Quote:
Originally Posted by BoilerMentor
In my FIRST career there are a number of things I've been conditioned to avoid because of bad experiences (none of these specifically from the three cim ball shifter situation discussed within this thread)
Aluminum gears, cantilevered shafts, and #25 roller chain are standouts on that list.
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Don't blame the parts, blame your implementation.
Hundreds of teams have used all of these things every year without any problems whatsoever. The only time I've shredded an aluminum gear is when it was taking huge shock loads that were far more than the gear was ever supposed to support at the end of a very large reduction. My old team has used cantilevered driveshafts since 2011 without any failures. We have never failed a 25 chain in any case, even when undertensioned and slightly misaligned. Avoid what doesn't work for you, sure, but if you can't make things work that work for everyone else, you probably have bigger problems.
Quote:
Originally Posted by GeeTwo
It depends on how much pushing you're doing, and (more importantly) how hard the collisions are. The case where you're most likely to need steel is on the bull gear (gear nearest the wheel) and the gear that engages it. It would take a truly extreme case to require steel gears in the earlier stages, or even on the bull gear for simple pushing without collisions.
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This is entirely conjecture. Properly aligned and sized for the application, in a drivetrain you should basically never fail an aluminum gear no matter how hard you're pushing. Maybe if your output gear is 14 teeth or something crazy like that you'll have a failure, but in normal applications you'll be totally fine.