Gearing the Enduro for speed

[Cuiken]

I'm building a pre-runner type truck from an element trailrunner chassis using a 3000kv motor. The low gearing of the platform though (stock spur gear) means it's not particularly fast.

In fact, the great calc app reckons I'm only getting ~8.5mph.

Now, I don't need this thing to fly but I was thinking maybe ~12mph would be a decent speed for it.

Easiest trick would be to pinion up but the largest opinion I can get in there is only 22T. So, I ordered a smaller spur gear (72T) that should allow me to use a 24T pinion if I want. This would give ~14mph which would be great.

Only issue then becomes motor temp.... At nearly twice the speed I fear I'll cook something.

Has anyone else geared up their Enduro for a bit more speed? What motor/spur/pinion did you settle on?

[Goro Majima]

I feel like 3000kv isn't enough umph but since you ordered your different gears for gearing up already and you may be worried of temps, I'd install a motor fan and go from there.

Is the 3000kv motor something you chose for this particular build or just something laying around? I feel like I would want to start with at least a 4k.

[Cuiken]

There's a couple of factors that led me to the 3000kv motor.

I decided to use the HW 10BL120 ESC because it is sensored, has some basic level of crawler functionality (a drag brake) and/or can be configured as Fwd/Brk/Rev. It's also cheap 😄

On 3S this ESC really wants a motor North of 10T so I went for a 13.5T (~3000kv). Arguably I could have chanced a 10.5T motor but, TBH, I couldn't find one with local shipping.

In an ideal world I'd go for a Mamba X and a 3800kv 1410 motor but they are crazily expensive here in the UK so I'm trying this cheaper for instead.

[smog]

What is your battery power 2s,3s,4s?

More powerful battery and a faster motor. Volt up yo!

[HumboldtEF]

I built a Gatekeeper to be a fast trail rig, 3500KV motor, 3S LIHV battery, pinion... I'll have to go back and check but it was close to stock maybe a 16T-18T pinion.

I made sure to use the 1/1 gears not the overdrive gears.

I havent run it for a little while but I recall the temps weren't bad though I dont just run full speed all the time, just a bit of bashing between spots. The wheelspeed I got was fun enough maybe in the 15mph range.

[Cuiken]

Should have said, I'm running 3S. It's the limit for this ESC.

And, yes, I'm also running the 0% overdrive gears.

Like I say, a quick test run with stock pinion and spur gear (18T, 87T) was a bit slow.

The gear calc app (RC Car GearCalc) has that pegged at only 8.15mph which seemed about right.

FYI, a Gatekeeper with no overdrive but otherwise stock gears would run at about 11.5mph with a 3500kv motor (larger wheels really help).

If I go all out on gearing (24T pinion, 72T spur) with my existing 3000kv motor and the stock 98mm tyres, I should get 13mph which I think would be fine. Like I say, only issue is the potential temperature rise since I'll be trying to get from ~8mph to ~13mph through gearing alone.

Starting to think I should have gone with the hobbywing g2 10.5T (3600kv) motor.....

[Steve g]

Honestly I'd avoid the x.5 turn motors (your 13.5t and the 10.5 you mentioned). They are 2 pole and have noticeably less torque then the usual 4 poles. I actually ran your same setup (13.5t with a 10bl120) years ago, and to me it was more comparable to a 550 brushed motor then a comparable 4 pole motor.
As for heat, you'll be fine. I ran no fan, and sealed all the vents in the motor with lexel, and it never over heated on a 2.2 wraith geared for about 10 to 12 mph.

Sent from my SM-G970U using Tapatalk

[Cuiken]

That's a really good tip, thanks.

I'd not realised the x.5T motors always meant 2 pole.

That said, I'm struggling to find a 4 pole sensored motor that I could use (potentially I'm looking in the wrong place/price range).

As it happens, I ran a quick test today on 3S with the 22T pinion. The motor got a bit warm, that was it. Theoretically I'm at 10mph now. I'll try the 72T spur and 24T pinion and see how I go (should get 13mph).

One counter to the 2 pole argument is that this particular truck is a pre-runner rather than a crawler. See the thread below if its not obvious:

Another enduro pre-runner (idea)

The fact that this is definitely not a crawler means torque may be less of a concern. Geared as it is, I'd say it still has too much punch off the line. It's a bit abrupt. Maybe 2pole geared up will work here.

[Steve g]

There are some x.5t motors that are 4 pole. I believe Novak make some (no longer around). Another option is 6 pole sensorless. Not as good as a 4 pole sensored motor for low speed control, but would be fine for a trail truck. I have a Dynamite 3300kv 6 pole that I was quit impressed with considering its sensorless and a high kv for a 6 pole. But again, that one specifically isn't made anymore. They still make a 550 sized 2800kv 6 pole, but its expensive. Tenshock makes a 540 sized 6 pole, from 1250kv to 2400kv that's not expensive. But like you say, your current setup is fine. Just giving some options for the future.

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[Cuiken]

Just an update.

Ended up running a 75T spur with 26T pinion, 13.5T (~3000kv) motor and class1 105mm OD tyres.

Theoretical top speed is ~14mph and, in practice, I'd say this is about as fast as I want the truck to run.

Great fun to drive. Plenty of poke, surprising low speed control and no heat issues to report. Really chuffed.

[CptKaos]

Good to hear.
I also have a Gatekeeper that will see mostly bashing.
I have a reedy 10t 5 slot on 3s for it and have a 23 pinion and 78 spur coming.

[CptKaos]

Still in search of more speed so I installed an AXE 550 3300kv esc and motor combo and installed a 56tooth 32pitch spur gear, just waiting for my pinions now.
The built-in bluetooth programing is awesome.

[Cuiken]

That's a great motor ESC combo. I use it in my TRX6.

My only concern is that it's got so much torque that you end up pulling wheelies the whole time (less of an issue in the longer TRX6).

I was also not a huge fan of its 'basher mode' when I originally tried it out in my Redcat Wendigo (though the crawler mode is fantastic). Even when basher mode is enabled, it still has some element of FOC running which messes with the coasting behaviour. It bothered me but may not bother others.

Let us know how you get on with it. I'd be curious to hear what you think.

FYI, I was so chuffed with the 10BL120/surpass 3000kv combo in the Element that I went ahead and installed one in my old Wraith. It works great there too. If you don't need waterproof or AXE level slow speed control, it is a bit of a budget wonder. Definitely good for a rock bouncer type rig.

[CptKaos]

17 tooth is the biggest pinion that will fit with the 58 tooth 32 pitch spur. The thing is a beast on a 30c 3s lipo. Wheelies are easy if you have enough traction and I am guessing top speed to be about 30mph(gyro stabilized receivers are great)

Bluetooth tuner makes changes esc settings very easy.
I did find that you can turn down the drag brake by first changing to “forward/reverse mode” then adjust “drag brake” and save settings, then go back unto “forward /brake/reverse mode” and it will save your previous drag brake settings .

Moving the battery to the rear and adding heavy 2.2” bead locks with 4.75" od tires enhanced stability greatly.

[CptKaos]

Now I need to find an IFS kit for it.

[tigris99]

Good luck, everyone is out of stock because new builders kit is coming with it from what I have heard.

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[CptKaos]

No IFS kits available
Next project is changing trans to 1/1 ratio