Not enough torque? What am I doing wrong? 13 lbs truck

[devuser]

Hello,

I'm running a RTR SCX10 with the following modifications:
QUICRUN WP 1080 brushed ESC

RC4WD 55T motor

GT3C hacked remote for 6CH

The battery is a new Turnigy 5000mAh 2S 20C Lipo

The servo is a cheap chinese 20kg one which I'm pleased with for now.

The wheels are aluminium with lead weights added, 1.9 RC4WD super swampers - they weigh close to 1.7 pounds.

My truck is close to 13 pounds in weight and I think that is the main problem

All the gears/pinions are the stock ones that came with the truck.

My problem is that is feels like it doesn't have enough torque/power to go over obstacles and I don't know what to do...

With the 55T motor I don't have any wheel spin when trying to get over rocks for example. I push the throttle and nothing happens, it just sits there, trying to move the wheels for half of inch.

It there a problem with the ESC configuration, GT3C configuration, motor quality or battery?

When the truck was 40% lighter, I ran a RC4WD 45T motor with the stock ae5 esc and it ran great.

Should I buy a different more quality motor? If so, which motor should I get?

Thanks for the help!!!

 

[devuser]

PS. I love using the winch, but not this often

Heavy SCX10 - Album on Imgur

 

[svt923]

When you say stock gears, does that mean 87/20 on the spur and pinion?

A pinion/spur ratio around 5:1 or higher will give you the torque you need but a 55T motor on 2S is uselessly slow in a SCX10 (in fact, I'm bored just thinking about how slow it is :mrgreen.

Consider a 27T 540 or a 21T 550 motor with a 13T pinion for a quick and easy upgrade in torque, low speed control, and wheel speed. Lose some wheel weight too, that is sapping a good portion of your already low motor power.

 

[JatoTheRipper]

13 pounds is heavy for an RC. A 55T motor is slow. That's why you have no wheel speed. But it should be able to move the truck so I would make sure you don't have any binding in the driveline. I would suggest going to a 3S LiPo on your current setup. But a better motor would also help.

 

[devuser]

I think i have the 32P 13T Pinion Gear and 32P 56T Spur Gear.

I'm going to try the 27t axial motor that came with the rig, but that was way too fast for my style.

The speed from the 55T is perfect for me, but I wanted it to have more life in it in terms of torque. If the rig can't pass an obstacle at least it should show that it's trying with some wheel spin like the 27t

When you say stock gears, does that mean 87/20 on the spur and pinion?

A pinion/spur ratio around 5:1 or higher will give you the torque you need but a 55T motor on 2S is uselessly slow in a SCX10 (in fact, I'm bored just thinking about how slow it is :mrgreen.

Consider a 27T 540 or a 21T 550 motor with a 13T pinion for a quick and easy upgrade in torque, low speed control, and wheel speed. Lose some wheel weight too, that is sapping a good portion of your already low motor power.

 

[devuser]

13 pounds is heavy for an RC. A 55T motor is slow. That's why you have no wheel speed. But it should be able to move the truck so I would make sure you don't have any binding in the driveline. I would suggest going to a 3S LiPo on your current setup. But a better motor would also help.

I'm running a drop setup (or i think i am)... I have the 100mm rc4wd king shocks with very fluid liquid so that they are very soft and they sit very compressed on the rig weight.

I have indeed very very little binding when the driveline angle is at its steepest - when sitting on a car stand for example - which doesn't happen when crawling.

 

[dieselmudder]

Have you ran the flysky the whole time? Did it do it okay with the other motor. If your stalling the motor on obstacles it's probably getting pretty hot. A 55 should have plenty of torque for your purpose.

 

[svt923]

I'm going to try the 27t axial motor that came with the rig, but that was way too fast for my style.

That is why you gear down, to increase torque while reducing speed. A 27T geared down with a 10T pinion (32P gears) is only a little faster on the top end than a 55T with a 13T pinion but the torque increases significantly because the overall gear reduction has been upped in a big way.

 

[devuser]

Have you ran the flysky the whole time? Did it do it okay with the other motor. If your stalling the motor on obstacles it's probably getting pretty hot. A 55 should have plenty of torque for your purpose.

Actually I haven't ran the flysky with a different motor. I checked after 20 minutes and the motor is very very hot. Also, I have a hunch that the battery drains more quickly.

With the 55T motor I wanted the rig to run slower(i don't care about speed) and have more torque to compensate for its increased weight.

When I ran the ae5 + rc4wd 45t + tactic ttx300 remote it worked like a charm (the rig was around 9 pounds then) - it just pulled itself over almost vertical obstacles - it was amazing...

 

[JatoTheRipper]

Buy a 3S battery. I'm betting that gets you to where you want.

 

[Constant Threat]

Loose some weight!!! Also checker your slipper either lock it out or tighten the heck out of it and use a jam nut. But seriously 13lb is alot

Sent from my SM-G900V using Tapatalk

 

[CoolRunning]

I guess the question to ask is if the truck moves over the same obstacles with the 27T motor where it doesn't with the 55T.

Basically, is there something wrong with the 55T motor or is your driveline binding up somewhere.

I cannot crawl with a 27T in my stock Bomber simply because it will cook. It crawled ok though and went great apart from that.

35T does have more torque but less speed but it doesn't struggle like the 27T. I would imagine a 55T to have way more grunt than a 27T but no wheel speed to hop up rocks.

A 3S lipo will definitely cause heat problems without the right setup and/or cook your electronics.

What have you got on your truck that makes it weigh so much?

 

[hotwheels000]

Guessing it is a setting in your radio or esc. Punch control, throttle end points, dual rate, throttle curve.... if the 27 turn worked with another radio and the 55 turn has less grunt in the new radio, it has to be a radio settting. Try another radio or motor combo, process of elimimation will lead you to the component issue, then you can dig into the programming.

 

[GLwagon]

The lowest gearing you can go is near a 56t spur depend on drive shaft size.
I have a 54t (32p) spur gear on my older Axial & have geared as low as 9t pinion (5.4" tires for crawling).
You have to choose kind of how fast you want to go & how hot you want to run.
If you do low speed crawling on near vertical surfaces you can use a 35 turn or 45 turn but they need to be geared down to control heat.
I have also used 550 motors with great success with proper gearing.
None of my trucks will do over about 6 to 7 mph...
Some of the cheaper cans do not have internal fans & every bit helps too.

 

[TacoCrawler]

lose the 2s for 3s (11.1V)

But remember... " Volt up, Gear down "

Even a 55t will be more spirited running on 3s
But a 55T tends to be more linear in it's torque delivery (smooth)
tho' wheel spin will increase at lower speeds it will still be minimal.

IMO the best middle road motor is a 35T running 3s voltage...
lots of torque and some tire spin if/when ya want/need that.

I run 87/14 (48P) 35T HH TM motor 5.80" tires on 3s.
Have no issue spinning the tires at slower speeds.

^ = 6.2... could it be geared a little taller ? sure,
but I want big torque with some wheel spin, not top speed.

But it's not really faster by much.
Top speed maybe 6 mph with a headwind.
but the increased low end grunt (torque)... will find you smiling "thumbsup"

30T - 27T if wanting more top end speed (RPM).

But as the voltage goes up and the motor winds become less...
you likely want to gear down even lower.

If you stick with using 2s... Likely need go with a 27t and gear down.

I switched to 3s and will never go back to using 2s.

 

[Hardcoretam]

When you say the wheels don't turn on the rocks, do you mean the motor is stalling?

I personally gear my truck as low as i can, then find a motor turn that suits my gearing.
To give you an idea, we done a hill climb for a few hours on a muddy hill at the weekend.
2 of the SCX10's had 35t 550 motors (different brands). 1 SCX10 was heavy and the other light. Both had standard 32p gearing and both burned up their motors
My truck was much heavier than both of them and i was running a less torquey 21t cheapo 540 motor. I'd geared really low on 48p (13/87) was running 3s
Despite my extra weight and less torquey motor the gearing and 3s gave me much more wheel speed, better battery life, less heat issues and a little more torque on the rocks.

If the 55t motor is stalling and the 45t motor is getting really and there are no binds in the transmission anywhere, i'd start with gearing down quite a bit


Is the Max Forward Force set to 100% on your ESC?
What about your intitial Start Force and Punch Levels?

 

[CoolRunning]

Some ESC's don't provide the same output in reverse compared to forward. 60A forward, 30A reverse. It'll make the ESC run really hot.

 

[Hardcoretam]

Some ESC's don't provide the same output in reverse compared to forward. 60A forward, 30A reverse. It'll make the ESC run really hot.

It will but the OP isn't experiencing a hot ESC

 

[mhowzit]

Did you calibrate the throttle on the esc with your radio system?

I'd also ditch some weight in the wheels.

With the 32p spur and pinion, try and take the pinion down to a 10t. I'd also recommend ditching the 55t and replace it with a 35t. As it's been said, the 35t is a good all around motor. Go with the 10t pinion for the slow crawl that you are looking for and try a 3s pack if you want more speed.

There is always a chance that you just got a bad motor. Those RC4WD motors are great for only $10, but it is after all only a cheap Chinese motor. Bad ones leave the factory.

 

[devuser]

Thank you for all the answers !!!

Update:

After resetting the ESC config and fiddling with the transmitter endpoints it seems that the rig has more torque now, although I haven't tested it on the rocks yet.

If I block the wheels from spinning, even with the slipper screw to minimum it doesn't slip, but instead, the motor gets very hot and smells burning after a few seconds

Should I get a better motor like the Tekin 55T and leave the pinion/spur as it is? Or should I get a Tekin 35T and change the pinion/spur for low speed and more torque? If so, what spur/pinion should I get for the transmission?

Please note that I want the rig to run very slowly, even a little slower that regular walking...

Thanks again for all the answers, they were very helpful