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Model Y Performance 21" Tires - Larger, More Comfortable Fitment Details and Experience - Michelin AS4's (With Photos)

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Your math is a bit off, probably because you're misunderstanding the numbers for the tire size.

275/45/20 doesn't mean the 45 is the height of the tire in mm. It means the height of the tire is 45% of the section width, in this case 275.

So the tire height is actually 275 x 0.45 = 123.75 mm for the front and 132.75 (296x0.45) for the rear. For the 21", it's 110.

Meaning, it's actually about 378 vs 377.

Your new purchase is going to be about 2" bigger in diameter than the factory setup in front and even more in back. Have fun!
Great, thanks for the reply. I just switched it to 295 40 r20 and 275 40 r20 before delivery.
Wanted to get feedback from the shipper as well b4 he shipped it. So glad for the instant reply. And all along I thought the middle number was the size in mm.
Much appreciated.
 
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Great, thanks for the reply. I just switched it to 295 40 r20 and 275 40 r20 before delivery.
Wanted to get feedback from the shipper as well b4 he shipped it. So glad for the instant reply. And all along I thought the middle number was the size in mm.
Much appreciated.

295 40 20 and 275 40 20 will fit. Post some pics when you get done. Not sure I've seen this fit posted yet with AS4's. Thanks.
 
Your math is a bit off, probably because you're misunderstanding the numbers for the tire size.

275/45/20 doesn't mean the 45 is the height of the tire in mm. It means the height of the tire is 45% of the section width, in this case 275.

So the tire height is actually 275 x 0.45 = 123.75 mm for the front and 132.75 (296x0.45) for the rear. For the 21", it's 110.

Meaning, it's actually about 378 vs 377.

Your new purchase is going to be about 2" bigger in diameter than the factory setup in front and even more in back. Have fun!
Could be a Speedo nightmare
1692284428186.png
 
I wonder if OP already had checks on on the steering rack, because I presume the meatier and wider tires would be heavier than OEM. Factory designed and calibrated the steering assembly to work with OEM wheels and tires as well as their total weight so I think OP would have premature wear in the long run.
 
I wonder if OP already had checks on on the steering rack, because I presume the meatier and wider tires would be heavier than OEM. Factory designed and calibrated the steering assembly to work with OEM wheels and tires as well as their total weight so I think OP would have premature wear in the long run.
Great point
A bit ago, I put huge tires and wheels on a sports car I had and I think there def was a negative impact to the steering rack
Starting to not want 275/315s
Besides rhe speedo issue
 
It would be so much easier if that were the case. But nope, the powers that be... are crazy.

The section width is in mm. Sidewall is an aspect ratio. The wheel they fit them on is in inches.

All three are just measurements in length.

What a PITA.
It would be so much easier if that were the case. But nope, the powers that be... are crazy.

The section width is in mm. Sidewall is an aspect ratio. The wheel they fit them on is in inches.

All three are just measurements in length.

What a PITA.
295 40 20 and 275 40 20 will fit. Post some pics when you get done. Not sure I've seen this fit posted yet with AS4's. Thanks.

Did a bit of research comparing the
295 45 r20 vs the 295 40 r21 and the total diameter is fractions of an inch difference.. the seller already shipped these and will send me free return labels for all 4 tires. I’m still debating but at least I have options. Thoughts ??
 

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Did a bit of research comparing the
295 45 r20 vs the 295 40 r21 and the total diameter is fractions of an inch difference.. the seller already shipped these and will send me free return labels for all 4 tires. I’m still debating but at least I have options. Thoughts ??
Fitment is always a bit of an issue… one you can’t really be sure of when the numbers are close, without doing a test fit.

Even for tires that are the same size in diameter, sometimes there’s a change in tread size/shape that makes the corner rounder or more square.

Communicate with the seller to see what you can do as far as test fitting. Local shops that sell tires might‘ve let you mount the tires to see if their tires fit. But seeing as this was not local, it’ll be difficult.
 
I recently had to replace my 2022 MYP OEM Michelin All Season 4's and after a lot of research, and tire hunting, wanted to share my experience and the direction I went. Valuable information for those close to ordering new tires. I just drive 2000 miles through Santa Cruz, San Jose, Sacramento, and did a weekend in Tahoe, driving on many dirt roads and rough roads.

First off, I will never go with another set of tires after having these. I made it to 37,000 miles with 3/32 left on all 4 tires. they wore evenly. Their performance in heavy rain and even 6" of snow was unbelievable. Ive had multiple cars with Pirellis, and always stuck with them, but was not happy with the miles I got out of them, and the thought of getting 27,000 miles on them with an EV just sounds terrible considering the price.

The Tires

I went up in size with width, and sidewall.

Stock/OEM for the MYP is:
Front: 255/35/21
View attachment 853290
Rear: 275/35/21
View attachment 853291

The tires I chose are:
Front: 265/40/21
View attachment 853292
Rear: 295/40/21
View attachment 853293
Fitment

Front wheels fully turned, there's still >1" to the inner tire well. So no rubbing at all, even with quick turns into parking lots (Where you would probably get rubbing the most)
Rear wheels haven't rubbed on any large bumps. I even tried to get them to rub. nothing.

The main bonus functionality wise is that the tires extend farther out than the rims. not much, but they do.
View attachment 853301

Look

The difference is huge. Pictures don't do it justice. When I see other MYP's now, the OEM tires look stretched and the amount of room in the tire well looks like a mistake. maybe not on the MYLR, but for a performance, the larger sidewall REALLY looks great. It creates the illusion that your car is lowered, but its actually ~1.5" higher clearance

It truly looks performance even though It can handle bumpy roads and "All Season" conditions even better.

Before:
View attachment 853299

After:
View attachment 853302
Efficiency

This part was really interesting.

Bigger tires have a higher rolling resistance than smaller tires which means they require more resistance and effort to get them rolling. However, if you do a lot of freeway driving at high speeds, larger tires can help increase your vehicle's efficiency.

So, days I drive a lot in the city with lots of stop and go, I get about 7% less range. but when I do a lot of freeway driving, I get about 7% better range.

I drive 150-350 miles a day, and have found zero difference in range because I do a wide range of road types. I really thought I'd lose range.

Feel

WOW, what a difference. Sure the suspension is still stiff, but I feel a LOT less of the small imperfections of the roads I drive on every day. even my girlfriend said she noticed it before I got to point it out. Speed bumps and things feel much better and not like im driving over a 2"x4". This is my favorite part of these tires functionality wise. Cant describe it.

There is no foam in the tires, but they are STILL quieter than the OEM with the foam. that stuffs a gimmick.

Things To Be Aware Of

Speedometer: It is not going to be accurate. Due to the larger diameter, it is off. I called Tesla, and talked to 2 different service centers, and there is nothing they can do about it. This seems like something Tesla overlooked. The only thing you can change is your rim size in your cars settings, but not the diameter...

So, when my car says im going 70MPH, im actually going 74MPH.
says 25, im going 26.5
says 40, im going 43
says 65, im going 68.5
says 85 (for AP max) im going 90.

This is something that as long as you keep in mind, it doesnt matter. I just changed my cruise control settings so it doesn't add 5MPH anymore. I chose 7% increase and it's fine.

I dont know if it's the new beta version, or that the car thinks its going slower than it is, but ive noticed that on AP/FSDbeta, it is taking turns a little wider and sometimes touches the lines on the outer edge of the turn if im going above 50mph. I'm pretty sure it's the speed issue.

This really needs to be able to be corrected by the user in the settings. sometimes switching brands can add .5in of diameter even if the tire is the same "size".

Conclusion:

Go Bigger! the OEM tires are actually stretched on your Uberturbines. they are meant for wider tires but Tesla went smaller for efficiency reasons, which in the end, didn't matter. Finding the OEM sizes of these wonderful tires is basically impossible. They are on a national backorder right now which is why I went for a different size in the first place. These tires arent cheap, but they ARE worth every penny.

American tire warned me that they weren't OEM sizes, and I told them I know for a fact they will fit and they had no problem installing them.

Here's some more pictures just for fun. These are some CHONKY tires. Thicc with 2 "C"s. tiny American tire man for reference

I recently had to replace my 2022 MYP OEM Michelin All Season 4's and after a lot of research, and tire hunting, wanted to share my experience and the direction I went. Valuable information for those close to ordering new tires. I just drive 2000 miles through Santa Cruz, San Jose, Sacramento, and did a weekend in Tahoe, driving on many dirt roads and rough roads.

First off, I will never go with another set of tires after having these. I made it to 37,000 miles with 3/32 left on all 4 tires. they wore evenly. Their performance in heavy rain and even 6" of snow was unbelievable. Ive had multiple cars with Pirellis, and always stuck with them, but was not happy with the miles I got out of them, and the thought of getting 27,000 miles on them with an EV just sounds terrible considering the price.

The Tires

I went up in size with width, and sidewall.

Stock/OEM for the MYP is:
Front: 255/35/21
View attachment 853290
Rear: 275/35/21
View attachment 853291

The tires I chose are:
Front: 265/40/21
View attachment 853292
Rear: 295/40/21
View attachment 853293
Fitment

Front wheels fully turned, there's still >1" to the inner tire well. So no rubbing at all, even with quick turns into parking lots (Where you would probably get rubbing the most)
Rear wheels haven't rubbed on any large bumps. I even tried to get them to rub. nothing.

The main bonus functionality wise is that the tires extend farther out than the rims. not much, but they do.
View attachment 853301

Look

The difference is huge. Pictures don't do it justice. When I see other MYP's now, the OEM tires look stretched and the amount of room in the tire well looks like a mistake. maybe not on the MYLR, but for a performance, the larger sidewall REALLY looks great. It creates the illusion that your car is lowered, but its actually ~1.5" higher clearance

It truly looks performance even though It can handle bumpy roads and "All Season" conditions even better.

Before:
View attachment 853299

After:
View attachment 853302
Efficiency

This part was really interesting.

Bigger tires have a higher rolling resistance than smaller tires which means they require more resistance and effort to get them rolling. However, if you do a lot of freeway driving at high speeds, larger tires can help increase your vehicle's efficiency.

So, days I drive a lot in the city with lots of stop and go, I get about 7% less range. but when I do a lot of freeway driving, I get about 7% better range.

I drive 150-350 miles a day, and have found zero difference in range because I do a wide range of road types. I really thought I'd lose range.

Feel

WOW, what a difference. Sure the suspension is still stiff, but I feel a LOT less of the small imperfections of the roads I drive on every day. even my girlfriend said she noticed it before I got to point it out. Speed bumps and things feel much better and not like im driving over a 2"x4". This is my favorite part of these tires functionality wise. Cant describe it.

There is no foam in the tires, but they are STILL quieter than the OEM with the foam. that stuffs a gimmick.

Things To Be Aware Of

Speedometer: It is not going to be accurate. Due to the larger diameter, it is off. I called Tesla, and talked to 2 different service centers, and there is nothing they can do about it. This seems like something Tesla overlooked. The only thing you can change is your rim size in your cars settings, but not the diameter...

So, when my car says im going 70MPH, im actually going 74MPH.
says 25, im going 26.5
says 40, im going 43
says 65, im going 68.5
says 85 (for AP max) im going 90.

This is something that as long as you keep in mind, it doesnt matter. I just changed my cruise control settings so it doesn't add 5MPH anymore. I chose 7% increase and it's fine.

I dont know if it's the new beta version, or that the car thinks its going slower than it is, but ive noticed that on AP/FSDbeta, it is taking turns a little wider and sometimes touches the lines on the outer edge of the turn if im going above 50mph. I'm pretty sure it's the speed issue.

This really needs to be able to be corrected by the user in the settings. sometimes switching brands can add .5in of diameter even if the tire is the same "size".

Conclusion:

Go Bigger! the OEM tires are actually stretched on your Uberturbines. they are meant for wider tires but Tesla went smaller for efficiency reasons, which in the end, didn't matter. Finding the OEM sizes of these wonderful tires is basically impossible. They are on a national backorder right now which is why I went for a different size in the first place. These tires arent cheap, but they ARE worth every penny.

American tire warned me that they weren't OEM sizes, and I told them I know for a fact they will fit and they had no problem installing them.

Here's some more pictures just for fun. These are some CHONKY tires. Thicc with 2 "C"s. tiny American tire man for reference.
View attachment 853304View attachment 853305
Are you using any spacers?
 
Just wanted to give an update to people. I’m writing this sitting at americas tire:

Today I’m replacing this set after 9 months and 34,500 miles of LOVING this setup. No matter what car I have, I will never buy another tire (until they come out with AS5s lol).

Final details:

Ending with ~3/32 on all tires at the lowest point.

I never got an alignment. Inner wear on all 4 tires is about 1/32-2/32 greater than the outside. Was told by Tesla service friend that an alignment could have easily solved that with zero third party changes needing to be made, but the difference in wear isn’t really worth the cost since the extra 3-4k miles I could get, would be 3-4 weeks for me. “Your mileage may vary”. Pun intended lol

I drive all over California for work. 150-350 miles a day, 4-6 days a week. And I drive HARD. Regular stretches at 85-90mph. Many windy mountain roads faster than the majority would drive. Awful gravel roads. All styles really.


These got me through plenty of dirt roads, roads with fresh 6” of snow. California deluges of rain where others were hydroplaning, I was comfortable. Never had a scary moment. Snow performance was impressive. Actually hard to slide out unless I actively tried.

I ran them with 38-39psi(cold) at all times. With my ~2000 miles some weeks, I kept on top of this. After driving for a while, they leveled out at 42-43psi.

If you’re reading this and contemplating the size upgrade, or even the quality of the Michelin AS4s, ease your mind. Worth every penny ($2000 for full set).

If you’re a conservative driver you will get 40k miles out of these.

Hope others have shared my positive experience as well!
Thanks for the thorough assessment and write-up. I now know what to get once the OEMs on my upcoming MYP need replacing.
 
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Reactions: Raurele
I wonder if OP already had checks on on the steering rack, because I presume the meatier and wider tires would be heavier than OEM. Factory designed and calibrated the steering assembly to work with OEM wheels and tires as well as their total weight so I think OP would have premature wear in the long run.
Never had them checked. But it performs flawlessly. And I drive like a maniac on many windy and twisty roads lol
 
I recently had to replace my 2022 MYP OEM Michelin All Season 4's and after a lot of research, and tire hunting, wanted to share my experience and the direction I went. Valuable information for those close to ordering new tires. I just drive 2000 miles through Santa Cruz, San Jose, Sacramento, and did a weekend in Tahoe, driving on many dirt roads and rough roads.

First off, I will never go with another set of tires after having these. I made it to 37,000 miles with 3/32 left on all 4 tires. they wore evenly. Their performance in heavy rain and even 6" of snow was unbelievable. Ive had multiple cars with Pirellis, and always stuck with them, but was not happy with the miles I got out of them, and the thought of getting 27,000 miles on them with an EV just sounds terrible considering the price.

The Tires

I went up in size with width, and sidewall.

Stock/OEM for the MYP is:
Front: 255/35/21
View attachment 853290
Rear: 275/35/21
View attachment 853291

The tires I chose are:
Front: 265/40/21
View attachment 853292
Rear: 295/40/21
View attachment 853293
Fitment

Front wheels fully turned, there's still >1" to the inner tire well. So no rubbing at all, even with quick turns into parking lots (Where you would probably get rubbing the most)
Rear wheels haven't rubbed on any large bumps. I even tried to get them to rub. nothing.

The main bonus functionality wise is that the tires extend farther out than the rims. not much, but they do.
View attachment 853301

Look

The difference is huge. Pictures don't do it justice. When I see other MYP's now, the OEM tires look stretched and the amount of room in the tire well looks like a mistake. maybe not on the MYLR, but for a performance, the larger sidewall REALLY looks great. It creates the illusion that your car is lowered, but its actually ~1.5" higher clearance

It truly looks performance even though It can handle bumpy roads and "All Season" conditions even better.

Before:
View attachment 853299

After:
View attachment 853302
Efficiency

This part was really interesting.

Bigger tires have a higher rolling resistance than smaller tires which means they require more resistance and effort to get them rolling. However, if you do a lot of freeway driving at high speeds, larger tires can help increase your vehicle's efficiency.

So, days I drive a lot in the city with lots of stop and go, I get about 7% less range. but when I do a lot of freeway driving, I get about 7% better range.

I drive 150-350 miles a day, and have found zero difference in range because I do a wide range of road types. I really thought I'd lose range.

Feel

WOW, what a difference. Sure the suspension is still stiff, but I feel a LOT less of the small imperfections of the roads I drive on every day. even my girlfriend said she noticed it before I got to point it out. Speed bumps and things feel much better and not like im driving over a 2"x4". This is my favorite part of these tires functionality wise. Cant describe it.

There is no foam in the tires, but they are STILL quieter than the OEM with the foam. that stuffs a gimmick.

Things To Be Aware Of

Speedometer: It is not going to be accurate. Due to the larger diameter, it is off. I called Tesla, and talked to 2 different service centers, and there is nothing they can do about it. This seems like something Tesla overlooked. The only thing you can change is your rim size in your cars settings, but not the diameter...

So, when my car says im going 70MPH, im actually going 74MPH.
says 25, im going 26.5
says 40, im going 43
says 65, im going 68.5
says 85 (for AP max) im going 90.

This is something that as long as you keep in mind, it doesnt matter. I just changed my cruise control settings so it doesn't add 5MPH anymore. I chose 7% increase and it's fine.

I dont know if it's the new beta version, or that the car thinks its going slower than it is, but ive noticed that on AP/FSDbeta, it is taking turns a little wider and sometimes touches the lines on the outer edge of the turn if im going above 50mph. I'm pretty sure it's the speed issue.

This really needs to be able to be corrected by the user in the settings. sometimes switching brands can add .5in of diameter even if the tire is the same "size".

Conclusion:

Go Bigger! the OEM tires are actually stretched on your Uberturbines. they are meant for wider tires but Tesla went smaller for efficiency reasons, which in the end, didn't matter. Finding the OEM sizes of these wonderful tires is basically impossible. They are on a national backorder right now which is why I went for a different size in the first place. These tires arent cheap, but they ARE worth every penny.

American tire warned me that they weren't OEM sizes, and I told them I know for a fact they will fit and they had no problem installing them.

Here's some more pictures just for fun. These are some CHONKY tires. Thicc with 2 "C"s. tiny American tire man for reference.
View attachment 853304View attachment 853305
Looks awesome! Im sold on these. Do you happen to know which models you got. I noticed there are a few with different load indexes and didn’t want to order the wrong ones.