BMW i3 Wheels and Tires: What you need to know

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

Note: This was originally posted on February 17th, 2014. I have had so many people message me about tire and wheel size information that I thought it would be a good idea to repost it.

One of the more talked about features of the i3 is its tires. Not for decades has there been a car with such tall and narrow wheels and tires. Since the 70's, the trend has been for tires to get wider and wider, and that is especially true for performance cars since more rubber on the ground generally means better roadholding.

Performance is critical for any BMW

Then came along the i3. It's BMW's quirky-looking mega-city car, and the first electric car from the brand. With all the incredibly unique aspects of this vehicle, it's still the tires that catch most peoples attention when they first see it in person. They just aren't used to seeing such tall and thin tires on a car, let alone a BMW. Actually, they look like they would be better suited for a motorcycle, but that's just because we just aren't accustomed to seeing tires like this. Rest assured the BMW engineers have done their homework, and the tires do exactly whet they were designed to. They provide excellent grip while increasing the cars efficiency with lower aerodynamic drag.

BMW commissioned Bridgestone to make special tires just for the i3. Even though they carry the "Ecopia" name, they are different from any other tire that Bridgestone makes. Franco Annunziato, CEO and President of Bridgestone Europe said: “The BMW i3 is very much a car for the future. Developing a unique tire for this unique vehicle was therefore an enormously challenging but also rewarding experience. Energy efficiency is an important development criteria for all our tires at Bridgestone. However, it becomes an even more critical factor in an electric car. Which is why we have put all our knowhow, skill and passion into developing this unique tire. One that we are confident delivers the premium performance, safety and economy towards consumers who have come to expect it from both brands.” As for performance, since BMW wanted to use a narrow tire for efficiency but not sacrifice on performance, they needed to use a much taller tire than most would expect on a car of this size. By increasing the height, they were able to increase the contact patch so it is similar to the contact patch of a MINI Cooper, which is well known for its great handling. Talking about the i3's tires and their grip on the road, Ulrich Krantz, BMW's product manager for BMW i 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". 
 

1) Standard Mega 19" #427  2) Tera World 19" #428   3) Giga World 19" #429   4) Optional 20" Sport  #430

So with the question of performance behind us let's focus on the tire and wheel sizes and combinations. BMW doesn't make it easy here. The standard wheel on the base Mega World interior is a BMW i Star Spoke (Style 427) wheel that is 19" x 5" on the front and rear and they use the 155/70 R19 84Q Bridgestone Ecopia EP600 all season tires that were specifically designed for the i3. Here is where it starts to get tricky. If you get a BEV i3 with the standard Mega trim, the wheels and tires are the same size on the front & rear, but if you get any other interior trim (Giga or Tera Worlds) the rear wheels are slightly wider (19" x 5.5") and the tires are wider and lower profile (175/60 R19 86Q). Also, if you get the standard Mega World trim but get the range extender, you also get the wider wheels and tires on the rears. Then there are the optional 20" Double Spoke sport wheels. They are also staggered in size and use Bridgestone Ecopia EP500 summer tires, not all-seasons. Up front you get 20" x 5" wheels and 155/60 R20 80Q tires and in the back there are 20" x 5.5" wheels and 175/55 R20 85Q tires.

EP600's on left & winter tire on right

So the wheel and tire size is staggered in every instance except for a base i3 with Mega World trim and no range extender, right? Kinda. Everything above applies for the standard 19" Bridgestone Ecopia EP600 and 20" Ecopia EP500 tires but not if you want/need winter tires. There will be two different winter tires available (Blizzak LM500 & Blizzak NV, though I'm not sure they will both be available in the US). However they will only be available in 155/70 R19, so if you want the winter tires you'll be using the same size front and rear tire. Furthermore, if you order your i3 with the optional 20" Sport wheels ($1,300 option) and you live in an area that would necessitate winter tires, then you'll need to buy a set of 19" wheels also, since there are no 20" winter tires that will fit the 20" sport wheels. I have spoken to BMW product managers about this and was told bluntly that the 20" tires are summer tires, not all-seasons and they will not perform well in snow and ice. So if you were considering the 20" sport wheels for your i3 and you live in a cold weather area, understand you'll likely need to spend another $2,000 or so to get a set of winter tires & wheels, since you can't just buy the tires. If you have any of the three 19" wheels then all you need to do is buy the winter tires and you can swap them for the winter and put your Ecopia EP600's back on in the spring.

One more thing. None of the tires are runflats, and the i3 does not have a spare tire. What you do get is a can of "Fix-a-Flat" tire sealant and compressed air, which if used properly should get you at least as far as your nearest BMW dealer which will likely be the only place that stocks there rare tire sizes. If not used properly it will blow up in your hand leaving you covered with the sticky goo meant to seal the hole and you'll be calling Roadside Assistance. Finally, if you are wondering how well the i3 does in the snow, below are a couple videos that were just posted on YouTube by a new i3 owner in Norway. I have also talked with a couple people that have driven the i3 in the snow and they have remarked about how well it has done, likely another benefit of the tall, thin tires that slice through the snow instead of rolling over it.

Bridgestone's "Ologic Technology" and the i3

Much has been made about the tall narrow tires on the BMW i3. They are really unlike any tire on any other car currently in production and they certainly don't look like they belong on a BMW. However BMW and Bridgestone did their homework on this, and accomplished the goals they set out to. That was to develop a tire that is not only efficient, but also delivers the performance expected of any BMW.

How did they do it? Ologic technology. Yep, they developed something so new and advanced you have never even heard of it before! So while I as the Geneva Motor Show a few weeks ago, I made it a point to stop by the Bridgestone exhibit to ask about this new mysterious "Ologic Tech". As I approached the Bridgestone area, I could see they had a Capparis White i3 on display with it all lettered up promoting this new Ologic technology, and they even had an award in a case next to it that proudly displayed that Bridgestone won the 2014 Tire Technology International award for Tire Technology of the year! Fantastic! I was even more pumped up to find out what this new Ologic technology was. Could it be a new special rubber compound or tread pattern?  I was about to find out.


Tire Technology International Awards 2014 winner interview – Tire Technology of the Year

So after asking the information desk for someone to interview I was introduced to a Brigestone product manager to answer my questions. I didn't waste any time. My first question was: What exactly is Ologic technology? I don't have the exact words he used but to paraphrase he basically said "Ologic Technology is our way of creating an efficient tire that still offers optimum performance. By using a very tall narrow tire we simultaneously reduce drag, rolling resistance and tire deformation. The height of the tire in relation to the width also increases the contact patch which allows for retain the dynamic driving characteristics of a much wider tire" So Ologic is just a name of a concept, not any specific rubber compound or such? Yes. Alright well that was a little let down because I figured I was going to get a lesson on rubber or tread or something other than what I heard.

So why are they so special? They must have done something right to win the Tire Technology of the Year award, no? Here is an excerpt of how Bridgestone explains why these are indeed special:

"A Unique Concept for a Unique Car
 
BMW has achieved a genuine milestone with the i3 electric car. Doing justice to its unprecedented levels of both efficiency and performance demanded more than just a new tyre but an entire new tyre concept. Bridgestone’s answer came in the form of the ologic technology, which capitalises on the synergies of a large diameter coupled with a narrow tread design. The result is a tyre that delivers significant improvements in aerodynamics and rolling resistance, while still offering outstanding grip in wet weather conditions.
Combining a large diameter with a narrow tread pattern has several advantages. While the tread on smaller diameter tyres is typically inclined to excessive movement or “deformation” during driving, the larger diameter and higher belt tension significantly reduce tyre deformation and therefore conserve energy that is otherwise lost through internal friction which helps to reduce rolling resistance. By the same token, the narrow tread concept improves aerodynamics. The most spectacular achievement, however is that these improvements do not involve a trade-off in terms of safety. The tyre’s long contact patch (relative to its narrow width),  revolutionary tread design and compound still ensure outstanding grip in both wet and dry conditions."

They have obviously done something right because even though they look like they would be better suited on a motorcycle, the i3 handles exceptionally with them. I've spoken to quite a few people now that have had an i3 on a race track and all of them were genuinely surprised at how well the car performed. In a few weeks I should be taking delivery of my i3 and I can the really put the "Ologic Technology" to the test. :)