Chain vs Gears

Hello, this was a question posted already, but since it was derailing the thread, I figured I’d ask it here.

What do you prefer to link up your drive, gears or chains? Why?

Also should I attempt to inhibit my robots climbing abilities so that I dont accidentally climb cubes?

Thanks!

I prefer gears just simply for the fact that they have a much lower possibility of failure, and have a lot less friction than any chain drive. You should also make your chassis so that you can’t go over cubes, but this should only mean that your wheels aren’t exposed on the front/ back of your robot.

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Gears are better, but chain has the advantage of being easier to set up and working no matter what the distances are between the wheels.

After our experience with chain drives at Worlds (our chain snapped like twice just due to tension caused by defense), we have decided to never use chain on our drives for sure. We are going to try to avoid chain as much as possible.

Gears have the advantage in that the only way they can break is if teeth physically snap. And even if that happens, at least the gear is still functional and you can use the device somewhat normally for the rest of a match.

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Gears are definitely better in the vast majority of cases (as others have already said) but chain is fine if you do it right. I had chain on all 4 of my robots that I used throughout Turning Point and it never snapped once. You just have to tune chain a little.

I prefer gears, but one thing that is useful for chain is to have your motors directly drive your wheels and then chain drive your wheels together. So if one wheel slips you don’t waste any energy. 11495B did this and it gave them a very strong drive train.

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Both chain and gears have their own strong and weak points and either could be used correctly or incorrectly.

If you tension the chain too much - you get a ton of extra friction, but gears are not immune from that either, if you don’t secure all bearings or don’t align all the axles properly.

If you have too much slop in the chain, or sprockets are not perfectly aligned to be in one plane, then it could easily break from sudden shocks.

In general, I would use gears if you need to transfer power over the short distance and chain if you need to do it over the long distance. Each axle adds additional friction and having geartrain going all the way from one side to the other is not very practical.

In the ideal chassis you would have all four wheels directly powered by a motor with chain connecting front and back wheel. This way it is used only in case if front or back wheels lose traction and you need to transfer excess power to the other side.

The trick to use chain is, first, to align the sprockets perfectly in one plane, and then make sure there is neither extra slop nor extra tension, to minimize friction. You need to do a free spin test (when motors are not connected) by initially spinning the wheels by hand and having it run for, at least, 8-10 sec after that. Otherwise, something is adding extra friction and you need to fix that.

Another good habit is to inspect the chain for any loose, tight, damaged, or crooked links. Each could introduce their own potential issues and it is always pays off to spend 1 hour at the beginning of the season and not having to worry about chain snapping in the finals, or when you need it to work the most.

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