cranky

hi what are the diff. between and uses of the following:
GRU 2:1
GRU 3:1
GRU 4:1
GRU 1:2

thanks

stanmondz

iTrader: (20)

the first 3 are slow and put out torque. every 2,3 or 4 rpm input, you get 1 rpm output.
last one is faster. 1 rpm in,2 rpm out

cranky

is it mean that 2:1 will slow down my motor and 4:1 is the slowest (having same motor power)?

assuming i have 35t which is best GRU for this motor or any chart to look on?
thanks

stanmondz

iTrader: (20)

i dont know which is best. iv never ran one.
is it a scale truck or comp truck your looking to put 1 in?
from what iv seen,most people run them in scalers as compact transmissions,mounted in the front of there truck and feeding power to a transfer case so they have clearance for a full interior

Slow1500

These look like the rc4wd ones. I just got in my 2:1 and 3:1 today, actually. I'm using both in my two Tamiya cc-01s. The 2:1 I will be paired with a 65t motor while the 3:1 (I just got finished installing about an hour ago) I'm using a 45t motor.

I bought the two GRUs as a test. I want to see the difference between a 2:1/higher torque 65t motor vs. a 3:1/lower torque 45t motor.

I've only driven it about 15 minutes but the 3:1 with 45t is an absolute beast. It is far superior in crawling than just using a high tq motor with no GRU.

All gear reductions increase torque, but given the same 35t motor the 3:1 will yield more low speed control and torque. The trade off will be a slower top speed. It all depends on the application.

cranky

I have 35t and i'm planning to get the 2:1 do you think its ok?