is the 13mm rotor roar legal?

Yes...

ROAR legal or not i haven't heard of anywhere allowing them for 10.5 or 13.5, so save your $40.

I don't believe they're legal in BRL either.

my friend tried one the other week in practice and it was considerably slower. he was mad that he spent the money to try out the thing and he went slower! he thinks its a good idea not to allow another rotor!

save your money - although from what I've seen in the HIGH wind motors (ie: 10.5, 13.5) they just SLOW you DOWN...and you are already low on RPM, and from what I understand the 13mm rotor drops the RPM even more)

Myself, I could probably benefit from one in 10.5 (I can use to SLOW down a bit)

I think I saw a mention in another forum that they were intended for the touring car crowd...

I was thinking about a 4.5 in dirt car?
any thoughts?
Thanks

Ralf, I believe you're right. It was developed for T.C. and offers more torque! No benefit for pan car oval.

This is the info I found about it.
Novak Sintered 13mm Tuning Rotor
Novak is pleased to introduce the #5909 Novak Sintered 13mm Tuning Rotor. This rotor was designed to alter the feel and experience of driving a Novak motor, and offers a new dimension of tunability. With a slightly larger diameter and improved magnetic material, the rotor can withstand a higher temperature threshold, improving its durability. It also increases the natural drag brake and opens up the motor’s gearing window to improve drivability. The Sintered 13mm Tuning Rotor is compatible with the Novak Velociti-series, SS Pro-series brushless motors and any Novak 540-size brushless motors with an oversized front end bell bearing.

With its larger diameter, the new Novak Sintered 13mm Tuning Rotor cuts down the air gap in the motor to improve the motor’s initial throttle response and natural drag brake. The new magnet material also performs better under extremely hot conditions and high loads.

The Novak Sintered 13mm Tuning Rotor excels in on-road applications because of its affinity to high-traction surfaces and is ideal for racers who want an edge in touring car, oval or 1/12-scale applications. Because each user has different driving needs, this tuning rotor may work well in other applications. In addition, gearing changes and lowering the speed control’s drag brake setting may be needed.

The Novak Sintered 13mm Tuning Rotor features an identifiable groove on the shaft bevel to differentiate it from other Novak rotors. It

I tried one in my 3.5 on a 140' carpet track. Worked awesome. Made it a lot easier to drive and just added a few teeth to keep the rip up.