Originally Posted by tfrahm

I originally posted this in another thread, but realized this is a better place to ask....

I've been racing my XXX-S locally with a GTB/13.5(bonded) setup. I had all the usual issues -- ran too hot until I geared down to around 6.2 FDR with rubber tires and finally got the temps down to around 150-160 (90+ F degree weather)...

SO - Tonight I replaced the rotor with a sintered rotor... (I've worked with brushed motors for 18 years or so, and I'm spoiled with having my Turbo Dyno 45 to allow me to test motors, etc.) When I first tested the converted motor (ONLY on the workbench so far) -- I thought I'd done something wrong... It sounded so SLOW compared to the way the bonded rotor sounded... Fully installed in the car, I realize it's working fine, but MAN! it sure is different! Before, the drag brakes (even manually applied brakes) were WEAK -- drag brake was almost unnoticable! NOW - ZAP! it appears to act almost like a brushed motor...

In reading about gearing recommendations, I always thought the sintered rotor versions "allowed" taller gearing -- now I am starting to think they MUST HAVE taller gearing to achieve the same speed...?

I'm guessing I will need to go from 6.2 FDR (bonded) to around 5.0 FDR (sintered) for our relatively small parking lot track with rubber tires...?

I won't get to track test until Sunday at the next HobbyTown races, so I want to make sure I'm understanding this right...?

Your thoughts?

Originally Posted by Steve Weiss

As far as the sintered rotor is concerned, yes, it is a smaller diameter than the bonded rotor.

Originally Posted by Steve Weiss

Yeah, that gearing sounds about right.

I have heard most people seem to have success in the 4.5 to 5.0 FDR ranges with sintered rotors.

Originally Posted by GCracker

Steve, I bit the bullet and got a #1711 and 13.5SS for BCR this weekend, whats your recommendation sir with the gearing?

Originally Posted by HB Moose

GG-- Didn't you quote Steve's answer in the question? I ran 4.97 at La Mirada last Sunday.

Originally Posted by Guo Chean

Hi Steve,
here is the problem i have right now when i using Novak SS13.5 with the combination of Nosram ISTC spec(similiar to LRP TC spec) throttle profile 2-8-2-2, FDR gear is 4.56, radio brake EPA 60%, i have very good braking at the begining of race but after 3 min race or qualifying the motor seem to be having fade brake until i can feel my car totally no brake at all, and i did check the temp was around 160F and also i did put a novak 30X30mm fan to blow the motor to keep the temp down it should't happen like that! some more is new i just got it from towerhobbies. thanks

Originally Posted by Steve Weiss

You got the 13.5 Pro with the sintered rotor? If not you need to gear down quite a bit to keep the motor cooler
If you have the sintered rotor you might want to gear down a tooth or two just in case.

Also, how hot is your ESC getting?

I think that the punch/speed setting of 8 might be a bit much... I would tone it down to about 4 or so... that setting they are playing with causes extra current draw and that might be what is causing your brake fade.

Originally Posted by Aid1970

thanks for the reply Steve
it is the new system can i adjust the trim on the stick to give me a little more like a auto brake?
thanks

Originally Posted by Aid1970

glad your back Steve can you help will i do any dammage??