Spektrum 3652 4000KV motor shaft diameter

[DavidB1126]

Was looking for a smaller and lighter motor for my slash and this came in at the lightest out of all the other options. In the description it says to use a 3.175 or 1/8in bore pinion but in the specs it says 3mm or 0.125in motor diameter. So would I be using a regular 3.175 bore pinion or a 3mm bore?

https://www.amainhobbies.com/spektrum-rc-firma-sensorless-brushless-motor-4000kv-spmxsm1400/p1210150

Maybe I'll just go with my normal hobbywing since it's cheaper and less confusing. Lol

 

[332_RC]

1/8"=3.175mm. It's a 3.175mm

 

[DavidB1126]

But why does it say 3mm motor shaft diameter? It would be 3.175 if this is all true?

 

[332_RC]

Amain & the Spektrum website have many errors. Amain copied the Spektrum specs. I have found so many errors on the Spektrum, HH, & Arrma site.

 

[332_RC]

For instance. The Spektrum Firma 4074 2050kv motor is really a 1900kv. And it states that. Not truly an error but it's a true 1900kv motor. The weight right next to the 1900kv spec, shows 319g & it's actually 390g. Shows 62 amps rating. It's a 162a.

 

[DavidB1126]

Ok HW it is. Horizon lies then.

 

[332_RC]

I wouldn't say lies, necessarily, I bet the technical writers are not college grads. Only interns. No double proofreading for those departments. Lots of errors.

 

[Jerold]

But why does it say 3mm motor shaft diameter? It would be 3.175 if this is all true?

The 5m & 8mm are actually metric shafts. The 3mm fractional English units. So I think they generically call them 3mm shaft to sound all fancy and stuff.

 

[ahr43]

1/8in. bore pinion works on the 3652 4000Kv. Here's the install on my Bandit build using 32p gears. -AC

 

[WickedFog]

3mm is 0.1181102362"
1/8" is .125"

They need to get their chit right in the descriptions. Neither size would be at all compatible if that was actually the case.

 

[CertifiedMike]

I went thru something similar with DeeRC... Some manufacturers DO use a 3mm pinion. Its pressed on and not intended to be reused.
I'm not 100% that its 3mm but they DEF don't fit a normal 540 motor shaft like pinions always used to.
No grub screw either.
They told me not to use the small ones and offered me free replacements.
I think 1 was steel and 1 brass.
I'm not sure if any 380 (28mm?)cans also use a smaller diameter pinion.

 

[Greywolf74]

99.99% of the time, when someone/something refers to a 3mm bore, they really mean 3.175mm bore. I've never seen anything different, although I'm sure some exceptions probably exist, like the press fit pinion that Mike mentioned. Generally speaking though, it's safe to assume 3mm bore really means 3.175mm because a lot of people just refer to it as a 3mm bore for the sake of simplicity.