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**Pinski1** · 20 July 2016, 17:59

Good choice of motors, however most beetleweight wheels are a little smaller in the 35mm to 50mm range.

I use brushless drive which uses separate motors and speed controllers but is a lot more fiddly.

**Niels - Team K.a.L.M.** · 20 July 2016, 19:35

Hi there, I too use those couplings with RC wheels. And they work well enough, although they are a heavier solution in comparison to other methods. Because of the bigger outer diameter you might want to look at the 800rpm or even 600rpm 25mm gearmotors. This will give you a lower speed but more pushing power for the same amount of weight.

Anyways, welcome and enjoy.

**TornTech** · 21 July 2016, 08:02

Originally posted by Pinski1 View Post

Good choice of motors, however most beetleweight wheels are a little smaller in the 35mm to 50mm range.

I use brushless drive which uses separate motors and speed controllers but is a lot more fiddly.

Hmm...I will have to design the bot up in CAD and play around with the wheelsize... i am swinging towards a pizza box type bot potenally with the wheels coming through equally as much on the otp as it does on the bottom to allow it to drive when inverted.... maybe larger wheels may be better for this?

Brushless motors huh? that does sound quite tempting... i like the idea of using slightly cheaper(they are cheaper right?) ESC's.... do they need gearing or can they connect directly onto a coupling and then onto simular RC wheels like above?

Originally posted by Niels - Team K.a.L.M. View Post

Hi there, I too use those couplings with RC wheels. And they work well enough, although they are a heavier solution in comparison to other methods.

Glad to hear the method works well. it seems the easiest to me as a newbie to get started.... heavier solution. do you mean effecting weight limits or that its a little overkill for a beetleweight?

Originally posted by Niels - Team K.a.L.M. View Post

Because of the bigger outer diameter you might want to look at the 800rpm or even 600rpm 25mm gearmotors. This will give you a lower speed but more pushing power for the same amount of weight.

hmmm... I didn't think about gearing the motors down to a lower RPM... do you not think 1000RPM motors on 60mm wheels will work well then?

Originally posted by Niels - Team K.a.L.M. View Post

Anyways, welcome and enjoy.

Thanks, i have a considerable amount still to learn but this forum is a massive archive of experience and help...

My birthday money(sound like a kid still lol) is coming together and im going to want to nail down my first set of components ready for biting the bullet and making a purchase...

**Niels - Team K.a.L.M.** · 21 July 2016, 09:53

What I meant with the heavier solution is that the couplings with the rc wheels weigh more than fingertech clamps and foamwheels. But I reckon they are far less fidgety to use. (no experience with fingertech t.b.h.)

Using 1000rpm motors with 60mm wheels will give you a machine that has a higher speed than the opposition and if you find that important it will work fine. If you want to be able to push your opponents around better (not saying you can't with 1000rpm) you could look at the lower rpm ones that uses the same motors but different gearing. They will have less trouble turning your wheels while pushing.

Remember there are possibly 1000's of way to build a bot, and a few hundreds ways to build a decent one.
There really isn't a single way to go about it. Anything can work. It's up to your preferences and your opponent as to what will work perfectly. Any design has it's flaws/weaknesses that can be exploited and the crappiest machine on paper can take the trophy home.

**TornTech** · 21 July 2016, 11:35

Pinski1 Could you give me some info on your brushless set up?

What are the benefits of using Brushless vs Brushed motors? IE why did you choose them over brushed?

Are the ESC's going to be cheaper?

what about motor price compared to 12v Brushed?

Do they need gearing?

I am presuming you just use the same type of coupling to RC car wheels?

Thanks

Tom.

**TornTech** · 21 July 2016, 11:41

Originally posted by Niels - Team K.a.L.M. View Post

What I meant with the heavier solution is that the couplings with the rc wheels weigh more than fingertech clamps and foamwheels. But I reckon they are far less fidgety to use. (no experience with fingertech t.b.h.)

The concept of foam wheels for a battlebot turned me off a little... are they resilient? i havn't paid much thought about weight... TBH... im merely doing this to develop a set of prototyping parts and to learn the process. i HIGHLY doubt this bot(or at least this version) will ever go to competition....

Originally posted by Niels - Team K.a.L.M. View Post

Using 1000rpm motors with 60mm wheels will give you a machine that has a higher speed than the opposition and if you find that important it will work fine. If you want to be able to push your opponents around better (not saying you can't with 1000rpm) you could look at the lower rpm ones that uses the same motors but different gearing. They will have less trouble turning your wheels while pushing.

undecided if speed or grunt is what i am after..... a nippy little bot is quiet appealing though....

Originally posted by Niels - Team K.a.L.M. View Post

Remember there are possibly 1000's of way to build a bot, and a few hundreds ways to build a decent one.
There really isn't a single way to go about it. Anything can work. It's up to your preferences and your opponent as to what will work perfectly. Any design has it's flaws/weaknesses that can be exploited and the crappiest machine on paper can take the trophy home.

Thanks, all your advice is really helping

**mark_m** · 21 July 2016, 14:00

Hi Tom,

I'm part of Hitchin Hackspace, it'd be great to see you down there and talk robots :-)

The 1000rpm motors you've selected should be fine with those wheels. My beetles all use four of those motors for drive with 55mm wheels and they've all had really good speed and pushing power. If you're only going to have two drive motors, like many beetles are, then you may find the acceleration is a bit slow but the top speed will still be there. That's probably why people are suggesting smaller wheels.
I use 3d printed hubs with my tyres. They've very lightweight but not really robust enough for combat. For a first bot, the ones you've selected should be good: easy and strong.
I also use the botbitz ESCs. they're some of the smallest available and actually fairly cheap on the scale of things. The Dimension Engineering speed controllers used to be an alternative but they're Â£45 each for an equivalent controller! There's also the VEX motor controllers: http://www.vexrobotics.com/276-2193.html They're much cheaper but lower voltage and lower current, you'll need to test or calculate if they'd be suitable for your drive setup.
Brushless isn't really used for lower cost drive systems, its because its lighter/smaller for the same power. They usually need slightly more gearing than an equivalent brushed setup as the motors are faster, so a common approach is to transplant a brushless motor onto a 500rpm gearbox. I think Pinski1's described his setup in another thread.

cheers

Mark

**TornTech** · 22 July 2016, 09:46