25.5 turn brushless on a truck with 2.8" badlands - HELP!!

[BobbyBlank]

I'm trying to get a motor/esc combo for a torment with 2.8" Proline Badlands...the only thing available in my area is a Hobbywing 25.5 turn motor setup. I'm not really familar with "turns" but I had my eyes set on a Castle 3800kv. I have a 32p 62t spur and no pinion yet. Can I use this without burning things to the groubd?? Thanks!!

 

[Heyitsme]

No real direct correlation between turns and Kv it can vary from one manufacturer to the next. If I had to guess your looking at something under 2000kv for a 25.5t brushless motor. The Castle 3800 would be a good choice it's a popular choice for bashers. I had a old cm36 2 pole 3800kv Castle before was a good motor. I mostly use cheaper motors (Goolrc, Surpass etc.) now and am fine with them. Get a good name brand esc (Hobbywing, Castle) and a cheap motor you should be fine. I burn up a cheap motor that's fine with me I'll just get another (usually around $20) but that's just me.

I don't use 32p so don't know what pinions will fit (stock motor mount hole positions without having to slot them more) with a 32p spur. Whatever you were using before stock 48p just try and find the same gear ratio and you can start from there. Say 87t spur 19t pinion 87 divided by 19 = 4.5 so 62 divided by 14 = 4.4.

 

[BobbyBlank]

man...I stabbed out and bought the 25.5, and a 15t pinion....it may go 10mph with a 62t spur. It's a 1600kv motor according to specs, so I expected it to be quite a bit slower - but 10mph? Does that sound right for that setup?

 

[BobbyBlank]

I did the calculations on an rc car gearing app and filled in all the info - including tire height and tranny gear ratio, and it says 23.3mph...no way is it doing 23.

 

[Heyitsme]

Never had a motor that low in kv (what the turns equaled out to be). Stock class I have seen is 17.5t usually this low in kv motor gives a lot of gearing options with 48p and 64t spurs to fine tune the speed but 25.5t (1600kv) sounds like crawler territory. Kv is rpm's per volt so with a 8.4v lipo running a 1600kv motor would only be 13,3440 rpm's so yeah slow. Difference is made up with voltage and gearing but with that low of kv your talking about really tall gearing, 4-6s lipos 8th scale territory to get speed.

Get another motor like the Castle 3800 or no less than a 3650 3100kv motor. I would also not go higher than a 4300kv motor. The higher in kv you go the higher the battery and amp draw.

Sorry you got stuck with a slooow motor.

 

[BobbyBlank]

thanks for the info....MOTOR FOUR SELL!!

 

[Heyitsme]

.........

 

[BobbyBlank]

nevermind...no longer four sell....I got the sensored cable, a 12t 32p pinion and I'm lovin' my unintentional, 2wd torment muck crawler. I just have to watch slinging too much water around because I dont think the system is waterproof. Nevertheless, it's great fun and runtime is off tha' chart!

 

[BobbyBlank]

btw - my sidewinder 4, 3800kv came in today. I'm not even in a hurry to try it out. In fact, I'm considering a Mamba X and a low-kv Castle motor to keep this thing as a creeper - just with waterproof capability. I live in a swamp down here in southern Mississippi, so things stay pretty moist.

 

[Heyitsme]

Don't know what esc you have but being sensored is probably not waterproof. Sensored motors usually have holes in the can of the motor leaving everything inside exposed.

I said what I said earlier no lower than 3650 3100kv for running on 2s and 3s batteries and thinking you were looking for something as fast or faster than brushed. I would try a motor like this 3650 2300kv motor first before buying a low kv Castle the motor can run on 4s. Dictate speed by battery choice don't have to change motors to get more speed. Want to go slower you could get away with a 7.2v nimh battery. Want to go faster pop in a higher voltage battery. Get longer run times and not need high capacity batteries. Going slower speeds don't need high capacity batteries so the batteries are cheaper even if you wanted open it up for speed (higher cell battery) still won't drain the battery that fast. For me just bashing around these around $20 motors have been great experimenting with.