So… how does a LEAF work?
[UPDATE] This article was written in 2010 and applies to the 2011 and 2012 models of the Nissan LEAF. A different electric motor is used on the 2013 and later models with slightly revised specifications.
* * *
We’re not really going to tell you how a LEAF works. But… we will give you a little insight into how the LEAF is different from the car that you are currently driving.
Recently, the good folks in Nissan’s European Newsroom provided us with some additional technical specifications for the LEAF that had not been previously released. For instance, we now know that the AC synchronous motor can turn a maximum of 10,390 revolutions per minute (RPM). We heard from some other sources as much as 18,000 RPM, but thought that might be on the high side. And most likely, you have heard by now that LEAF does not use a conventional automatic or manual transmission. It uses a single speed reduction gear with a final drive ratio of 7.9377. So what good does that do anyone? Good question. Divide 10,390 by 7.9377. Go ahead… we’ll wait. Come up with 1308.94? Good! So did we.
1308.94 is how fast the tires will rotate when the motor is turning the maximum 10,390 RPM. Why is this important? Because, since we know that the tires are a Bridgestone Ecopia model, size 205/55R16, we know that the tires have a diameter of 24.9″ and will turn 837 revolutions per mile (not per minute). With these givens, at 60 miles per hour these tires will turn 837 RPM. But if the electric motor is turning 10,390 RPM, and the tires are turning at 1308.94 RPM, how fast are we going? Simple… do the math!
1308.94 RPM divided by 837 RPM equals 1.56. So at maximum motor RPM, we are traveling at 1.56 times 60 MPH, or 93.8 MPH. We think that we recall reading that the fastest the LEAF has traveled (at least in road tests that we have seen) has been 94 MPH or 95 MPH, so these calculations are probably fairly accurate. Here at Living LEAF we’re car geeks… what can we say?
Some other numbers released: curb weight 1,525kg (3,355 pounds) minimum 1,595kg (3,509 pounds) maximum. These are based on some European spec that we are not familiar with, but we expect US numbers to be similar. The variance is likely due to the trim level and associated equipment differences.
One other little bit that we picked up – both front and rear brake rotors are ventilated. Typical practice on compact cars is to provide vented front rotors and solid rear rotors. Venting the brakes at both ends of the car offers several advantages – cooler brake operation, longer component life, improved performance, along with potentially less maintenance. This is the type of treatment typically found on more expensive performance oriented vehicles. Nice to see on the LEAF.