New T1 Primacy MXM4 tire

[Zoomit]

Along with all the other 2021 Model 3 refresh activity, it looks like Tesla and Michelin have released a new Primacy MXM4 original equipment tire for the 18” wheel size (235/45R18). This is annotated as a T1 spec, replacing the original T0 specification tire. It’s now available on Tirerack.com and a comparison of the available spec data shows the only difference being the tread width has been reduced from 7.8 to 7.5”.

Speculating on their motivation, a narrower tread width can make the tire more aerodynamic. It seems unlikely they’d roll a revision of the spec just for this one parameter, so there’s a reasonable chance that the tire changed in other minor ways.

T0 spec: https://www.tirerack.com/tires/tire...odel 3&autoModClar=Dual Motor All-Wheel Drive

T1 spec: https://www.tirerack.com/tires/tire...odel 3&autoModClar=Dual Motor All-Wheel Drive

 

[chrstna4]

I’m hoping it would increase range and decrease noise. That’s the dream!

 

[Zoomit]

I’m hoping it would increase range and decrease noise. That’s the dream!

Well, it’s unlikely they’d tweak the design to offer more cornering grip or wet traction, as an example. This is their least sporty and most efficient tire option, so making it slightly more efficient is plausible.

Maybe they changed the tread pattern for better aero or reduced noise. Maybe they changed the compound for better rolling resistance. It’s hard for consumers to compare tire compound, but we should be able to discern any changes to the tread visually. All the pictures on Tirerack.com are of a generic MXM4 tire and don’t help in that regard.

I expect the changes are going to be incremental and hard to notice, but these tires are probably helping the car achieve the new increased EPA range.

 

[jerry33]

Noise deadening foam perhaps?

 

[Zoomit]

Noise deadening foam perhaps?

Both the T0 and T1 tires already have it, but it’s certainly possible they changed the foam density or volume.

 

[NJP3]

I have the same Primacy 18" on the aeros of my Stealth M3P as when I received the car last August.. any recommendations for an upgrade?

 

[Knightshade]

I have the same Primacy 18" on the aeros of my Stealth M3P as when I received the car last August.. any recommendations for an upgrade?

In NJ? Michelin Pilot Sport All Season 4s if you stay off the roads when there's more than light snow... probably the Michelin Cross Climates otherwise (unless you're willing to get a second set of wheels and run dedicated winter and summer tires)

 

[Zoomit]

In NJ? Michelin Pilot Sport All Season 4s if you stay off the roads when there's more than light snow... probably the Michelin Cross Climates otherwise (unless you're willing to get a second set of wheels and run dedicated winter and summer tires)

Neither of those is an "upgrade" if your desires are for the longest range or the quietest ride. Point being, the MXM4 tires are good IF your requirements align with the Tesla engineers. If they don't, then there are many different options available depending on the specific characteristics of interest, which were not stated in the question.

 

[Knightshade]

Neither of those is an "upgrade" if your desires are for the longest range or the quietest ride.

I didn't notice any significant noise difference upgrading to the AS4s.

The car stops like 20% shorter though which is a pretty huge upgrade even if I lose a few percent range in exchange, in addition to noticably better cornering, and objectively better wet weather performance and safety as well.

 

[Fernand]

@Knightshade Wouldn't the Michelin Pilot Sport AS4 also allow normal response to a puncture: canned slime or standard repair plug + inflator?

Since they are a little cheaper, can you see a down-side?
.

 

[Knightshade]

@Knightshade Wouldn't the Michelin Pilot Sport AS4 also allow normal response to a puncture: canned slime or standard repair plug + inflator?

Since they are a little cheaper, can you see a down-side?
.

Oh without the tesla foam? good point... really only downside I'd see is a bit less range- but outside of road trips that's a non-issue for most, yet braking distance always matters.

 

[Fernand]

What exactly would give it "a little less range"? Did you observe that, as a fact?

 

[jerry33]

What exactly would give it "a little less range"? Did you observe that, as a fact?

Yes, the foam is for sound deadening, it should have almost no effect on range and that effect should be a reduction (in range), not an increase.

 

[Zoomit]

What exactly would give it "a little less range"? Did you observe that, as a fact?

He’s referring to the difference in range between the Primacy MXM4 tires and the Pilot Sport All Season 4 tires. The latter has a higher rolling resistance (and higher grip) tire compound that results in about 10% less range. The tread shoulder shape could also have a slight effect on range as a more rounded edge will have more favorable aerodynamic characteristics.

 

[MacGreiner]

I have the PS4s. The range hit/efficiency has been way less than 10% - in fact less than 5%. 'Thinner' (front profile) tire will get better efficiency, no doubt. This is why the i3 tires are so narrow.
Maybe I'm in the minority, but I will never buy the MXM4s again. I found the wet weather performance borderline dangerous.

 

[Knightshade]

Yup, exactly.

FWIW I've got like 1500 miles only so far on the AS4s and the range hit is definitely LESS than 10%, something around 7-8% currently vs the MXM4s but it's probably less as the tires wear in.

 

[Zoomit]

For those curious, it looks like the 19” Continental ProContact RX tire also got updated from the T0 spec to T1. The T1 tire isn’t in tirerack.com yet to compare details.

 

[EfficientWatts]

https://www.discounttire.com/buy-tires/michelin-primacy-mxm4-ac/p/89901

Saw this on discount tire. Is this the same one as the revised one?

Also for anyone that has taken delivery of 2021 models, can they check to see if they have the revised tire? Is it even possible to check based on tire markings?

 

[Zoomit]

https://www.discounttire.com/buy-tires/michelin-primacy-mxm4-ac/p/89901

Saw this on discount tire. Is this the same one as the revised one?

Also for anyone that has taken delivery of 2021 models, can they check to see if they have the revised tire? Is it even possible to check based on tire markings?

I would want to contact Discount Tire to see if that particular tire is made to the T1 specification. It's not obvious from the webpage.

Anyone can look at the outside sidewall markings of the tire and see if it's made to the T1 spec or the original T0 spec. It'll indicate "T0" or "T1" in letters about half an inch high after the Primacy MXM4 marking. Here's a picture of a tire that has the T0 marking:

 

[Zoomit]

Here's a picture of the T1 tire from another thread. The T1 marking is visible on the sidewall on the left.