Hi I need help in deciding which drivetrain to go with, we only have 4 blue carts and only have 4inch wheels, so I came up with 2 drivetrains,
you can gear Option 2 up. if you do 84t gear on 200cart and then 60t gear on wheel that gives you 280rpm which is faster and better than either of these withouth alot of work
You should probably go with the 257 drive, but this years game needs a good drive, so I’d suggest a different drive with about a 350-400 drive
dont do 4m 257, do 6m 257 or 280, this game requires speed and pushing power
is this on 4 inch wheels? i would highly recommend 3.25 or 2.5 instead if you could. On 4 inch wheels finding a good ratio could be hard. I would probably try to run a higher speed on 4 inch wheels with 6 motors. Maybe like 257 or 343 on 4 inch could work. 200 would be slow and 257 would be weak in torque and acceleration.
Always do a 66w (6 motor) drive. 4 motors are usually never competitive.
Checking out Xeon’s great post:
I would go 200 rpm (green motors) geared up 72:48. May be a little slow for this season, but that’ll be the best for 200 rpm on 4 in wheels. Most drivetrains in VRC are around 62-72 in/sec, so you’ll be on the low end in terms of speed.
Hello, I’m 79419 from fall off pole alliance
(but at school so I can’t use discord)
I just realised one thing you can do is to build a 6m 257rpm drivetrain. How you ask? Basically use the 4 blue carts to make 4m 257rpm, then gear up a green motor 3 to 1 so it spins at 600rpm and then basically it works like a blue cart
It’s basically what people do a lot of the time when they want to use half motors on drivetrains
Try something like this (if the image loads properly, idk if it’ll upload)
wait, i am still figuring out how to calculate torque, but would these mean that the torque would be lower than going with 280rpm???.
No, it would be higher torque than 280rpm (assuming the same amount of motors for both options)
A general idea is that when motor amount + wheel size are constant, torque is inversely proportional to rpm; that is, the higher the rpm the lower the torque
257rpm slower than 280rpm therefore has more torque
yes but even while pushing much higher speeds that 280 teams have had plenty of torque. I’d aim for minimum 60 ins/sec.
I have a whole sheet i made here but I would recommend 72 to 48(62 ins/sec) or 60 to 36(69 ins/sec).
Also a bit technical but the old “4 inch” omni wheels(the green ones) are actually 4.15 inches while the new ones(gray) are pretty much exactly 4 inches. For that reason if you are using the old omni wheels your speeds will actually be about 64 ins/sec for 72 to 48 and about 72 ins/sec for 60 to 36.
Hope this helps
I have zero experience with doing a 6 motor drive and have no idea how to code one. I am definitely interested in learning how to do something like that. I use VEXcode V5 btw
thats great! I’m not my team programmer though, I’m the builder and driver, but from the little I know, it is fairly easy to code a basic 6-motor drive, especially with the amount of resources at your disposal like other posts, the sigbot wiki, and youtube tutorials.
Good luck!
