pic: Prototype 6WD

[Jim Zondag]

I totally agree, #25 chain is more than adequate. We have used #25 chain in our Drivetrains for years and never had any issues (providing that everything is assembled correctly). #25 chain will not break until you put over 900 lbs of tension on it. It is pretty much impossible to apply this level of force in a FIRST robot drivetrain.

The 3 main issues I see team have with #25 chain are:
1. Alignment - If you don't line up your sprockets you will have issues
2. Frame Rigidity - If your frame is not bolted together tightly, things will come out of alignment when torque is applied.
3. Workmanship - I see lots of teams who mangle #25 chain when removing links. This can create a stiff spot in the chain where it will not bend properly. This will make it more likely to derail. It is much harder to do this to #35.

So basically, the advantage of #35 is that it allows you to be sloppier in your design and fabrication. If you pay close attention to these details, you will never have a problem with #25 chain.

[MrForbes]

Originally Posted by Jim Zondag

So basically, the advantage of #35 is that it allows you to be sloppier in your design and fabrication.

This is a big benefit for many teams....maybe not yours...but still.....

[Rick TYler]

Originally Posted by Jim Zondag

So basically, the advantage of #35 is that it allows you to be sloppier in your design and fabrication. If you pay close attention to these details, you will never have a problem with #25 chain.

This is part of what I think of as fault tolerance. You can stack a lot of errors a #35 chain will still work.

[AdamHeard]

Originally Posted by Rick TYler

This is part of what I think of as fault tolerance. You can stack a lot of errors a #35 chain will still work.

Fault tolerance is good, but there can be several pounds difference between #25 and #35 chain in a drive. As far as I've been on 973, running a west coast drive with #25 chain, we've yet to throw a chain. I know many other teams have similar successes with #25 chain.

To me, it's a no brainer, if you can allign it right..... which isn't very difficult, it's an easy choice.

[Cory]

We've never broken a chain since I've been on 254.

We've never thrown a chain either.

The one time we "lost" a chain was when we got hit so hard a sprocket broke, at which point the chain derailed.

It didn't even break. It stayed on the drive sprocket in the gearbox and somehow just kept spinning without completely destroying the gearbox.

I can't ever imagine using #35 chain in a drive again. The added size of the same tooth count #35 sprocket makes every gearbox, mechanism, etc larger, not to mention the additional weight of the chain and sprockets.

I don't believe that there's any team that's not capable of properly aligning and tensioning #25 chain if they put a little thought and planning into it, regardless of their manufacturing resources.

[MrForbes]

You're probably right Cory, but there are a lot of teams who's effort might be better spent working on the game playing parts of the robot....

#35 works, it's easy, it's cheap, it's in the kit, etc.

[Gary.C]

Originally Posted by AdamHeard

Fault tolerance is good, but there can be several pounds difference between #25 and #35 chain in a drive. As far as I've been on 973, running a west coast drive with #25 chain, we've yet to throw a chain. I know many other teams have similar successes with #25 chain.

To me, it's a no brainer, if you can allign it right..... which isn't very difficult, it's an easy choice.

Originally Posted by Cory

We've never broken a chain since I've been on 254.

We've never thrown a chain either.

The one time we "lost" a chain was when we got hit so hard a sprocket broke, at which point the chain derailed.

It didn't even break. It stayed on the drive sprocket in the gearbox and somehow just kept spinning without completely destroying the gearbox.

I can't ever imagine using #35 chain in a drive again. The added size of the same tooth count #35 sprocket makes every gearbox, mechanism, etc larger, not to mention the additional weight of the chain and sprockets.

I don't believe that there's any team that's not capable of properly aligning and tensioning #25 chain if they put a little thought and planning into it, regardless of their manufacturing resources.

Same Here, Madtown has been using #25 chain after there rookie year back in 2004. We have never tossed chain during Competition. Its a pretty simple concept, line up the chain and tighten the set screw on the sprocket.

[Sam N.]

I really like the use of your slotted bumper mounts.

[spazdemon548]

Everything looks very sound. One trick I learned from Simbotic's drivetrain back in 2008 is, if you line up the pneumatic cylinders on the shifters, you can eliminate a cylinder by linking both to an end of a new one with double the stroke.