Gravity Tire Challenge

[hmp10]

Yes, stock tire size, large front wheel and medium rear wheel combination. 265-285/40

Doesn't having the same aspect ratio on two different widths mean the diameter of the front tires has shifted from the stock diameter on the front wheels?

 

[037]

Doesn't having the same aspect ratio on two different widths mean the diameter of the front tires has shifted from the stock diameter on the front wheels?

Diameter did not change, I got more sidewall in the rear and less wheel.

 

[hmp10]

Diameter did not change, I got more sidewall in the rear and less wheel.

But aspect ratio is a measure of the sidewall height compared to the width of the tire. Thus a sidewall height that is 40% of 265mm is going to be different than a sidewall height that is 40% of 285mm. And if both tires are on 22" wheels, the rear wheels are going to have a larger rolling circumference than the front wheels. I know the circumferences are not quite identical on the stock setup, either, but the car's software is set up to deal with that particular difference.

 

[037]

But aspect ratio is a measure of the sidewall height compared to the width of the tire. Thus a sidewall height that is 40% of 265mm is going to be different than a sidewall height that is 40% of 285mm. And if both tires are on 22" wheels, the rear wheels are going to have a larger rolling circumference than the front wheels. I know the circumferences are not quite identical on the stock setup, either, but the car's software is set up to deal with that particular difference.

The tires are OEM size, the difference front to back did not change. Trust me, I did the math.

 

[hwy17er]

My question was the tread width, not circumference or aspect ratio, which were the numbers you provided.....you're saying the widths are the LM1 specs from the chosen OEM tires from the two larger wheel sizes...clever

 

[hmp10]

The tires are OEM size, the difference front to back did not change. Trust me, I did the math.

Yep, interesting. The OE Primacy Touring (265/45/R21) on the 21" Lucid wheel rotates 685 per mile -- the same as the Michelin All Season 4 (265/40/R22) on your 22" wheel.

 

[EVCar]

According to the MR review, doesn't look like Gravity Touring tires are staggered. ( 285/45R21 113Y).
If true, I suppose GGT can do this, albeit some performance compromise.
But how significant?

 

[037]

According to the MR review, doesn't look like Gravity Touring tires are staggered. ( 285/45R21 113Y).
If true, I suppose GGT can do this, albeit some performance compromise.
But how significant?

They only list the rear tire. It’s all the same as GT.

 

[037]

Yep, interesting. The OE Primacy Touring (265/45/R21) on the 21" Lucid wheel rotates 685 per mile -- the same as the Michelin All Season 4 (265/40/R22) on your 22" wheel.

As I said, I did the math, it’s all Lucid spec. The part you don’t easily see is the part that touches the road, here I went much much wider than even the Lucid 23” rear tire.

TireRack has the data

 

[hmp10]

TireRack has the data

Yep, that's where I looked.

As I said, I did the math, it’s all Lucid spec. The part you don’t easily see is the part that touches the road, here I went much much wider than even the Lucid 23” rear tire.

Have you driven them enough to detect any significant difference in range/efficiency?

 

[037]

Yep, that's where I looked.



Have you driven them enough to detect any significant difference in range/efficiency?

Not yet, I didn’t even drive it enough before the swap.

I will be taking a 200 mile NYC to Baltimore trip end of the month and back so that should give me some highway data.

I have another local NYC Gravity around and one day I will drive side by side and see what the most efficient 5 seater will look like against a wheel swapped 7 seater.

I will have the data one day.

 

[Klinkman]

Nealy repair kits are the best. I’ve driven tens of thousands of miles on repairs with no issues. Just not for sidewalls.
Certainly good enough to stop you from being stranded if you have a pump as well

I just picked up my gravity, and this was one issue I had a long conversation over with the delivery advisor. I do some regular driving in rural areas and I was a bit concerned about getting stranded by a flat on the 22/23s and out of a service area.

Fix it yourself is a great solution. I didn't think about this type of kit because they'd been outlawed in my state, no service station or tire repair place will use them. But what a perfect answer. I generally only pick up a nail or screw when my tire has a non-wear problem, easily repaired by this kit. But one will likely need to carry some pliers, a knife and as you say -- an inflater -- for this.

 

[Ron_Burgundy]

Anyone know how many miles, with normal driving, I can expect on the 21/22 AS stock tires? I know I can’t rotate, but have no idea how long they “should” last…

 

[Ron_Burgundy]

Anyone know how many miles, with normal driving, I can expect on the 21/22 AS stock tires? I know I can’t rotate, but have no idea how long they “should” last…

Ignore…manufacturer says 45-55k. I don’t expect that much, but it’s a lot more than I had thought.

 

[037]

Ignore…manufacturer says 45-55k. I don’t expect that much, but it’s a lot more than I had thought.

Are they saying that for a 6000lb vehicle? I think 30k would be a nice number to hit.

 

[Ron_Burgundy]

Are they saying that for a 6000lb vehicle? I think 30k would be a nice number to hit.

Agreed. They’re saying 45,000 for a heavier car, but not specifically EV. I will be thrilled if I get 30,000 miles out of these.

 

[hmp10]

We've lost two tires (one on each Gravity) a week apart from each other. Fortunately, I bought a road hazard tire warranty on both Gravities after the first flat (which was a $984 Pirelli 23" tire.) This second flat has already almost paid for the warranty on one of the cars.

Here's what punctured the Michelin Primacy tire on a 21" front wheel. It was a slow leak of about a pound a day.

 

[037]

We've lost two tires (one on each Gravity) a week apart from each other. Fortunately, I bought a road hazard tire warranty on both Gravities after the first flat (which was a $984 Pirelli 23" tire.) This second flat has already almost paid for the warranty on one of the cars.

Here's what punctured the Michelin Primacy tire on a 21" front wheel. It was a slow leak of about a pound a day.

View attachment 34621

You sir are a magnet for low probability mishaps aren’t you…

 

[hmp10]

You sir are a magnet for low probability mishaps aren’t you…

The chances of this actually penetrating an almost new tire were so small that it makes me wonder just how much crap we're running over all the time without knowing it. The whole 10-mile radius around us is a giant construction site these days, so this is going to go on for a while. It's why I sprung for the road hazard warranties on both cars as soon as I found out they were available for factory-mounted tires.

 

[037]

The chances of this actually penetrating an almost new tire were so small that it makes me wonder just how much crap we're running over all the time without knowing it. The whole 10-mile radius around us is a giant construction site these days, so this is going to go on for a while. It's why I sprung for the road hazard warranties on both cars as soon as I found out they were available for factory-mounted tires.

I feel what you need is a very very old tank that’s been thoroughly tested over decades and I still think there is a chance you might be the one to finally break it somehow…with your luck