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?
 
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 .
 
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