like the wheels as much. I think it's really weird that the smallest wheel is only available in "Onyx Grey" even when platinum trim is selected, so it just looks off to me in that combo. Plus, although I like grey or dark grey rims in the right circumstances, I almost never like black. It's really hard to tell in any of the photos currently available how "black" the rims are (20/21 or 21/22); that could be a deal breaker for me. The Orion wheel looks a bit silly in the photos in the platinum trim - it's just too plain. But we also have precious few photos available of these smaller rims a) in daylight or from multiple angles and b) without the plastic inserts. So it's just awfully hard to make this call sight unseen. I guess I have to wait until there are some samples available at the showrooms - Gosh I hope they can at least ship a few wheels and tires to the experience centers in the various colors so that we're not making this decision blind even once showroom cars arrive.

I will admit there is a slight tug pulling me back to the biggest rims just to be earlier in the queue.....

Am I the only one struggling with this decision?

I been wheel and tire shopping for some months, ordered the 20/21 and will move them to winter and will go 22” all around for summer.

No silly sizing for me, not on purpose anyways. As far as base wheels with no covers, I seen it all of one time and in a video at that. Just raise the brightness of your phone to see

 

[PetevB]

I'm really struggling with what to do wheel- and tire-wise.

Am I the only one struggling with this decision?

I’m really not struggling at all- 20/ 21s all the way. I personally got over the “they look better” thing a while ago — form follows function. So when my BMW 1M came on ‘19s but takeoff M3 18’s on extreme performance summer tires proved more fun (more playful over the limit as well as faster at the autocross) the 19s sat in the garage and I didn’t miss them a bit. I simply wasn’t willing to compromise performance and enjoyment for looks.

My bet is that in many ways the larger wheel options will compromise big parts of the Gravity’s real world performance. 10% shorter range means you charge 10% slower in miles per minute, ie more time on a road trip stopped at a charger — you’re actually slower over ground. Ride obviously, but also how progressively the car breaks away and hence how it talks to you around the limit. I’m sure the 22s/23s will be faster against the clock, but is that something I need to prioritize in this car? No, even if I look forwards to humbling some sports cars at the autocross once or twice…

More minor factors were pinch flats, bent rims, rubber replacement and electricity bills (the bigger wheels are around another ~$1k in juice at PG&E rates). Factor these in and the biggest rims are likely more like $7k option over five years. For a car that will get me from A to B less comfortably and more slowly (real world)? Made it a pretty easy call for me, but looking at the reservation tracker I can see I’m in the minority. To each their own obviously, and for a different driver I could see going another way, but the engineer in me is simply too practical.

 

[WeighingGravity]

I’m really not struggling at all- 20/ 21s all the way. I personally got over the “they look better” thing a while ago — form follows function. So when my BMW 1M came on ‘19s but takeoff M3 18’s on extreme performance summer tires proved more fun (more playful over the limit as well as faster at the autocross) the 19s sat in the garage and I didn’t miss them a bit. I simply wasn’t willing to compromise performance and enjoyment for looks.

My bet is that in many ways the larger wheel options will compromise big parts of the Gravity’s real world performance. 10% shorter range means you charge 10% slower in miles per minute, ie more time on a road trip stopped at a charger — you’re actually slower over ground. Ride obviously, but also how progressively the car breaks away and hence how it talks to you around the limit. I’m sure the 22s/23s will be faster against the clock, but is that something I need to prioritize in this car? No, even if I look forwards to humbling some sports cars at the autocross once or twice…

More minor factors were pinch flats, bent rims, rubber replacement and electricity bills (the bigger wheels are around another ~$1k in juice at PG&E rates). Factor these in and the biggest rims are likely more like $7k option over five years. For a car that will get me from A to B less comfortably and more slowly (real world)? Made it a pretty easy call for me, but looking at the reservation tracker I can see I’m in the minority. To each their own obviously, and for a different driver I could see going another way, but the engineer in me is simply too practical.

I was totally on board with you and was gonna change my order but now that there's a Dream Edition.....

Does anyone know of good Aero wheels that might fit the Gravity for me to get aftermarket?

 

[mutant9]

My initial GT order has the 21 22. Switched to DE and moved it to 22 23 since no additional cost. I will look for a set of 21 22 for winter use... the 22 23 look super nice and will be way easier to keep clean!

 

[hmp10]

I just switched my Dream order from the 22/23" to the 21/22" and plan to mount Pirelli P Zeros as soon as the car arrives. (I live in south Florida and don't take road trips up north during cold season.)

The two smaller wheel options open up the tire choices considerably compared to the largest wheel option.

Also, the two smaller wheel options appear to have aero blades which are absent on the largest wheels. I'm pretty sure the wide range advantage of the smallest wheels derives largely from the Hankook Ion tires which have some of the best efficiency numbers in the industry (at the considerable price of wet grip, it seems). I also suspect that the identical range between the two larger wheels options is due to the lower efficiency of the Michelin Primacy all-season tires compared to the Pirelli P Zeros which actually get pretty good efficiency ratings in tire tests. So I'm guessing that mounting the Pirellis on the mid-size wheels with the aero blades will improve the range, perhaps noticeably, above the largest open wheels.

Also, as @PetevB explained, stepping down in wheel diameters can actually bring some performance and handling advantages, although it will probably be fairly marginal with a 1" step-down. And, when it comes to straight-line acceleration and braking, more sidewall flexion allows the tread to grab harder. There's a reason that drag racers use high-profile tires, after all.

I was also waiting to see if Pirelli brings its "seal inside" feature to a wider range of P Zeros, but I have found out it adds 3-4 pounds to the tire weight, depending on tire size. And that weight is exactly where you least want it on a tire/wheel combo.

 

[illopp00]

I'm really struggling with what to do wheel- and tire-wise.

On one hand, I think the look of the 22/23 is BY FAR the best of the bunch, and I want to minimize the minivan aesthetic.

On the other hand, I have always had terrible luck with big rims and low profile tires. The ride is rough, they get killed in potholes, I tear through tires. And the tires on this puppy are NOT going to be cheap. Plus, I do need to navigate the snow sometimes (I live in the Mid-Atlantic, so we get plenty of rain and a handful of snow events on average each year). Snow tires are usually overkill, so I've done really well in general with all-season tires which are a nice compromise (though I know in a Lucid I should be thinking "compromise nothing!") that don't require me to change rims or tires out in the winter (either is a massive PITA). I'm tempted by the Pirelli Scorpions but holy hell are the rears really $1100+ A TIRE??? Wow. I'll be furious when I slam a pothole, or just rip through the rubber after too much aggressive acceleration out of stoplights etc. I am not going to drive this car anywhere close to its limits most of the time, so the max performance is overkill for me, and besides, it's going to cost me $3K on top of the price to mount the all-seasons, since it comes with just summer tires.

So I'm tempted to go with one of the smaller set-ups, which handily include all-season tires (and I think more tire options at lower cost moving forward), but aesthetically I just don't like the wheels as much. I think it's really weird that the smallest wheel is only available in "Onyx Grey" even when platinum trim is selected, so it just looks off to me in that combo. Plus, although I like grey or dark grey rims in the right circumstances, I almost never like black. It's really hard to tell in any of the photos currently available how "black" the rims are (20/21 or 21/22); that could be a deal breaker for me. The Orion wheel looks a bit silly in the photos in the platinum trim - it's just too plain. But we also have precious few photos available of these smaller rims a) in daylight or from multiple angles and b) without the plastic inserts. So it's just awfully hard to make this call sight unseen. I guess I have to wait until there are some samples available at the showrooms - Gosh I hope they can at least ship a few wheels and tires to the experience centers in the various colors so that we're not making this decision blind even once showroom cars arrive.

I will admit there is a slight tug pulling me back to the biggest rims just to be earlier in the queue.....

Am I the only one struggling with this decision?

I have all the same concerns. I don't want black wheels, and I don't want the compromise of cost, availability, ride comfort, range from the biggest wheels. I had considered optioning the small wheels and then buying the mid-size set in Silver. But I am leaning towards just optioning the mid-size wheels and then replacing tires as needed.

 

[PetevB]

Also, as @PetevB explained, stepping down in wheel diameters can actually bring some performance and handling advantages, although it will probably be fairly marginal with a 1" step-down. And, when it comes to straight-line acceleration and braking, more sidewall flexion allows the tread to grab harder. There's a reason that drag racers use high-profile tires, after all.

To nerd out a little…

Drag tires are trying to lengthen the tire contact patch with tall sidewall tires run at lower pressures. This does two things: it puts more tire surface area in contact with the road, but more importantly it leaves rubber in contact with the road for longer. Doubling the length of the contact patch doubles the time any individual bit of rubber is in contact with the ground. Rubber is viscoelastic, meaning it “flows” into imperfections in the pavement given time, and that’s an important way it generates grip, so longer time in contact means more time to flow and hence more grip.

So why use short side walled tires in the first place? It turns out that to maximize cornering you actually want a wide contact patch. Slip angle, which is difference between where the tire is pointing and where it’s actually rolling, can typically be in the range of 3-7% at max grip the limit. This means you’re “drifting” slightly even if the car hasn’t broken away. When we say a car understeers we’re experiencing that slip angle, and when we say a car is slow to respond we’re complaining that the car is taking time to get to that slip angle. Wider tires with a bigger diameter on large rims have downsides, particularly weight, but they reduce slip angle and improve both cornering grip and response. If that’s always a good thing or not depends: in a car like my BMW 1M, which was a drift machine, the name of the game was increasing slip angle (drifting) even at the expense of response. And responsiveness is also highly tire dependent (stiffer sidewalls, larger tread blocks, etc all play a factor).

At the limit and all else being equal if your goal is speed around a track a larger wheel is usually better if you have the power to push it. People often point to F1 cars or sports racers as examples of the opposite, but these are largely rules defined. Sports prototypes were rules limited at 18” for decades. When they weren’t Porsche did take advantage of this to make 20” wheels and tires for their LeMans cars one year, which was successful and then quickly banned.

In this size range for handling I’d be choosing between the bigger two sizes mainly based on rubber, both stock and aftermarket. The smaller size is for those who prize efficiency and/or slip angle, meaning they’d like to feel the car move around a little (not clear if the stock tires will be great for that).

 

[hmp10]

Wider tires with a bigger diameter on large rims have downsides, particularly weight, but they reduce slip angle and improve both cornering grip and response.

The Gravity is a bit unusual, first in offering three wheel size options, and second in keeping the same tread widths across all three options. With lessening the role of tread width in the equation, how much does wheel diameter alone affect cornering grip and response? I assume a shorter sidewall would keep the contact patch a bit wider, all other things being equal? But wouldn't sidewall construction (stiffness) throw in another significant variable?

In this size range for handling I’d be choosing between the bigger two sizes mainly based on rubber, both stock and aftermarket.

Lucid's decision to stagger both tread width and wheel diameter throws a real monkey wrench into tire choices. Although I have found a few tire sets that will fit that are not in the Tire Rack catalog, their inventory does seem to cover the vast majority of tires on the market -- and their tire selection feature show precious few tires that will fit both the front and rear wheels of any of the Gravity wheel options. For the 22/23" wheels, the Pirelli P Zero summer tire and the Pirelli Scorpion All Season are just about it. And even those two choices aren't exactly matched sets (with the acoustic foam only available for one axle with either the summers or all-seasons).

 

[illopp00]

The higher aspect ratio tires will have more sidewall flex under load, which then causes changes in response, breakaway and the load changes. It's a hysteresis effect, once you start sliding and exceeding the limit of grip and slip angle, you actually have to straighten the tire up and slow down more to get it back. You get this effect of the taller sidewall rolling over first before the tire starts sliding (especially on a big heavy car). Lower sidewall would also give a more responsive steering feel and transfer more feel to the wheel.

I linked a great channel to nerd out on tires, along with Tirerack's own channel of course.

 

[PetevB]

With lessening the role of tread width in the equation, how much does wheel diameter alone affect cornering grip and response? I assume a shorter sidewall would keep the contact patch a bit wider, all other things being equal? But wouldn't sidewall construction (stiffness) throw in another significant variable?

So typically cornering response will improve with a shorter sidewall. It helps to have a mental image of how the tread is connected with the rim through the sidewall, and how those things move relative to each-other under load. Below for example you can see the tread isn't rotating on the same axis as the rim- that's where some of the slip angle and delayed response comes from. That can be mitigated by a stiffer sidewall, but that can reduce grip by overloading the outside edge of the rubber, which grips best at a specific PSI of ground pressure. So in general grip is reduced with uneven pressure/ loading at the contact patch.

The question you're really asking gets tricky to answer, however, when we combine the wheel and tire with the car. Suspensions are carefully designed with a camber curve, a toe curve, kinematic toe, etc. To over-simplify the engineer knows things like how much the car will roll in a 1.1G corner, how much the tire will deflect (see below) and how much slip angle/ understeer is expected. Because those are known they can design the suspension with camber gain, etc to effectively cancel that out, keeping the rubber face square to the road and neutralizing the slip by steering into it. But what do you do if you've got three different diameter options and hence three different tires to optimize for? That's leads to an important question I'd like to know: what was the baseline tire assumed during the Gravity's suspension development and tuning? Often it's the middle option as both bigger and smaller diameters will be close. Porsche GT cars solve the problem by not offering the choice: they are highly optimized for one tire. The point being that if they optimized camber gain for the smaller wheels then there might be too much for the bigger ones, and hence either the gains you're expecting don't materialize or the car "feels weird". For example too much rear kinematic toe, that is passive rear wheel steering where the rear wheel turn into a corner when they load up, and make the back end feel like it's got a mind of its own.

Two options here: either Lucid went all out in pursuit of the best possible handling numbers and optimized for the biggest wheels at the expense of the others, or they took the middle ground and tried to make everything work well at the expense of a fraction of absolute performance on the biggest tire package. If I was a betting man, especially as this car wasn't built to concur the Nürburgring, my money would be on the latter.