[BrendanB]

A downside to shifting is the added complexity of your robot and maintainence. More moving parts, more components, etc. Another area with increased chance of failure if not done properly and the last place you want failure is your drivebase!

We have had a issues in the past two seasons with our pistons slipping out of gear either limiting us to either low, high, or neutral. Thankfully our team has never experienced neutral in match but it has happened during drive practice. We use AM Supershifters and we haven't found much of a remedy aside from checking the pnuematic mounts every few matches but once you release the air from the system its not hard for the AM shifters to switch gears. If we use shifters again in the future we'd look into better ways to get around this problem like using springs to keep the piston in low gear when their isn't pressure in the system and redo some of the mounting for a more permanent/solid fit.

We did have an issue during 2011 where the shifter was sent with an extra washer resulting the one gearbox being compressed when assembled. It resulted in the jags on one side being overworked and shutting down at various points in the match. It was hard to chase because we took apart that shifter so many times each time it was tighted differently. Our first event it happened once a match but during our second event it was happening every 5 seconds. Lesson learned: make sure you know everything about your shifter what belongs and what doesn't!

When using shifters especially COTS you really need to make sure you need them. For teams who make their own transmissions it is easy to customize your ratios and mountings for better speeds to fit your strategy and save weight.

Of the robots I've worked on we have used supershifters three times:

2010 (1519): We used supershifters mainly to have high torque and low speed for crossing the bump and defense. They were very handy to have we spent most of our matches in low gear but high was great for quickly transitioning from one goal to another to get around defenders or get another balls. Super low speeds were used to get balls off the wall and line up with the goal.

2011 (3467): Our design as a rookie placed defense as a top strategy with our minibot and low row arm. We had a nice 6wd and planned to use shifters for defensive pushing matches. IMHO bad move. It was hard for our driver to transition from low to high speeds easily to adjust for what was happening on the field. Low gear was too slow to keep up with opponents and instead we played in high gear to keep up with faster robots and once we got into a T-bone push we'd were supposed to switch to low. I believe our driver kept just kept it in high gear to keep up some quick machines like 177, 40, 131, 33, 1718, 118, etc. We could have done the same with toughboxes and used the weight elsewhere but since defense was our priority it served us well. If we replayed 2011 I would push for single speeds dependent on our strategy.

2012 (3467): Used them for crossing the bump, balancing, and lining up on the bridge. I know a lot of people asked why you would need high gear but we made use of it by quickly going to the other side to grab balls before heading back and spent most matches collecting balls in high gear. Great choice for our robot.

It really comes down to your robot as a whole and the field you play on when decided whether to shift or not. While most powerhouse teams have two speeds they aren't required to win events or do well on the field. Using single speeds is one way you can keep your robot simple and focus energy on other areas.

As for when to shift it depends on why you put those shifters on. Was it to push? Was it to cross something that required low speed? How high is your center of gravity and what speed is safest for when your manipulator is up in the air?