pic: 2009 robot idea

[AndyB]

You want to shoot for around 120 degrees of chain wrap as a minimum and I think with your current run, you will see major slippage problems with you center axle.

Try moving your tensioners inward or split it into two separate chain runs.

[pacoliketaco]

yeah, i guess i didnt make that clear enough, there would be a separate chain going in each direction

[tseres]

this is the classic thread of one infected with the FIRST bug. i love it!

[AndyB]

Oh, sorry. Looks good then. I know you designed this to fit the supershifter gearbox, but it might be easier to make if you used 4" tall sides instead of 5".

With 5" sides, you would need to order plate and cut it to length and width.

With 4" sides, you can just purchase 4"x3/16" Extruded Flat Bar and cut it to length.

I guess if your gonna CNC or waterjet them anyways, it isn't that big of a deal, but I'm pretty sure flat bar is cheaper than plate anyways. (I can not find 5"x3/16" extrusion anywhere).

[s_forbes]

Looks good, nice and simple like it should be. I'd prefer just using dead axles in this particular set up for the end wheels, it would probably cheaper and easier to build. Either way, it looks like a very solid drivetrain.

Does anybody else notice the trend lately of putting the wheels between two plates held together with standoffs? I may be imagining, but there seem to be a lot of teams using this method recently...

[sdcantrell56]

I agree there has been a trend for this and we are guilty of it as well. I have tried many different drivetrains and this method (2 plates with standoffs) really seems to be the best one I have done. It is particularly good if you are sponsored by or have access to sheetmetal stuff aka Laser or waterjet because the entire frame for the drivetrain can be knocked out in a couple hours. Also it allows for really quick assembly and wheel changes as well as it is super easy to incorporate the transmission into the frame, thus reducing weight.

[Tom Line]

One thing - I always like keep things simple and easy with few parts.

Have you considered just using aluminum C-channel (or even square tubing) for the left and right areas where the wheels are? A hole saw can make quick weight savings holes, and you don't need the fasteners, the machining, etc. It's stronger, lighter, and easier to make. Just a suggestion.

[EricH]

Originally Posted by AndyB

You want to shoot for around 120 degrees of chain wrap as a minimum and I think with your current run, you will see major slippage problems with you center axle.

Try moving your tensioners inward or split it into two separate chain runs.

If that's one chain run, then I want to know how he got a spiral chain wrap.

It's two, with about 180 degrees for each chain and sprocket.