cup and cone to sealed bearing

diceman2004

diceman2004

New Member
I had mentioned in another thread on a fix i did to my sachs moped wheel .
Since the hubs are 36 spokes , I intend to lace them up to some 26 inch rims , for a MB that i have planned to build . They will be sweet when they are done ( drum brakes front and rear ... rear hub already has sprockets on both sides )

SO , I thought i might as well do a post on the conversion .

The axle for the wheel is 11 mm ( yup thats right 11 mm ) .
The axle had bent slightly and fried the cups and cones .
I couldn,t find a replacement so i decided to convert it to sealed bearings .
I got lucky , the bore through the hub is 30 mm press fit .

Sorry i don't have pics , and its in storage now .

FIG 1 ... original axle setup

FIG 2 and 3 ... knock out the bearing cups

FIG 4 and 5 ... figure out the length of the internal spacers

FIG 6 ... this spacer needs to be welded in .
I drilled 4 holes in each end of the spacer roughly 1/2 in from the edge .
I mig welded the spacer through the drilled holes into the hub

FIG 7 and 8 ... the axle spacer MUST NOT BE SHORTER than the outer bearing spacer that was just welded in .
make the axle spacer ( + .001 / + .005 )

FIG 9 ... install axle axle spacer , the other bearing outer spacers and nuts .
No need for double nuts , because there is a spacer between the bearings .

FIG 10 ... was thinking of installing 2 sets of bearings .

sachs-hub-fix-1.jpg


FIG

FIG
 
Very nice, excellent tutorial and presentation, thanks.
The trick is lucking out and not having to size the bore for a press fit.

BTW, mind me asking what graphic interface you used for the illustrations?
 
The axle spacer just floats inside between the bearings (but snug against the bearings)?
What is its purpose, to keep the bearings in place? Doesn't the internal spacer (orange) take care of that?
My electric moped has a similar setup in the front wheel, but I don't think it uses the axle spacer.
 
OK , a little more detail .

Take in account that my hub has a strait good , press fit , 30 mm bore all the way through .

Allthough the bore is a good press fit ( and the bearings " probably " won't shift ) you still need a solid face to block any movement of the hub over the bearins . Otherwise the whole hub could potentially slide right off the bearings .
.
The spacer that is welded inside the hub , does basicly the same job as the lip on the outer edge of a bearing cup . ( stops the cup from going through the bore ) This is what keeps your wheel in location .

But we going to use a sealed bearing , which brings us to the spacer on the shaft ( and why it needs to be a .001 / .005 longer )

Your average sealed bearing is not designed for sideways load . and even tapered bearing ( such as on a car wheel bearing have a predetermined tightenig load ) ... you can't just reef the nut down until it won't turn any more , unless a properly fitted preload spacer is installed .

The spacer on the shaft is our prelaod spacer .
because we are making it .001 / .005 longer than the spacer that is welded into the hub , we will be able to tighten it as hard as we possibly can , and it will not apply any sideways load to the bearing ( because the outer bearing race will have .001 / .005 clearance with the welded in spacer )

On a personal note : I can't stand bicycle axles .. they are 150 year old technology . The only reasons they are still built that way are ... cheaper ... less parts ... it doesn,t require much space ... i could kick a bicycle in the double nuts .
 
rohmell : I couldn't tell you without seeing it , but almost anything nowadays that is motorized will have some sort of method to limit the side load on a bearing . Your scooter , unless it is very old like my moped ( bicycle axle technology ), more than likely uses more of a motorcycle axle type setup .
It could use something as simple as a shoulder bolt as an axle , where you could bottom out the nut , but still wouldn't damage the bearing .
 
Thanks for the explanation.
It's been a while since I looked at the moped axle, but I think it does use an axle with a shoulder.
 
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