XRAY - Model racing cars

Could someone please clear this up for me once and for all?

Are serrated brushes used so that they break in quickly, used to give higher rpm (through less drag), or some other reason?

Also, does chamfering the trailing edge of the brush reduce heat build up?

Thanks.

this is just so difficult!!!

you're right, it is difficult.

Its worth it for some though.

i have just spent the last week playing with a dyno out of desire.here is what i found.which may be different on the track please remember this.serations in the brush do not give more power it actually gives slightly less about 2% and the same with torque.a brush with no seration and a clean comm yeild the best starting point .with brush hood aligned tried removing the leading edge and then trailing edge the leading edge gained 0.5%, used ready 767 ,h1 doms ,trin 4499 and fline brushes the f line gained 2% on effiency nothing else the rest yielded the same powe and torque, springs seems to gain the most moving from lighter to heavier on the positive and heavier to lighter on the neg yielded 6% gain.
not this works on a dyno but could be crap on the track...the only reason i see for the dyno is a guide for what the motor should be like .......like i said these where my finding i listned to a lot of talk and this is why i bought one .and most of it is in our heads just my views

Like you said, what happens on the track is what counts. That is what my earlier statements were reflecting. Problem with Dynos is that they don't measure the performance at the loads that the motors must actually pull on the track.

Anyway, I agree with you that springs and brush compound are much, much more important than the question "to serrate or not to serrate"

For those investigating only trimming the leading or trailing edges instead of an equal amount of both, make sure you check the rules for the events you race in. Trimming only one edge changes the timing which is illegal if the rules state the timing must be fixed at .. degrees (often 24 degrees in stock and 19t classes).

i found a tool that can cut away serrations.

i didnt know that. thanks