tires prone to puncture?

I wouldn't hold up Tesla as having done tires right.
http://insideevs.com/examining-tesla-model-s-excessive-rear-tire-wear-via-thermal-camera-video/

WoodlandHills said:

There is already a ride and handling impact from the rock-like rim protectors currently installed.

Perhaps the engineers over at Tesla, Audi, MB, Chevy, Toyota, etc should also read these posts as they seem to have completely missed the boat on Finite Element design. Why, not a single one of them are using these wonderful skinny rim protectors on their EVs! It is almost as if those other companies decided that the drawbacks are not worth the advantages. Either that or all the good engineers are at BMW and everyone else has a bunch of losers :roll:

Seriously, if these were really such great tires why are they not being used on other hybrid BMWs? All of the spy shots I have seen show normal dia. and profile tires and wheels on their upcoming PHEVs and hybrids.

IMHO, BMW found themselves with an EV that was going to have a lot of difficulty reaching a marketable range and they threw these silly wheels on the car in an attempt to wring every last bit of range from a smallish battery. BMW knew how the public would react to a $50k EV with only 60 to 70 mile real-world range and they did whatever it took to bump their numbers on the various gov't tests, including using unique high pressure large diameter tires.

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Oh really? All those other manufacturers with the Tyres you love beat BMW on their efficiency? I don't think so. The i3 has been out for a while, and there is still no more efficient EV on the market. It's not just the wheels and Tyres, but they are part of the design.

Not putting i3 wheels and Tyres on a completely different vehicle is showing us that the design is specific to the i3.

psquare said:

Man, I wish more of the BMW engineers would read this forum, as these guys clearly know nothing about designing cars down there in Munich.

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Yes, they should've come here first. Think of how much time it would've saved them!

WoodlandHills said:

There is already a ride and handling impact from the rock-like rim protectors currently installed.

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Both of our cars, an i3 BEV and a 2000 Honda Insight, have Bridgestone low rolling resistance (LRR) tires installed. The ride and handling of our i3 are considerably better compared with our Insight, but tires aren't the only factor that affects ride and handling. Unless you were able to compare different tires on your i3, I don't see how you could blame the tires for what you feel are poor ride and handling.

WoodlandHills said:

Perhaps the engineers over at Tesla, Audi, MB, Chevy, Toyota, etc should also read these posts as they seem to have completely missed the boat on Finite Element design. Why, not a single one of them are using these wonderful skinny rim protectors on their EVs! It is almost as if those other companies decided that the drawbacks are not worth the advantages.

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Or that it's not possible to fit such tires on their EV's which, except for Tesla, are all derived from ICE models with standard non-LRR tires. The Model S has similar large diameter 19" and 21" tires but because it's so heavy, its tires must be much wider to support the car's weight.

WoodlandHills said:

Seriously, if these were really such great tires why are they not being used on other hybrid BMWs?

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Maybe because they're all derived from existing ICE models with standard non-LRR that are considerably heavier than the i3.

WoodlandHills said:

IMHO, BMW found themselves with an EV that was going to have a lot of difficulty reaching a marketable range and they threw these silly wheels on the car in an attempt to wring every last bit of range from a smallish battery. BMW knew how the public would react to a $50k EV with only 60 to 70 mile real-world range and they did whatever it took to bump their numbers on the various gov't tests, including using unique high pressure large diameter tires.

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It's no secret that BMW designed the i3 to be as fuel efficient as possible which includes the tire design. The i3 is a clean slate car, so BMW could design it to accommodate tall, narrow tires which have some advantages and disadvantages. Like most engineering decisions, using these tires involve trade-offs. A narrow width reduces aerodynamic drag but results in a smaller contact area and thus poorer traction. A large diameter increases the contact area which offsets the smaller contact area of a narrow tire. Pretty clever!

Narrow tires also impinge on the interior space less which makes the i3 more roomy than if it had wider tires.

But tall tires reduce the wheelbase which makes the ride more choppy while at the same time making a smaller turning circle possible.

Tall tires reduce the distance between the rear edge of the front tire and the front edge of the rear tire resulting in not enough space for normal front-hinged rear doors. Rear-hinged rear doors allow easier rear seat ingress/egress compared with the same width front-hinged door, but rear-hinged doors have other problems that don't exist with front-hinged doors, so this is a trade-off.

The i3 is a radically different car in many respects. I value BMW's design decisions, including the wheel/tire sizes, but BMW's software engineering seems particularly poor.

alohart said:

It's no secret that BMW designed the i3 to be as fuel efficient as possible which includes the tire design. The i3 is a clean slate car, so BMW could design it to accommodate tall, narrow tires which have some advantages and disadvantages. Like most engineering decisions, using these tires involve trade-offs. A narrow width reduces aerodynamic drag but results in a smaller contact area and thus poorer traction. A large diameter increases the contact area which offsets the smaller contact area of a narrow tire. Pretty clever!

Narrow tires also impinge on the interior space less which makes the i3 more roomy than if it had wider tires.

But tall tires reduce the wheelbase which makes the ride more choppy while at the same time making a smaller turning circle possible.

Tall tires reduce the distance between the rear edge of the front tire and the front edge of the rear tire resulting in not enough space for normal front-hinged rear doors. Rear-hinged rear doors allow easier rear seat ingress/egress compared with the same width front-hinged door, but rear-hinged doors have other problems that don't exist with front-hinged doors, so this is a trade-off.

The i3 is a radically different car in many respects. I value BMW's design decisions, including the wheel/tire sizes, but BMW's software engineering seems particularly poor.

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Alohart,

I wish you'd stop making sense with facts and all that.

What's wrong with some generalisations, loose assumptions and a bit of fear for good measure?

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The issue is not "tall"tires, but thin sidewalls. There is no design requirement for a tall narrow tire to also have a thin sidewall. Thick sidewalls and tall rubber not incompatible at all. If Bridgestone wished they could make an 18" tire to fit the i3 with the same circumference as the current 20" AND with the same width. It just would have a taller sidewall, a smoother ride and less risk of a pinch blowout and it would have the same range.

WoodlandHills said:

If Bridgestone wished they could make an 18" tire to fit the i3 with the same circumference as the current 20" AND with the same width. It just would have a taller sidewall, a smoother ride and less risk of a pinch blowout and it would have the same range.

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Low rolling resistance (LRR) and a high aspect ratio (i.e., a sidewall that's tall relative to width) might not be compatible because sidewall flex increases rolling resistance. The sidewalls of higher aspect ratio tires tend to flex more than lower aspect ratio tires. To maintain the same outside diameter, an 18" i3 front tire would need to have an 80% aspect ratio which is quite high for a modern tire. The sidewalls could be made of thicker rubber to reduce flex, but that would increase the tire's weight and thus angular momentum which reduces range (changing a tire's rotational velocity consumes energy). Increasing the inflation pressure could reduce sidewall flex, but that would make the ride rougher as would thicker sidewall material.

So it seems to me that LRR tire design is a very tricky business trying to balance LRR with ride comfort, traction, tire life, etc. BMW wanted a narrow tire for lower wind resistance and a larger diameter to increase the contact patch area. Perhaps a wheel smaller than 19" just would not have allowed Bridgestone to fulfill BMW's design criteria while maintaining a LRR.

LOts of people seem to be second guessing BMW's design decisions. Their decisions were not made in a vacuum, LOTs of engineers worked on the design, and with a clean sheet of paper, they ended up having to design a new way to do lots of things. Everything in design is a compromise...personally, I think they did a good job given the design goal. Now, that goal may not coincide with everyone's needs or desires, but you can't blame BMW for optimizing the one they chose. If it doesn't fit your needs, you should look elsewhere.

There will, eventually, be additions to the I-line, designed for different purposes, that are likely to have similar innovative features. And, as battery tech improves, range will go up and, I fully expect drivetrains similar to that on the i8 will also be offered to allow unlimited trip length using the existing fuel infrastructure. Fuel cells will likely show up at some point, but right now, their refueling capabilities are very restricted - far worse than an EVSE or CCS network, and those are poor. FWIW, making elemental hydrogen takes a fair amount of energy...hydrogen has a really high affinity for binding to other elements to make incompatible molecules...stripping those away takes energy, and compressing it to become dense enough to be useful takes a fair amount, too.

Just had my first puncture, but nothing to do with tyre size/design, inch wide chunk of metal dug into it and popped the tyre, luckily kwik fit had a 20" in stock, but charged an eye watering £230 for a rear, it was a bank holiday and I needed it so took the pain. shit happens

If Peugeot produces a car based on its Fractal concept EV, it would likely have '19” Tall&Narrow wheels' which sound a lot like i3 wheels. So I suspect that we'll be seeing more EV's with wheels and tires similar ours.

alohart said:

If Peugeot produces a car based on its Fractal concept EV, it would likely have '19” Tall&Narrow wheels' which sound a lot like i3 wheels. So I suspect that we'll be seeing more EV's with wheels and tires similar ours.

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If this becomes the norm, municipalities are going to feel the pressure to fix potholes and improve and then actually maintain roads and streets. Right now we are all paying a "tax" in repairs to suspensions and wheels and tires in lieu of one to the Street Repair Department of our local government. I would rather make my contribution to the government than to the tire store and the auto parts supplier, dealer or otherwise. At least good roads stimulate commerce and mobility.........

I agree, a good infrastructure is good for everyone rather than hidden taxes we pay for bad roads, bridges, etc. But, how often do people baulk at higher gas taxes (federal tax hasn't changed in ages, few states have updated theirs and cars today are getting LOTS more mpg than old, and there are a lot more cars on them)? This stuff doesn't come for free, and we as EV drivers aren't paying (yet?!) for the required maintenance to our roads.

Politicians are loath to raise taxes, especially close to an election year, and look at what Congress has been doing about funding the Federal Transportation bill, IMHO, it's criminal, as many projects wont' be started without long-term commitments to funding.

Nothing will change until people become enlightened, and with the state of the education system, I'm not sure that will ever happen. Then, you have too many people that only look out for themselves, verses long-term consequences - live for the moment seems to be the normal way of thinking (Dam the torpedoes, full speed ahead!). It's a sad state, and nothing will happen until enough people complain AND accept the financial consequences, or nothing will be fixed. Things don't happen for free...somehow, they have to be paid for.

I've had an i3 for less than 4 months, with 3200 in-town miles, and have had to replace all 4 tires, each in separate incidents the last being yesterday when we ran over a small rock, which put a hole in the tire that your little finger could enter. Some owners have had no unusual problems, others like me have had extreme problems. That strongly suggests a quality control problem with tire manufacture. I've been driving for 45 years, 24 of them the same route I've taken these past 4 months, and of course have never experienced this level of problem with tires.

sclark1 said:

Hello - within 6 months I have had 2 nail hole punctures and a shredded tire due to hitting a small piece of metal on the highway. Yes, 3 tire incidents all involving 3 different wheels! Wondering if anyone else is having similar tire problems or if it's just my very bad luck...

Thanks!

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I've had an i3 for less than 4 months, with 3200 in-town miles, and have had to replace all 4 tires, each in separate incidents the last being yesterday when we ran over a small rock, which put a hole in the tire that your little finger could enter. Some owners have had no unusual problems, others like me have had extreme problems. That strongly suggests a quality control problem with tire manufacture. I've been driving for 45 years, 24 of them the same route I've taken these past 4 months, and of course have never experienced this level of problem with tires.

I've just added to my frunk contents a tire repair kit that I hope I'll never have to use. But I need to add some pliers to extract the nail, screw, etc., that caused the flat. I've read a recommendation of needle-nose pliers. While they are good at gripping small things, they don't have much purchase on what they grip, so I would think that they might not work well to extract something that's tightly imbedded in tire tread.

For those who have actually used a tire repair kit or have an opinion, what tool would you add to a tire repair kit?

alohart said:

I've just added to my frunk contents a tire repair kit that I hope I'll never have to use. But I need to add some pliers to extract the nail, screw, etc., that caused the flat. I've read a recommendation of needle-nose pliers. While they are good at gripping small things, they don't have much purchase on what they grip, so I would think that they might not work well to extract something that's tightly imbedded in tire tread.

For those who have actually used a tire repair kit or have an opinion, what tool would you add to a tire repair kit?

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At home, I use a pair of side cutters to grip and extract screws, nails, other miscellaneous puncture objects from my tires before plugging. They provide a great way to pry out nasty objects. I've been plugging tires for years. At home, I use Safety Seal products and a new untried motorcycle product for the road.

FWIW, the tire industry says the only correct way to repair a puncture is a plug installed from the inside of the tire. Probably millions have been done with a plug from the outside, but it can lead to failure down the road. Probably easier and faster then the goop in the can with the compressor, but that's not a permanent fix, either.

The only way to tell if there's possibly more damage than you think, is to look at it from the inside. Not something you're likely to do on the road.

I know your correct, but I've had 40 years of positive reinforcement. I know what's safe and when it's time to buy another tire. I just don't take it to the race track.

jadnashuanh said:

FWIW, the tire industry says the only correct way to repair a puncture is a plug installed from the inside of the tire.

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Correct. We have such a repair kit for our off road vehicle. Works really well in those situations, but not so sure on the lighter tyre construction of normal road vehicles. Need to be careful not to damage belts.