how should I pick a servo - tamiya tt02b

[gkatz]

Hi all;

what should be my criteria when choosing a servo? for a neo scorcher beginner driver that does not race

there are 10usd ones and 40usd ones....

hard for me to undersdtand

[Twinfan]

I currently look for metal gears and a speed as close to ~0.10s as I can get for reasonable money.  If going in a 2WD car they don't need to be super strong, 5-10kg seems to work fine for me.  In a 4WD I aim for 10kg.  Having said that, I've got a cheapo Carson CS-3 that came with my radio gear in my Lunchbox which has been heavily abused and the servo is still working great!

As mentioned on another thread, these are my current two go-to servos although I've not fitted any toa car yet.  They get great reviews and can be picked up on eBay for around £15 each and being low profile they'll fit in just about anything:

SPT 4412LV (12kg, 0.09s)

JX PDI-4409MG (9.2kg, 0.11s)

or for a regular size servo:

JX PDI-6208MG (8.2kg, 0.07s)

[alvinlwh]

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[gkatz]

should i be worried if the default tamiya esc outputs 6V and the servo operate between 6-7.4? i guess 6 is the common denomenator but there are servos with 4.8-6.8V operations out there - would they work better?

[Twinfan]

Which servo are you looking at?

[gkatz]

found this one now with 4.8-6.8 https://www.amazon.com/gp/product/B01MU7TQV8/ref=ox_sc_saved_image_1?smid=A1L550QEP2LVNB&psc=1

looks ok to me but I am not an expert by any means...

[Twinfan]

Given that it's 20kg, and based on Alvin's experience, that might be an issue with a Tamiya TBLE ESC.  I don't use anything that strong.

[gkatz]

hard to find on amazon something else TBH...

[Twinfan]

What about eBay?

https://www.ebay.com/itm/334061739618

[Kowalski86]

@gkatzI had a used Rally Beetle with one of those in it, it was fine enough for that role. It did cause the TBLE-2S to brown out occasionally though. Its one of the few decent off-brand servos out there, even if the "25kg" rating is slighlty exagerated.

Otherwise most of my other servos are cheap Futabas, but these are in cars like a Grasshopper and a Lunchbox, 2WD and not something that really warrants a fancy servo.

[alvinlwh]

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[alvinlwh]

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[Frog Jumper]

I used to get Futaba 3003 and 3004 servos, but recently I’ve bought 3 Power Hobbies servos to replace them.

https://www.powerhobby.com/powerhobby-130mg-waterproof-servo.html

 

[sosidge]

3 hours ago, gkatz said:

hard to find on amazon something else TBH...

Try an RC shop. Much better selection than Amazon, which is not a good place for RC.

[gkatz]

the thing with amazon is that they are the only ones i can trust with shipping, shipping prices (usually zero) and no hassle returns.
of course many things could not be found there...

most hobby shop will charge 30 USD/EU even to send a sheap 9$ servo...

BTW, in my whole shopping for items, apperantly the most difficult thing to deliver overseas is the tamiya spray paints... I guess there are rules on sprays in general or somethihng

 

[gkatz]

but back to the topic at hand...

so assuming I see the specs below for a servo 

there is a rated current of 1A and blocking current (what ever this is) of 1.8A

does this mean the servo draws 1A of the ESC (which is well which the tamiya default tt02b ESC) so thats a good servo example?

Specifications:

Type: SPT4412LV 12KG, SPT4412LV-210, SPT4412LV-320, SPT4412LV-360(optional)

Motor: Core

Voltage Range: 4.8V / 6.0V

Signal Frequency: 330HZ

PWM Voltage: 3.3V-5. 0V

Feedback Angle: no

Cycle: 20ms

Default Direction: CCW

Yes / no Lock: Lock

Quiescent Current :50mah

Rated Current :1.0A

Blocking Current : 1.8A

Weight / Dimensions: 50g / 40*20*28.3mm

Output Gear: Futaba 25T

Gear Material: All Metal Gear

Shell Material: Half Aluminum Shell

Bearing: 2BB

Connector Wire Length : 260MM

line Definition: Brown- / Red + / Orange s

Operating Speed: 4.8V/0.11″/ 60° 6.0V /0.09″/60°

Stall Torque: 4.8V/10kg.cm 6.0V/12KG.cm 

 

Package Included:

Digital Servo * 1

[BuggyDad]

44 minutes ago, gkatz said:

the thing with amazon is that they are the only ones i can trust with shipping, shipping prices (usually zero) and no hassle returns.
of course many things could not be found there...

most hobby shop will charge 30 USD/EU even to send a sheap 9$ servo...

BTW, in my whole shopping for items, apperantly the most difficult thing to deliver overseas is the tamiya spray paints... I guess there are rules on sprays in general or somethihng

 

Where are you based? I have used Aliexpress for those servos. Have 2, and ordered a pack of 4 more recently because they come out so cheap I may as well have stock, although they do estimate about 6 weeks postage to UK. 

I don't know how fast the servos really are but they'll do me. I have yet to break one. 

[alvinlwh]

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[gkatz]

can you post a link to a aliexpress valid servo for my tt02b neoscorcher?

that would be great

thanks!

[alvinlwh]

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[alvinlwh]

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[BuggyDad]

10 minutes ago, gkatz said:

can you post a link to a aliexpress valid servo for my tt02b neoscorcher?

that would be great

thanks!

Well, the ones I ordered are low profile but, to my (limited) knowledge I think they should be fine in that. I'm using one in something very similar. 

https://a.aliexpress.com/_mN7xfvk

It might be prudent to wait for others to confirm this is right and not dodgy for you - I haven't received them yet, although I haven't myself had an problems with aliexpress either. 

I have followed advice on here to aim for around 10kg and a speed of about 0.1 secs. This one is near enough that. 

[gkatz]

thanks for all the info

I have recently posted many question (and probably will have some more)

I think I will eventually post a summary of what I bought based on this forum's reccomendations and my research

it will be good for others like me navigating this waters - i can tell you that it was a lot easier 35 years ago  - i simply went into the biggest toy shop (Hamleys in london on a family trip there) - took a new tamiya thundershot, a 8.4 nimh, a technigold motor, a 2 channel futaba with servo all over the counter.  - there werent 50 types of servos, motors, transmitters, recievers, etc to choose from

[Jonathon Gillham]

14 hours ago, BuggyDad said:

Well, the ones I ordered are low profile but, to my (limited) knowledge I think they should be fine in that. I'm using one in something very similar. 

https://a.aliexpress.com/_mN7xfvk

It might be prudent to wait for others to confirm this is right and not dodgy for you - I haven't received them yet, although I haven't myself had an problems with aliexpress either. 

I have followed advice on here to aim for around 10kg and a speed of about 0.1 secs. This one is near enough that. 

Yep they're the right ones, I have loads of them. And the .10secs and 10kg is a good starting point.

Also, I run them with TBLE-02S ESC and they're fine. Servos are always rated based on volts, not amps. I don't think they draw many amps as I haven't had issues. I have run Savox (known for high current draw) on TBLE-02S and they worked fine. I suspect current draw may go up when the servo is working harder such as binding in the steering, but don't know for sure. Motors get faster with volts not amps too (simplistic, but 3s is faster than 2s etc), although I have experienced when a battery can't supply the power a motor wants too and that is down to amps (NiMH vs lipo)

However, I have loads of TBLE-02S ESC and the early ones were great and still work, but a whole lot of newer ones have failed. The BEC is what fails in them, and an external BEC isn't worth the money for one of these. I suspect that some newer members experience with them is that the QC is awful and they're bad ESC rather than the specs aren't up to running some servos. I have one from 2017 which is in my sons TT02 racer with the SPT 4412LV and its fine. The esx that came with the car is long gone, but because of class rules it has to be a Tamiya esc so I put an old one in and 3 years later its still going.

As for the original question, what Twinfan said sounds right to me, and the SPT 4412LV is my goto for fun cars. Race cars are another story...

[alvinlwh]

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