215/50R18 Tire?

[pdx_m3s]

OP, maybe a better first step would be to lower the car. This has a decent impact on range.

 

[dfwatt]

OP, maybe a better first step would be to lower the car. This has a decent impact on range.

And way safer because it means you don't have to run bicycle tires.

 

[Mash]

And way safer because it means you don't have to run bicycle tires.

I'm not entirely certain how that would impact braking distance. Maybe not at all for a single stop from highway legal speed.

For braking the main issue with narrower tires is faster overheat on powerful cars. Once tire goes out of ideal temperature range, it's friction coefficient drops significantly.

50 tall street tire is also not very controllable in turns, but plenty of cars have it in stock and most people don't seem to mind it.

Moose test speed also gets worse, but most people fail it in real life due to absence of skill and unpreparedness.

 

[dfwatt]

I'm not entirely certain how that would impact braking distance. Maybe not at all for a single stop from highway legal speed.

For braking the main issue with narrower tires is faster overheat on powerful cars. Once tire goes out of ideal temperature range, it's friction coefficient drops significantly.

50 tall street tire is also not very controllable in turns, but plenty of cars have it in stock and most people don't seem to mind it.

Moose test speed also gets worse, but most people fail it in real life due to absence of skill and unpreparedness.

If you look at the latest tyre reviews testing it shows the predicted difference in dry braking between wider versus narrower. It's fairly modest with using ultra high performance summer Tires however. There's probably a bigger difference in terms of Tire compounding and tire type, with Pilot Sport 4S tending to be excellent in dry braking and the Op's preferred 215/50 probably not available in anything but a touring compound and therefore likely to be significantly poorer.

 

[MacO512]

Found two 215/50R18 tires at Walmart that are XL rated! First is 460 TW second is 400 TW. That size tire needs a rim 5.5-8" so I'll need to find a new rim; only 18's I have are 8.5". Gosh wonder if a 7" wide rim would be best... probably would need a very low offset so its not sunk way into the wheel well. Probably crazy hard to find something that size but still strong enough for a model 3. Would be fun to grab a set of these and see how low I can actually get my Wh/mi.

Maxtrek Sierra S6 215/50R18 96V XL AS A/S All Season
Walmart link

Accelera Phi-R 215/50ZR18 215/50R18 97W XL A/S High Performance Tire
Walmart link

 

[MacO512]

Well discount tires has five rims that are 18x7.5 and four of those meet M3 weight rating. Cheapest is $186 with a 42 offset. There is one thats $189 with 45 offset. I guess I could actually go through with this nuts idea.

discount tire wheel

 

[dfwatt]

Its a decent argument you make, and something I should consider. However I believe if the tire load rating still met the vehicle weight requirements I'd be fine.

If there is a legit safety risk I wouldn't want to drive it. However there are plenty of vehicles on 215 tires; and I would suspect some could handle the weight. Yes the M3 is heavier than many tiny ICE sedans, but its not a 9000lb hummer.

Talk to your insurance company. I don't think you have any idea what you're talking about. When you say if it might not be safe, the load rating on the tire is not going to be adequate, and you're talking about going from 120 ft to stop from 60 mph to 160-180 ft. Are you that seriously obsessed with range and efficiency that you're willing to risk your own life or somebody else's? Please get a major reality check on this issue. Also if you get into a serious accident and someone checks your internet profile and sees that you've been obsessing about this issue through 30 posts and ignoring advice, your chances of a punitive judgment go up quite a bit. I think you should talk to somebody about this. You're obsessed with range to the exclusion of safety and everything else. Please consider that you are taking serious risks with your life and other people's lives in the event that you would ever have to make a panic stop. How much money do you think you're actually going to save by creating an unsafe vehicle? 25 cents a day? $1 a day even? If you drive 100 miles a day and saved 20-25 watt hours per mile which is the max that you could realize from this misinformed approach, that would mean you would save 2 KW hours which is at current supercharging rates = 50 cents. So to save a dollar a day you would need to drive 200 miles every day. Like I said this is seriously misinformed, and at the very least you should talk to your insurance company about this modification.

In case you think I'm just blowing smoke I do forensic consultation for a living. This is the kind of stuff that we would love to find on the other side of any kind of adversarial process. Someone who does not understand what they're doing who has ignored advice and to then gets into a serious mess. You would not stand a chance in court of not having a more punitive judgment if someone finds out that you have rendered your car unsafe, and that even might include situations in which the modification is not to blame.

 

[pdx_m3s]

This is a dumb idea. You’re going to spend more money/time and take on more risk than you’ll ever save on efficiency by doing this.

 

[dfwatt]

Yes a M3 on 215 would likely need more feet to stop. Would it stop much quicker than an F250? I sure would think so, and plenty of people drive those big trucks around. Yes a M3 driver would have to leave a lot more distance with 215 efficient tires than a M3P on sticky performance tires.

If you really want to be as safe as possible its probably best to never drive at all. I'm fine with some tiny one in a million risk. Now if 215 tires would take double the distance to stop as an F250 there is a major problem and no I wouldn't use such a vehicle.

Increasing your Panic stop Difference by 25-30% is not creating a one in a million risk. You are also deteriorating your emergency handling significantly. Especially if you're used to decent Sports sedan emergency braking and handling capabilities. You're driving a performance model 3 and you're saying well gee maybe it's stopping distance won't be any worse than a big F250 truck. That's not much of an endorsement. You've ignored a lot of advice in this form suggesting that this is not wise. As I've said you are exposed.

 

[MacO512]

Talk to your insurance company. I don't think you have any idea what you're talking about. When you say if it might not be safe, the load rating on the tire is not going to be adequate, and you're talking about going from 120 ft to stop from 60 mph to 160-180 ft. Are you that seriously obsessed with range and efficiency that you're willing to risk your own life or somebody else's? Please get a major reality check on this issue. Also if you get into a serious accident and someone checks your internet profile and sees that you've been obsessing about this issue through 30 posts and ignoring advice, your chances of a punitive judgment go up quite a bit. I think you should talk to somebody about this. You're obsessed with range to the exclusion of safety and everything else. Please consider that you are taking serious risks with your life and other people's lives in the event that you would ever have to make a panic stop. How much money do you think you're actually going to save by creating an unsafe vehicle? 25 cents a day? $1 a day even? If you drive 100 miles a day and saved 20-25 watt hours per mile which is the max that you could realize from this misinformed approach, that would mean you would save 2 KW hours which is at current supercharging rates = 50 cents. So to save a dollar a day you would need to drive 200 miles every day. Like I said this is seriously misinformed, and at the very least you should talk to your insurance company about this modification.

In case you think I'm just blowing smoke I do forensic consultation for a living. This is the kind of stuff that we would love to find on the other side of any kind of adversarial process. Someone who does not understand what they're doing who has ignored advice and to then gets into a serious mess. You would not stand a chance in court of not having a more punitive judgment if someone finds out that you have rendered your car unsafe, and that even might include situations in which the modification is not to blame.

Post you replied to is 5 months old.

Could literally make all these same arguments your stating to someone who puts 275/35r19 tires on their vehicles. People do that all the time.

 

[MacO512]

This is a dumb idea. You’re going to spend more money/time and take on more risk than you’ll ever save on efficiency by doing this.

Agreed its a total waste of time and money. I think it would be very interesting to test out the efficiency numbers.

 

[dfwatt]

Post you replied to is 5 months old.

Could literally make all these same arguments your stating to someone who puts 275/35r19 tires on their vehicles. People do that all the time.

Nope. You really don't understand the legal issues here. Augmenting traction is never going to get you to additional liability. Putting on a tire that is way outside the load rating for your vehicle in an obsessive search for range exposes you in court to a charge that you are recklessly endangering other people based on an obsession with saving money.

 

[MacO512]

Increasing your Panic stop Difference by 25-30% is not creating a one in a million risk. You are also deteriorating your emergency handling significantly. Especially if you're used to decent Sports sedan emergency braking and handling capabilities. You're driving a performance model 3 and you're saying well gee maybe it's stopping distance won't be any worse than a big F250 truck. That's not much of an endorsement. You've ignored a lot of advice in this form suggesting that this is not wise. As I've said you are exposed.

Did you measure the vehicle stopping distance with 215 tires? Not sure where you got a 25-30% factor - seems like you pulled that out of your butt.

Maybe it takes 90% longer or maybe it takes less than 10%. I really don't know - I'd be interested to test this to see the difference.

Your throwing around statements as facts and truths when you have no data to back it up. Then using that to pass judgement on me for something I haven't done where you have no ideas what controls, safety measures, inspection, precautions I may or may not have in place if I ever proceeded with those actions.

I've driven a Suburban around many tens of thousands of miles. Yeah I drive it slower with much more space. If I'm in my model 3 performance I have driven it very aggressively when in a rush or an empty area, I'd never drive the Suburban in the same manner. I've owned about a hundred cars and owned an auto business.

I'd be pretty damn confident to test a model 3 on 215 tires/wheels that had proper weight ratings for the vehicle - on an empty stretch of roads in good weather. Am I going to load up with kids in car seats in heavy traffic? No.

 

[MacO512]

Nope. Dead wrong. Augmenting traction is never going to get you to additional liability. Putting on a tire that is way outside the load rating for your vehicle in an obsessive search for range exposes you in court to a charge that you are recklessly endangering other people based on an obsession with saving money.

The two tire's I linked to meet the Model 3 load rating.

 

[MacO512]

Nope. You really don't understand the legal issues here. Augmenting traction is never going to get you to additional liability. Putting on a tire that is way outside the load rating for your vehicle in an obsessive search for range exposes you in court to a charge that you are recklessly endangering other people based on an obsession with saving money.

I don't think buying a 4th set of wheels and tires is about saving money. It would be a test of efficiency.

Basically a test of the M3P performance in terms of going efficient.

 

[dfwatt]

I don't think buying a 4th set of wheels and tires is about saving money. It would be a test of efficiency.

Basically a test of the M3P performance in terms of going efficient.

If you were to do this on a test track under controlled conditions and not endanger other people with a car that has altered handling and braking that would be one thing. If you take this vehicle out on the public roads and you get involved in an accident, and someone on the other side in other words the other side of an adversarial process notices that you have bicycle tires on your car, you are exposed at that point. You really don't seem to understand this single basic issue. You are assuming additional liability for no substantive benefit. Like I said if you believe you have no additional liability, please consult with your insurance company and get them to sign off on this modification. How much would you like to wager that they won't!

 

[MacO512]

If you were to do this on a test track under controlled conditions and not endanger other people with a car that has altered handling and braking that would be one thing. If you take this vehicle out on the public roads and you get involved in an accident, and someone on the other side in other words the other side of an adversarial process notices that you have bicycle tires on your car, you are exposed at that point. You really don't seem to understand this single basic issue. You are assuming additional liability for no substantive benefit. Like I said if you believe you have no additional liability, please consult with your insurance company and get them to sign off on this modification. How much would you like to wager that they won't!

I see you have a lowered vehicle in your picture with what appears are non stock tire size. Did your insurance company sign off on that size tires and that lowered profile that is clearly outside manufactures specifications? Let me know how that request goes.

Your assuming a lot of things from my post and arguing against them. I never stated those strawman arguments. Congrats on your self anointed deep understanding of legal liability, tort law, as well as your career consulting.

 

[MacO512]

Your gut is right; this is an internet myth.

You could be high on every drug imaginable and drive your car at 100mph into a school, and your insurance will cover up to your contract. Yes, your insurance company will at best deny future coverage and at worst sue you for additional damages, but it is a complete myth that insurance companies will just arbitrarily deny your contracted payout based on any non-stock alteration.

What is a bit more plausible is getting sued in civil court for negligence or even wreckless endangerment after the fact. In most cases, as long as you check basic numbers (like the tires load rating), it will likely just be a waste of money for everyone. If you have 245s instead of 235s and hydroplane into oncoming traffic, it would be REALLY) hard to prove that your 245s were the culprit or even a notable contribution. What is more likely is that you’d be cited for driving faster than the conditions allowed.

I found one extreme case where a guy caused an accident that killed a van full of people on the highway. His truck was lifted 12”, he was towing above his truck’s limits, and driving 15mph over the speed limit at the time. Insurance wasn’t an issue, but I believe the victims’ family took everything but his skin in civil court.

This is an example of a good understanding of legal liability.

 

[dfwatt]

I see you have a lowered vehicle in your picture with what appears are non stock tire size. Did your insurance company sign off on that size tires and that lowered profile that is clearly outside manufactures specifications? Let me know how that request goes.

Your assuming a lot of things from my post and arguing against them. I never stated those strawman arguments. Congrats on your self anointed deep understanding of legal liability, tort law, as well as your career consulting.

I'm trying to give you some friendly advice. What you're doing is not safe, although I have to confess I'm glad to hear that you do not plan on loading the car up and that you will be driving more conservatively with this undertired car- that's good. You appear to want to turn all this into something personal - it's not, so in that context just please go away (I have you on ignore).

 

[MacO512]

I'm trying to give you some friendly advice. What you're doing is not safe. You want to turn it into something personal please go away I have you on ignore.

Making definitive statements as you have done in tons of post and even here with "you're doing is not safe" is not friendly constructive feedback. If you wanted to just say hey "I think this is a bad idea and it may be very unsafe" that would be fine. But that was not the tone of your replies. I replied with your personal career comment since you brought up your career first as a basis for your legal expertise. Yeah I might be a bit of a smart ass in my posts some times, but only when I first receive that tone directed to me.

Have a nice day.