Hobbyist Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
1,571 Posts
Discussion Starter #1
Hi, I am new to brushless racing and have a question for the seasoned brushless racers. How often do you have to change the rotors to stay competative. I herd a rumor that at the birds the fast guys were changing rotors every three runs to stay fast Fact or Fiction?
 

·
Registered
Joined
·
2,790 Posts
Well I can't speak to what guys were doing at the Birds, but I wouldn't bother replacing the rotor more than once per season.

I was worried about the field strength myself about a year and a half ago so I tested it. I compared the flux(measure of field strength) of a rotor that had been used for 1 4 minute run to a rotor that had been run weekly for about 10 months. The difference in field strength was a bit less than 2% which is within the acceptable tolerance range for the magnet material itself, so effiectively there was no difference.

This was done with the old bonded rotor that ran much hotter than the new sintered rotor. The new rotor would be even better.
 

·
Premium Member
Joined
·
6,312 Posts
Been using brushless for almost 2 yrs now. I agree 100% with pmsimkins.....Once a season is plenty. I also run the 5800 brushless motor in a B4 buggy for our buggy class. It's 2 years old and nothing has been changed on it and it's still very fast..using the original SS ESC too. The only thing I do is oil the bearings about once a month.

RC
 

·
Registered
Joined
·
219 Posts
Brushless rotor

I have run the 5.5 and 4.5 rotors for over a year now and haven't noticed ANY loss of performance of either one! I have switched to the 5.5 using 7.4 (4800) lipo pack,which probably makes up for any performance loss.Prior to that we were running 4-cell and my 4.5 was always one of the strongest cars on race day.Both have the stock rotor in them.I do have a 3.5 but shut-down problems with a 4-cell have prevented me from running it more than a couple of times.
 

·
Registered
Joined
·
5,426 Posts
its nice to see that atleast from the guys that run these motors weekly dont think its reasonable to be changing rotors alot. what i would like to see is if anyone that was in the top 20 or so at the birds for 4300 could come on here and explain if they felt they needed to change rotors after a round or 2 for speed? or if they felt it wasnt needed. so if anyone knows someone that could comment it would be nice!
 

·
Registered
Joined
·
640 Posts
I have run My brushless About 2 weeks before the birds and then maybe 10 or 15 runs at the Birds. I have not changed a thing.It has the upgraded endbell and Rotor Part # 5908 and 5919 and the Novak GTB Speedo.
 

·
Registered
Joined
·
5,426 Posts
Thank you ALan for the input. im guessin the guys that did change every run just got there stuff way to hot and figured to be safe they would change the rotor. and most likly the guys that change it every other round probly had the parts givin to them for free or cheap cause otherwise it could be exstremly costly!
 

·
Registered
Joined
·
3,089 Posts
the roll out down there was like 2.68 all the way to 3.04 who knows
 

·
Registered
Joined
·
7,343 Posts
...You know RACERS, they will do ANYTHING for an edge. Sometimes that 'edge' is purely all in their mind...but it doesn't matter where it is...it still gives them an edge.

'perception' plays such a big part in racing..and just like with DYNOS at the track...dozens of battery packs, etc. If the "FAST GUY" does it... the 'OTHER GUY' thinks he needs to too.

More often than not...the 'other guy' would have been better off to spend MORE time on the track...and adjusting the car. But that has been said at least 2 million times on this board.
 

·
Premium Member
Joined
·
2,251 Posts
Im with alan on the heat... I rolled the shiznit out of mine one round.. the car was really quick..BUT when I came back in the rotor had no magnetic stregnth left... It felt like the stock 4300 rotor.. I did not have a temp the motor after that run.But you could have welded with the can... I did have to go and buy a new rotor. Before that I had run on the same one locally for about 6 months.. I never saw it fall off...I guess Ill see this weekend on the new rotor weather or not its faster than when I left..
 

·
Registered
Joined
·
877 Posts
Finished second in the B main ..Rolled out at 3.04 motor came of at 135 to 140 ran 4.0s up front and finished with 4.1s with rotor I have ran for over 3 months...Charlie at Novak checked it after the race and said the numbers were awesome on his checker ....Dont know what he was checking but he asked how long it had been run and was very happy with that ...
 

·
Registered
Joined
·
2,790 Posts
If you were to change your rotor every run it would not even be tiny advantage. You would have just as good a chance of hurting yourself as helping. There is some variation in the magnetic properties of the material from batch to batch. You would be just as likely to take a rotor out of your car that was on the high end and replace it with a rotor on the low end as you would be to help yourself.

Now if you wanted to spend thousands of dollars for a teeny tiny advantage you could buy a flux meter, coil and fixturing to check the strength of the rotors and pick out the best rotor out of a large group. Of course in the end it would help you very very very little on the track.
 
1 - 16 of 16 Posts
Top