Motor RPM in reverse

[PaulRC10 61]

Anyone know how to find out what a motors’ RPM is in reverse?  I think this could only be different than forward RPM in those motors that have been tuned or have adjustable timing.  But I could be wrong? 
Specifically I’m after the Sports Tuned numbers.  

[Rich_8717 114]

This thread might help,

 

[Juggular 5234]

It would be nice if there were some charts. But I haven't seen it.

Which left me to get a tachometer.  Aside from the silver can, most Tamiya motors have some timing.  Come to think of it, most brushed motors had timing in my experience.  

At least I tested Sport Tuned. It's about 12% faster going forward.  At 3.7v, 11100 RPM going forward vs 9900 RPM going backward. 

If it's going 18,000 RPM at 7.2v (NiMH), it should be about 16,000 going backward (I haven't tested at higher voltages because it tends to char contacts--I should build a proper test rig with a switch).  

 

[PaulRC10 61]

1 hour ago, Juggular said:

It would be nice if there were some charts. But I haven't seen it.

Which left me to get a tachometer.  Aside from the silver can, most Tamiya motors have some timing.  Come to think of it, most brushed motors had timing in my experience.  

At least I tested Sport Tuned. It's about 12% faster going forward.  At 3.7v, 11100 RPM going forward vs 9900 RPM going backward. 

If it's going 18,000 RPM at 7.2v (NiMH), it should be about 16,000 going backward (I haven't tested at higher voltage because it tends to char contacts--I should build a proper test rig with a switch).  

 

Interesting stuff.  I had assumed these motors were tuned forward.  Great test results.  Thanks for the link @Rich_8717