pic: 18 Tooth #25 Sprockets Inside VersaChassis

As I was playing around in Solidworks with the new VexPro/WCP lineup, I discovered that the switch from the standard .125" wall tube used in a WCD to a .1" wall tube grants enough clearance to allow for the use of a Vexpro #25 18 Tooth Sprocket. This really helps to save space in the drivetrain!

It’s safe to say that I’m a fan of these new products. Can’t wait to see this in use during the 2014 season!

With the sprocket and chain installed, how much clearance do you have between the chain and inner wall of the tube?

SolidWorks tells me it’d be around .055" clearance vertically without chain installed. I don’t know off the top of my head how much the chain would extend past the teeth. Either way, it’s a cozy fit, but it “works” in CAD (granted, that’s not a guarantee of success). I’ll have the opportunity to test it using real parts sometime in the future, so i’ll post results when I get the opportunity to mock it up.

The 16T sprockets are plenty big for 4" wheels and give you a tad more clearance.

Really, now… I wasn’t sure if 16T would be big enough.

Do you have right to left clearance in those tubes to run dual sprockets on one shaft with the .1 wall thickness? I tried last season for our shooter gear box but had to make two plates instead of using our 1x3x.125 Al box.

Nice looking model.

We have been putting 16T #25 chain inside 2 x 1.5 tube for a couple of years. If you want to do a drop center 16T is as small as you can really go. Your chain will start to stretch and loosen up, rub a bit against the wall of the tube. Assembly of 18T will be almost impossible and if you are just running a 1:1 ratio between wheels why go with an 18T?

I really believe Versa is going to really change things for teams with limited fabrication abilities.

The main reason for going with a higher tooth count sprocket is to reduce the load in the chain and increase # of teeth that are meshed. Both influence how robust the system will be.

Two strands of #25 fit side-by-side inside a standard “1x2"x.125” wall tube.

We use 17 tooth double sprockets inside of our SimpleTube Chassis.

You cannot have any drop in this setup because of clearance around the chain.

Otherwise the system is great and is a nice volume save. FRC118 used this same setup for 2013 with zero failures and maintenance issues.

How do you get away without any drop? No problems turning?

They had different diameter wheels. Pretty cool stuff!