Originally Posted by Slapmaster6000

Guys,
Here's something interesting that a buddy and I stumbled across recently that I want to share. I don't use dual rate very much, but my buddy does and discovered a what appeared to be a problem. When turning his d/r down, he found that the end points of the steering limits did not follow proportionally. For instance, if a 12th scale car could turn 2 foot circles at max steering in both directions and then you were to turn the d/r down, you might find that the car might turn a 3 foot circle one way and 4 foot circle the other direction.

Well this seemed like an obvious flaw in the radio. Who would want non-proportional side to side d/r like that? I have always found that when I set my radio up that my end points are not always the same side to side (90% vs 75%), but once set, the car always acted correctly. So thinking this was odd, I thought that I would ask our radio control Team Manager this question.

It turns out, that if you center a servo with "trim" to achieve the mechanical center that you are looking for in your servo arm/saver... you will have uneven end points and this problem will effect the way your d/r acts as you reduce it!

The correct way to set up your servo is to find the least amount of off center to mount your arm/saver and correct it with "sub-trim" to the nearest amount of mechanical center that you can. But first, you must make sure that your steering trim is at "zero". Make sure that your d/r is maxed out. Then set your epa's. You might find that your epa's are much closer percentage-wise then before. With any car, you will have to check all the steering links for equal lengths and a proper length steering rack link. Then use the "trim" to fine tune your car on the track. Now, your d/r will reduce proportionally correct all the way! Maybe as a rule, if you get steering trim more then 5% off of center, you may want to fix some of that through sub-trim. For some reason, the software that is in today's radios do not treat trim and sub-trim as the same, especially involving dual rate.

Check it out, it's worth a look!

Brian