SMT10 Grave Digger battery question

[CBR954RR]

I'm obviously a newbie to the RC model world and recently got an Axial SMT10 Grave Digger truck and after reading through the manual, I came across this...


540-/550-size closed endbell motors: 2S Li-Po
down to 12T;3S Li-Po down to 35T


Can someone please explain to me exactly what this means, as in, if I decide to use a 3S LiPo battery, what does the down to 35T mean?


I am assuming it is referencing teeth on a gear, but exactly what gear is referenced? Is it the spur gear, pinion gear, both, neither?


Any assistance greatly appreciated as I don't want to use a 3S LiPo and burn up the motor or ESC.


Dan

 

[lonleycreeper]

It is refering to the Turns of a motor...

A 35t motor in the 540 size used to be a standard "crawler motor"... 550 size motors are a little longer, a touch slower and have a little more torque.

 

[CBR954RR]

lonelycreeper,

Thanks for the clearing that up for me. Makes some sense to me now. Based on your info, if I wanted to use a 3S LiPo battery, I would have to change the motor first or risk burning some things up, correct? I believe, based on the manual, that the Grave Digger comes with a 550 Brushed 12 Turn motor.

Thanks again for helping me out.

Dan

 

[Jay-Em]

Indeed. On 3s a 550sized 12-turn motor will burn. If You insìst on 3s, it’s advisable to purchase a 21-turn 550 sized motor. Surpass, Traxxas, and I believe Turnigy ( not sure) all offer 21-turn 550 motors. But - in my experience- any China made 21-turn 550 will do just fine.

Advantage of using a higher voltage on a high turn motor, is that it usually means longer runtimes, without extra heat too. 12t 550 motors are rather Amp-hungry and heat-up significantly in heavy use, like in a monstertruck.

Personally I’d advise to save a bit and go for a brushless system ( motor ánd ESC) in the 3000kv to 3500kv range. About $60.- gets You a fully waterproof HobbyKing Turnigy 4-pole 3000kv system. ( Hobbywing is a bit more expensive, but not by much, and Castle is the absolute top afa quality, but also price, goes) Brushed motors wear significantly faster than brushless too. Something to consider if the price seems a tad much at first.

I use a Turnigy 3520kv waterproof system in my 1st gen -all metal geared- SMT10. Plenty power, reasonably frugal with the amps, and runs 2s and 3s without much drama, on the original gearing. I just took the pinion gear from the included brushed motor, and stuck it on the Turnigy. Done.

 

[CBR954RR]

Jay-Em,

Thanks very much for the detail on the motors. Extremely helpful for me. I'm looking to just have a play toy but want to make sure any changes I make won't do damage to the vehicle just because I didn't know what I was doing.

I have added steel axle tubes, HD ring gears and pinion gears, metal drive shafts, and am looking at metal sway bars down the road. I don't plan on beating the truck in any way such as racing or hard jumping, just a play toy to take out every now and then and ram around the yard for bit.

I realize that adding all the things I have and will down the road is definitely overkill due to the way I will be using the truck, but it's fun to tinker in that manner so...

Can you tell me if the tranny has all metal gears or should I be looking at replacing the gears in there too?

Thanks again for the very informative and helpful info.

Dan

 

[Jay-Em]

Gen2 SMT10 has metal gears. If it has the long-can 12t 550, it is gen2 and has metal gears in the tranny.
If You want to stay brushed, be sure You get 550 motors. The rig is wholly unsuited for the shorter 540-type brushed motors ( never understood why Axial included a 21-turn 540 in Gen 1.. Slow, ran hot, wore like mad.. ugh.. ) unless You only want to slowly crawl and stay at 35turns or more.

The only really ‘vulnerable’ parts after that, are the lower swing arms. Either purchase the axial aluminium side plates for them, or go for 2 sets of cheapie STRC ( or other china-brand) aluminium lower arms for the Yeti 1/10. The SMT10 plastic arms WILL eventually bend when doing jumps and such.

Ow. Forgot to link the type of brushless I use. : https://hobbyking.com/en_us/turnigy-trackstar-waterproof-1-10-brushless-power-system-3000kv-80a.html

This is a 2-pole. The 3520kv variant is 4-pole ( = more torque, but uses more amps —> Shorter run times)

 

[dCowler]

Personally I’d advise to save a bit and go for a brushless system ( motor ánd ESC) in the 3000kv to 3500kv range. About $60.- gets You a fully waterproof HobbyKing Turnigy 4-pole 3000kv system. ( Hobbywing is a bit more expensive, but not by much, and Castle is the absolute top afa quality, but also price, goes) Brushed motors wear significantly faster than brushless too. Something to consider if the price seems a tad much at first.

I use a Turnigy 3520kv waterproof system in my 1st gen -all metal geared- SMT10. Plenty power, reasonably frugal with the amps, and runs 2s and 3s without much drama, on the original gearing. I just took the pinion gear from the included brushed motor, and stuck it on the Turnigy. Done.

Sounds like getting the Turnigy is the best option for bother's SMT10. We'll have plenty of hobby time next week after we finished installing the set of tires from 4Wheelonline onto the Wrangler.