Replacement tires

[nate704]

See post #9 above, which is BRIDGESTONES'S OWN internet site says. Also TireRack has ZERO runflat rated tires listed for a Tesla MY.

XL load rating, 104, NOT 100. No reputable shop would mount these on a Tesla MY.

Do your own research.

Load index is load index. If the load index is higher than GVWR of any car. it will be okay. Do your own "real" research. Look at the actual spec and actual load index and learn what load index is and how it works to choose tires.
Even at Load index 100 which supports up to 7000 lbs GVWR, MY GVWR (5700lbs) will not even come close to the same universe to be unsafe.

 

[Pianewman]

I understand what you're saying. Why do you assume Tesla's (required?) load rating isn't important?

The manufacturer's specs (and your insurance company!) have to assume fully loaded, at speed, in an emergency braking/steering situation, which puts incredible weight/force on a single tire/wheel, which could possibly exceed the lower load rated tire's strength.

OF course your (any) vehicle will function with load ratings below the auto manufacturer's specs. No reputable shop would mount them, though.

We could run a test, have 100 members of this club mount sets of 100 load index tires, and monitor tire issues. They will report a smoother, gentler ride, sloppier handling, and possibly, 1 or 2 unexpected blowouts, "for no apparent reason."

YMMV. Specs are specs, and for a reason.

 

[TomB985]

Meh.

Costco installed Driveguard runflats on my Model 3 that lacked the XL load rating, and they worked out just great. My winter tires are 100 load index p225-60r18s, and they also do fine. They exceed the maximum axle capacities of the Model Y, which most users will never come anywhere close to. I liked the Driveguard, and they’re on my list of options when my factory tires wear out.

You’re perfectly fine running 100 load index tires. The front tires on the Performance trim are 98 load index, and the rears are 103. The 20” Induction factory tires are 101 load index.

 

[Pianewman]

...and the tech at the Costco should be fired for installing tires on your Model 3 that aren't XL rated. Their policy requires it.

I know. I tried at my local Costco. They refused. Ditto for Discount Tire.

Of COURSE your non-XL rated tires "do fine." Doing "fine" isn't the issue. Doing fine under extreme load is the potential issue.

 

[avs007]

...and the tech at the Costco should be fired for installing tires on your Model 3 that aren't XL rated. Their policy requires it.

I know. I tried at my local Costco. They refused. Ditto for Discount Tire.

Yeah, normally Costco is pretty strict. They normally will refuse to install a tire whose specs do not meet the minimum specs of what came on the car. I've ran into that a few times a while back. One time they refused to install a V-rated tire, because my car came with W rated tires, even tho the OEM speed limiter was set for an H rated tire.

 

[gx9901]

FWIW, my local Discount Tire refused to sell me a set of 255/40/R20 Pilot Sport 4S I wanted to mount on a set of wheels with the same dimensions as Induction wheels on my MYP. They said the load rating specified for the MYP is higher than what those tires had. They would only sell me a set of 265/40/R20. I’m pretty sure the 255s would be fine but when they won’t sell them to me there’s not much I could do. At least the 265 tires provide slightly more sidewall and maybe a tiny smidge more comfort, so I just went with them.

 

[avs007]

FWIW, my local Discount Tire refused to sell me a set of 255/40/R20 Pilot Sport 4S I wanted to mount on a set of wheels with the same dimensions as Induction wheels on my MYP. They said the load rating specified for the MYP is higher than what those tires had. They would only sell me a set of 265/40/R20. I’m pretty sure the 255s would be fine but when they won’t sell them to me there’s not much I could do. At least the 265 tires provide slightly more sidewall and maybe a tiny smidge more comfort, so I just went with them.

Get them in 255/45-20. They are significantly cheaper than 255/40-20 (at least the A/S is, not sure about the summer version), and has a higher load rating... I got my tires in 255/45-20 and couldn't be happier.

* Nevermind, I just checked, only the A/S version is cheaper in that size.

 

[avs007]

For future reference, Discount Tire was prob referring to the rears, where the OEM tire has a 103Y load rating. The 255/40-20 tire only has a 101Y load rating... But the 255/45-20 tire I was referring to, has a 105Y load rating.

 

[gx9901]

For future reference, Discount Tire was prob referring to the rears, where the OEM tire has a 103Y load rating. The 255/40-20 tire only has a 101Y load rating... But the 255/45-20 tire I was referring to, has a 105Y load rating.

Yeah, they said the 255/40-20 is OK for the front but not the rear. They didn't mention 255/45-20 as an option, but if that works I suppose I could try it in the future.

 

[dafish]

Guys, there is always going to be a bureaucracy (costco above), luddite, or ultra-cautious person telling you "Only Follow The Manual". Is what it is, just part of life. For those comfortable thinking for themselves well, your options are quite a bit wider.

I'll attach a link to some deeper discussion with a lof of reference links to so you can reach your own conclusions, but having spent some time looking at this I'm comfortable sharing my personal conclusions. YMMV:

1. Yes, you can run lower tire pressure in almost all situations, and lower tire load ratings too.
2. No, your insurance company isn't going go deny coverage, sue you, or etc. Thats just fear mongering.
   1. Drunks, speeders, over-loaded cars, etc are covered, unless you do something incredibly stupid and high profile.
3. Given the modeling I did, I was able to see one occasion where 101XL was justified. As such, I'm sure Tesla delivers the car with 101XL on purpose.
   1. If you put a light driver in a Y, load it to max GVWR with all the weight in back (say loaded coolers and a 3500lb trailer with 15% tongue), AND lower tire pressure to 36 PSI, you will both not set off the tire pressure alert and be at the load limit of a 101XL at the rear. My personal assumption is that's why Telsa specified that tire as an OEM. You should model and decide for yourself.
      1. Is there something that says you must follow OEM tire sizes? Nope.
4. So yea, it's POSSIBLE, but I can tell you I'll spend no time at all doing such a thing. When I replace I'll likely look for an XL so I can air up (I run 36-38 PSI in normal use), but I won't be pushing for 101 load rating. Why? Because my personal use case will never match this "worst possible" scenario.
   1. For the rare times I load the Y to any degree I'll simply air up a bit.
   2. If you didn't know, XL simply means the tire allows higher tire pressures, and every time made increases load rating as tire pressure goes up.

Link:Deeper Discussion W/Reference Links

 

[TomB985]

I had a response typed up, but thought better of it. Glad I did, because dafish did a much better job.

Guys, there is always going to be a bureaucracy (costco above), luddite, or ultra-cautious person telling you "Only Follow The Manual". Is what it is, just part of life. For those comfortable thinking for themselves well, your options are quite a bit wider.

I'll attach a link to some deeper discussion with a lof of reference links to so you can reach your own conclusions, but having spent some time looking at this I'm comfortable sharing my personal conclusions. YMMV:

1. Yes, you can run lower tire pressure in almost all situations, and lower tire load ratings too.
2. No, your insurance company isn't going go deny coverage, sue you, or etc. Thats just fear mongering.
   1. Drunks, speeders, over-loaded cars, etc are covered, unless you do something incredibly stupid and high profile.
3. Given the modeling I did, I was able to see one occasion where 101XL was justified. As such, I'm sure Tesla delivers the car with 101XL on purpose.
   1. If you put a light driver in a Y, load it to max GVWR with all the weight in back (say loaded coolers and a 3500lb trailer with 15% tongue), AND lower tire pressure to 36 PSI, you will both not set off the tire pressure alert and be at the load limit of a 101XL at the rear. My personal assumption is that's why Telsa specified that tire as an OEM. You should model and decide for yourself.
      1. Is there something that says you must follow OEM tire sizes? Nope.
4. So yea, it's POSSIBLE, but I can tell you I'll spend no time at all doing such a thing. When I replace I'll likely look for an XL so I can air up (I run 36-38 PSI in normal use), but I won't be pushing for 101 load rating. Why? Because my personal use case will never match this "worst possible" scenario.
   1. For the rare times I load the Y to any degree I'll simply air up a bit.
   2. If you didn't know, XL simply means the tire allows higher tire pressures, and every time made increases load rating as tire pressure goes up.

Link:Deeper Discussion W/Reference Links

This is pretty much what I’ve concluded over the last few years, and I‘ve saved his document for the links. I’ve always focused on matching the tire and load inflation pressure to the GAWR, and I’ve never had a bad experience. Everything is a compromise, though. My skinny 225 snow tires handled some of the worst potholes I’ve ever seen last winter, much like the ones that have been known to defeat stock tires and bend rims. That comes at the expense of handling, and the car felt like it was riding on razor blades when I switched to Überturbines this spring.

I have three sets of tires and wheels, and the handling difference between them is striking. Everything is a compromise, and just because you choose a compromise the factory didn’t does not make it unsafe.

 

[Pianewman]

I agree with the above 2 posts. You've explained even further why load ratings exist, and why it's important to "read the manual" first and then follow with appropriate research. This thread has benefitted from both sides of the discussion, and that's why we're all here.

Indeed, YMMV. Anyone interested in going against what OEM recommends now has more info to possibly justify their decision. My intention with my posts was simply to alert others as to why OEM specs exist, for the "luddites and ultra-cautious" amongst us. OEM specs should be respected unless you fully understand why/how you're choosing to go against them.

dafish: I'm interested in your comment that "XL simply means the tire allows higher tire pressures," How does the manufacturer engineer a tire that "allows higher tire pressures?" Doesn't that mean that the tire carcass is beefier/more reinforced/stronger than a lower load rated tire? Won't this mean a firmer sidewall, stiffer ride, etc?

 

[nate704]

No matter what tire you install (regardless of the load rating), you will not have blow out. Just enjoy driving instead of focusing/wasting on something meaningless.
Please show me one post/picture of Tesla with blowout tires due to the lower load rated tires, and then I will go away.

 

[Pianewman]

This thread has been very informative and I believe benefits anyone who reads it. Differences of perspective are important, and polite discourse allowed all participants to voice factual information.

As with any well-researched discussion, it may appear "meaningless" to those that have done the research and have made their own decisions.

To the unenlightened, this thread was far from meaningless.

 

[dafish]

Glad I could help guys.

Painew:

I don't have facts on the following, so let's be clear what I say next is opinion and based only on my experience (in terms of science a pretty small sample size).

My experience has been that the largest issue at higher air pressures isn't the sidewall at all, but the tread surface. A tire designed to lay "flat" on the ground at 35psi will tend to show a bowed shape and treadwear pattern at 42 PSI, and vice versa. I assume, but DO NOT KNOW, that's the biggest issue.

As to ride comfort, I can speak with a bit more certainty: A sidewall, if allowed to flex, acts like a shock absorber. However, this really works best when the rim width is staggered realative to the natural tire bead width. Meaning that if you can get some natural concave of the sidewall the tire is much more easily able to move and in down and absorb impacts. This motion causes some mild energy loss, and of course heat.

Tesla intentionally uses overly wide rims relative to the bead placement to minimize sidewall shock absorption and maximize resultant range. Terrible decision in my opinion, but this is part of why have the rep of hard ride/great range.

I do agree some tires ride better than others, but in our case rim selection is the bigger culprit, and I don't expect (as in don't have fact) load capability relative to XL vs non XL to matter. In fact, an XL rated tire and a non XL rated tire, both at 35PSI, will have the exact same load rating. The implication being the sidewall must be quite similar.