Drive question (yet another from Gigabyte)

[Gigabyte]

Is running a 36:60 on a 4 motor green drive not 360 rpm

[Elephanf]

No. Running 60:36 would be 333 RPM, and running 36:60 on BLUE motors would be 360. However 36:60 on green motors is 120 RPM, which is a super slow drivetrain.

[Gigahertz.t]

@Elephanf

120 RPM, which is a super slow drivetrain

To be specific, about 20 in/sec

Hey, it’s got a lot of torque though

As a rule of thumb, green motors are almost always geared up (meaning big gear connected to the motor shaft) and blue motors are almost always geared down (meaning small gear connected to the motor shaft).
Red motors are a no-no

[79419]

I have two things to add to this thread

Firstly you now have a Gigabyte and also a Gigahertz on this VEX Forum

Secondly you can gear up red motors 36:12 to get 300rpm (which works for 4" wheels I guess) (the original person who invented this regrets it terribly if I remember correctly)

Thirdly, generally (in case you aren’t aware) it is better to use blue motors and gear down to a suitable speed (if I remember correctly, it’s something that has to do with how blue cartridges have less slop and are lighter. The other benefit from my own experience is that the larger gears overlap with the silhouette of the wheels, so you aren’t going to have to space crossbars up super high in order to get them to fit)

[Gigabyte]

Ok, Thanks! But I already switched to 333 RPM by gearing up green motors

My motor said no to blue motor drive

[Gigahertz.t]

@79419

Secondly you can gear up red motors 36:12 to get 300rpm (which works for 4" wheels I guess) (the original person who invented this regrets it terribly if I remember correctly)

36:12? I think you mean 72:24, as 36:12 would mean the 4’’ wheel would overlap with the motor axle. But as you stated later, this does negetate cross-bracing, and…:

Gearing up low-RPM motors vs. Gearing down high-RPM motors

I believe (someone correct me if I’m wrong) that 600rpm cartridges have fewer internal gears than the other two, and thus less internal friction. Additionally, gearing up 100 or 200 rpm cartridges would involve backtracking of sorts from the internal motor, where the cartridge gears it down, and then you externally gear it back up again, which can be redundant and add more friction and slop. Also, gearing down 600 rpm will have less slop than gearing up 100 or 200 rpm, because the slop from th…

@79419

if I remember correctly, it’s something that has to do with how blue cartridges have less slop and are lighter

Yeah it’s rumored that they have less gears inside, with also means less friction. Plus, this is just a personal thing, but gearing down a motor via the cartridge and then back up via the geartrain is kinda ironic and, as stated above, has slightly more friction and slop.

@79419

The other benefit from my own experience is that the larger gears overlap with the silhouette of the wheels, so you aren’t going to have to space crossbars up super high in order to get them to fit

Agreed, especially because having large non-wheel gears allows for an easy implementation bottom crossbrace, which is great for drivetrain structure.

@79419

Firstly you now have a Gigabyte and also a Gigahertz.t (everyone forgets the “.t” ) on this VEX Forum

Now we just need a Gigabit, and we’ll have the computational trifecta…

[79419]

@Gigahertz.t

36:12? I think you mean 72:24, as 36:12 would mean the 4’’ wheel would overlap with the motor axle. But as you stated later, this does negetate cross-bracing, and…:

If I may (and I hope it is not over-extending a solved topic) let me find the originator of the design and see if I may share it, because I think it’s quote interesting (atrocious, yes, but also interesting)

@Gigahertz.t

also a Gigahertz.t (everyone forgets the “.t” )

My apologies, I intentionally omitted it to make it flow smoother

[Gigabyte]

I could get one of my teammates to join so we can finish the trio no one ever knew they needed