25 Series Chain

[abrown128]

I was wondering if I could get an opinion on 25 series chain and whether it would be strong enough for a swerve drive, rotating the modules and driving the wheels.

[AdamHeard]

Originally Posted by abrown128

I was wondering if I could get an opinion on 25 series chain and whether it would be strong enough for a swerve drive, rotating the modules and driving the wheels.

The short answer is yes. We've done it, I know 1625 has done it, I think 118 did it and I'm sure there are others.

The long answer is it depends. The Size of the wheels, torque of steering motors, size of sprockets, etc... Chain manufacturers post specs for their chain, and it actually isn't too difficult to check if your within the working range.

[DonRotolo]

Strong enough? Yes, plenty.

Easy to work with? Not exactly. Because of the smaller sprocket tooth size, the tension of the chain is critical, much more so than #35. But, manage that properly and it'll be fine. Key word: Properly.

[ttldomination]

We made a C-base this past year with #25 chain on it. We put it through it's paces and put it in some tough pushing matches and it faired really well, meaning it didn't break.

[Nick Lawrence]

Yes, #25 chain is plenty strong enough, as long as it's tensioned properly, and is not subjected to any twisting forces. Because it's so small, #25 chain is quite sensitive to being twisted, much more than #35 chain.

We used it to steer our swerve modules on our 2007 robot, and it faired pretty well.

-Nick

[Matt382]

I just want to add a few things about #25 chain. You can really only buy master links for #25 chain online, most local retailers won't have any smaller than #35. Also, the clips on the master links really like to pop off (it has happened to our robot twice last year, once during build, once during a match, and our chains were properly alligned with little or no twisting forces). Check them frequently to see if they are bent if you can, and if you have to take on off, replace it with a different clip.

[AustinSchuh]

Originally Posted by Matt382

Also, the clips on the master links really like to pop off (it has happened to our robot twice last year, once during build, once during a match, and our chains were properly alligned with little or no twisting forces).

Interesting. Apart from one time*, I've never had that problem on any of the bots I've helped with. That comes from 3 years of using #25 chain on 971's drivetrains and arms, and mentoring 254 this year (though I haven't heard of them having trouble with that in the past either). I'd say you guys need to make sure that the clip on the master link seats in it's grove before you call it done.

*The only problem I have ever had with that was when the kid who cut the chain to the right length inadvertently pried apart the sides of the link with the chain breaker so that it was too wide for the clip on the masterlink to seat. He didn't know that that could happen and cause a problem, so he didn't worry about it when he cut the chain. I carefully squeezed it back into shape with a wrench, and we never had a problem again.

[sgreco]

25 chain should be strong enough for pretty much all applications on a first robot. My team used it on our swerve steering in 2008, and never had a problem.

[Al Skierkiewicz]

We use #25 and custom built adjustable chain tensioners for the obvious reasons and for wheel alignment.

[martin417]

1771 has used #25 chain as our drive chain for the past two years w/o a failure. Although the floor and wheels made this year a poor example since they limit the stress on the whole drive train.

[Tom I]

I would recommend using a spring tensioner for it, because this way you're guaranteed to have tight chain. The problem with adjustable chain tensioners with screw adjustments is that they can come loose.