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Ball bearing cups for bicycle hubs ?

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Rich250209/05/2022 23:44:56
73 forum posts
2 photos

How would you make these bearing cups for bike wheel hubs?

I'm thinking you would need a tool ground to the correct profile to do the finish cut, how much distortion would you get after hardening and what surface finish do bearing surfaces have?

What is the correct profile for a ball bearing ?

most of them are pressed cups but the pockets in the hubs are square shouldered so they could be made thicker with a solid flat back face. bscavel08rhbc_p1.jpg

Hopper10/05/2022 00:01:35
6393 forum posts
334 photos

I have made similar for veteran motorcycles. Use a form tool ground offhand and stoned to the same radius as the balls. Distortion from hardening was not an issue on the ones I did.

Mike Poole10/05/2022 06:37:39
3338 forum posts
73 photos

The wear marks on these cups usually show a thin line so the curve of the race does not match the ball. The commercial items would seem to be ground after hardening but getting the hardening right is probably the most important thing as if too soft the Brinelling effect will occur and the bearing will be rough. Steering head races where this has occurred are scrap as it ruins the steering. A fine turned finish without any chatter is essential but the long cutting edge of a form tool can make this a challenge.


DC31k10/05/2022 07:18:01
686 forum posts
2 photos

Mike makes a very good point above about the contact of the balls with the cup. If there are two lines of contact, one generally on the flat part, the other generally on the side, that means the dimension and finish of the curved part of it does not matter at all as long as it is of no lesser radius than the balls.

Consider the other part that threads onto the spindle and contacts the balls. Have a look at its contact patch. Maybe the balls themselves are simply in three point contact (unequal - 90, 135, 135 degrees), all that is needed to resist combined axial and radial load.

Find an off the shelf one, paint it up with marking blue and operate it a few revolutions to see what touches what.

Chris Evans 610/05/2022 08:18:43
2057 forum posts

Some I have come across have a smaller radius than the ball, say 5/64" for a 3/16" diameter ball. For motorcycle use I bin the cup and cone and fit sealed ball races with suitable spindle and spacer although this sometimes means altering the hubs.

Hopper10/05/2022 09:03:16
6393 forum posts
334 photos

Is the bike a racing bike? Long distance tourer? Kid's hack? Or vintage restoration for display mostly? You might adjust tolerances and methods accordingly,

Nigel Bennett10/05/2022 12:33:02
456 forum posts
20 photos

Many years ago, I used to buy new Campagnolo cups as spares from an outfit called JD Whisker in London. Gone, now, sadly but depending on what hub it is, you may be able to source some NOS ones.

Getting the old ones out of a hub wasn't easy and for Shimano ones later it was virtually impossible - by design, presumably.

Surface finish and the heat-treatment of it is very important as others have said, so it won't be easy to make them. I did find in impecunious times I could just about turn the cones with a round-nosed carbide tool to remove pitting but it was never the best solution.

Jouke van der Veen10/05/2022 13:05:53
174 forum posts
17 photos

I cycle a racing bicycle fitted with Shimano Ultegra hubs, I think generation 6600 or 6700.

Now I am riding on my last set of front wheel bearing cones. Shimano does not sypply them anymore.

Wheelsmanufacturing used to supply replacement cones (CN-093?) but it looks like they stopped as well.

I am considering to regrind and polish worn cones. Possibly you have to be careful with going through the hardened surface, if they are not hardened completely through.

You can find people on the internet who do this kind of cone repair.

Another option would be to machine completely new cones from silversteel and harden them.

I would think radii of cone and cup are both significantly larger (factor 2?) than that of the balls in between.

What do you think?

ega10/05/2022 14:35:04
2539 forum posts
201 photos


Not an answer to your post but have you considered rebuilding the wheel with a suitable new hub?

Wheel building, as you may well know, is within the scope of the amateur and can be very satisfying. I assume you are on rim brakes and that at some time your rims will wear out - another reason to consider a rebuild.

Edited By ega on 10/05/2022 14:35:46

Jouke van der Veen10/05/2022 18:56:49
174 forum posts
17 photos

To be honest.
I ride on a bicycle that was assembled by myself. It is a steel Gazelle Special frame from around year 2000. Painting and decals were subcontracted. All the other was done by myself, including wheel building, etc. It is a bit vintage but not completely: in the front 3 chainwheels and at the back a 10 gear sprocket.

I could decide to replace the hubs by myself. But they should fit a bit to the Shimano Ultegra Group appearance. First option is to stay with the existing hubs. But at the end it may be necessary to replace them.

bernard towers10/05/2022 19:50:42
617 forum posts
109 photos

I have made these for vintage bikes over the last 25 years and to my knowledge they are still running. I make mine in a similar vein to Hopper.

Rich250210/05/2022 23:57:49
73 forum posts
2 photos

What prompted the question was seeing a stack of 20+ wheels in the bike shop going for recycling, the only thing wrong with them was worn out cups, some of them were £80-90 when new, the mechanic in the shop there told me the cups couldn't be removed but I took a few home and punched the cups out easily.

Making new cups would get me free top grade wheels for life.

None of the pockets for the cups match any stock sealed bearing units unfortunately.

Hopper11/05/2022 00:27:11
6393 forum posts
334 photos

Excellent work! Turn a couple up from silver steel. Harden and temper and ride on.

ega11/05/2022 09:27:37
2539 forum posts
201 photos
Posted by Nigel Bennett on 10/05/2022 12:33:02:


Getting the old ones out of a hub wasn't easy and for Shimano ones later it was virtually impossible - by design, presumably.


This prompted me to dig out the extractor I made up years ago:


The slit cone is inserted into the cup and expanded behind it by the cap screw which is tightened from the other side (the cap screw head has been turned down to fit the hole through the spindle). The cup is then extracted by tightening the nut - a suitable washer is interposed.

I remember being told then by my LBS (local bike shop) that replacement cups would no longer be available.

Hopper11/05/2022 10:24:28
6393 forum posts
334 photos

If the old races are through-hardened rather than case hardened, you can set them up in the lathe and regrind the ball track with a toolpost-mounted die grinder with a stone dressed to the right radius. This is standard procedure on vintage Harleys where the races are machined directly into the front hub and not replaceable. For a bicycle, a Dremel grinder would probably do the job.

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