This topic recently came up at mynissanleaf.com recently too.
Here is what I posted there:Driving a Prius -- or any car for that matter -- for better than EPA fuel economy
typically involves using a tactic called "driving without brakes." Of course you do
have brakes, but you allow for some extra space ahead and try to anticipate stops
well ahead so that you can glide up to it. Better yet, if you're good enough or lucky
enough to time stop lights correctly, you roll right on through.
Driven like this the Prius brakes get hardly warm to the touch.
Granted, regen has a lot to do with it. Driven carefully, the hydraulic brakes only
come into play as the car slows to ~8 MPH. Quite a few Prius drivers have installed
aero wheel covers without brake overheating issues.
Wouldn't this same situation also apply to the LEAF?
It's also a frequent DIY modification at ecomodder.com for non-hybrid
cars. (They prefer flat disks made from Coroplast plastic; think political campaign
signs.) Other than some creativity needed in installing the full covers, I can't recall
any difficulties or reported instances of brake overheating.
At any rate, you pays your money and takes your chances.
FWIW, I drive an '08 Prius with 50.2 MPG over 65K miles.
FWIW, if you look closely at the picture posted, these wheel covers are held on by
drilling and tapping holes directly into the rims. Most folks will not want to do that.
IIRC, MoonEyes also has these covers with the spring tabs around the perimeter
meant to lock into the groove that the OEM covers use. All well and good, but...
I have read on multiple forums that the spring tab covers have a reputation for
coming off when the car is underway.
Just thought that you ought to know.
Here's the whole thread if you want to read more:Aero Wheel Covers