BMW i3 Wheels: Efficient & Effective or Skinny & Skidding?

You get a better view of just how tall and thin the tires on the i3 without the body in place.

One of the features on the i3 that have had many BMW loyalists cringe when see them is the tires. They are tall and thin, and look more like you would expect them on a Toyota econo-box, than from the engineers in München.  The standard rubber on the i3 will be custom made for the car, low-rolling resistance 19-inch Bridgestone Ecopia tires, sized 155/70 R19. They are mounted on  featherweight 19" x 5" wheels, weighing only 15lbs. There will also be a 20" wheel option, but BMW hasn't disclosed the exact size of that wheel of the tires that they will mount on them. 

The stock 19" wheels

I suspect many potential i3 buyers will get past the thin, underwhelming look of the tires as long as they perform admirably. After all, they only look bad from the from or rear; when looking at them from the side it's difficult to see how thin they actually are. But what do I mean by perform admirably? That may be different for different people. Low rolling resistance tires typically aren't good for the "ultimate driving experience" the rubber is hard and doesn't usually offer premium grip for cornering. Sticky high performance tires usually deliver bad fuel economy because the rolling resistance is high. I suspect many i3 buyers will be most concerned with efficiency and range in which they would probably favor efficiency slightly over performance. But let's face it they still expect it to perform like a true BMW, and that's something BMW has promised will be the case with the i3. 

What may be the 20" optional wheels

When discussing the tall, narrow tires with Georg Kacher of Car Magazine, Ulrich Kranz of BMW said "It’s not rocket science. All that matters is the size of the contact patch. The 19-inch tires may be skinny, but their tall height generates the same contact patch as a low-section 16-inch MINI tire"  Kacher then went for a ride in a pre-production i3 and wrote this about the handling: "This is extraordinary. The i3’s most awesome dynamic talent is its incredible grip. The made to measure tires are about as narrow as those of a 125cc motorbike, yet they hang on almost as tenaciously as BMW’s latest DTM racer... The car zooms towards the apex, kisses the cobbles and flies out onto the short straight. There is very little lean considering the considerable pace, and I don’t recollect more than a faint trace of front end pitch and no yaw at all. This i3 appears to handle like the best BMWs."
 

The original i3 concept wheels

Then Michael Specht from the Automotive News wrote this after driving an i3 a couple days ago: 
"BMW's i3 electric car looks set to be a winner. I drove it recently and I can only say: Wow! Whoever drives this car will want one immediately. I can't remember when I was more surprised by a car's driving dynamics. One of BMW's marketing slogans is "sheer driving pleasure." BMW was keen that this should apply to the automaker's new electric vehicles sold under the "i" subbrand and the company has succeeded with the i3."

The i3 concept coupe's 20" wheels

However Autoblog had less than total praise for the i3's handling: "The test cars were fitted with skinny, rock-hard and low-rolling resistance 19-inch Bridgestone Ecopia tires, sized 155/70 R19. After just a single spirited lap of the set course in 93-mph v-max Comfort mode, it was clear that we were driving the i3 in a style for which it was never designed. If you try to make the i3 live up to the well-honed definition of "Ultimate Driving Machine," you are categorically missing the entire point of the i3." That's not what the majority of potential i3 buyers want to hear - me included. Don't tell me I'm missing the point if I buy a BMW and expect it to handle like a real BMW! I don't care what type of fuel it uses or whether it's a hatchback or sedan, it's a BMW!  However this is the only article I've seen that criticizes the handling and I've probably read about a dozen that have said they were impressed. The final verdict for me will be when I get behind the wheel of on myself and I urge everyone else to do the same thing. It's nice to see car reviews but let yourself be the judge when you are purchasing a car. After all, it's your money and you'll be driving it!

BMW has done everything they reasonably could to cut the weight of the i3. This allowed them to use a smaller battery and still get their tareted range of 80 to 100 miles with the i3.With the battery being the most expensive component of an EV by far, it's not surprising they are so obsessed with weight savings. However what is the perfect balance of efficiency and performance? No doubt the car would handle even better with wider, stickier tires on there which would need wider wheels, which would then weigh considerably more. Finding the perfect balance was BMW's task, it's just up to us to drive and enjoy the car. I hope they got this one right because the i3 won't be the Ultimate Driving EV if it isn't fun.

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BMW i's Ulrich Kranz Talks About How BMW i Started

Kranz stands in front of the CFRP passenger cell of an i3 used for crash testing.

BMW i Project manager Ulrich Kranz recently spoke with Automobilwoche about how BMW i came to be. Automobilwoche's sister publication Automotive News Europe then posted the following interview on their site:


How did Project i get started? Did BMW CEO Norbert Reithofer knock on your door one day and say: The two of us need to discuss the future of the automobile?
- It wasn't entirely like that. At that point, some management board workshops were under way and dealing with the future of BMW. A number of initiatives were developed to get BMW in shape for 2020. Project i was an initiative that we carried out as part of our Number One strategy.

Was it already called that?
- Its name was already Project i, and in 2007 I got the job of turning it into a reality.


What were you asked to do? 

- The job was to position BMW for the future -- and that was in all fields: from materials to production, from technologies to new vehicle architectures. The agenda included the development of sustainable mobility concepts, new sales channels and marketing concepts, along with acquiring new customers.


How great was your freedom?
- I had the freedom to assemble a team the way I wanted. The project was not tied to one of the company's brands so it could tackle any problem. We were allowed to completely break away from the existing structures.


How big was the team at the start?
- Besides myself, it was a team of seven at first: a designer; a vehicle architect; a purchaser; and three other specialists in production, marketing and finance; and then someone to keep the whole organization running. We call that individual a process steerer.


How big is your team now?
- Today several hundred people work on the development of the BMW i vehicle and the mobility services associated with it.


What criteria did you use to choose your people? Did you look for visionary types?
- I was allowed to obtain the right employees both internally and externally, and that is what I did. One issue was very important to me: I looked for people who had once been independent professionals or were operating their own businesses because they approach an issue holistically, consider the long term and think strategically. In addition, I brought a mix of young guns and veterans who had already brought a vehicle to volume production.


How did everything proceed after the team was established?
- At first, we launched an intensive research phase that dealt with mobility questions and customers' future needs. Where do we need to delve deeply into the issue of sustainability? How well will customers accept a new product and a new technology such as electric mobility? Urbanization was one of the identifiable trends. In 2007, more people already lived in cities than in the countryside. Based on forecasts, more than 60 percent of the world's population will live in an urban environment in 2030. We wanted to see what that meant concretely on site.


Where did your team travel?
- We traveled to a total of 20 mega-cities, including Los Angeles, Mexico City, London, Tokyo and Shanghai. We met people who live in metropolises and who indicated that they had a sustainable lifestyle. We lived with them, traveled with them to work and asked questions.


What did you ask them?
- We wanted to know the products that they would like from a car manufacturer, how their commute to work could be improved and how they imagined their mobility in the future. As a second step, we asked the mayors and city planners in each metropolis about their infrastructure problems, the regulations for internal combustion engines and the advantages of electric vehicles.


What findings did you reach?
- One finding was that there are great differences between the metropolises. For example, Barcelona is an old city with narrow streets that has grown over time. The demand for scooters is high there. In Mexico City, cars provide protection and a retreat to escape all the hectic activity there. In Tokyo, there is a good traffic control system; customers want to be well networked in their vehicles and get an overview of all the control systems. Some cultural circumstances surprised us as western Europeans. For example, a large portion of the Japanese living in Tokyo between the ages of 18 and 22 are not even interested in getting a driver's license.


Why has no special small car been developed for metropolises with little space for parking?
- That also occurred to us. But all our inquiries told something else: Customers do not want to do without comfort and safety. They are actually very sensitive to environmental issues, but they are not willing to put up with substantial limitations in their vehicles.


How do your respondents plan to travel in the future?
- Despite the traffic jams, many people do not want to do without a car of their own.


Parallel to your research, you promoted the pilot project for the electric Mini E. Why?
- It was clear to us relatively quickly that the first stage in development would be a car that operated as environmentally friendly as possible, meaning emission-free. The simplest, quickest way to see how an electric vehicle would go down with the public was to convert an existing car and send it into the market. A Project i team had customers test electric Minis in Europe, Asia and the U.S. The findings proved extremely valuable to us.

Where did you get the idea to construct the passenger compartment of carbon?
- We knew that we needed a lightweight vehicle and that we had years of expertise in carbon-fiber reinforced plastics and mixes of materials. We asked ourselves how we could reduce throughput times and the investment in manufacturing through the use of a new vehicle architecture.


Can you cite an example?
- One example is the paint shop: a large building involving high investment and long throughput times. If it were no longer needed, we could save a tidy sum of money. The desire for a completely corrosion-free vehicle emerged from the development department. Carbon-fiber reinforced plastic met these standards, but it had to be cost-effective -- or we had to compensate for the price somewhere else. A smaller vehicle could get by with a smaller battery, and the battery is considerably more expensive than carbon-fiber reinforced plastic. So one thing led to another.


When did it become clear that the Megacity Vehicle would be a carbon vehicle?
- We discussed the issue with the management board in 2008.


What was Project i's greatest challenge?
- This is a very comprehensive project. One is developing a technology separately within one team. Balancing out the entire Project i, considering all the aspects and keeping them all in view, that was each of the participants' true masterstroke.


Initially, did you think the job would be so wide-ranging?
- That was clear to me immediately. I saw it as a real opportunity. But you have to find good people who also see such a major undertaking as an opportunity. And we have these people.

Kranz gave Georg Kacher of Car Magazine a ride in a test i3 a few months ago. Kacher was very impressed and wrote a glowing article on his impressions.

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BMW Allows The First Journalists Ever To Take A Ride In An i3

An i3 test car going through cold weather testing in Sweden.     Photo: Autocar

For the first time ever BMW has allowed a few journalists take a ride in i3's. One of the test rides took place in Sweden where a small fleet of i3's is finishing up their final cold weather testing. BMW has actually been conducting cold weather testing of the i3's there for over two years now, as the conditions there are perfect for this kind of validation. The other drive happened in Ismaning, Germany at another of BMW's test facilities.

Kacher poses as BMW's Kranz looks on. Photo: Car Magazine

In the past two days Autocar and Car Magazine have published articles on their impression of the experience. It appears nobody was allowed to actually drive the i3, they were passengers. Autocar writer Greg Kable had Patrick Mueller, head of BMW i drivetrain development as his pilot and Georg Kacher of Car Magazine had the privilege of being chauffeured by non other than Uli Kranz, the project leader of BMW i. You can click on the above links to read the full reports and I'll summarize the revelations that I believe are most important here:

1) The i3 is faster than what we thought. Until now BMW had said two things about the speed of the i3. In one instance they said the concept i3 will go 0-100km (62mph) in 7.9 seconds. Then in most recent marketing venues we were told the "Concept i3 goes 0-60mph in under 8 seconds". It's important to note they always referenced the "Concept i3" not the production car. Now for the first time journalists have quoted 0-60 times. Kable from Autocar said the i3 will do 0-60 in 7.2 seconds and Kacher said it will do it in 7.3. The i3 is clearly going to be a quick car. My MINI-E did 0-60 in about 8 seconds and it was a blast to drive. The ActiveE is no slouch either, but it takes a little over 9 seconds to hit 60mph. Cutting two seconds off the ActiveE time will certainly make for a spirited drive. 

2) The i3 achieved an official 140 miles of range on the European test procedure. What does this mean? Well the 2011/2012 LEAF achieved a range of 107 miles on this same test and that translated into a 73 mile EPA rating. Translated to the i3 that would then give it an EPA rating of 95 miles per charge. I know you can't make that exact assumption, but if you simply roll the numbers and say the i3 achieved a range of 130%(140/107) that's what it converts to and it's all we have to go on at this time. I would be happy if that is the EPA range rating for the i3. I have contended all along that I would prefer a 100 mile EPA rating, but as long as it is over 90 miles per charge, then I believe it will do just fine. It will then have the highest EPA rating of any EV that doesn't have a Tesla powertrain.

The 20" wheels on the concept coupe

3) It will come standard with 19" wheels and 20" wheels will be optional. The concept cars had 20" wheels, but concept cars frequently have oversized wheels that don't make it to production. These wheels are huge for a car of this size. There isn't any production car anywhere that is this small and has 20" wheels! You usually only see 20" wheels on huge SUV's and trucks. The whole concept of these tall wheels and thin tires is to maximize efficiency by reducing rolling resistance and drag, while still providing great road holding for high performance driving. When questioned about how the thin tires can manage to give the car such great handling Kranz said: "It’s not rocket science. All that matters is the size of the contact patch. The 19-inch tires may be skinny, but their tall height generates the same contact patch as a low-section 16-inch MINI tire". Kacher was very impressed with the handling and he said: "The i3’s most awesome dynamic talent is its incredible grip. The made-to-measure tires are about as narrow as those of a 125cc motorbike, yet they hang on almost as tenaciously as BMW’s latest DTM racer."

This is the engine to be used for the REx

4) The range extender will be a 650cc two-cylinder gas engine borrowed from the BMW C650GT motorcycle. When used for the motorcycle it has a maximum of 60hp but on the i3 it will be highly optimized for efficiency, and will run at lower RPM's for a quiet, low vibration operation. This lowers the power output to 35bhp. It will be mounted close to the rear wheels and accompanied by a 2.3 gallon gas tank which will be positioned behind the front axle. This makes sense since the gas filler door is on the front passenger quarter panel. I imagine 35 hp will be enough to allow the i3 to continue at highway speeds of 65-70mph on flat surfaces, but I don't believe it will be enough to allow the car to climb steep grades at highway speeds. It's worth noting that BMW has hinted that the range extender is not meant for full time driving like a Chevy Volt. It's main purpose to to allow you to get you to your destination or the nearest charge point once you have exhausted the battery and allow you to do so without worry of being stranded, it's not designed for prolonged high speed driving. If you frequently need to drive more than 100 to 120 miles or so, perhaps the i3 with a range extender isn't the best plug-in choice for you, but let's wait for the official specifications before we conclude that for sure.

5) Kacher wrote: "BMW has tooled up initially to produce 30,000 cars a year, but this can be extended to 50,000 units if the i3 takes off". I had heard rumors of production estimates being 30,000/year initially but they were never really confirmed. If Kacher got this directly from Kranz then it's really the first time an official production goal was offered by BMW. It's a lofty goal. No other EV has even come close to selling that many in any year, let alone it's first year. One advantage the i3 does have though is it will be available in markets all over the world, unlike many of the other plug in cars that are available today. However the LEAF is available in many countries also and it hasn't hit the 30,000/year mark after more than two years and it's a much more affordable car then the i3 will be. It's difficult to gauge the plug in vehicle market. Government incentives play a big role and so does the proliferation of public charging infrastructure. However the i3 is the only EV in it's price class that will offer the performance and range that it does, as well as an optional range extender and the premium driving experience that is expected of a BMW so it will be interesting to watch how the sales figures progress.

Since I wasn't lucky enough to be one of the first outside BMW to hitch a ride in an i3 I'll just reprint Kacher's conclusion. He makes his thoughts on the car very clear:

"The i3 is shaping up to be a breakthrough electric car. It delivers dynamic thrills like no electric car before it. The steering seems highly involving, the drivetrain’s punch would flatten a Leaf, and the handling and road-holding seem up there with BMW’s best. Ulrich Kranz and his team appear to have succeeded in bringing pure driving pleasure to the environmentally friendly car. We’ll know for sure when we drive the car in summer 2013"

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