Help! Important Question about DD Hub Motor Spacers

izy

Finding my (electric) wheels
Nov 28, 2020
14
0
Does anyone know the actual thread size on the 14MM Axles

Im trying to get a custom threaded spacer that fits between the cassette and frame.

I am using a normal unthreaded spacer thats 14mm 20 diameter and 21MM
the problem with this is when I tighten the axle bolts to secure them the spacer still rubs against the bearing inside the cassette and also the frame
this adds noticeable resistance and wears down the spacer

What i would love is this but i dont know this names and cannot find them if i could get one of these thats 14mm and fits hub motor threads would solve any problems for many users

"edit apparently they are cone nuts but its the thread distance and finding them thats impossible it seems

 
Last edited:

Surf_Wonder

Pedelecer
Jul 15, 2020
29
8
Yes. Do a search for stomp, dirt or pit bike parts/supplier, either in google search or ebay. Use all labels ie Dirt Bike Parts, Pit Bike Parts etc.

I guarantee you'll find a supplier of 12 and 14mm axles and rear axle spacers.
 

izy

Finding my (electric) wheels
Nov 28, 2020
14
0
BTW - MY custom spacer ended up being originally for a dirt bike and then my mate cut it down to size, I then added a washer to the cut edge so that the washer/cut edge was flush against my frame. You'll see the issues here https://www.youtube.com/results?search_query=ebike+rear+hub+spacer The first 2 vids should help.
Yup I already have a custom insert made from stainless steel.

The problem is this isn't ideal as the original was threaded meaning you didn't put pressure on the bearings or increase resistance to the motor when tightening the axle nut as it pushes down on the spacer .

If it pushed down the nut thats threaded that would be that
 

Surf_Wonder

Pedelecer
Jul 15, 2020
29
8
Yup I already have a custom insert made from stainless steel.

The problem is this isn't ideal as the original was threaded meaning you didn't put pressure on the bearings or increase resistance to the motor when tightening the axle nut as it pushes down on the spacer .

If it pushed down the nut thats threaded that would be that
So you're after a threaded washer?
 
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izy

Finding my (electric) wheels
Nov 28, 2020
14
0
for anyone reading this thread about DD Hub spacers on chinese kits etc


You want a Steel spacer 14mm inner diameter 20 outer and 20 length and a 17/16mm diameter x 1mm long step. Keeping the overall length 20MM

so M14x20mmx20mm + 1mmx17mm longstep (you can request this on ebay from generic sellers of spacers)

thanks again the length could depend on your motor and so can diameter but mostly its fine

 
Last edited:

vfr400

Esteemed Pedelecer
Jun 12, 2011
7,899
3,132
Basildon
You don't want anything threaded. You need a chamfered washer, which you can make yourself by filing the one you already have. you only have to chamfer a tiny amount to stop the outer part touching the outer part of the bearing.
 
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izy

Finding my (electric) wheels
Nov 28, 2020
14
0
You don't want anything threaded. You need a chamfered washer, which you can make yourself by filing the one you already have. you only have to chamfer a tiny amount to stop the outer part touching the outer part of the bearing.
im getting confused what would that look like and wouldnt that still spin against the bearing and still put pressure on bearing when tightened

im losing track of what i should be looking for
sorry but can you explain it better or link to what you mean


currently im using one of these 15mm inner diameter, 20 outer and 21mm length ( it was a tester)

im planning to replace with 14mm inner 19 outer and 19/20 mm length

do you mean file the ends so it grips the frame better?

 

izy

Finding my (electric) wheels
Nov 28, 2020
14
0
Yeah perfect spoke to the guy making the spacers for me.

14mx20mmx20mm spacer being made
And 1mm at the end is 17mm

Thats whats being made
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
7,899
3,132
Basildon
im getting confused what would that look like and wouldnt that still spin against the bearing and still put pressure on bearing when tightened

im losing track of what i should be looking for
sorry but can you explain it better or link to what you mean


currently im using one of these 15mm inner diameter, 20 outer and 21mm length ( it was a tester)

im planning to replace with 14mm inner 19 outer and 19/20 mm length

do you mean file the ends so it grips the frame better?
It doesn't matter if it's up against the bearing inner because that doesn't move. The only thing it mustn't touch is the outer. You only need to remove a few microns from it, which would take about 2 minutes.

40910
 
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izy

Finding my (electric) wheels
Nov 28, 2020
14
0
update spacer should arrive today

but i think you guys missed the point where I needed the nut to stop pressure on the wheel entirely
 

Surf_Wonder

Pedelecer
Jul 15, 2020
29
8
update spacer should arrive today

but i think you guys missed the point where I needed the nut to stop pressure on the wheel entirely
Probably - but at least you found a seller or person that is selling you're looking for - so a solution was got and the it's the solution you wanted/needed so it's a win.
 

izy

Finding my (electric) wheels
Nov 28, 2020
14
0
yeah good idea on getting a custom made spacer my original aluminium was right size but i had trimmed it manually down steel will be better but i have to tighten the wheel extra which makes it harder to pedal but at least its electric lmao

still doable on lower gears
 

izy

Finding my (electric) wheels
Nov 28, 2020
14
0
:-o to what torque?
i dont know lmao i just have it tightened extra on gear side sometimes it loosens again if i dont tighten it enough to affect the freewheeling on the DD hub

i have it tight enough that the rear wheel barely gets a rotation i can have it looser but with a 1500w motor I want the extra security even with 2 torque arms

makes a big difference when pedalling like i said


also in other news i was going up a mountain and my controller cut off was hot to touch
so hot it melted one of my phase wires connectors specifically the one that makes throttle/pas throttle work mr green boy.

luckily it was all downhill to my house.

checked the controller turns out the end screw went all the way loose and the mini bus bar fell off ontop of the shunt and the solder already on shunt kept it attached
even did a loud pop when i tried to remove it with battery disconnected.

heat shrinked my phase wire back together (these anderson connectors suck)

would bullet connectors work fine want to replace all the phase connectors with something more consistent?

https://www.ebay.co.uk/itm/100Pcs-Heat-Shrink-Bullet-Female-Male-Wire-10-22WAG-Connector-Crimp-Terminal-Kit/143823307082

also since the controller gets warm im probably gonna replace the mosfets its a 35amp kt controller with 17amp continuous

probably some IRFB4110 fets since i plan on running a a slightly bigger 52 volt battery through it


so far max speed hit was 32mph on throttle on smooth road and 36mph while pedalling at max gear 3x8
but i was at 50% battery and the unless i hit rpm limit on motor since it was only pulling 1200watts at the time its a voltage difference.