Author Topic: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks  (Read 21526 times)

BullCrusher

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Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« on: September 22, 2017, 11:03:44 am »
Hello, we're entering our first robot combat competition.. myself and my 3 sons (7, 7 and 9).  One of their favorite movies is Real Steel (mine too! Ha).  They play it on Xbox and were super excited when I told them we might enter a robot fighting competition.  I actually bought an Ant Class kit and have it at my house, only to find that the Ant class was full.  Since, the next local competition is next year, I looked at the other weight classes and the only one they had open was 30 Pound Sportsman's Class.. ha.  So we’re going for it..  We have pretty much 0 experience, so we’re relying on your advice and what we can get from YouTube/online searches.  Ah.. and the best part, is that it’s in 4 weeks.. ha.  I don’t expect to win, but it would be great to enter and last 30-60 seconds.. ha.  And learn a lot in the process..

Here's the event:
http://buildersdb.com/view_bots.asp?eventid=474&classid=123


The rules for "Sportsman’s Class" are different than normal (basically I have to make a robot w/out a weapon, no spinners like Tombstone, etc):
http://www.nerc.us/rules.html



Ha, please bear with me here because I know this total a newbie post, but you have to start somewhere.. ha.  Any advice would be much appreciated.  I'm basing a lot of my info below on this YouTube series:

https://www.youtube.com/watch?v=8_kWYewQmV0&t=239s


So, here is what I think I need:

speed controller
drive motors
battery
receiver
main power switch
led light
Chassis
Weapon



2 of these for the motors (I'd like to use 4, but I'm not sure how much harder that would be to add with the speed controllers, etc):
https://www.amazon.com/LDX120-Cordless-Lithium-Ion-Without-battery/dp/B014F13ZQK/ref=sr_1_13?ie=UTF8&qid=1506086991&sr=8-13&keywords=drill+20v



Battery (not sure if this would power the 2 (or 4) drill motors):
https://www.amazon.com/Duratrax-5000mAh-Battery-Standard-Connector/dp/B004AF88K0/ref=pd_lpo_vtph_21_tr_t_2?_encoding=UTF8&psc=1&refRID=8YNSH1DYN28YZBFNSXCW
(Onyx 7.2V 5000mAh)

Charger:
https://www.amazon.com/Duratrax-Onyx-Sport-Peak-Charger/dp/B001BCF4YS/ref=pd_bxgy_21_img_2?_encoding=UTF8&psc=1&refRID=M9QRDAZK43478TJZ8Z3X



For the mounts, I'd use a bracket and a hose clamp



Wheels, I'd use something like:

https://www.vexrobotics.com/colsonhubs-g.html (live hub, would this work w/ the drill motor?)

https://www.vexrobotics.com/colsonperforma.html (Colson Performa (4" x 2", 1/2" Hex Bore), I think this would fit the live hub above.  If not, I'm not sure how to mount the wheel to the motor)



Speed Controller:
2 of these (I'd like to use 4, but I'm not sure if it will make it more complex w/ the speed controllers):
https://www.amazon.com/FPVDrone-Brushless-Controller-Quadcopter-Multicopter/dp/B06XKTRZB7/ref=sr_1_2_sspa?ie=UTF8&qid=1506086805&sr=8-2-spons&keywords=esc+bec&psc=1

or 1 of these:
https://hobbyking.com/en_us/turnigy-brushless-esc-85a-w-5a-sbec.html (not sure if 1 would power 2 motors (or 4), or if I need 2 of them)



Transmitter & Receiver (not sure if this is overkill??  I'd go cheaper if it didn't matter):
http://www.robotcombat.com/products/0-SPM6750.html



Power Switch (not sure if 40w is enough):
http://www.robotshop.com/en/fingertech-40a-mini-power-switch.html?gclid=EAIaIQobChMIqd_VqPy41gIVlUsNCh3klwkbEAkYASABEgLg8fD_BwE



LED Light:
https://www.vexrobotics.com/276-2176.html



We'd need a weapon since it's 30 pound Sportsman, so I guess I'd get another drill motor and make a hammer?? Ha.  Not sure how to mount that one, or hook it up to the receiver/transmitter.



For the Chassis, I know this may not be ideal.. ha.  I was thinking about using something like this (one on bottom, one on top.. since it's the Sportsman’s Class, I don't know if I'll need that much enforcement for the body.)  I may coat them in a metal sheet once everything is put together, then put the weapon on top:

https://www.amazon.com/gp/product/B072Q1BVN1/ref=ox_sc_act_title_1?smid=A14OC4U1AR3DMT&psc=1


Anyway, thanks for reading this far!   We appreciate any advice you can give here.. Thanks!




BullCrusher

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #1 on: September 22, 2017, 08:59:09 pm »
Any small piece of advice on even 1 part of the robot would be awesome!  Thanks!!

MikeNCR

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #2 on: September 22, 2017, 11:34:46 pm »
A few quick things-

I haven't used those drill motors myself, they may work fine, they may not. Banebots and e0designs both have higher quality options that'll work. There's also http://ttrobotics.com/19-2-volt-robot-motor-new/ which is a pre-hacked drill motor that'd be reasonably suited for combat. If you're using a drill motor you'll also want to look at these for hubs and match the wheels to it- http://ttrobotics.com/tiki-tophat-drill-motor-colson-hub/

Assuming you're planning to wire the batteries in series, 14.8v, 5000mah will be plenty for a 30lb bot. For Franklin another option would be LiFe batteries as they've got a better power to weight ratio. You'll want to match the charger to whatever battery type you're planning to use. (and ideally, consider what types you'll want to use in the future so you don't have to buy a new charger soon) In addition to that, you may not have time to fully charge your batteries later in a tournament so having a full spare set of batteries is a good idea in the long run. With that said, you'll probably be able to run two fights on 5000mah unless your weapon's drawing a massive amount of power.

Colsons are a good baseline wheel option, you'll need to match up your wheels to your hubs, and your hubs to the shaft they ride on. Live hubs are for spinning shafts, dead hubs are for fixed shafts.

If you're using drill motors they're almost certainly going to be brushed, not brushless unless they specify otherwise. The Holmes Hobby BR-XL is a good 30lb esc option, the RageBridge from e0designs is another good one. ESC's are one area I'd strongly suggest not skimping on as a good esc that's well matched to your motors will likely outlast the bot.

The DX6 is fine as a transmitter, I use spektrum transmitters with the hobbyking OrangeRX receivers (make sure you're getting the right type) and have been happy with that mix. Be sure that whatever rx you get failsafes correctly.

The Fingertech Switch has been used in harsher applications. I prefer the Whyachi MS-05 or a removable link for 30lb bots but if you're not drawing a ton of current it'll work.

For LEDs this is a better option: https://www.fingertechrobotics.com/proddetail.php?prod=ft-power-led

For a 3rd motor you'll need an esc to run it and for a hammer you'll probably want to hook it up to the rudder channel on the rx. A drill powered hammer won't be the most powerful weapon, but that's not really the point and building the bot will be a good learning experience.

Cutting board can work as structure/armor. It's not the best option but you'll likely manage to get by. I'd suggest extra layers/armor in areas that are likely to get hit in combat.

If you want to take a look at another 30lb build for ideas I've got a full instructable up for my sportsman class bot Nyx at http://www.instructables.com/id/Nyx-30lb-Fighting-Robot-Re-Made/

BullCrusher

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #3 on: September 23, 2017, 04:00:10 pm »
Nice!  Thanks for your reply.  Your Nyx bot is awesome!  Yea, I'm definitely not expecting anywhere near that level right now.  Just something that qualifies to fight!  ha.

If you have a few minutes, I could really use your advice on the following..


So I'm 100% open to specific suggestions.  From what you said:

Battery (would this be good?):
https://www.amazon.com/Hobbico-LiFeSource-Phosphate-Transmitter-Connectors/dp/B00NE05F8A/ref=sr_1_1?ie=UTF8&qid=1506193299&sr=8-1&keywords=%2BLiFe%2Bbatteries&th=1


Charger:
https://www.amazon.com/Hobbico-Lifesource-AC-Balance-Charger/dp/B004QJTSVS/ref=pd_bxgy_21_img_2?_encoding=UTF8&psc=1&refRID=65D6PQFYYAT6SEAFAHSZ&dpID=51vdtdfM47L&preST=_SX342_QL70_&dpSrc=detail


ESC (Is this the ESC you recommend.. would I need 2 or just 1?  It says brushed, so this would work w/ the drill motors?):
https://www.hobbytown.com/torquemaster-brxl-brushed-esc-by-holmes-hobbies-hhbtmbrxl/p195994?gclid=EAIaIQobChMI-rXmgIG81gIVhLXACh307AM4EAkYASABEgIbVfD_BwE


LED Light:
https://www.fingertechrobotics.com/proddetail.php?prod=ft-power-led


With the motor, I would def be good with buying the motor from RobotShop or whatever, but I'm not sure what size to buy or how that would affect the ESC.  I'm basing it off the YouTube video.  I don't really get the gearbox / motor.  Do I need both?  I thought I could only use a motor and connect that to the wheels somehow.. ha.  You mentioned the Magnum 775:
http://www.robotmarketplace.com/products/0-magnum775.html


Wheels (I don't really understand how this will attach to the motor.. I'd need a wheel hub?  But would I make it?  It seems like TeamTiki may not be servicing their website orders anymore b/c when I went to purchase a drill motor, it said they were out of stock and I don't see a contact form):
https://www.amazon.com/Performa-Bearing-1-3-441-Hi-Tech-Encore/dp/B0195V3FD8


Switch:
I'm having a hard time finding the Whyachi MS-05.  I checked a bunch of sites.  Would this one work?  Not sure b/c it says 40w on it (I'm def open to whatever here):
http://www.robotshop.com/en/fingertech-40a-mini-power-switch.html?gclid=EAIaIQobChMIqd_VqPy41gIVlUsNCh3klwkbEAkYASABEgLg8fD_BwE


I'm just throwing this out there, but I'd shoot you $50 through paypal for at max a 20 minute phone call, just to make sure I'm getting the right components..  I'm sure it would save me $50 in wrong parts ordered.. ha.  If not, no big deal.  Advice here on the forum is awesome..


Thanks a ton for your time!!  I'll def let you know how the bot turns out either way!!


BullCrusher

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #4 on: September 23, 2017, 04:09:09 pm »
On a side note, if you want to see something really funny!  Ha.. I was looking for combat robot / fighting robot forums when I signed up for this one yesterday and found this one..

http://war-robots-forum.freeforums.net/thread/14507/newbie-advice-pound-sportsmans-class


lol!  This guy made me laugh!! (orkannnnnns)

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Andrew Burghgraef
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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #6 on: September 23, 2017, 11:33:41 pm »
Thanks RC Junky!!

MikeNCR

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #7 on: September 24, 2017, 03:49:00 pm »
Nice!  Thanks for your reply.  Your Nyx bot is awesome!  Yea, I'm definitely not expecting anywhere near that level right now.  Just something that qualifies to fight!  ha.

If you have a few minutes, I could really use your advice on the following..


So I'm 100% open to specific suggestions.  From what you said:

Battery (would this be good?):
https://www.amazon.com/Hobbico-LiFeSource-Phosphate-Transmitter-Connectors/dp/B00NE05F8A/ref=sr_1_1?ie=UTF8&qid=1506193299&sr=8-1&keywords=%2BLiFe%2Bbatteries&th=1


Charger:
https://www.amazon.com/Hobbico-Lifesource-AC-Balance-Charger/dp/B004QJTSVS/ref=pd_bxgy_21_img_2?_encoding=UTF8&psc=1&refRID=65D6PQFYYAT6SEAFAHSZ&dpID=51vdtdfM47L&preST=_SX342_QL70_&dpSrc=detail


ESC (Is this the ESC you recommend.. would I need 2 or just 1?  It says brushed, so this would work w/ the drill motors?):
https://www.hobbytown.com/torquemaster-brxl-brushed-esc-by-holmes-hobbies-hhbtmbrxl/p195994?gclid=EAIaIQobChMI-rXmgIG81gIVhLXACh307AM4EAkYASABEgIbVfD_BwE


LED Light:
https://www.fingertechrobotics.com/proddetail.php?prod=ft-power-led


With the motor, I would def be good with buying the motor from RobotShop or whatever, but I'm not sure what size to buy or how that would affect the ESC.  I'm basing it off the YouTube video.  I don't really get the gearbox / motor.  Do I need both?  I thought I could only use a motor and connect that to the wheels somehow.. ha.  You mentioned the Magnum 775:
http://www.robotmarketplace.com/products/0-magnum775.html


Wheels (I don't really understand how this will attach to the motor.. I'd need a wheel hub?  But would I make it?  It seems like TeamTiki may not be servicing their website orders anymore b/c when I went to purchase a drill motor, it said they were out of stock and I don't see a contact form):
https://www.amazon.com/Performa-Bearing-1-3-441-Hi-Tech-Encore/dp/B0195V3FD8


Switch:
I'm having a hard time finding the Whyachi MS-05.  I checked a bunch of sites.  Would this one work?  Not sure b/c it says 40w on it (I'm def open to whatever here):
http://www.robotshop.com/en/fingertech-40a-mini-power-switch.html?gclid=EAIaIQobChMIqd_VqPy41gIVlUsNCh3klwkbEAkYASABEgLg8fD_BwE


I'm just throwing this out there, but I'd shoot you $50 through paypal for at max a 20 minute phone call, just to make sure I'm getting the right components..  I'm sure it would save me $50 in wrong parts ordered.. ha.  If not, no big deal.  Advice here on the forum is awesome..


Thanks a ton for your time!!  I'll def let you know how the bot turns out either way!!

Haven't done much with LiFe lately, so I can't speak to the quality of those packs but I do recall people suggesting this site a while back- http://www.buddyrc.com/power-system/battery/a123-life-batteries.html

Two of these would likely give you plenty of run time- http://www.buddyrc.com/a123a-2s2p-1.html

The charger looks like it'll probably work, but I strongly suspect you'll get to a point where you'll want more than what it'll do out of it. You'd also need two of them at a minimum to charge a full set of batteries for your bot. I recently switched my charging gear over to one of these and have been very happy with it- https://www.venompower.com/collections/battery-chargers/products/venom-pro-quad-100w-7a-4-port-ac-dc-lipo-lihv-nimh-battery-balance-charger-1

They've got a lower cost option that'll do two packs at once here that's effectively the same cost as doing the chargers you were looking at- https://www.venompower.com/collections/battery-chargers/products/venom-pro-duo-80w-x2-dual-ac-dc-7a-lipo-lihv-nimh-rc-battery-balance-charger

With the BR-XL you'd want one esc per motor. The Ragebridge is a dual channel esc, so for the drive you'd only need one ragebridge (which means they're effectively the same cost for the same utility)

The DeWut is the good & easy drive option - http://e0designs.com/products/dewut-3-speed-gearmotor-kit/
The drill setup hear is the cheap option - http://ttrobotics.com/19-2-volt-robot-motor-new/
The BaneBots boxes are somewhat middle of the road, two 16:1's or 26:1's would make for an ok drive, 4 would make for a fairly nimble bot with a good bit of push with 3-4" wheels- http://www.robotmarketplace.com/products/0-pdx16.html
The Magnum775's sadly no longer available as they were a really solid option a bit below the dewut but a bit above the banebots in suitability for the 30lb class.

The nice thing with the DeWut/BaneBots options are they're ready to go with hubs that are available. If you want to run 1.5" wide colsons I do hubs for those - http://nearchaos.net/chaos-hubs/

Someone already linked to the MS-05, so I'll skip that part. Here's an example of a removable link: http://www.etotheipiplusone.net/pics/nh/nh38.jpg

Nobody really sells them, because it's just a normal connector with a loop of wire that's used to complete the circuit in the bot to power it on.

BullCrusher

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #8 on: September 24, 2017, 06:40:23 pm »
Mike, thanks a ton for your responses.  I've learned a lot from looking in to what you suggested.  I'm actually going to hold on to the ant weight kit I got from RobotShop and put it together (I was going to send it back for a credit, so I could buy the parts for the 30 pound robot).  I feel like I'll have a much better idea of what I need after that (and it has all the parts that fit together.. ha).  Maybe I could use it as a multibot if my Sportsman is 29 pounds!  lol..

One thing I've realized is that I really want to put the lifter arm like Nyx has (it's definitely my ideal weapon.. really thought out well!):

https://cdn.instructables.com/FRB/GYYX/I28OJS5X/FRBGYYXI28OJS5X.MEDIUM.jpg


The one on Nyx looks really complicated though.  Is there any simple way to build that?  Ha.. Something rigged, etc that probably won't be as efficient, but would work in a similar manner?

Thanks again for all the suggestions.  I'll keep you posted once I get the ant weight together (and learn some more)..


Thanks!!!

« Last Edit: September 24, 2017, 06:59:51 pm by BullCrusher »

BullCrusher

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #9 on: September 24, 2017, 06:47:39 pm »
Also, no pressure, but I wrote these questions down at 5AM today.. Maybe you have an answer to one or 2 of them..

Do I need 3 ESC's because I need one for both sides of the robot (left wheel and right wheel) and then 1 for the lifter?

How do I attach the lifter to a motor like an A28-150, etc?

What is the best choice for a body without having the ability to cut steel and weld (or are there other alternatives that I'm missing)?

How do you choose which amp ESC to use?

Which BEC do you use when you have 3 ESCs?


Thanks for any help here!  Chris

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #10 on: September 24, 2017, 08:04:46 pm »
Mike, thanks a ton for your responses.  I've learned a lot from looking in to what you suggested.  I'm actually going to hold on to the ant weight kit I got from RobotShop and put it together (I was going to send it back for a credit, so I could buy the parts for the 30 pound robot).  I feel like I'll have a much better idea of what I need after that (and it has all the parts that fit together.. ha).  Maybe I could use it as a multibot if my Sportsman is 29 pounds!  lol..

One thing I've realized is that I really want to put the lifter arm like Nyx has (it's definitely my ideal weapon.. really thought out well!):

https://cdn.instructables.com/FRB/GYYX/I28OJS5X/FRBGYYXI28OJS5X.MEDIUM.jpg


The one on Nyx looks really complicated though.  Is there any simple way to build that?  Ha.. Something rigged, etc that probably won't be as efficient, but would work in a similar manner?

Thanks again for all the suggestions.  I'll keep you posted once I get the ant weight together (and learn some more)..


Thanks!!!

Starting with a small bot to figure everything out is a good plan. The lifter on Nyx isn't too complicated when you break it down a bit. The gearmotor for the lifter is a DeWut in low gear, and there are two 3:1 gear stages out from that, so all you really need to do is figure out the spacing for the gearing you'd like to use and drill a few accurate holes. Beyond that it's just getting the connection from the shaft to the arm solid. (that's why there are multiple 1/4" plates sandwiched together as it brings it up to 2" of keyway)

There's an Australian bot that does a somewhat different take on the setup using a linkage between a winch gearbox and the arm to drive the lifter- https://www.youtube.com/watch?v=zJjcvkFFV6U&t=11s

Also, no pressure, but I wrote these questions down at 5AM today.. Maybe you have an answer to one or 2 of them..

Do I need 3 ESC's because I need one for both sides of the robot (left wheel and right wheel) and then 1 for the lifter?

How do I attach the lifter to a motor like an A28-150, etc?

What is the best choice for a body without having the ability to cut steel and weld (or are there other alternatives that I'm missing)?

How do you choose which amp ESC to use?

Which BEC do you use when you have 3 ESCs?


Thanks for any help here!  Chris

Yep, 3 esc's would be the right balance. On Nyx I used a ragebridge for the weapon as that let me adjust the current limit to each of the weapon configurations (as an example, the lifter's limited to 50A which provides approximately 45lbs of force at the tip of the forks with the gearing I use)

The A28-150 has a 1/2" keyed shaft, so you'll need to find gears or sprockets with a 1/2" bore and a keyway or modify ones without that to fit it. From there it'll be sorting out the geartrain to get the ratio you want.

Nutstrip is a wonderful thing for holding parts together- https://www.fingertechrobotics.com/proddetail.php?prod=nutstrip and http://www.bigbluesaw.com/ is a great fabrication option if you've got access to cad software. Here's a good walkthrough showing a bunch of other fabrication/assembly techniques you may find handy- http://www.instructables.com/id/How-to-Build-your-Everything-Really-Really-Fast/

Choosing an esc is about matching it with the motor. Generally, the motor will be cheaper than the esc so you'd rather have the esc ratings exceed that of the motor. With esc's like the ragebridge, the current limiting is adjustable and you can get a bit tricky with that. For BattleBots Season 2 we used a single ragebridge per A28-150 in our drivetrain with a good bit of success because we kept the limitations of the esc in mind and pushed right up against, but not past them.

If you've got multiple bec's between your esc's you'll often want to use just one (you can remove/cut the red wire on the pwm cable for the ones you don't want to use) but some esc's will work with multiple bec's connected without issue. Big thing is to check with the manufacturer or vendor to see if they know if it's compatible before applying power.

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #11 on: September 27, 2017, 08:03:46 pm »
Hey Mike!  Thanks a ton for your reply here!!  I figured I'd wait until I built the Viper with the lifter kit before I responded.  It's up and working!  I did learn a good amount from it with the wiring, etc.

I'm not 100% on how I would connect a motor like this:

https://www.amazon.com/gp/product/B009YJOD56/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

to wheels like this:

https://www.amazon.com/gp/product/B00O3OOAWS/ref=ox_sc_act_title_1?smid=A3RKQJMJN4135X&psc=1


What do I use to connect them?  Thanks!

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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #12 on: September 27, 2017, 10:18:54 pm »
I think this might do it, right?

https://www.youtube.com/watch?v=28-VLKM3Wy0


Just need to find a wheel that works with the wheel hub..

https://www.youtube.com/watch?v=28-VLKM3Wy0


Does this sound right?  Thanks!


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Re: Newbie! Advice On 30 Pound Sportsman's Class... in 4 Weeks
« Reply #14 on: September 27, 2017, 11:50:35 pm »
The Colson is by far the better option in the 30lb class vs. the pololu wheel. With that said, you'll want some sort of gearing on the E30-150 as it'd have far too high a top speed and far too little torque in that configuration to be useful as a drive system. The Ampflow itself is also a bit large as a drive motor for a 30lb bot with a weapon. Ampflow does sell a compatible gearbox (and the wheels that fit them) here: http://ampflow.com/wheelmotors.htm