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Michelin Primacy MXM 4 235/45 R18 OEM tire life
- Thread starter Bobbo8
- Start date
Knightshade
Well-Known Member
10% more power consumption for ~20% shorter braking distance seems like a pretty solid trade.
Occhis
Member
It does not appear that these tires have an XL rating, a spec that is called for on M3s. Car weighs almost 5,000 lbs. and should wear an XL tire.
XL just means that the max load rating is specified at 42psi instead of 36psi. The number (e.g. 98) is what designates the load rating. https://www.discounttire.com/learn/load-range-load-index
Occhis
Member
Knightshade
Well-Known Member
Why is losing 10% efficiency worth 20% shorter stopping distance?
Because I always have way more than 10% battery left when I plug in at home at night (and for the rare road trip where it'd matter it'd likely mean nothing but an extra 5 minutes at a supercharger).... in exchange it significantly increases the chances I don't hit someone or something if idiot in front of me prompts an emergency stop.
Hadn't seen data showing a 20% decrease in braking distance. That's pretty significant, particularly at higher speeds (40 feet or so). Can you post a link to the data showing this? Tested on a Model 3, or some other kind of car.
Keith
Knightshade
Well-Known Member
Do a search- several folks have switched from the crappy MXM4s to performance Michelins and gotten those results (the PS4s mostly, but tirerack testing shows the PS4s and AS/3s very very very close on braking tests)
Or you can just look at the magazine tests of braking distance on a P3D+ versus a non-P that came with the 18s (which come with the MXM4 tire)- where you see results in the ~130 foot range on MXM4s and ~100 feet on the PS4s...
130, minus 20%, is 104 feet.
And those are differences from 60 mph, I'd expect even larger differences at 70-80 where most people actually drive on highways.
(not strictly on topic for this thread- but those running the 19s on somewhat stickier-than-MXM4 OEM Conti tires can still expect an improvement with even stickier tires like A/S3s or PS4s, but it'll be more on the order of ~10%, likewise the mileage hit wouldn't be as bad since that tire is already stickier than the MXM4s are)
I believe this is the post @Knightshade is referring to:
POLL: What will my 60-0 stopping distance be with Pilot Sport 4S 265/40R18s be?
It’s good information but I’d like to see more results before making a decision on which tire to buy. The Performance model has different brakes so I’m not sure how useful it is to compare results of Performance to non-Performance. And there was at least one software update to improve braking performance in 2018. It’s possible that subsequent updates further improved performance, although I don’t recall specifically hearing about that.
I can sort of buy into the trade off of 20% better braking in return for 10% less range as long as I know I’m really going to get that. But the 10% range is something I’m going to live with every day. The improved braking performance is something I may never need. But yes, the one time I really need it is all that matters.
POLL: What will my 60-0 stopping distance be with Pilot Sport 4S 265/40R18s be?
It’s good information but I’d like to see more results before making a decision on which tire to buy. The Performance model has different brakes so I’m not sure how useful it is to compare results of Performance to non-Performance. And there was at least one software update to improve braking performance in 2018. It’s possible that subsequent updates further improved performance, although I don’t recall specifically hearing about that.
I can sort of buy into the trade off of 20% better braking in return for 10% less range as long as I know I’m really going to get that. But the 10% range is something I’m going to live with every day. The improved braking performance is something I may never need. But yes, the one time I really need it is all that matters.
Knightshade
Well-Known Member
Brakes have nothing to do with typical stopping distance tests on modern cars. The only reliable way to reduce stopping distance is better tires.
This has been covered pretty exhaustively elsewhere...but if you're still unsure of the physics of why this is so, read this:
GRM Pulp Friction
Nope.
It was an update to fix a bug that made stopping progressively worse on repeated stops.
CR had gotten much longer distances with the bug in place after repeated braking tests- this fixed that bug and got stopping distance back to the original 133 foot spec.
As noted swapping to PS4s tires gets you down to around 100 feet instead.
Unless you routinely run the battery down really low not sure why it'd matter much every day? Slightly higher overall electric cost I guess, but still likely a lot cheaper than whatever you spent on gas- and as you note the upside the time you NEED the braking is almost infinite.
That is significant....guess I really never appreciated the large differences (yes, 20% is large) that tires give in braking performance. 5-10% difference I would have expected, but not 20%. Wow.
I'm running the AS/3 tires on my Maxima, and really like them. I'm highly considering them for my Model 3 when my MXM4 tires wear out. That just went up based on this revelation....
Keith
You can get this one if you like, I didn't see it before.
https://www.americastire.com/buy-tires/nankang-tire-ns-25-a-s-uhp/p/41069
Again I'm using as spare, as the mxm4 run their life, don't want to buy 1 new one, then have to buy 4 new after.
I recently put these tires on my M3P Stealth (18" tires). I've also had them on a Model S. I've got 2000 miles on them and I'd say my efficiency hit is closer to 15%. Part of this is the cooler weather, but overall I'm seeing ~40 W/mile difference from the OEM tires. Tires are inflated to 42 psi.
So I'm at 12,100 miles on my OEM MXM4 tires, and at about 6.5/32" of tread remaining. So, at this rate, about halfway worn.
What I think I'm going to do is run them through the winter, and then in April-ish, switch out for brand new 19" wheels I have tucked away. (Picked them up from one of my fellow Model 3 owners locally.). The question is, what to shoe the 19's with? I'm looking at the Bridgestone Turanza QuietTracks as summer tires. I can then re-shoe the 18s with some winter tires next fall.
I'll leave some meat on the MXM4's behind, but I'm sure someone locally would take them off my hands with 6/32" of tread for $40/ea. Would make great spares.
Anyone have thoughts on the Bridgestones?
What I think I'm going to do is run them through the winter, and then in April-ish, switch out for brand new 19" wheels I have tucked away. (Picked them up from one of my fellow Model 3 owners locally.). The question is, what to shoe the 19's with? I'm looking at the Bridgestone Turanza QuietTracks as summer tires. I can then re-shoe the 18s with some winter tires next fall.
I'll leave some meat on the MXM4's behind, but I'm sure someone locally would take them off my hands with 6/32" of tread for $40/ea. Would make great spares.
Anyone have thoughts on the Bridgestones?
TomB985
Member
I remember lurking through this thread a few months ago wondering why such a disparity in tread life with the OEM Michelin's. Still doesn't make sense to me.
I keep track of my tread depth at each time I rotate, and mine have been extremely stable up to 13,000 miles when I swapped
them for my winter set. I'm careful not to apply full throttle below 50 mph, but I don't exactly drive this thing gently. I expect to see 30,000 miles at least out of the OEM set, so why do some go through them so much faster?
I keep track of my tread depth at each time I rotate, and mine have been extremely stable up to 13,000 miles when I swapped
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