Tekin ROC412 RX4 not very slow

[AKayl]

Hello,
I am trying to figure out an issue with my ROC412 3100KV with RX4. The setup is in my Element Enduro running a 16t pinion. According to my admittedly inexperienced math I should be around 53:1 final drive ratio. Now for the kicker, I am running this setup on 4s. I did this after a bit of research (supposedly startup speed should be the same regardless of voltage per Holmes) and after seeing Ty run his VS4-10 with the same electronics setup. In his video from the Tekin builds series his truck is substantially slower/smoother than mine(I have no idea what the VS4-10 gearing is.) I figured it was a programming issue and borrowed my brothers Hotwire to check it out, and was unable to find anything wrong, minimum throttle was set to 0, timing set to 0, I even added expo. At this point I am kind of ready to go out and buy a Mamba X as I suspect this is an ESC issue not a motor issue. I figure before I do that I would see if anyone on here had any ideas. For reference the build thread for the truck can be found here.

 

[Voodoobrew]

Stock VS4-10 is 13t pinion and 50.88:1 Stock Enduro with the lowest trans gears and a 16t pinion is 42.35:1 unless the rear has an underdrive I am un aware of. But I added the Element Enduro to my calculator https://tinyurl.com/t3r5t6j

 

[Cyclist]

A 3100kv motor on 4s is going to be damn fast, probably too fast for a crawler. Heck, that motor on a basher on 4s would easily go over 50-60mph. Gear down some more and try your setup on 3s and you'll be able to control it better. Just my opinion.

 

[AKayl]

Stock VS4-10 is 13t pinion and 50.88:1 Stock Enduro with the lowest trans gears and a 16t pinion is 42.35:1 unless the rear has an underdrive I am un aware of. But I added the Element Enduro to my calculator https://tinyurl.com/t3r5t6j

I think there is an error in your calculator for the Enduro.
The gearing is as follows 20->28 28-52 In you calc you show it as 28-52 without taking the input shaft gear to idler gear reduction into account. If I am doing my math correctly this makes the transmission reduction 2.6:1 instead of 1.86:1. This is for the non overdrive option, which is actually rear underdrive. This comes out to a final ratio (16t pinion) in non overdrive or as you have it listed element high of 53:1, similar enough to the VS4-10 that Ty was running on 4s that I would expect similar results.

 

[AKayl]

A 3100kv motor on 4s is going to be damn fast, probably too fast for a crawler. Heck, that motor on a basher on 4s would easily go over 50-60mph. Gear down some more and try your setup on 3s and you'll be able to control it better. Just my opinion.

From my research startup speed is supposed to be identical between KV of motor. This was from a Holmes post, given the level of technical knowledge he brings I did not question it. I think the issue may be the resolution from the RX4 as it does require finer control to get the same startup speed on 4s as 2s. That is what I am trying to find out I suppose.

 

[Steve g]

I had start up issues with tekin aswell. Didnt notice any difference between battery voltage and low speed control though. My issue was it wouldn't start from a stop slowly with the drag brake on. Deactivate it and it was fine. Didnt matter if active drag was on or off. Never figured it out, as one of the posts desoldered itself, tekin would only offer me a new one for 126 plus shipping and taxes, so I tossed it out and bought a castle. Honestly the only good thing about tekin is how quite it is.

Sent from my SM-G970U using Tapatalk

 

[AKayl]

I had start up issues with tekin aswell. Didnt notice any difference between battery voltage and low speed control though. My issue was it wouldn't start from a stop slowly with the drag brake on. Deactivate it and it was fine. Didnt matter if active drag was on or off. Never figured it out, as one of the posts desoldered itself, tekin would only offer me a new one for 126 plus shipping and taxes, so I tossed it out and bought a castle. Honestly the only good thing about tekin is how quite it is.

Sent from my SM-G970U using Tapatalk

Posts not posting test.

 

[AKayl]

I had start up issues with tekin aswell. Didnt notice any difference between battery voltage and low speed control though. My issue was it wouldn't start from a stop slowly with the drag brake on. Deactivate it and it was fine. Didnt matter if active drag was on or off. Never figured it out, as one of the posts desoldered itself, tekin would only offer me a new one for 126 plus shipping and taxes, so I tossed it out and bought a castle. Honestly the only good thing about tekin is how quite it is.

Sent from my SM-G970U using Tapatalk

For some reason I could not get this to post last night so hopefully it will work this morning.

I did some testing playing with drag brake and voltage. Not surprisingly 2s was slower/smoother than 4s. Interestingly the drag brake issue you describe was not present on 2s but was present on 4s. This makes me think there are some firmware issues that show up at higher voltages. I think I will visit the LHS this week and pickup a Mamba X and see what happens.

 

[Steve g]

I think I only really tested it on 3s and 4s. Only ran 2s a couple times before my kid got his own and was still learning. For the price they should blow the mamba x out of the water, and they sure don't.

Sent from my SM-G970U using Tapatalk

 

[AKayl]

I plan to do some more testing, but I picked up a Mamba X/Slate 1900KV for my Gatekeeper. And even geared tall (24t) it is smoother than the RX4 on 4S, at 2s I feel like it is still smoother but it is a toss up. Now obviously this is not a fair comparison as the RX4 is running a 3100kv motor vs the 1900kv slate. The other thing I have noticed is the drag brake on the Mamba X/Slate combo will not hold the truck. I plan to pick up a set of 6mm bullet connectors so I can swap motors and try all 4 combos, I will also probably pick up a 2700kv Puller Pro or ???? to test as well. If I do go to that effort and expense I will post reviews of all including all combinations.

 

[Voodoobrew]

I think there is an error in your calculator for the Enduro.
The gearing is as follows 20->28 28-52 In you calc you show it as 28-52 without taking the input shaft gear to idler gear reduction into account. If I am doing my math correctly this makes the transmission reduction 2.6:1 instead of 1.86:1. This is for the non overdrive option, which is actually rear underdrive. This comes out to a final ratio (16t pinion) in non overdrive or as you have it listed element high of 53:1, similar enough to the VS4-10 that Ty was running on 4s that I would expect similar results.

I based the trans gearing off of these numbers

then listed them as (28/52 high)(27/53 med)(26/54 Low) options you can select. I don't actually do the math, google sheets does it based off the numbers. That's not to say there isn't an error.

Or are you saying the input gear is always 20 and the idler gear that gets thrown away in math is the 28t?
so it should be (20/52 high)(20/53 med)(20/54 Low)?

Ok, I see, Hrm I am not 100% sure if the calculator will be accurate but because there is a 20t input, then a (overdrive option 2) 28t idler gear for the front and a 52t so simply (52t/20t) (which will be accurate)
But then for the rear which is usualy what I calculate its (28t/20t)*(52/28).
I can probably do that, at least that 28t always needs to be the same. I will use the naming from the manual too.

Ok I corrected it , Probably. Thanks for the info.

I still dont get 53:1 final drive ratio, with a 16t pinion I get one of these 3 depending on your gearing...
Derp...oh I see, no over drive or the front is 53:1 and med (stock rear) is 56:1 low (over drive option 2 rear) is 59:1

What was the question again?

 

[Voodoobrew]

I cant speak much on the ROC412 3100KV with RX4, I know they will probably not be as good as a puller pro/castle combo for crawling, but will probably produce more power per weight to the puller pros. Because the ROC412 3100KV is probably designed for more racing, the motors are tuned for a specific need. although they can do anything, some are better at some things then others.
I cant speak to Ty's video either, I haven't seen it. but On castle esc's I know there are some tweaks to get better startup, like changing some torque values, or initial startup power. the RX4 may or may not have similar settings that are not intuitive that can smooth it out. I never had a Tekin setup though.
I know people are very interested in comparisons between slate/rock412/puller motors and teakin vs castle esc's. Seems nobody has ever done great comparisons, especially for the esc. Hard to quantify the differences I imagine without a dyno. and reliable/repeatable tests.

 

[AKayl]

I based the trans gearing off of these numbers

then listed them as (28/52 high)(27/53 med)(26/54 Low) options you can select. I don't actually do the math, google sheets does it based off the numbers. That's not to say there isn't an error.

Or are you saying the input gear is always 20 and the idler gear that gets thrown away in math is the 28t?
so it should be (20/52 high)(20/53 med)(20/54 Low)?

Ok, I see, Hrm I am not 100% sure if the calculator will be accurate but because there is a 20t input, then a (overdrive option 2) 28t idler gear for the front and a 52t so simply (52t/20t) (which will be accurate)
But then for the rear which is usualy what I calculate its (28t/20t)*(52/28).
I can probably do that, at least that 28t always needs to be the same. I will use the naming from the manual too.

Ok I corrected it , Probably. Thanks for the info.

I still dont get 53:1 final drive ratio, with a 16t pinion I get one of these 3 depending on your gearing...
Derp...oh I see, no over drive or the front is 53:1 and med (stock rear) is 56:1 low (over drive option 2 rear) is 59:1

What was the question again?

Yep sounds like it, glad you saw the post so you could update the calculator. As for the original question, I do not think the gearing is enough different between the element and the VS410 to cause the issue.

 

[AKayl]

I cant speak much on the ROC412 3100KV with RX4, I know they will probably not be as good as a puller pro/castle combo for crawling, but will probably produce more power per weight to the puller pros. Because the ROC412 3100KV is probably designed for more racing, the motors are tuned for a specific need. although they can do anything, some are better at some things then others.
I cant speak to Ty's video either, I haven't seen it. but On castle esc's I know there are some tweaks to get better startup, like changing some torque values, or initial startup power. the RX4 may or may not have similar settings that are not intuitive that can smooth it out. I never had a Tekin setup though.
I know people are very interested in comparisons between slate/rock412/puller motors and teakin vs castle esc's. Seems nobody has ever done great comparisons, especially for the esc. Hard to quantify the differences I imagine without a dyno. and reliable/repeatable tests.

I have some testing ideas. For instance testing with stock settings, vs tuned. And using throttle trim to figure out minimum speed by timing travel time between two set points. Primitive but effective. Unfortunately the smoothness testing would be subjective.

 

[GTSLOW]

With a 3100 on 4S you should have as small of a pinion as possible. Additionally can you add a throttle curve like you can with the Castle Link? The RX4 is a fantastic ESC and it sounds like a potential gearing/software tuneup will get you right.

 

[AKayl]

With a 3100 on 4S you should have as small of a pinion as possible. Additionally can you add a throttle curve like you can with the Castle Link? The RX4 is a fantastic ESC and it sounds like a potential gearing/software tuneup will get you right.

I could go to a smaller pinion (I actually bought one just haven't installed yet.) I have already programmed expo into the esc, I borrowed my brothers hotwire to do so. Because I do not currently own a hotwire I am not able to change it further at this time. I basically followed Ty's setup from the Tekin website except I used a steeper expo curve (more low speed control)