19" vs 21" Tires: Ride Quality/Range Difference

[Demosthenes]

I've read opinions that wheel weight doesn't really impact EV efficiency (i.e. range) since it only has an impact during acceleration (and regenerative deceleration) whereas once you're cruising at a steady speed, aerodynamics take over. But when I look at my speedometer, it's clear that constant acceleration and deceleration are happening with the slightest variation of pressure on the pedal no matter how smooth I'm trying to be. The only time where there would be theoretically no acceleration or deceleration is when driving on a completely straight road with zero traffic and ACC engaged (which seems to be a situation that happens 0% of the time driving in southern California). Even highway driving in southern California with ACC engaged is frequently accompanied by changes in speed to accommodate traffic, curves, bends, variable vehicle spacing etc.

So I'm really curious what the effects will be on my range when I minimize wheel weight and rotational inertia but worsen my aerodynamics when I replace my OEM wheels. Or maybe wheel weight and rotational inertia reduction (as well as impaired wheel aerodynamics) will end up being insignificant compared to the relatively enormous weight and overall aerodynamics of the entire car.

 

[hmp10]

EV range only becomes an issue for most people when they are taking long road trips. And that is exactly the situation in which aerodynamics will play a much larger role in range than wheel weight. In fact, at highway speeds on relatively flat roads, aerodynamic drag is easily the greatest single force being exerted on the vehicle.

If trip range is an issue for you, I would recommend a heavier aero wheel over a lighter open wheel.

 

[Demosthenes]

EV range only becomes an issue for most people when they are taking long road trips. And that is exactly the situation in which aerodynamics will play a much larger role in range than wheel weight. In fact, at highway speeds on relatively flat roads, aerodynamic drag is easily the greatest single force being exerted on the vehicle.

If trip range is an issue for you, I would recommend a heavier aero wheel over a lighter open wheel.

That’s assuming that the vehicle is traveling at constant speed for long periods of time. And it’s also assuming that whatever aerodynamic effect that is solely attributable to the wheel would have any significant impact to the overall vehicle aerodynamicity (ha is that a word…).

No matter how long the road trip is, for me personally it would probably be broken down to 4-6 hour segments with 2-3 segments per day. I could easily do much of that without ACC meaning that my speed would be no where near constant. Watching the energy output versus regenerative recovery dial graphic on the cockpit display really got me thinking about this ‘constant speed’ concept. In fact, the only ‘constant’ about my speed is that it’s constantly accelerating or decelerating, even if in minute quantities. But add up all of that constant acceleration and deceleration, wouldn’t then wheel weight and rotational inertia play an increasingly greater theoretical role?

I searched a long time but couldn’t find any really convincing EV range comparisons where everything except wheels was kept constant over a long distance. Would love to read about those tests if someone has done them.

 

[Demosthenes]

Oh and it’s a purely academic interest on my end. To be honest, I just want cooler looking wheels and don’t mind if my range takes a hit

 

[Bunnylebowski]

Oh and it’s a purely academic interest on my end. To be honest, I just want cooler looking wheels and don’t mind if my range takes a hit

The mobile service guy came by for the recall check today (my car was fine). He said it was a good move I got the 19”. He’s had to replace 50 of the 21” Pirelli so far due to sidewall bubbles, has only had to do one 19” from an owner hitting an unsealed manhole cover. Their mobile service van is awesome, it’s like a portable tire one stop shop machine. He had 5 busted Pirellis in there so I got to see the noise insulating foam, it looks very solid, he said he’s never seen it dislodge so if there’s any NVH complaints from the tires it’s not because of that. He also said one DE owner he knew of got the Michelin 21s and they’re much noisier than the Pirellis. I may stop complaining about the Pirellis…

 

[DeaneG]

...I searched a long time but couldn’t find any really convincing EV range comparisons where everything except wheels was kept constant over a long distance. Would love to read about those tests if someone has done them.

Nothing quite like that, that I am aware of, but there have been a few tests of consumption with and without aero covers on Tesla Model 3 cars with 18" wheels. Tesla's 18" wheel is shaped pretty similarly to Lucid's 19" wheel.

 

[Thinjake]

He said it was a good move I got the 19”. He’s had to replace 50 of the 21” Pirelli so far due to sidewall bubbles, has only had to do one 19” from an owner hitting an unsealed manhole cover.

DAMNIT! I really don't like the look of the 19s but I don't want the Pirelli sidewall problems either. What to do....what to do....

 

[hmp10]

That’s assuming that the vehicle is traveling at constant speed for long periods of time. And it’s also assuming that whatever aerodynamic effect that is solely attributable to the wheel would have any significant impact to the overall vehicle aerodynamicity (ha is that a word…).

No matter how long the road trip is, for me personally it would probably be broken down to 4-6 hour segments with 2-3 segments per day. I could easily do much of that without ACC meaning that my speed would be no where near constant. Watching the energy output versus regenerative recovery dial graphic on the cockpit display really got me thinking about this ‘constant speed’ concept. In fact, the only ‘constant’ about my speed is that it’s constantly accelerating or decelerating, even if in minute quantities. But add up all of that constant acceleration and deceleration, wouldn’t then wheel weight and rotational inertia play an increasingly greater theoretical role?

I searched a long time but couldn’t find any really convincing EV range comparisons where everything except wheels was kept constant over a long distance. Would love to read about those tests if someone has done them.

There are so many variables at play that it's impossible to do definitive calculations for all cases. For example, where the weight in the wheel is located affects rotational inertia forces. Two wheels of equal weight can vary, with the wheel with more mass located near the hub will generate less rotational inertia forces that a design with more weight toward the perimeter of the wheel.

Oh and it’s a purely academic interest on my end. To be honest, I just want cooler looking wheels and don’t mind if my range takes a hit

If extracting every last bit of range is not your top priority, I think you'll be perfectly fine choosing a wheel for looks without paying any material penalty in other aspects of driving the car. Just be sure to verify that the wheel is engineered to handle the weight of an EV.

 

[Bunnylebowski]

DAMNIT! I really don't like the look of the 19s but I don't want the Pirelli sidewall problems either. What to do....what to do....

The 19s look good in person, it’s just that the 21s look sooooo good. BUT when you see those 21 tires not on the wheel, holy crap they are thin, I’m surprised they last one day.

 

[hmp10]

The 19s look good in person, it’s just that the 21s look sooooo good. BUT when you see those 21 tires not on the wheel, holy crap they are thin, I’m surprised they last one day.

Thin where? Sidewalls? Tread?

It's easy enough to check for bulges on the outward-facing sidewalls. Any idea how many bulges are showing up on the inward sidewalls and how they're being detected?

 

[Bunnylebowski]

Thin where? Sidewalls? Tread?

It's easy enough to check for bulges on the outward-facing sidewalls. Any idea how many bulges are showing up on the inward sidewalls and how they're being detected?

The tread is fine, I was just amazed at how thin the whole tire is aside from the trim. It’s like a racing bike tire (except for the tread). The sound foam is pretty cool though, it’s very solid and uniform, I thought it was like a spray foam but it’s like a dense sponge. I didn’t ask whether he saw more inner or outer sidewalk bulges.

 

[joec]

The tread is fine, I was just amazed at how thin the whole tire is aside from the trim. It’s like a racing bike tire (except for the tread). The sound foam is pretty cool though, it’s very solid and uniform, I thought it was like a spray foam but it’s like a dense sponge. I didn’t ask whether he saw more inner or outer sidewalk bulges.

I’m very glad that living in Colorado pretty much makes snow tires a requirement, which left me with no real choice but the 19s. I, too, prefer the look of the 20s and 21s, but the 19s have grown on me.

 

[DeaneG]

DAMNIT! I really don't like the look of the 19s but I don't want the Pirelli sidewall problems either. What to do....what to do....

I'm guessing that the "Pirelli sidewall issues" are caused by road irregularities causing a pinch-bruise on the sidewall. Sidewall height is your friend except for steering feel and looks.

 

[Demosthenes]

The mobile service guy came by for the recall check today (my car was fine). He said it was a good move I got the 19”. He’s had to replace 50 of the 21” Pirelli so far due to sidewall bubbles, has only had to do one 19” from an owner hitting an unsealed manhole cover. Their mobile service van is awesome, it’s like a portable tire one stop shop machine. He had 5 busted Pirellis in there so I got to see the noise insulating foam, it looks very solid, he said he’s never seen it dislodge so if there’s any NVH complaints from the tires it’s not because of that. He also said one DE owner he knew of got the Michelin 21s and they’re much noisier than the Pirellis. I may stop complaining about the Pirellis…

Did the service guy mention if any of the side wall bubbles actually resulted in a blown tire? Or were they all caught before that happened?

 

[steveairgt]

DAMNIT! I really don't like the look of the 19s but I don't want the Pirelli sidewall problems either. What to do....what to do....

I felt the same way which is why I originally ordered the 20”. But when the 20” was delayed for a 3rd time and after I saw Pam’s pictures in this thread showing the 19” with the middle silver disc, aero covers off and with black lug nut covers, I decided to go with that combination.

 

[Demosthenes]

If extracting every last bit of range is not your top priority, I think you'll be perfectly fine choosing a wheel for looks without paying any material penalty in other aspects of driving the car. Just be sure to verify that the wheel is engineered to handle the weight of an EV.

Yes I just quadruple checked. Per HRE phone rep: since every wheel is custom forged for each individual vehicle, they are custom load rated to be exactly appropriate for each vehicle. The style that I chose has a theoretical maximum load rating of up to 9000kg, but obviously that won't be necessary for the Air.

 

[victoryroad]

DAMNIT! I really don't like the look of the 19s but I don't want the Pirelli sidewall problems either. What to do....what to do....

I had the same problem but chose the 19." Not just because of the Pirelli tires on the 21's but the fact that wheels are cast, not forged so are much more susceptible to road damage with the low aspect ratio tires. The 20" wheels come with Michelins and may be available in Q4, so depending on the actual brake distance experience with the 19" wheels I may get a set of the 20's.

 

[hmp10]

Yes I just quadruple checked. Per HRE phone rep: since every wheel is custom forged for each individual vehicle, they are custom load rated to be exactly appropriate for each vehicle. The style that I chose has a theoretical maximum load rating of up to 9000kg, but obviously that won't be necessary for the Air.

That would explain the $3,000+ price per wheel.

 

[DeaneG]

I had the same problem but chose the 19." Not just because of the Pirelli tires on the 21's but the fact that wheels are cast, not forged so are much more susceptible to road damage with the low aspect ratio tires. The 20" wheels come with Michelins and may be available in Q4, so depending on the actual brake distance experience with the 19" wheels I may get a set of the 20's.

Just put a set of Pilot Sports on your 19s. No need to swap rims to get a tire with more traction (and lower efficiency).

 

[AIR.LUCID]

DAMNIT! I really don't like the look of the 19s but I don't want the Pirelli sidewall problems either. What to do....what to do....

find other 19” wheels?