21 vs 20 inch tire life questions

[Jordan0301]

anyone have a general idea on how many miles you would get out of the average stock 21 inch tires vs 20 inch tires?

My order locks at midnight and I can't decide between stock 21 wheels and aftermarket 20s.

 

[kirkbauer]

I'm pretty confident my 20" tires will get twice the mileage than my 21" tires would have (and they cost half as much). But I haven't had to replace them yet so who knows. But getting the 21" wheels is the one thing I really regret on my MS purchase. Read on if interested.

I really preferred the 21" wheels especially because when I first priced out my P85D they were mandatory. But before I ordered I could have saved $4500 by going 19". Everybody talked about potholes but I almost never hit potholes. Sure if I hit 10-20 potholes every year (or month?) like in New England then I could understand but I decided I would simply drive carefully and avoid them.

So for about 6 months I drove paranoid and did OK until I hit a pothole at night that I totally didn't even see until it was too late. It was on a turn onto an onramp, I was going about 35mph when I hit it, maybe less. I hit it, and then about 10sec later I got a low tire pressure warning. An then another. Yeah, one pothole, two tires. On top of that I was on my way back home after taking the kids away for the weekend to give my wife some time off. Well, one of my kids was in the rear-facing seats which means I didn't have a car seat for her. I was also about 100 miles away from home. Tesla couldn't get an Uber, but even if they could they may or may not have a car seat. Or I could ride with her on my lap in a tow truck on the freeway for 100 miles. Or I could call my wife while we sat on the side of the road for 1.5 hours. So yeah I did the latter. I had to pay for part of the tow, two new tires, and alignment, so I think it was about $1200.

Then about a month later I walked out to my car and noticed something strange with a rim (NOT one of the ones that was involved in the pothole). Its outer lip was bent and the inside portion was completely cracked. It was either me or Tesla Service since nobody else drove it. I have no idea how I did it, assuming I did. New wheel: ~$1500.

So I knew the 21" wheels wouldn't get along well with potholes, but I didn't realize that I could pretty much NEVER hit a pothole. There is just not enough sidewall for the weight of the MS in my opinion. If I could go back I'd save the $4500 and then spend $2k on aftermarket wheels instead.

As for me, when I lost the wheel, I spent $1k on 20" aftermarket wheels and $1k on a set of four tires, or only slightly more than it would have cost to replace the one wheel. So I ended up spending $5500 more than I could have to end up in my current state. And now a full set of tires is $1k instead of $2k and they last twice as long. And I think there are some great looking 20" wheel options out there (check tirerack.com).

And, finally, now that I have been using Autopilot a lot in the last 6 months, I think being really paranoid about potholes will take some of the benefit of AP away from you.

 

[Jordan0301]

I'm pretty confident my 20" tires will get twice the mileage than my 21" tires would have (and they cost half as much). But I haven't had to replace them yet so who knows. But getting the 21" wheels is the one thing I really regret on my MS purchase. Read on if interested.

I really preferred the 21" wheels especially because when I first priced out my P85D they were mandatory. But before I ordered I could have saved $4500 by going 19". Everybody talked about potholes but I almost never hit potholes. Sure if I hit 10-20 potholes every year (or month?) like in New England then I could understand but I decided I would simply drive carefully and avoid them.

So for about 6 months I drove paranoid and did OK until I hit a pothole at night that I totally didn't even see until it was too late. It was on a turn onto an onramp, I was going about 35mph when I hit it, maybe less. I hit it, and then about 10sec later I got a low tire pressure warning. An then another. Yeah, one pothole, two tires. On top of that I was on my way back home after taking the kids away for the weekend to give my wife some time off. Well, one of my kids was in the rear-facing seats which means I didn't have a car seat for her. I was also about 100 miles away from home. Tesla couldn't get an Uber, but even if they could they may or may not have a car seat. Or I could ride with her on my lap in a tow truck on the freeway for 100 miles. Or I could call my wife while we sat on the side of the road for 1.5 hours. So yeah I did the latter. I had to pay for part of the tow, two new tires, and alignment, so I think it was about $1200.

Then about a month later I walked out to my car and noticed something strange with a rim (NOT one of the ones that was involved in the pothole). Its outer lip was bent and the inside portion was completely cracked. It was either me or Tesla Service since nobody else drove it. I have no idea how I did it, assuming I did. New wheel: ~$1500.

So I knew the 21" wheels wouldn't get along well with potholes, but I didn't realize that I could pretty much NEVER hit a pothole. There is just not enough sidewall for the weight of the MS in my opinion. If I could go back I'd save the $4500 and then spend $2k on aftermarket wheels instead.

As for me, when I lost the wheel, I spent $1k on 20" aftermarket wheels and $1k on a set of four tires, or only slightly more than it would have cost to replace the one wheel. So I ended up spending $5500 more than I could have to end up in my current state. And now a full set of tires is $1k instead of $2k and they last twice as long. And I think there are some great looking 20" wheel options out there (check tirerack.com).

And, finally, now that I have been using Autopilot a lot in the last 6 months, I think being really paranoid about potholes will take some of the benefit of AP away from you.

Thank you for the awesome detailed response.

Couple other questions...

Have you noticed a difference in the ride?

And

I'm new to buying wheels and tires, now does that mean I have them shipped to a mechanic that installs them? How much does that run?

 

[Sir Guacamolaf]

Does anyone know if the 21" turbines are cast or forged?

 

[Superloud]

This thread (post #5) says they are cast

Are the OEM wheels cast or forged?

 

[lolachampcar]

I took the stock 19s, pulled them off at delivery and have run 20" Nurburgrings and Pilot Super Sports. The rims are 10lbs per wheel less and the PSS' have better grip, wear longer and are less expensive than Tesla's 21" PS2 combination. My whole package cost 1/2 what Tesla wants for their 21"s and I have a complete spare set of wheels/tires when I go to sell the car.
2015 P85D

 

[ron8853]

An after market wheel company (Asanti) informed me that one can't go from 21"s to 20's. Said there is an issue with the brakes/caliper fitting as 21's have larger brakes. Not certain if this is accurate.

 

[Sir Guacamolaf]

This thread (post #5) says they are cast

Are the OEM wheels cast or forged?

Cool. I think the arachnid forged wheels would be the ideal 21" wheel for this car.

 

[lolachampcar]

Nope, only one set of calipers and rotors on MS. You can exchange 19s for 21s all day long. The only issue I had with my 20"s was the need to grind down the rotor retaining bolt as it is proud of the rotor a bit. The Tesla wheels are pocketed for this where the Nurburgrings are not.

 

[kirkbauer]

Thank you for the awesome detailed response.

Couple other questions...

Have you noticed a difference in the ride?

And

I'm new to buying wheels and tires, now does that mean I have them shipped to a mechanic that installs them? How much does that run?

Contrary to other posts on here I had no problem getting them installed. I ordered the wheels on tirerack.com for about $1k and had them delivered to a local tire shop who sold me the tires plus installation for about $1k. They told me they possibly could have got the wheels for me cheaper too.

The tires are slightly louder than the ContiSilent ones that came with my MS but that is not an issue of 20" vs 21", just tire choice. These longer-life tires (supposed to have a 30k mile life) have slightly less traction. That's good since I love fishtailing around turns, but bad because I think it has slightly slowed down my 0-60 time.

I don't notice any difference in ride quality or handling other than the fact that bumps are less brutal (on the 21" some seemingly minor bumps can really feel hard on the car since there is so little cushion).

 

[benjiejr]

anyone have a general idea on how many miles you would get out of the average stock 21 inch tires vs 20 inch tires?

My order locks at midnight and I can't decide between stock 21 wheels and aftermarket 20s.

Just another data point, I got 20k out of my stock 21 inch Michelin PS2s and I'd estimate they had another 5k left at least.

As a side note, now I'm on 20 inch Pirelli P-Zeros and I've gotten 14k out of them so far and I'd say they have less than 5k left on them. So my 20s didn't last as long as the 21s but I attribute that mostly to the tire. I plan to go back to Michelins when these are done. The Pirellis have been a good tire and I'm glad I tested them out, but I feel like the Michelins were slightly better overall in tire wear and grip.

Good luck!