Chain vs. Belts?!?

[DrewMatic]

Hey everyone. I'm from team 240 T.E.M.P.E.S.T.

The past 2 years we have used chain everywhere. There was one thing that happened, we had to fix the chain a lot more than we liked too. I know this could be due to poor alignment, etc. but next year we plan on using belts.

What are your thoughts on Chains? Belts?

Thanks, Drew

[pilleya]

This is a topic that is discussed quite often.

There is a good white paper written by team 234 which evaluates the power transmission methods:

https://www.chiefdelphi.com/media/papers/2216

[DrewMatic]

Originally Posted by pilleya

This is a topic that is discussed quite often.

There is a good white paper written by team 234 which evaluates the power transmission methods:

https://www.chiefdelphi.com/media/papers/2216

Thank you! I'll check it out

[Sperkowsky]

Its worth mentioning that if the issue was alignment whether you are using chains, belts or interlocking plastic monkeys the issue wont be solved.

If you are using #25 chain and there are alignment issues switching to #35 could help but really the best thing to do is fix the alignment.

If your issue has to do with master links I would buy a dark soul chain remover.

iirc belts actually are more sensitive to being out of alignment so switching to belts is only going to make things worse.

[Monochron]

Originally Posted by Sperkowsky

iirc belts actually are more sensitive to being out of alignment so switching to belts is only going to make things worse.

QFT.

If alignment or tolerance is what is causing you problems now, switching to belts will make the situation much worse.

[InFlight]

We successfully used a Polycord drive system in the past. One of the center wheels was direct driven by a custom super shifter based gearbox. The other wheels are all direct driven by Polycord using custom pulleys directly attached to the wheels (Dead Axles). This is the best picture I could find of the drive train. (This is one of our signature Round Robots)

[ASD20]

Originally Posted by InFlight

We successfully used a Polycord drive system in the past. One of the center wheels was direct driven by a custom super shifter based gearbox. The other wheels are all direct driven by Polycord using custom pulleys directly attached to the wheels (Dead Axles). This is the best picture I could find of the drive train. (This is one of our signature Round Robots)

Attachment 20906

Out of curiosity, what year was it? Also, did you have any problems with the polycord slipping in shoving matches or other high-torque situations?

[InFlight]

Originally Posted by ASD20

Out of curiosity, what year was it? Also, did you have any problems with the polycord slipping in shoving matches or other high-torque situations?

That was the 2014 season, Our Jupiter Robot. No real noticeable issues with belt slip.

Here a match from that season with plenty of pushing.
http://www.thebluealliance.com/match/2014pncmp_qm41

[ASD20]

Originally Posted by InFlight

That was the 2014 season, Our Jupiter Robot. No real noticeable issues with belt slip.

Here a match from that season with plenty of pushing.
http://www.thebluealliance.com/match/2014pncmp_qm41

Wow, I never would have thought that polycord would work in a year like 2014. I'm impressed.

[Michael Hill]

There's no single correct answer (despite what some CDers would say) of what you should use. It all depends on your situation. If you need the weight, you may need to go with belt. If it's going to be a giant PITA to change a belt, you may need to go with a chain.

In my opinion, the "default" choice, when nothing really matters, you just need a reliable drivetrain, is to go with #35. It doesn't break, it's dead simple, it's forgiving, but is heavy. However, the "nothing really matters" portion is rarely the case and each situation needs to be handled on a case-by-case basis. What is important is knowing the tradeoffs (which have been outlined pretty well already in this thread). I wouldn't, however, deviate from the "default" of #35 chain without a good reason. The good reason may be weight related or space related, but you should at least have one.

[ASD20]

Originally Posted by Michael Hill

In my opinion, the "default" choice, when nothing really matters, you just need a reliable drivetrain, is to go with #35. It doesn't break, it's dead simple, it's forgiving, but is heavy. However, the "nothing really matters" portion is rarely the case and each situation needs to be handled on a case-by-case basis. What is important is knowing the tradeoffs (which have been outlined pretty well already in this thread). I wouldn't, however, deviate from the "default" of #35 chain without a good reason. The good reason may be weight related or space related, but you should at least have one.

Agreed. My team has learned the hard way to just use #35. The way I like to think about it is that #35 is complete overkill for FRC, which is why its the best option for FRC. Since it is overkill, it is a lot harder to mess up and will just work, which is exactly what you want for a drive train. The question you should be asking whenever you use chain should be why should I use #25, not why should I use #35.

[MichaelBick]

Originally Posted by ASD20

The question you should be asking whenever you use chain should be why should I use #25, not why should I use #35.

This year my team's robot had 8" wheels and 22t sprockets, which stressed #25 chain more than in any of our previous drivetrains, and had zero issues. On the other hand, we broke our #25 intake arm chains multiple times, and in the future we will likely use #35 chain for arm applications. At least for our team, we have found applications for both #25 and #35 chain.

[asid61]

Originally Posted by Michael Hill

There's no single correct answer (despite what some CDers would say) of what you should use. It all depends on your situation. If you need the weight, you may need to go with belt. If it's going to be a giant PITA to change a belt, you may need to go with a chain.

In my opinion, the "default" choice, when nothing really matters, you just need a reliable drivetrain, is to go with #35. It doesn't break, it's dead simple, it's forgiving, but is heavy. However, the "nothing really matters" portion is rarely the case and each situation needs to be handled on a case-by-case basis. What is important is knowing the tradeoffs (which have been outlined pretty well already in this thread). I wouldn't, however, deviate from the "default" of #35 chain without a good reason. The good reason may be weight related or space related, but you should at least have one.

Belt and chain weight is the same when you factor in pulleys/sprockets. That being said I 100% agree that #35 is bulltproof and should be used for a "first chassis" sort of deal.

[FrankJ]

Originally Posted by asid61

Belt and chain weight is the same when you factor in pulleys/sprockets. That being said I 100% agree that #35 is bulltproof and should be used for a "first chassis" sort of deal.

Assuming you are using aluminum pulleys, the pulley/sprocket weight is probably close to a wash. Factor in 35 chain, the chain is a lot heavier.

Polycord will slip given enough torque. That is either a bug or a feature depending on your needs.

[asid61]

Originally Posted by FrankJ

Assuming you are using aluminum pulleys, the pulley/sprocket weight is probably close to a wash. Factor in 35 chain, the chain is a lot heavier.

Polycord will slip given enough torque. That is either a bug or a feature depending on your needs.

I was thinking about #25. For #35 nothing beats it in terms of weight.

EDIT: InFlight, that is a gorgeous robot and a great performance! I can't believe polycord drive worked that well.