Before you buy or lease an i3 Be Aware of the Tire Problem

[czarmar]

While contact patch is dependent on weight of the car over the tire (~total car weight/4)/ air pressure in PSI:
3000/4=750/37.5psi~=20 sq inches contact patch regardless of tire shape, I would still say that the tread wear is going to be associated with the total tread area/contact patch ratio which on an i3 tire is smaller than a conventional tire.

 

[alohart]

While contact patch is dependent on weight of the car over the tire (~total car weight/4)/ air pressure in PSI:
3000/4=750/37.5psi~=20 sq inches contact patch regardless of tire shape, I would still say that the tread wear is going to be associated with the total tread area/contact patch ratio which on an i3 tire is smaller than a conventional tire.

The i3's larger tire diameter means that at a particular forward velocity, the tires rotate at a lower angular velocity than conventional tires with smaller diameters. So a particular point on the tread of an i3's tire contacts the road less often at the same forward velocity compared with smaller diameter tires. A tire tread doesn't wear when it's not in contact with the road, so an i3's tire's wear rate should be lower.

 

[SesameCrunch]

I had two Chevy Spark EVs before my i3 (recently purchased). The Spark tires only lasted 14K and 16K respectively. In both cars, I replaced the low rolling resistance Ecopias with standard Kumho tires and they've gone >30K miles each time. Same car, same driver, same routes. By the way, I estimate that my range efficiency went down between 10-12% with the non-LRR tires. Wasn't a big deal to me, even with the all BEV Spark. With my i3 REX, the 10% less range is even less of an issue.

I think it's unfair to blame BMW for this, except to conclude their design criteria optimized range over tire wear. Living with trade-offs is part of being an EV pioneer. In the case of the Spark, I had a choice of tires, but not yet for the BMW. I'm hoping that as more EVs come onto the market with larger wheels for aero benefits, we'll see more tire choices too.

 

[bwilson4web]

A nice description of the tire technology: http://www.bridgestone.com/technology_innovation/ologic/

Bob Wilson

 

[bwilson4web]

Thanks!

You're not crazy:

. . .

Is that an overreaction? Perhaps, but the Bridgestone Ecopia EP600 tires, the tires BMW specs for my 2014 BMW i3 ReX are UTQG 440 AA rated - which means that they are the highest traction rated tires available in their class (AA), and have a wear life of 440 - which means that they should last 4.4 times as long as the standard tire on the UTQG test. That test requires a driving length life of 6,700 miles. In other words, Bridgestone expects these tires to last for 29,480 miles (4.4 times the standard 6,700 mile cycle). Despite these tests and ratings my tires are completely done with measured inner tread depth of 1-3 MM for each tire at 13,690 miles.

The tires are all worn on the inner most grove of the tires - the inboard grove on each side. They have been properly inflated over my ownership and there have been no accidents or any other issues with the car. The tire pressure monitor has never come on, and I check pressures regularly. It seems to be a design related issue, not a user error.

. . .

So this morning, 63F, I ran at 60-75 mph on an extended commute and used an IR thermometer to measure the driver-side, rear wheel tread temperatures going from outside to inside:

• 
  87.3 1st
  88.0
  85.9
  86.1
  86.4
  86.6 2nd
  86.1
  86.4
  88.6
  87.2
  87.6
  86.4 3d
  86.2
  86.3
  86.1
  85.8
  86.8
  88.4 4th
  88.1
  88.4
  88.1
  88.4
  88.6
  88.9
  88.8

The temperature profile shows the inner tread it doing more work than the outer tread. This is the signature of negative camber that would wear out the inner tread of the tires first. So I checked the training charts, pp. 24:

• IO1 Chassis and Suspension
  2. Axles
  . . .
  Rear axle adjustment values . . . I01 Standard chassis and suspension
  Camber ... -1 degrees 40 minutes

Now this bothers me because the outer tread has the deeper groove. The inner tread starts with the shallower groove. This leads to two hypothesis:

• The camber is wrong and should read +1 degree 40 minutes.
• The tires have been mounted wrong side out.

Regardless, it is worth sharing this information with NHTSA, Bridgestone, and BMW. I'm not terribly concerned about how this came about. But I am interested in getting serious people to start talking with each other.

FYI, negative camber (tops closer together) in theory makes a car corner better as the lateral force would tend to move the tires into a more vertical orientation. But if you're going to do that, the thickest tread should be on the inside to wear the tires evenly and get a firm grip. Our tires are the reverse and that would lead to early wear of the thinnest part.

It is not enough to have the tires mounted so the outside is now the inside. The grooves and tread pattern are critical to getting water out of the way so the tires won't hydroplane. If we become our own auto/tire engineers, we would need to quantify what happens in rain as well as on a track.

Bob Wilson

 

[I33t]

Interesting data there Bob!

My guess is that BMW is somewhat more interested in road handling than tyre life.

When I had my first car, I spent a lot of time on the local racetracks. Without changing the tyres or the power in the car, I altered the camber front and rear (full independent suspension on that car). The original front was 1 degree positive and I took it to 2 degrees negative with some extra caster. Took the rear to 1 degree negative (the rear camber on that car alters when the wheel moves vertically). Body roll was well controlled with anti-roll bars. The result was that on the racetrack, the car with the same driver (me!) and the same track conditions, was recording much faster lap times. My non-scientific view is that when cornering, the wheel becomes close to zero camber and the outside tyre with the most mass applied to it has the maximum available grip. The tyres were Bridgestone RD102.

On the daily driving, the car was excellent at cornering. The downside was the inner tyre wear.

 

[bwilson4web]

Based on this, I've scheduled an appointment to have the rear wheel camber adjusted as close to positive as their specs allow ... with the existing, worn tires. I'll then take the car out for another set of temperature profile runs. If it comes back flat, the problem is solved.

I'll run these rears until the tread groove depth is too low and replace with a new pair. Meanwhile, the front tires remain a problem.

On our Prius, there is a camber adjustment bolt we can order and have installed. I used this to even out the front tire wear.

We'll let you' all know how it comes out.

Bob Wilson

. . .
So this morning, 63F, I ran at 60-75 mph on an extended commute and used an IR thermometer to measure the driver-side, rear wheel tread temperatures going from outside to inside:

• 
  87.3 1st
  88.0
  85.9
  86.1
  86.4
  86.6 2nd
  86.1
  86.4
  88.6
  87.2
  87.6
  86.4 3d
  86.2
  86.3
  86.1
  85.8
  86.8
  88.4 4th
  88.1
  88.4
  88.1
  88.4
  88.6
  88.9
  88.8

The temperature profile shows the inner tread it doing more work than the outer tread. This is the signature of negative camber that would wear out the inner tread of the tires first. So I checked the training charts, pp. 24:

• IO1 Chassis and Suspension
  2. Axles
  . . .
  Rear axle adjustment values . . . I01 Standard chassis and suspension
  Camber ... -1 degrees 40 minutes

Now this bothers me because the outer tread has the deeper groove. The inner tread starts with the shallower groove. This leads to two hypothesis:

• The camber is wrong and should read +1 degree 40 minutes.
• The tires have been mounted wrong side out.

Regardless, it is worth sharing this information with NHTSA, Bridgestone, and BMW. I'm not terribly concerned about how this came about. But I am interested in getting serious people to start talking with each other.

FYI, negative camber (tops closer together) in theory makes a car corner better as the lateral force would tend to move the tires into a more vertical orientation. But if you're going to do that, the thickest tread should be on the inside to wear the tires evenly and get a firm grip. Our tires are the reverse and that would lead to early wear of the thinnest part.

It is not enough to have the tires mounted so the outside is now the inside. The grooves and tread pattern are critical to getting water out of the way so the tires won't hydroplane. If we become our own auto/tire engineers, we would need to quantify what happens in rain as well as on a track.

 

[Mito]

Wonder why the tires are wearing out so quickly then?

The i3's low rolling resistance tires contribute to faster wear because they have shallower tread depth than most tires when new, and their design emphasizes low rolling resistance over long tire wear.

.

I think this is on the right track but only partially true. The Bridgestone tyres have a design whereby the outer tread bands are joined by bracing bars to prevent block squirm at the edges which would lead to inaccurate steering and wear when the blocks shuffle relative to one another and the road surface. Tread blocks with bracing bars are often erroneously mistaken for the actual root of the tread which is what I think has happened when the vehicle was originally examined at the inspection. It's obvious to see and many people have mentioned the unequal tread depth over the tyre and this is the reason for it. From a point of view of UK law a tyre worn to the bracing bar is not deemed to be an infringement of the law because the bracing bar is not a "major feature" of the tyre but many people think the tyre is worn and will sell tyres based on this reason. When considering the performance of the tyre you must consider that the tyres ability to evacuate water through the area that is now worn away and so resistance to aquaplaning is significantly reduced. I am not sure how this is interpreted legally in the USA.

 

[ZeroEmissionz]

sucks to hear what happened hey

 

[i3marc]

My front tires lasted 53k miles so far.

The back pair has been replaced at 27k at 120 each and still seems to have some life in them for maybe 10k more.

 

[brastic]

If I can get 10-15k out of these tires, I will be happy. My M3 would eat $1,300 in tires every 5-6k miles. That got old.

 

[Mason123]

Nếu lốp xe bị mòn bạn có thể có được lốp thay thế bất cứ nơi nào bạn muốn trước khi kiểm tra cuối cùng. Miễn là lốp xe được BMW chấp thuận, bạn sẽ không có vấn đề.

 

[Milam]

Just leased a 2017 i3 with Range Extender.

Any concerns about the alignment, etc.

Love the car.

Kick to drive.
My second electric car.

Tom

Any suggestions on how to improve the ownership experience?

 

[revenson]

I'm 99% convinced of buying a used i3, and have noticed that tires seem to be the #1 "problem". My solution, retrofit a more "standard car" set of wheels and tires.

After a thorough investigation, wheels and tires for a Mercedes GLA will fit with ~30mm spacers. It uses 215/55-18 tires which are virtually identical in diameter and offer a huge selection of tire options, many of which will undoubtedly offer better treadwear and durability to potholes. The GLA happens to have the same wheel bolt pattern and centerbore. The only rub would be from the backspacing, which can be fixed with spacers.

Will it look like a clown car, or a redneck pickup truck with tires protruding past the wheel wells? Maybe. But the i3 is already eye-catching. Let's push the envelope!

Another option is to only fit these on the rear and keep the stock wheel and tires on the front. Sticking my hands around the rear tires at a dealership leads me to believe there is quite a bit more room than the front, and maybe only a 15mm spacer in the rear will allow suspension clearance. This would cause the tire to only slightly protrude, as it's about 10mm within the lip (just a visual measurement, don't hold me to it).

Will economy suffer? Yes, probably 5-10%. But that's a price I'm willing to pay for durability. Handling might improve too.

Has anyone considered or tried going down this path?

 

[vinc]

No one should be measuring tread depth on the inner tread groove as that isn't a full height groove. A new EP600 should measure ~10/32" on the center groove and 6/32" on the inner groove.

I posted some pics of the tread depth of brand new EP600 tires on another thread if anyone wants to reference this when getting their tires measured. I measured between 6/32" & 7/32" on the inner tread though.

http://www.mybmwi3.com/forum/viewtopic.php?f=2&t=4360

I am returning my 2015 REX and after the inspection the dealer flagged one front tire and one back tire for being below 4/32. And this is exactly the reason, they measure the inner tread.

Sucks, but no way to argue it. They are instructed to measure the shallower part of the tire. :x

 

[vinc]

Quick update. I went to return the car (12K) and got to speak to a different associate this time. Props to BMW, they waived the fee without me even asking. He acknowledged that charging for new tires with that mileage is unreasonable.

 

[714wasfast]

I had a blow out on the freeway with my i3 - the 3rd set of tires for this vehicle with 26,000 miles 2018 model. I have a subaru that has over 100,000 miles and never had this problem. I have one more year on the lease. This is my third tow, I have had 3 blowouts on this vehicle on the freeway which is dangerous, tires have less than 10,000 miles. Needless to say I had to get once again 2 new rear tires, spent 3 hours at the tire place. The tow truck driver couldn't let me ride with him, I was out of my area by 30 miles, and had to find travel 6 miles to the tire place. Thanks BMW.

I called BMW and they didn't care. Sent me a total irrelevant unreply email (said I would have a case manager). BMW is jerking me around. Their service has been horrible and worst case scenario for me is I finish out one more year on the lease. As much as I like BMW, I previously had a BMW motorcycle, and I love driving cars, with the latest customer service I will never do business with them again.

I called the National Safety Highway Traffic Admin and opened up a case. I was told by the lady that took my case that i was her second call that day complaining on these tires. I am putting the contact info below. She did state that several complaints were coming in. It takes several complaints for them to take action, please take a few minutes if you have had this problem and notify these people. You will need the tire size for your car, the make. Mine was bridgestone, and I had the size. BTW BMW backs this as they put this together with the car.

https://one.nhtsa.gov/About-NHTSA/NHTSA-Contact-Information
Phone number 888-327-4236

 

[Anonymous]

Which tires. The 20 inch sport tire, or the 19 inch all-season tire?

 

[Mastedon]

We bought our i3 used from BMW dealer with the "certified program (extended) 2 year warranty. The car came with new tires. We immediately noticed tire noise and irregular tire wear from bad alignment. They claimed that was not covered under warranty as it was a wear item. Now were up for new tires based on the significant wear on them. With only one tire manufacturer (Bridgestone) and ONE design, I'm not inclined to replace these narrow bicycle tires with a 440 mileage rating. When I buy tires I always try to go for a high rating (600+) for longevity, even though it means less friction due to a harder tread material.. Because this car was designed with a narrow tread, apparently to reduce the frictional component of a wider footprint, we pay the price with significantly faster wear.

So I'm looking to see if anyone has changed out their rims to allow for a wider rib and tread, which would allow for using a more popular tire size which would allow for more brand choices and a lower price tag.

 

[Anonymous]

So I'm looking to see if anyone has changed out their rims to allow for a wider rib and tread, which would allow for using a more popular tire size which would allow for more brand choices and a lower price tag.

I look at it this way. The i3 was designed/engineered from the ground up to be the one-of-a-kind EV it is, including tires designed and engineered for just this car's weight, suspension, and performance parameters - bespoke tire engineering/design the likes of which is usually reserved for cars like Ferraris, Maseratis. Lamborghinis, and Bentleys. The sports/performance tires wear faster than the all seasons (as they do for any car), which is why I switched to the 19 inch all seasons on mine, as well as getting away from the harsher ride on the 20 inch tires. Some have put the wider rear tires on all four corners to allow for tire rotating to even out tread wear - which then increases the turning radius and decreases steering nimbleness (steering nimbleness that enabled my wife to avoid a head-on collision with an idiot in a truck traveling at high speed, passing cars on a two-lane blind corner). For me, focusing on tire longevity or tire price-point, and ignoring the engineering/design/handling characteristics of the bespoke OEM i3 tires doesn't make sense - handling and performance is a much more important consideration for me. And as far as price goes, my bespoke OEM i3 tires cost half of what bespoke OEM tires cost for a Lambo, and a third of what bespoke OEM tires cost for a Bentley, so I consider them a bargain

On top of that, my i3 running cost savings alone, compared to my old ICE car would pay for a new set of OEM tires for my i3 every six months

https://www.bmwblog.com/2015/04/24/bmw-i3s-tires-more-important-than-youd-think/