King Hauler motor for pulling semi trailer question

[AndyjcClod 389]

Hi Guys

I have finally got a Tamiya semi trailer for my King Hauler but my Hauler seems to struggle to pull it.

Im using a Carson Poison Truck Motor, can anyone recommend a better motor for my truck for pulling the large heavy trailer?

[topforcein 1764]

well tbh i only use the tamiya tr tuned truck motor in my 2 trucks 

[Mad Ax 9311]

How heavy is your trailer?  I use a Carson Poison in my rigs and they pull my trailers no problem, even in high gear.  In low gear they'll pull the trailers up the steep overpass ramps used on the layouts - never tried in middle or high gears as we only use low on the layouts.  My pole trailer is probably lighter than a normal Tamiya trailer but my low-loader carries battery packs and a TT-01E race rig on the back, it's not super-heavy but not a lightweight.

These rigs should be able to pull a lot of weight.

Do you have the MFU fitted, and do you have the microswitch fitted to the fifth wheel?  IIRC there is functionality to reduce torque if the trailer is disconnected but I can't remember if it applies to all gears.  If your MFU thinks you don't have a trailer you might not get full torque.

[Big Jon 684]

If you really want to drag some heavy weight with authority, try a Holmes or Brood brushless out runner and a Castle Sidewinder 4. Absolutely brutal torque and phenomenal low speed resolution. They're noisy, though. Hobbywing AXE systems are much quieter and have less torque, but even better low speed resolution (and are almost twice as expensive). 

[AndyjcClod 389]

13 hours ago, Mad Ax said:

How heavy is your trailer?  I use a Carson Poison in my rigs and they pull my trailers no problem, even in high gear.  In low gear they'll pull the trailers up the steep overpass ramps used on the layouts - never tried in middle or high gears as we only use low on the layouts.  My pole trailer is probably lighter than a normal Tamiya trailer but my low-loader carries battery packs and a TT-01E race rig on the back, it's not super-heavy but not a lightweight.

These rigs should be able to pull a lot of weight.

Do you have the MFU fitted, and do you have the microswitch fitted to the fifth wheel?  IIRC there is functionality to reduce torque if the trailer is disconnected but I can't remember if it applies to all gears.  If your MFU thinks you don't have a trailer you might not get full torque.

Its pretty heavy as its all metal, Yep I have a MFU fitted but I dont know what you mean by the (Microswitched fifth Wheel) So now you are saying that i am guessing I have never set my MFU up properly.

[berman 5315]

1 hour ago, AndyjcClod said:

Its pretty heavy as its all metal, Yep I have a MFU fitted but I dont know what you mean by the (Microswitched fifth Wheel) So now you are saying that i am guessing I have never set my MFU up properly.

Does it make the electronic attachment (clunk) sound when the trailer attaches?

There is a tiny micro switch that you install in the fifth wheel, that gives the truck full power (and oddly, %100 reverse instead of 50% with no trailer 🤷‍♂️) when it is connected. 

The all-alloy 2 axle semi trailer, seems to be the heaviest of the Tamiya range. You shouldn't struggle to pull it though.

It would make sense if the 5th wheel switch isn't connected, as the truck is a lot slower in 1st and second gear without a trailer connected, as opposed to if the switch has been activated.

You should have a small red and black wire going to the fifth wheel if it is in there 👍

[Mad Ax 9311]

Yep, as @berman says, there is a tiny little electric switch that you install into the fifth wheel coupler when you fit the MFU.  I thought the wire on mine was green and black but I could be wrong and I can't get to my rigs to check right now.  Anyway, as said, the speaker should make a "clunk" sound effect when you connect the trailer while the truck power is on.  It's worth checking that before splashing out on stronger motors  

[djmcnz 754]

I suspect you need a Conrad 240826, start here: https://www.tamiyaclub.com/forum/index.php?/topic/6411-amazing-rumour-about-a-genuine-conrad-240826/ but also search this site for more info.

FWIW, I have two and I used them in parallel mode to reorient my house so it was north-west facing (southern hemisphere). They didn't break a sweat and my house probably weighs 10 tonne.

 

 

[Jeepy2013 575]

For pulling heavy loads, I would suggest a 55t or 80t brushed motor. It's a simple solution and works great. I typically use the inexpensive ones from RC4WD

[berman 5315]

On 6/2/2021 at 8:35 PM, Mad Ax said:

I thought the wire on mine was green and black but I could be wrong and I can't get to my rigs to check 

You could be right. I thought it was red and black but after you mentioned green, I think it could be green and black. ☺

On 6/4/2021 at 12:24 AM, Jeepy2013 said:

For pulling heavy loads, I would suggest a 55t or 80t brushed motor. It's a simple solution and works great. I typically use the inexpensive ones from RC4WD

The RC4WD ones work, I bought a few of them, but they don't have a lot of torque. I switched one out to a Tekin 55t HD and it made a night and day difference. 

[Jeepy2013 575]

On 6/4/2021 at 2:58 PM, berman said:

You could be right. I thought it was red and black but after you mentioned green, I think it could be green and black. ☺

The RC4WD ones work, I bought a few of them, but they don't have a lot of torque. I switched one out to a Tekin 55t HD and it made a night and day difference. 

cant even compare the two....they literally are night and day. I've also run those and the older Novak 55t brushed motors.