directional wheels

[TEG]

When heat is a serious issue (in racing), they tend to have ducts that take air from the "air dam" up front and blow it right onto the rotor...

 

[wiztecy]

Right, they sell brake ducts for the rears too which redirect under-body air to the rotors. But having a duct as shown above should have the least impact to underbelly aerodynamics. Also from talking to those who race the Elise and what I felt from the Roadster is that we don't heat up the brakes / rotors enough to worry about this since the cars are in the lighter class. With the old stock rotors, same design as the Elise basically, it was the glazing that was eating into the brake performance when full hard out demand of performance was needed. The custom CRF rotors alleviated that problem.

 

[hcsharp]

The rims are also stamped on the inside that indicate which side they need to be on, such as RH and LH. Also the 2.5 sport/forged rims are in theory functional to help cool down the rotors if mounted correctly. But in reality most people won't be driving hard enough to drive up the heat anyways unless they're very spirited or on the track.

This is correct. Stamped on the inside is what I meant by "marked" for direction. I was told by a seasoned Roadster tech (which doesn't make it true) that the direction of the 2.x forged rims affected their wind resistance, but had little effect on brake cooling. Mount them in the proper direction and you get more range. Teg posted a couple of Roadster pics with the rims backwards (Orange #06 and green) posts 72 & 73.

 

[TEG]

I have seen quite a lot of Roadsters that had all 4 wheels the same directionality, so half of them were always "backwards".