AndyMark 3CIM Single Speed Gear Box

[underdog1924]

Does anyone have a picture of an AndyMark 3CIM Single Speed Gear Box (http://www.andymark.com/product-p/am-14u-tc.htm) that is installed in their AM14U drive base? I'd like to get an idea of the space it takes up and any clearance issues.

[Spirator]

I have an image, but it's missing a miniCIM at the top.

http://i.imgur.com/kj65I7O.jpg

[Richard Wallace]

You can see ours in a few places:

https://twitter.com/rwallace931/status/437745447239569409/photo/1

http://www.chiefdelphi.com/media/photos/39384

http://www.chiefdelphi.com/media/photos/39382

[underdog1924]

Thanks for the pics. Definitely not enough room in our drive base for those to fit. Oh well...

[Oblarg]

Out of curiosity, is it possible to change the gear ratio in the AndyMark 3CIM gearboxes? 8.46:1 is a bit slow for three CIMs on a 4'' wheel.

[z_beeblebrox]

Out of curiosity, is it possible to change the gear ratio in the AndyMark 3CIM gearboxes? 8.46:1 is a bit low for three CIMs on a 4'' wheel.

Look here for more ratios:
http://www.andymark.com/ToughBox-p/am-2760.htm

[sailer99]

Out of curiosity, is it possible to change the gear ratio in the AndyMark 3CIM gearboxes? 8.46:1 is a bit low for three CIMs on a 4'' wheel.

Yes, you can definitely change the gear ratios. The internals of the 3 CIM gearbox are the same as the regular toughbox mini so you can change gear ratios using the same upgrade packages. We use the 3 CIM upgrade gearboxes with the second stage reduction changed using 24 Tooth Gear (http://www.andymark.com/product-p/am-0177.htm) to a 40 Tooth gear (http://www.andymark.com/product-p/am-0178.htm). This changes the overall reduction to 5.95:1 which we find works quite well.

[Oblarg]

Look here for more ratios:
http://www.andymark.com/ToughBox-p/am-2760.htm

Ah. 5.95:1 is far more reasonable.

Might try these out next year instead of the WCP gearboxes, if they stick with the AM14U-style kitbot.

[Billfred]

Ah. 5.95:1 is far more reasonable.

Might try these out next year instead of the WCP gearboxes, if they stick with the AM14U-style kitbot.

Knock on wood, they've been dead-on reliable through Palmetto and a lot of driver testing. We'd do it again!

[Michael Yeh]

Out of curiosity, is it possible to change the gear ratio in the AndyMark 3CIM gearboxes? 8.46:1 is a bit low for three CIMs on a 4'' wheel.

We purchased VexPro 44t and 20t gears and just the plates for the AndyMark gearboxes, intending to achieve a 7.86:1 ratio if we needed it. We also had the gears from the kit drivetrain, which seem to be identical.

The VexPro gears are thicker than AndyMark's due to the nub on both sides, though since we made our own spacers (churro tube) it wouldn't be difficult to grind down the nub or make longer spacers.

Another question about the 3CIM4U: is the output shaft supposed to be longer than the kitbot's? We recycled the one from the kitbot but since there's now 1/8" of gearbox in between it doesn't fully extend into the outer bearing.

[Oblarg]

Knock on wood, they've been dead-on reliable through Palmetto and a lot of driver testing. We'd do it again!

Yeah, I don't see any reason to pay 2x the price for fancy looks; I'd have gotten these this year if we hadn't ordered our gearboxes on kickoff.

I've never had any problems with AM gearboxes with aluminum cases, and I've used loads of them over the years. I find their plastic ones are unsatisfactory, though.

[nixiebunny]

Another question about the 3CIM4U: is the output shaft supposed to be longer than the kitbot's? We recycled the one from the kitbot but since there's now 1/8" of gearbox in between it doesn't fully extend into the outer bearing.

We used the long shaft that came with the upgrade kit. It doesn't protrude fully into the bearing, but it is in deep enough to work. No troubles through the Hub City regional.

Beware that the inner spacing is also different due to the gearbox plate - we had to add a VexPro 1/2 hex plastic spacer between inner plate and wheel to keep the wheel hub bolts from scraping the inner side plate. We also had to file the AM14U bearing holes as the spacing between them was different from the 3CIM gearbox.

[Oblarg]

we had to add a VexPro 1/2 hex plastic spacer between inner plate and wheel to keep the wheel hub bolts from scraping the inner side plate.

We did this for our WCP gearbox, too, and it worked like a charm.

[Michael Yeh]

Not having any of the Vex spacers on hand, we found that a 1/2" sch 40 PVC pipe fits loosely onto hex shaft. (0.622" nominal ID on .578" diagonal of the hex).

We didn't notice any issues with bearing spacing on the AM14U and 3CIM4U, but we'll double check when we get to Greater DC.

Also, clarification of "doesn't fully extend into the outer bearing" - the shaft from the plastic default box does ride on the outer bearing, just not all the way through so I assume the shafts are the same.

[nuclearnerd]

I have an image, but it's missing a miniCIM at the top.

http://i.imgur.com/kj65I7O.jpg

You should sell those yellow corner braces for the AM14U! We had to whip up something similar a day before bag-day on account of bent churros.