RC-Monster Forums - View Single Post - Who follows the 1" per rev. gearing rule (rollout ratio)?

BrianG · 08.03.2009, 12:52 AM

This is interesting. I have heard this 1:1 rollout rule too, but never thought much of it.

For instance, say I have truggy tires that are 5.65". That's 17.75" circumference. That would mean I would need a total diff and spur/pinion ratio totaling 17.75:1 in order to follow this rule? Following that logic, most truggies have a 4.3:1 diff ratio. That would mean the spur/pinion ratio would have to be 4.13:1. And if I'm using a 48T spur, that would mean I need a 11.6T pinion (ok, round down to 11). Which would put the top speed of a 2000kv motor on 5s at 33mph. Sounds pretty good to me.

If everyone agrees this is a good rule of thumb, I can add this feature to the calc page.

	(#5)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	08.03.2009, 12:52 AM This is interesting. I have heard this 1:1 rollout rule too, but never thought much of it. For instance, say I have truggy tires that are 5.65". That's 17.75" circumference. That would mean I would need a total diff and spur/pinion ratio totaling 17.75:1 in order to follow this rule? Following that logic, most truggies have a 4.3:1 diff ratio. That would mean the spur/pinion ratio would have to be 4.13:1. And if I'm using a 48T spur, that would mean I need a 11.6T pinion (ok, round down to 11). Which would put the top speed of a 2000kv motor on 5s at 33mph. Sounds pretty good to me. If everyone agrees this is a good rule of thumb, I can add this feature to the calc page.