SCX10.3 build - Tekin or HH brushless?

[Bowtiewarrior]

Hello All,

I am collecting parts for a SCX10.3 build, I currently have a TRX4 stock electronics running a 3S pack.

I know that the SCX10.3 has a 2 speed, for my motor choice I really want to have LOW speed control with the ability to toss in the 3s or 4s, shift to the higher speed and have some fun. (yes I am trying to have get best of both world)

So basically I would like to gain more control in low gear than the TRX4 and be faster than it in the High gear.

Looking at the:
--ROC412 - 3100KV
--HH PPV2 Stubby 2700KV

ESC I am still unsure about I know that the RX4 is good, but I am scared by their "waterproof" I doubt this truck will see water like the TRX4 because it is my "basher" but I don't want to end up frying a ESC because I ran it in the snow or through a puddle. So I am open to recommendation to pair with the above motors.

Thanks,
Joe.

[Topher Builds]

I’ve never been disappointed in any of my mamba x and hh motor combos. I’d look for a 2200kv puller pro 540, that should be able to run on 4S for when you’re looking for some speed.

Unfortunately, the 2 speed on the 10.3 isn’t very useful. The ratios are so close together that there really isn’t much of a tangible gain in throttle control or wheel speed in either low or high gear, so beating the 2 speed in the trx4 for slow crawling and high speed just really isn’t possible here.

[$uicide $hift]

Originally Posted by Bowtiewarrior

Hello All,

I am collecting parts for a SCX10.3 build, I currently have a TRX4 stock electronics running a 3S pack.

I know that the SCX10.3 has a 2 speed, for my motor choice I really want to have LOW speed control with the ability to toss in the 3s or 4s, shift to the higher speed and have some fun. (yes I am trying to have get best of both world)

So basically I would like to gain more control in low gear than the TRX4 and be faster than it in the High gear.

Looking at the:
--ROC412 - 3100KV
--HH PPV2 Stubby 2700KV

ESC I am still unsure about I know that the RX4 is good, but I am scared by their "waterproof" I doubt this truck will see water like the TRX4 because it is my "basher" but I don't want to end up frying a ESC because I ran it in the snow or through a puddle. So I am open to recommendation to pair with the above motors.

Thanks,
Joe.

I am sure you have seen others state that they wish the SCX10 III had more of a difference between the gears. This is a true statement. You may see a 2MPH difference between the gears at most.

I have the SCX10 III and have used two setups on it so far.

You stated this may see some water but not like your TRX-4. If you will be hitting mud and water I would go with the Hobbywing AXE 550 3300Kv setup. That proprietary sensor wire for the motor is going to be the best sealed setup. Dropping in an 11T pinion you will see about 13MPH in second gear. It will be faster than the TRX-4 on stock electronics (Have have the bronco fully stock as well) If you go this route get the extended wire and sensor cable Hobbywing sells for the Axe. It will fit without it but the sensor wire is a bit tight and you will only be able to mount the ESC on the front left side of the rig without the extension wires. The only thing with this setup is you cannot adjust the throttle curve in the ESC, it must be done with expo in the transmitter. This works fine and will allow the slow startup you desire but it is a little better to adjust via ESC. This ESC however can only handle up to 3S.

The other option I would recommend is the Mamba X with either Holmes Puller Pro brushless or Castle slate motor. I would run anywhere from 2800Kv to 3300Kv. With the Mamba you can dial in the throttle curve so you have really slow smooth startup and when your trigger reaches 75%, or however you set it, the rig will wake up and rip down the trail.

With these options I think you will be able to find your sweet speed spot changing out pinions. To assist you in your choice I have a gear ratio / speed calculator I setup in Excel. You can download a copy and make adjustments to the values. This will show you what you can expect for speed and gear ratio with the changes you make to pinion, motor, tire size, and battery.

SCX10 III Gear Ratio Calculator

**EDIT**

I just noticed Tophers reply. I forgot you mentioned capable of 4S. If going 4S look at lower KV motors. My motor KV recommendations were based on what you want and 3S Lipos.

[Topher Builds]

Axe 3300kv may be a good happy medium here for the throttle control and speed. Just can’t run 4S but I agree with SS that it seems like a good fit.

[mikemcE]

I love my 2700 stubby in mine on 3s.
I would do the 2200 on 4s.
I’m running a 12t pinion and plenty fast for me


Hang up and Drive

[Bowtiewarrior]

Originally Posted by $uicide $hift

I am sure you have seen others state that they wish the SCX10 III had more of a difference between the gears. This is a true statement. You may see a 2MPH difference between the gears at most.

I have the SCX10 III and have used two setups on it so far.

You stated this may see some water but not like your TRX-4. If you will be hitting mud and water I would go with the Hobbywing AXE 550 3300Kv setup. That proprietary sensor wire for the motor is going to be the best sealed setup. Dropping in an 11T pinion you will see about 13MPH in second gear. It will be faster than the TRX-4 on stock electronics (Have have the bronco fully stock as well) If you go this route get the extended wire and sensor cable Hobbywing sells for the Axe. It will fit without it but the sensor wire is a bit tight and you will only be able to mount the ESC on the front left side of the rig without the extension wires. The only thing with this setup is you cannot adjust the throttle curve in the ESC, it must be done with expo in the transmitter. This works fine and will allow the slow startup you desire but it is a little better to adjust via ESC. This ESC however can only handle up to 3S.

The other option I would recommend is the Mamba X with either Holmes Puller Pro brushless or Castle slate motor. I would run anywhere from 2800Kv to 3300Kv. With the Mamba you can dial in the throttle curve so you have really slow smooth startup and when your trigger reaches 75%, or however you set it, the rig will wake up and rip down the trail.

With these options I think you will be able to find your sweet speed spot changing out pinions. To assist you in your choice I have a gear ratio / speed calculator I setup in Excel. You can download a copy and make adjustments to the values. This will show you what you can expect for speed and gear ratio with the changes you make to pinion, motor, tire size, and battery.

SCX10 III Gear Ratio Calculator

**EDIT**

I just noticed Tophers reply. I forgot you mentioned capable of 4S. If going 4S look at lower KV motors. My motor KV recommendations were based on what you want and 3S Lipos.

Thank you for the reply, honestly this really helps. I am sad to learn that the 2 speed isn't a very steep change, I wonder why they bothered to even have it?

If the stock TRX4 on 3S in HIGH gear is sub 10MPH and the SCX10.3 is 12-13MPH that is an appreciable increase in top speed.

Can I change the gearing of the 1/2 speed internally on the SCX10.3?

Originally Posted by Topher Builds

Axe 3300kv may be a good happy medium here for the throttle control and speed. Just can’t run 4S but I agree with SS that it seems like a good fit.

Honestly the 4S was sort of a back up, kind of like a hidden bottle of nitrous haha! I will likely stick to the 3S packs so I can swap them between the two easily.

[Topher Builds]

There are optional transmission gears that add (iirc) 70% more reduction to the transmission.

I have two 4S batteries sitting around for the same reason, haven’t used them yet but need to give that a shot.

[Bowtiewarrior]

Originally Posted by Topher Builds

There are optional transmission gears that add (iirc) 70% more reduction to the transmission.

I have two 4S batteries sitting around for the same reason, haven’t used them yet but need to give that a shot.

Dang, do you know if it is 70% over all reduction? So effectively lowering both gears (high/low) by the same amount. I wonder if I can use the Low from 70% reduction and the HIGH from the stock configuration.... that would make a pretty good step up/down.

[Topher Builds]

It is 70% overall, it replaces the gears after the spur gear, intended to add reduction for straight non portal axles when they release those.

There isn’t a way to change the high and low gear that I’m aware of. Just the overall ratio.

[$uicide $hift]

Originally Posted by Bowtiewarrior

Thank you for the reply, honestly this really helps. I am sad to learn that the 2 speed isn't a very steep change, I wonder why they bothered to even have it?

If the stock TRX4 on 3S in HIGH gear is sub 10MPH and the SCX10.3 is 12-13MPH that is an appreciable increase in top speed.

Can I change the gearing of the 1/2 speed internally on the SCX10.3?

Don't worry about the speed difference between the TRX and SCX.

My TRX Bronco has an 11T pinion. It is completely stock so we are talking a 2200Kv motor and brushed.

The SCX10 III ran about 13MPH in second with an 11T pinion and the HW AXE 550 3300Kv motor. Right now however I dropped in the 1:7 gears which makes it MUCH slower. I then dropped in the Mamba X with Slate 3800Kv and now in 1st is 6MPH and 2nd is 8.8MPH. Much slower than my TRX now!

So this explains the speed difference. Drop that HW Axe setup in my TRX and it is going to go much quicker.

The only gearing you can change is the transfer case gears that stock are 27 / 27 and the 1:7 reduction gears are 34 / 20. This set of gears was intended to be used with straight axles (non portal) that Axial plans to release. If the portals are removed the rig would be way to fast so they have this gear set to slow it back down.

There is currently no optional gear that will widen the gap in speed between 1st and 2nd. I have yet to hear any ramblings of Axial planning to do this. I do not even know if they can depending on how much space there is in the existing tranny.

[$uicide $hift]

Here is a list of what speeds you can expect from the SCX10 III running 2700, 3300, 3800 KV motors with 11T and 13T pinions. I am hoping this will give you a better view as to what each setup brings in differences. With this list I think you can determine what KV / Pinion you want to start with for your desired top end speed.

SCX10 III - 2700Kv running on 3S with 11T pinion

Final Drive Ratio (FDR) Speed MPH

1st Gear 58.08 7.29

2nd Gear 39.77 10.65

SCX10 III - 3300Kv running on 3S with 11T pinion

Final Drive Ratio (FDR) Speed MPH

1st Gear 58.08 8.92

2nd Gear 39.77 13.02

SCX10 III - 3800Kv running on 3S with 11T pinion

Final Drive Ratio (FDR) Speed MPH

1st Gear 58.08 10.27

2nd Gear 39.77 14.99

Now same setup with 13T pinion. This gives you some idea of the speed differences between motors and how much speed differences you will see with pinion changes.

SCX10 III - 2700Kv running on 3S with 13T pinion

Final Drive Ratio (FDR) Speed MPH

1st Gear 49.15 8.62

2nd Gear 33.65 12.59

SCX10 III - 3300Kv running on 3S with 13T pinion

Final Drive Ratio (FDR) Speed MPH

1st Gear 49.15 10.54

2nd Gear 33.65 15.39

SCX10 III - 3800Kv running on 3S with 13T pinion

Final Drive Ratio (FDR) Speed MPH

1st Gear 49.15 12.13

2nd Gear 33.65 17.72

[Bowtiewarrior]

Thanks!

Based on your information it appears I would probably want a 3300KV, and start with a 13 and drop to an 11.

I have an 11 on my stock TRX I felt that it was needed running 3S & low gear. The crawling response was much much better than 2s factory gearing.

Is it safe to assume any sensor’d brushless motor will be even better at low speeds especially being compared to the brushed factory TRX?

[$uicide $hift]

Originally Posted by Bowtiewarrior

Thanks!

Based on your information it appears I would probably want a 3300KV, and start with a 13 and drop to an 11.

I have an 11 on my stock TRX I felt that it was needed running 3S & low gear. The crawling response was much much better than 2s factory gearing.

Is it safe to assume any sensor’d brushless motor will be even better at low speeds especially being compared to the brushed factory TRX?

The motor does have an effect so I would not say ANY sensored motor. In this case the sensored motor would not be the difference in the way your rig will run against the stock TRX setup.

My SCX10 III has a better startup and can crawl slower very smoothly. This is due to my gear reduction which is about 100:1 as well as the Mamba X ESC. Setting the throttle curve so that the first 70% of the trigger has a very slow ramp up and 70 to 100 is steep.

If you were to simply get a HW 1080 and a HH brushed motor for your TRX you would see improvement. I am fine with the way the TRX runs on stock electronics until something burns out. I know once that happens the TRX will have a better slow startup / crawl with HW 1080 and a HH brushed motor.

[Bowtiewarrior]

Originally Posted by $uicide $hift

The motor does have an effect so I would not say ANY sensored motor. In this case the sensored motor would not be the difference in the way your rig will run against the stock TRX setup.

My SCX10 III has a better startup and can crawl slower very smoothly. This is due to my gear reduction which is about 100:1 as well as the Mamba X ESC. Setting the throttle curve so that the first 70% of the trigger has a very slow ramp up and 70 to 100 is steep.

If you were to simply get a HW 1080 and a HH brushed motor for your TRX you would see improvement. I am fine with the way the TRX runs on stock electronics until something burns out. I know once that happens the TRX will have a better slow startup / crawl with HW 1080 and a HH brushed motor.

Okay so the Mamba X, seems to be the correct ESC based on what I’m reading, are these precise adjustments able to be done with a stock ESC or would I need a special cable similar to the Tekin RX4?

For clarity, you are saying your low speed crawl is amazing because of your set up, that includes the 3300kv, 70% lower gears, 11t and 3s?

[$uicide $hift]

Originally Posted by Bowtiewarrior

Okay so the Mamba X, seems to be the correct ESC based on what I’m reading, are these precise adjustments able to be done with a stock ESC or would I need a special cable similar to the Tekin RX4?

For clarity, you are saying your low speed crawl is amazing because of your set up, that includes the 3300kv, 70% lower gears, 11t and 3s?

Mamba X is a great versatile ESC. I would recommend this due to the fact that you can use different motors. In the event you decide you want to speed things up or slow them down you are able to across all brands (Except the HW Axe of course)

You have two options with the Mamba X. Usually there is a coupon to get their program card for free. (Currently out of stock) You could do basic settings on the card plugging it directly into the ESC. You get to advanced settings for throttle curve adjustments by connecting the card to a PC and using their CastleLink software.

2nd option is to buy their bluetooth adaptor kit $50.00, plug it in between your ESC and Receiver and use the CastleLink App on your phone to make all adjustments.

The lower the gear ratio the easier it is to creep but not the only way. I would not recommend you putting in the 1:7 gear reduction. You will get that rig to creep with a 2700 - 3300Kv motor. You will get this by setting the throttle curve on the ESC. This way you can also have a fun top speed in 2nd gear.

I would start with the stock transmission gears. When increasing the gear ratio you are making the motor work less thus running cooler and you are getting more torque to the wheels. When gearing this low the transmission gears will be much louder especially in this transmission. You would also then want to either go with a higher tooth pinion or a higher KV motor as the 1:7 reduction is a LOT.

[Inspector86]

Personally, I would not dismiss a brushed setup. I know they are not as sexy as brushless but they can actually work better in a crawler. I have run a Mamba X and 1406-2850 and it was great but very spendy at $200+. I also run the HW1080 with a HH Crawlmaster Sport 550 15t and for the $62 price it can't be beat.

[Bowtiewarrior]

Thank you for all the help, I am impressed with the knowledge on this site! I have decided on the Mamba X, I need to choose a motor now.

I have a buddy with a VS4-10 with the Tekin ROC412 3300KV & RX4, its runs super smooth, but I am not sure if that is the motor/ESC or if it the transmission/portals/gearing/quality of the Vanquish?

Id like to obtain similar or better crawling as the VS4-10 but even with this set up, it seems over all slower than expected, this is my why my fingers are crossed that the SCX10.3 is just as smooth and faster due to the second gear.

[$uicide $hift]

Originally Posted by Bowtiewarrior

Thank you for all the help, I am impressed with the knowledge on this site! I have decided on the Mamba X, I need to choose a motor now.

I have a buddy with a VS4-10 with the Tekin ROC412 3300KV & RX4, its runs super smooth, but I am not sure if that is the motor/ESC or if it the transmission/portals/gearing/quality of the Vanquish?

Id like to obtain similar or better crawling as the VS4-10 but even with this set up, it seems over all slower than expected, this is my why my fingers are crossed that the SCX10.3 is just as smooth and faster due to the second gear.

You can get your SCX10 III to crawl the way you want. Many here use and like the Tekin ROC412. That motor would be fine as well as a Holmes Hobbies Puller Pro and a Castle Slate motor. Many here swear by Holmes, I have yet to try one but I would based off of the thousands on this site. Many use the Tekin but they are on the higher end of price. That is why you don't see them mentioned as much but still great choice. Castle motors are the same, many here use them and love them. If you had three crawlers all setup the same, but each using one of those three motors, I think you would still have a hard time picking which one you think is the best.

As for the 2 speed, yes the spread is not that much. My initial setup on the III was a HW Axe 3300KV. I could dial in expo and crawl slow and smooth, if I put it in second I could still crawl slow and smooth. Once I squeezed the trigger however past a certain point it woke up and took off like a raped ape! It was not controllable full speed on this setup as expected. I mean ripping straight with a very slight turn of the wheel OK. Turn the wheel more at full speed and you are rolling.

With the Mamba X you will instead of expo put in a throttle curve so that the first say 60 or 70% of throttle does not ramp up fast and when you hit that 60 or 70% the ramp is steep and it will take off for a speed run. With that Mamba you can also try out different setups if you want. You can go with brushless or brushed and go up to 6S not that you are going to do that but you CAN! LOL

Bottom line pic any of the motors you like based off of recommendations, Tekin ROC, Holmes Hobbies Puller Pro, or Castle Slate. You will have a great setup and as you get to know the rig you may want to try a different motor out just to see the difference. Overall though you will not be disappointed with any of those motors.

[mikemcE]

Speed will be impacted by things you can change. Throttle curve first, proper pinion for KV and power source.
I’m running a 2700 stubby on 3s and an 12t pinion. We creep fine.


https://youtu.be/RiLYVmb-2zY


Hang up and Drive

[Bowtiewarrior]

So it seems that all these crawlers motors are out so stock everywhere.

I can find a Tekin Roc412 3100KV and a HH Trailmaster 3300KV

Is there a major difference between the Trailmaster and the PullerPro from HH?

Also, will there be a noticeable difference between the 3300KV Stubby PPV2 and the 3500KVPPV2?
Is the stubby a better motor?

Thanks,
Joe