Rear axle nut external size on Bafang BFSWX02?

[Manc44]

I know these axle nuts are M12 internally with a 1.25mm pitch thread, but does anyone know what size spanner is needed on the outside?

Are they 22mm?

I got the schematic and made it actual size. Measuring the left axle nut it is 22mm so I am guessing that's right?

Cheers.

 

[Nealh]

19mm on my hubs.

 

[vfr400]

I think there are three different sizes. I've definitely seen both 18mm and 19mm, and I think I've seen 17mm too or maybe 20mm. I can remember cursing when I had to keep changing spanners when swapping motors. You'll have to see which spanner fits or measure them. The drawing shows corner to corner, not flat to flat, so you can't get the spanner size from it.

The standard size for an M12 flange nut is 19mm.

 

[Manc44]

Cheers folks. The left nut on that diagram shows flats top and bottom, the right nut shows the top and bottom as 2 points. Although it seems to be 22m on that diagram, some parts of it aren't to scale when other parts are, so overall it's not to scale.

 

[Woosh]

the supplied nuts vary. Some nuts fit 22mm spanner, some 23mm.
The diagram shows the plastic boots covering the nuts.

 

[Manc44]

Cheers Whoosh I didn't even think about that.

I'm just trying to avoid riding around with a Bahco adjustable spanner, probably 3 times heavier than a 1-size spanner.

 

[flecc]

As VFR400 mentions, 18mm was a common spanner size for their hub nuts on M12 spindles, see the link below for two of my Bafang motors:

tools

.

 

[vfr400]

I don't understand the big mystery. All you have to do is measure one with a ruler, then you can tell us what it is.

 

[Manc44]

Even if someone does, it could be 22mm while others are 23mm, or 23mm while others are 22mm lol. When I eventually get mine I'll just fit it with an adjustable to start with and get hold of a 6-point ring spanner that size, maybe cutting it down to 6" like flecc suggests above, although I can fit a 35cm pump in my bag so I'm safe on that front, but the open end of such a spanner is going to be useless for this, so it makes sense to cut it down.

 

[StuartsProjects]

An M12 uses a nut that requires a 19mm spanner when to DIN standard
An M12 uses a nut that requires a 18mm spanner when to ISO standard

My own Bafang 36V 250W rear hub motor has an M12 axle with nuts fitted to ISO standard, so they need an 18mm spanner.

A standard 18mm combination spanner cut in half would weigh around 70g, you dont need to carry a full one. The length would be around 110mm. Costs around £3.50. Cut in half with angle grinder.

I carry one of those thin 18mm cycling spanners, it weighs 72g. The length is around 190mm so plenty of leverage.
It could probably be cut down too. Is 2.1mm thick. Costs around £4.50.

 

[vfr400]

Even if someone does, it could be 22mm while others are 23mm, or 23mm while others are 22mm lol. When I eventually get mine I'll just fit it with an adjustable to start with and get hold of a 6-point ring spanner that size, maybe cutting it down to 6" like flecc suggests above, although I can fit a 35cm pump in my bag so I'm safe on that front, but the open end of such a spanner is going to be useless for this, so it makes sense to cut it down.

A normal ring spanner often doesn't fit on the derailleur side. Also, you have the cable to contend with. I can't think of any reason why you'd need to take the wheel off during a ride, so why do you think you need to carry a spanner?

 

[Manc44]

A normal ring spanner often doesn't fit on the derailleur side. Also, you have the cable to contend with. I can't think of any reason why you'd need to take the wheel off during a ride, so why do you think you need to carry a spanner?

In case I get a puncture.

 

[JPGiant]

Slime, fit and forget.

 

[sjpt]

Slime, fit and forget.

Slime, fit, and get a terrible mess next time you get a puncture, and an almost impossible to repair inner tube. (Some people love it, but that's my experience)

Marathon Plus is the answer as far as I'm concerned. (They do have disadvantages too)

 

[vfr400]

In case I get a puncture.

You don't take the wheel off to fix a puncture. Just pull the tyre off one side, extract the tube, patch it, remove whatever punctured it and reassemble. Better still, get a Schwalbe Marathon Plus tyre and never worry about punctures again. Don't waste your time with slime. It's very hit and miss on tubed tyres, and it can render the tubes irreparable.

 

[Manc44]

Already on M+ tyres... I'm just paranoid lol

Now I'm realizing this torque arm might not quite fit with it rotated how it needs to be and so it goes on...

 

[sjpt]

Already on M+ tyres... I'm just paranoid lol

Gaadi inner tubes can help as well to allow you to replace a tube without removing the wheel.

If you fit them in advance you can just remove a punctured one and replace it with another; the repair the puncture later. Or you can carry one as a spare, and sacrifice the old punctured tube by cutting it out.

 

[StuartsProjects]

Better still, get a Schwalbe Marathon Plus tyre and never worry about punctures again.

I have a Schwalbe Marathon Plus Tour on the rear, with a Tannus insert (240g), reducing the chance of a puncture even more.

I tried the tour + tannus on the front but it was difficult to get the insert straight, which made the steering wobbly, so there is a standard marathon plus on the front now.

I do carry a spanner for the rear wheel.

 

[Manc44]

Kit turned up, the axle nuts (12x10 axle) are 18mm (17.8mm to be exact).