Spectrum Radio too responsive
 

I have a Spectrum DX5C transmitter. I have begun racing onroad after years of offroad racing. When racing I find that the car is very "twitchy" or when turning the wheel, the car responds too fast for my driving ability. I know what the exponential adjustment does but am a bit confused as to the "rates" adjustment and "speed" adjustments do and how they differ.
What I want to accomplish is to make the car react a bit more slowly with steering inputs and not react so quickly to steering.

Any help or advise is welcome...........
Rick in South Florida

Most likely the cars fault, not the radios.

Exponential, as you know, takes the linear input and can make it so that 25% steering gives you 10% steering on the car but then 75% steering gives you 75% on the car again. To me this is probably the adjustment you should use if you still need full turning ability for some corners.

The speed adjustment is also a good option for what you want as it adjusts response time. It should basically mimic having a slower servo. Any input you provide on the radio won't be sent to the servo or ESC as fast. Obviously too much here will feel like you have lag playing video games but maybe a small speed adjustment combined with a small expo adjustment combined will feel good.

The rates adjustment was often called "dual rates" and this is intended for if you have a track with a very narrow straight in some spots and lots of turns in others, oval racing, or if you want to bash and drive but also want to do speed runs, you can toggle the rate between full proportional control and a much more gentle steering response so that you don't roll the car trying to correct it with too much steering input at high speed. Rates set a flat modifier on the input so you could try a 50-75% steering rate and see if that helps, if your track isn't too windy, or if you don't mind toggling it on and off during the race.

Before adjusting expo/rates etc., you need to make sure the servo is set up properly in the car.

1. Make sure it is centred and the linkages are geometrically even. Use sub-trim instead of trim to get this right (I will use Futaba naming, not sure what Spektrum call it)
2. Set the end-points (EPA). Do this with the dual rate set at 100% (no more no less). You should be hitting full lock, but not straining the servo.
3. On the track, set the trim for straight line running
4. Dual-rate limits overall steering
5. Expo can be used to make the steering less responsive near the centre
6. Speed will slow the servo down

4/5/6 should all be used in moderation - go too far and you will make the car safe but slow. Try and be smooth with your inputs instead of relying on the radio.

If the car is still very twitchy, it's going to be a build or setup issue.

Thanks for your inputs guys, I will test out your recommendations.