Losi 22S SCT - Pinion & Spur Gear Option

[kdecesari]

After quite a summer of enjoying the stock setup for a Losi 22S SCT, I decided to mess around with the gearing.
And things have gone sideways quickly.
The objective was go get more speed with a change to the pinion & spur gears.

Stock Pinion: 48p, 14t
Stock Spur: 48p, 84t

I changed those out to Losi branded parts:
Pinion: 16t
Spur: 81t* (TLR Part TLR232078)

*My first attempt was to change the spur to a 78t (TLR 232010), but that didn't work because the motor mount prevented the gears from touching, let alone meshing.

After a single session on a dirt track that seemed to go great, the next time out within minutes the spur gear was toast.
Oops.

I can only speculate what went wrong. Did I not screw the motor back to the motor mount tightly enough resulting in a loose mesh and thrashing the spur gear? That wasn't immediately evident.
The pinion gear is still in place - no glaring problem there either.

I looking for feedback as to what I may have done wrong. At the same time, I am trying to locate a metal spur gear that might work with the (Brushed) 22S SCT. That search hasn't proven fruitful yet. Anyone know where I might find a solution for a metal spur gear? There is a slipper setup currently...not sure if that will require additional changes at this point.

So - How badly did I F up? Where should I go from here?

Thanks!

 

[9x19]

Here's an 84T, steel

https://www.amazon.com/Powerhobby-Hardened-Steel-Spur-Slipper/dp/B0BYM5JDHM/ref=sr_1_22?crid=3G5BXNUBN5L5X&keywords=team+losi+spur+gear+48p&qid=1699756216&sprefix=team+losi+spur+gear+48p,aps,96&sr=8-22

But I'm not sure that's your answer. I'd go back to the stock Spur and just go up on pinion size, and set the slipper tight.

 

[kdecesari]

Here's an 84T, steel

https://www.amazon.com/Powerhobby-Hardened-Steel-Spur-Slipper/dp/B0BYM5JDHM/ref=sr_1_22?crid=3G5BXNUBN5L5X&keywords=team+losi+spur+gear+48p&qid=1699756216&sprefix=team+losi+spur+gear+48p,aps,96&sr=8-22

But I'm not sure that's your answer. I'd go back to the stock Spur and just go up on pinion size, and set the slipper tight.

Cool. Thanks for the link.
I clicked around the power hobby website and didn’t find a metal 81t spur. Your suggestion about the larger pinion might be the ticket.
Going to try again…

 

[WickedFog]

So it ran fine, then next time out the spur gear was destroyed? Did you happen to look at the spur between runs? Any changes from one run to the next? Have you checked your motor temps after running? The only thing I can think of that may have caused the mesh to change is if your motor was running hot, the motor screws may have became loose and the motor slipped. Were there any hard bumps or collisions from the first run to the time the spur shredded? If none of this caused it I can only guess your mesh wasn't quite right.

 

[kdecesari]

So it ran fine, then next time out the spur gear was destroyed? Did you happen to look at the spur between runs? Any changes from one run to the next? Have you checked your motor temps after running? The only thing I can think of that may have caused the mesh to change is if your motor was running hot, the motor screws may have became loose and the motor slipped. Were there any hard bumps or collisions from the first rto the time the spur shredded? If none of this caused it I can only guess your mesh wasn't quite right.

WickedFog, these are all good questions. Thank you.

No, I did not think to check to open up the cover to check the spur gear between runs.
The next run lasted only a few min & there was some odd noise present almost immediately.
Hard bumps during the previous run? Yes. There was one tumble I recall.

Engine temp - I need to be better at checking this after making gearing changes like this. Lesson learned.

A few rookie mistakes were made. I am still learning, but this is turning out to be a good lesson.

Thanks again.

 

[WickedFog]

Do some slow driving around with the cover off and listen for the mesh. Shouldn't be too noisy or chunky sounding. Do a quick throttle blip. If it sounds good, do another. Inspect the mesh by rocking the spur gear teeth against the pinion teeth. With a 48p gearset, if I just barely feel any slop in the mesh whatsoever, I am good. If I can't feel any, I know I'm too snug.

if that all checks out, do a couple longer runs back and forth to heat things up. Check motor and ESC temp (stay below 160°F) and recheck mesh. If ok, repeat with longer runs. Stop for another check. Repeat.

Once you have managed to run through a pack, things should be good. That is, as long as there wasn't any adjustments needed and your temps stayed cool. But after/before every run, if you can check your mesh, it's a good practice to do so. Even after you have ran a number of packs through it.

 

[J’sCrawler]

I had this same issue at one time, I figured out that my pinion wasn’t lined up with the spur, like the spur had just a teency weency amount not in contact with the spur. I also had the mesh too tight so since then I use a piece of paper to set it. on Stock gearing I burned up 2 brushed motors running in grass and decided to go brushless. As far as gearing though, I went to the avid slipper using 84,87 spurs along with 17 and 19 tooth pinions. On a brushless system I’ve had zero issues. I don’t see the need for a steel spur with properly set mesh. Depending on terrain thats how I set my slipper but it’s usually pretty tight. I have heard some roll the car by hand and sort of tighten the slipper nut just until the car tries to stop or lockup, if you can picture what I’m saying. Anyway good luck

 

[kdecesari]

I had this same issue at one time, I figured out that my pinion wasn’t lined up with the spur, like the spur had just a teency weency amount not in contact with the spur. I also had the mesh too tight so since then I use a piece of paper to set it. on Stock gearing I burned up 2 brushed motors running in grass and decided to go brushless. As far as gearing though, I went to the avid slipper using 84,87 spurs along with 17 and 19 tooth pinions. On a brushless system I’ve had zero issues. I don’t see the need for a steel spur with properly set mesh. Depending on terrain thats how I set my slipper but it’s usually pretty tight. I have heard some roll the car by hand and sort of tighten the slipper nut just until the car tries to stop or lockup, if you can picture what I’m saying. Anyway good luck

Thanks for the informative post. Yesterday I put it together with a metal 84t spur & 18t pinion. It was OK after a very short test run. I put loctite on the pinion & motor screws and figured I should let it dry/cure. Hopefully that 18t pinion doesn’t cause overheating, but I plan to be diligent about checking temps when I take it out next.

Brushless. I am thinking about this change again. What have you had luck with in the 22S SCT? I have my eye on the Hobbywing quicrun WP 10BL 120 G2 combo, but am not sure which variant to go with. Measurements need to be taken, but I am thinking the 3660 3150kv G2 motor might be the ticket.

Let me know what worked for you, please. I will post again about this rig as work through changes. Thanks again.

 

[J’sCrawler]

I first put the max10 with a 3660 3200kv. It’s too much motor, it will rip through outdrives and slipper pads, the slipper is always finicky to even minor adjustments. Get that esc but with a 3650 sized can, the kv you are at will be fine for 2&3S. Start with a 17/84 or 87 tooth pinion to spur. Then go up as you see fit. Is that a Sensored motor and esc? If it is you won’t really need it especially if you won’t be racing, Sensored motors are somewhat delicate in the bashing application. However you could run that sensor less, then for kicks plug into Sensored mode to see how it improves.
For now on brushed I would back down to like a 16 or 17tooth pinion with that spur. Did it come stock with an 18T pinion I cannot remember

 

[kdecesari]

I first put the max10 with a 3660 3200kv. It’s too much motor, it will rip through outdrives and slipper pads, the slipper is always finicky to even minor adjustments. Get that esc but with a 3650 sized can, the kv you are at will be fine for 2&3S. Start with a 17/84 or 87 tooth pinion to spur. Then go up as you see fit. Is that a Sensored motor and esc? If it is you won’t really need it especially if you won’t be racing, Sensored motors are somewhat delicate in the bashing application. However you could run that sensor less, then for kicks plug into Sensored mode to see how it improves.
For now on brushed I would back down to like a 16 or 17tooth pinion with that spur. Did it come stock with an 18T pinion I cannot remember

The WP 10BL 120 G2 combo is sensorless.
So, there is a 3652 & 3250 option. That is the option I should be looking at?

I was considering the larger can to help keep run temp lower, but maybe that won’t be a concern.

The stock brushed set up is 12t motor with 84t spur and 14t pinion.
I have a 16t, but was thinking…wellll, let’s see what happens with the 18t pinion since it’s also on the table just staring at me.
If it blew up the stock motor I would not be heartbroken. I think a replacement motor for the same is less than $20. It would be worth the fun experiment/learning experience.

 

[J’sCrawler]

Go 3652, any longer of a can is just too much torque on the outdrives and differential, ask me how I know this. the 3250 is too small, that’s not a typo is it?
stick with the 14t pinion or try the 16 at the most while brushed. Don’t waste any money on another dynamite brushed replacement motor, just put it towards a brushless system, you will thank me later.
And one more thing, I don’t know the terrain you run, but the mx badlands aren’t a good choice for this platform, almost too much grip which can wreak havoc on the drivetrain as well. Go with a smaller tread, I actually prefer the og badlands design. Slides over grass and dirt a lot better rather than trying to dig in and tear the crap out of the earth. Although I’m not recommending grass bashing either.

 

[DavidB1126]

So, there is a 3652 & 3250 option. That is the option I should be looking at?

There is a 3652 size motor (540) there is no such thing as a 3250, I think that is the kv rating for that motor. The kv ratings for the 3652 is 3250, 4000, and 5400kv.
HW also has the 3660 size motor (550) with 2 different kv options being 3700kv and 3150kv.

Since this is a 2wd sct, any of those motor sizes and kv can fit, but it depends what your doing with the car.
If I were me, id go for the 540 (3652) and 4000 or 5400kv motor. More kv equals more top speed / top end torque. Less kv meaning more low end torque and less top speed. This also depends on your gearing aswell. Also to note, higher the kv, the less voltage you will be able to run on that motor. For 3250, 2s and 3s, 4000, 2s and 3s, 5400, 2s only.

For reference:
Currently in my builds
Rustler 2wd: Max10 G1 60A sensorless - 3652 4000kv G2 SL motor
Slash 2wd: Max 10 G1 SCT 120A sensorless - 3660 4000kv G2 SL motor
Since I am racing the slash, I was thinking last night about putting my system from the rustler into my slash (as I'm not using the rustler currently) and being 540 motor and a 60A esc, it should weigh less.
General rule in the ROAR rules for 2wd SCT class are a 540 motors as 2wd SCT chassis are based off of 2wd Buggy and Truck chassis, but just longer.

Gearing with my builds:
Rustler 2wd: 23/86
Slash 2wd: 23/86
Now with the slash since I have the 3660 (550) motor, those motors come with a 5mm shaft size so you would need a 5mm bore pinion. The 3652 (540) motors have the standard 3.175 shaft so you would need a 3.175 bore pinion, which I believe is the right size stock in the 22S. So ideally if you don't want to buy extra gears, 540can or the 3652 would be best. And ideally it would weigh a bit lighter than the 550 motors.
I also ordered some spur gears which are the Traxxas 76T ones so I might go up on my pinion, maybe around 26/27T, we will see.

I also been looking at that same combo (10BL120 G2 with the 540 motor) to replace my older Max10 SCT in the slash as that esc, I had since October last year, worked fine, and out of no where, the fan/program port went dead so I can't program it (well I could but with the set button tho) and I been having to run the esc fan off of the receiver via a servo extension.

 

[J’sCrawler]

There is a 3652 size motor (540) there is no such thing as a 3250, I think that is the kv rating for that motor. The kv ratings for the 3652 is 3250, 4000, and 5400kv.
HW also has the 3660 size motor (550) with 2 different kv options being 3700kv and 3150kv.

Since this is a 2wd sct, any of those motor sizes and kv can fit, but it depends what your doing with the car.
If I were me, id go for the 540 (3652) and 4000 or 5400kv motor. More kv equals more top speed / top end torque. Less kv meaning more low end torque and less top speed. This also depends on your gearing aswell. Also to note, higher the kv, the less voltage you will be able to run on that motor. For 3250, 2s and 3s, 4000, 2s and 3s, 5400, 2s only.

For reference:
Currently in my builds
Rustler 2wd: Max10 G1 60A sensorless - 3652 4000kv G2 SL motor
Slash 2wd: Max 10 G1 SCT 120A sensorless - 3660 4000kv G2 SL motor
Since I am racing the slash, I was thinking last night about putting my system from the rustler into my slash (as I'm not using the rustler currently) and being 540 motor and a 60A esc, it should weigh less.
General rule in the ROAR rules for 2wd SCT class are a 540 motors as 2wd SCT chassis are based off of 2wd Buggy and Truck chassis, but just longer.

Gearing with my builds:
Rustler 2wd: 23/86
Slash 2wd: 23/86
Now with the slash since I have the 3660 (550) motor, those motors come with a 5mm shaft size so you would need a 5mm bore pinion. The 3652 (540) motors have the standard 3.175 shaft so you would need a 3.175 bore pinion, which I believe is the right size stock in the 22S. So ideally if you don't want to buy extra gears, 540can or the 3652 would be best. And ideally it would weigh a bit lighter than the 550 motors.
I also ordered some spur gears which are the Traxxas 76T ones so I might go up on my pinion, maybe around 26/27T, we will see.

I also been looking at that same combo (10BL120 G2 with the 540 motor) to replace my older Max10 SCT in the slash as that esc, I had since October last year, worked fine, and out of no where, the fan/program port went dead so I can't program it (well I could but with the set button tho) and I been having to run the esc fan off of the receiver via a servo extension.

All good points. For the 22s I still recommend no larger than the 3650, the drivetrain simply does not hold up to a 3660. Unless you want to constantly replace outdrives, slipper pads, and always be into the differential, go ahead and dump a 3660 for some non stop wheelies and earth excavation! I prefer lower kv because I have more room for gearing options and I don’t have long stretches to hit top speed. I guess a 4000kv on 2s would be fine too. Typically you select the motor for the voltage you plan to run. Most motors are rated for 50k rpms. So multiply the kv and a fully charged lipo (4.2 per cell?) to get rpm the motor will see. Now there’s all the gearing to factor in yada yada yada, pick a voltage, a motor, and monitor temps with your gearing. The 22s is discontinued so who knows how long parts will be available for it, just keep that in mind.
here’s another thought, the hobbystar motors from rcjuice are so affordable, you can get a lower kv and a higher kv to figure out what works best.

 

[RustyUs]

The WP 10BL 120 G2 combo is sensorless.
So, there is a 3652 & 3250 option. That is the option I should be looking at?

I was considering the larger can to help keep run temp lower, but maybe that won’t be a concern.

The stock brushed set up is 12t motor with 84t spur and 14t pinion.
I have a 16t, but was thinking…wellll, let’s see what happens with the 18t pinion since it’s also on the table just staring at me.
If it blew up the stock motor I would not be heartbroken. I think a replacement motor for the same is less than $20. It would be worth the fun experiment/learning experience.

I couldn't decide for another person. Me, I'd be more than content with a 3250kv motor in a 1/10 scale SCT 2wd platform... on 3S it would be bonkers to me... would need a lot of open space to open 'er up.

 

[DavidB1126]

The 22s is discontinued so who knows how long parts will be available for it, just keep that in mind.

yea thats the con. I been looking at SCTE rollers on eBay to get more into SCT racing, but those are long discontinued and I can't really find that much parts. I do want to go with Tekno route but will be double the price. Maybe a slash 4x4 can be better? Idk. (Also another reason I wanted SCTE route is that my uncle had them years ago and I know where I can get help if needed, and I might have some SCTE compatible stuff (like bodies and wheels)

So multiply the kv and a fully charged lipo (4.2 per cell?)

Yep 4.2v/cell for a normal lipo (2s fully charged = 8.4 3s fully charged= 12.6) unless its a LiHV High Voltage pack it will be 4.35v/cell. Also a little fact, some tracks use LiHV batteries for stock racing but only allow users to charge them up to 8.4 or 8.44 max. Idk why.

 

[J’sCrawler]

yea thats the con. I been looking at SCTE rollers on eBay to get more into SCT racing, but those are long discontinued and I can't really find that much parts. I do want to go with Tekno route but will be double the price. Maybe a slash 4x4 can be better? Idk. (Also another reason I wanted SCTE route is that my uncle had them years ago and I know where I can get help if needed, and I might have some SCTE compatible stuff (like bodies and wheels)

Yep 4.2v/cell for a normal lipo (2s fully charged = 8.4 3s fully charged= 12.6) unless its a LiHV High Voltage pack it will be 4.35v/cell. Also a little fact, some tracks use LiHV batteries for stock racing but only allow users to charge them up to 8.4 or 8.44 max. Idk why.

Get a Tekno, even the .3 as those should be hitting the used market. I’m salivating to try mine.

 

[DavidB1126]

Get a Tekno, even the .3 as those should be hitting the used market. I’m salivating to try mine.

speaking of kv and size motors, I think the combo I have right now in my slash would be perfect for a new (to me) tekno. Could go with a lower kv, but I can just stick with what I have and just gear down a little bit. My uncle had a 4.5T 550 novak motor in his scte, he had to dial it way down for an indoor carpet track. It was a 90-100ft straight depending on the layout.

 

[J’sCrawler]

speaking of kv and size motors, I think the combo I have right now in my slash would be perfect for a new (to me) tekno. Could go with a lower kv, but I can just stick with what I have and just gear down a little bit. My uncle had a 4.5T novak motor in his scte, he had to dial it way down for an indoor carpet track. It was a 90-100ft straight depending on the layout.

The 3660? Yea it would be perfect. Didn’t @bill_delong run a 4000kv in his?

 

[DavidB1126]

Back in 2017 if I can remember, the good old days. Too bad he sold them before I was actually into RC, because I wanted them instead of my trashy slash. Lol

 

[RustyUs]

.... the hobbystar motors from rcjuice are so affordable, you can get a lower kv and a higher kv to figure out what works best.

That's exactly what I used to do. I'd buy/bid on no name motors listed on eBay for testing... narrowed down my Kv sweet spots for my rides over the years. Speed calculators, and recording temps helped a bunch. I went from 5700-ish > 4600-ish > 3800-ish > to my now current 3000~3500kv sweet spot 3650 4-pole 2S usable power for 1/10 scale 2wd trucks on rough terrain.