Lars Halstrom

I have cup and cone bearings on a 12mm thru axle front hub. Why is it so hard to find a replacement cone fo one that is starting to pit? it is not a Shimano cup and cone either.

Crankycrank

What brand and model hub? Photos would also help. Have you checked any bike shops yet?

CliffordK

The problem is that solid axles, quick releases, etc, all stopped at about 10mm.

12mm were specialty items found on a few tandems and etc.

Some of the new oversized axles use larger cones, but generally a proprietary design.

Have you checked with your hub manufacturer? What is the brand & model?

Oh, I thought the Shimano Dynamo cones were 12mm, but I think they're 11mm.



Are you sure your cone size is 12mm? If the thru axle is 12mm, then I'm betting your cone will be 15mm, maybe larger.

Andrew R Stewart 

This speaks to the market more then anything. The manufacturer has decided it's not profitable to produce aftermarket/service parts. The suppliers have decided it's not profitable to stock many service parts. The LBS has found that customers, more often then not, will just replace a complete assembly (like a wheel), and get a lot else that's new then just the one bad part, then replace the one part.

At Full Moon Vista we sell common "repair grade" wheels at around $75 installed, depending on spec, by that day's end. A cone, replacement balls and labor will run about $35 and they will need to leave the wheel/bike for it's turn in our system. If there's any question about the condition of the old wheel's spokes or rim guess which way the customer will likely go. When I started this stuff we would rebuild many hubs over the season, we stocked cones and axles from the 3 or 4 major manufacturers (even had Campy shell cups in both NR and GS!) But times and consumer trends change and these days it's too easily a loosing investment for a reseller to try to stock this stuff, if it's even available.

Wheels Manufacturing (used to be Wheels of Boulder) has done a great job at reproducing many cones and axles. It's worth a visit to their site to see the complexity involved in deciding which cone to get. Good luck. Andy

CliffordK

If this cone has very limited scope, Wheels Manufacturing might not be interested.

But, it might be worth documenting the cone carefully. Inner diameter, outer diameter, etc.

Then send them a note asking if they might reproduce a pair.

Lars Halstrom

I sent a note to Wheels Mfg and they said no. I believe Andrew Stewart nailed the reason. I went to every bike shop in Seattle practically and nobody had anything. They did question if these were actually sealed bearing cartridges and they needed to open it up $$$, which already had been done. Time to save up for new wheels that have replaceable parts.

Andrew R Stewart 

+1! Andy

dsbrantjr

I'd stock up on those parts against the time (likely not too far in the future) when the manufacturer decides to discontinue them or "improve" them in a non-backwards-compatible way, in the name of "product improvement" AKA planned obsolescence.

CliffordK

Photos?

How bad are the pits?

I've been hand polishing my cones with a mini-drill press and sand paper.

I can make considerably smoother races, and can take out minor pits in the process.

What hasn't been clear is whether some cones are being case hardened over much softer steel. So some brands may polish better than other brands.

Anyway, it would be worth a try as there isn't much to lose.

CliffordK

Here is the Shimano Y3TL98030 cone:

https://www.sjscycles.co.uk/hub-spar...98030/?geoc=US

15mm cone + locknut. It fits on several of the Shimano 12mm Thru Axle hubs.

JoeTBM 

Wow.. not cheap at all and I believe the op said it's not a Shimano.

CliffordK

The part number might be something a local shop could look up, and order if they wish.

The OP did specify "not Shimano", without further clarification. However, it is still worth looking at what is offered.

Unfortunately, detailed part information isn't available. Knowing one or two dimensions, one might be able to estimate others.

JoeTBM 

I see what you mean....his edit yesterday... My bad

Mad Honk 

CliffordK,

I do the same here if pitting is not giant deep in the cones. And rubber infused diamond grit points in a Dremel for the outer races. Labor time: about one hour. Smiles, MH

Lars Halstrom

My LBS dealer called and wants to take pics of the hub to send to the manufacturer. Sounds strange, it's their bike. One of the manufacturer's stickers on the wheel said AlexRims in really fine print next to theirs. AlexRims is a Taiwan wheel company.

WizardOfBoz

I'm amazed that works, Clifford. Bearing surfaces are typically polished to 32 - or 16 - microinch finish (this is the root mean square variation in the surface - way too much info to discus here - suffice to say :"Really, really smooth").

If you were being flip and yanking our bike chain, fine. But what grit sandpaper can you use on a bearing that leaves it smooth enough for use? And how do you avoid destroying the bearing figure (i.e. "shape") in this operation?

CliffordK

I'm not sure about the finish sizes, but for bike cones, it depends on the models.

Vintage Campagnolo Record series cones had a mirror polish.

Ultegra & Better cones are nice.

For Shimano, my experience is that most of the mid-range parts have a distinct roughness which is due to poor cone polish. The cups seem to be generally good on all the Shimano.

Other brands have been a mix, but I did encounter one that had the entire cones and cups spray painted black.

For sand paper, I usually do progressive 220/320/400/600 (600 + oil).

I've experimented with chainsaw files. But, they do best as a dowel to hold the sandpaper for the courser grits, rather than cutting with a file.

By doing the polish on a drill, any scratches, or slight profile shape changes come in a circumferential pattern, and doesn't create a problem as it is parallel to the running the bearings.

Why doesn't a pit create a flat spot when hand polishing?

Again, I said pretty mild pitting. By spinning pretty quick, I think even if holding by hand, the tool jumps over the pit as effectively as if one was using a tool holder in a lathe.

I did try cutting my Campy bottom bracket spindle in a lathe a while ago. WOW, that was HARD. Plus, I had really deep pits, so that was only moderately successful.

Now, the question comes down to hardness. I've meant to set up a way to test cone hardness, and perhaps depth of hardness.

I presume there are a number of approaches to hardness. If one starts with a high carbon spring steel or tool steel, then it could be shaped, then hardened and polished. Perhaps do some kind of differential hardening or tempering. The resulting hardened surface would be deep.

On the other hand, one could start with a relatively low grade steel and case harden it. Done right, one could harden to a depth > 1mm. But, some brands may do a mere surface skim. And don't even polish (giving a black cone). And I wonder if those take well to polishing. Unpolished, and they're rough. Polished, and smooth, but potentially softer.

WizardOfBoz

Clifford,

You've hit a bunch of key elements. These days, you can make these things a lot of different ways. Modern CNC machines have such impressive bearings (smooth, incredibly rigid, concentric, nearly unmeasurable runout) you can almost turn bearing races on a lathe and forego polishing. In the old days you'd turn to near diameter, heat treat, then grind and polish to get things perfect. But with more modern cutting tools (carbide, polycrystalline diamond) cutting tools you can heat treat, then cut to dimension. I've seen lathes turn out mirror finishes using PCD tools.

As you know, annealed steel is both soft and is weaker that the heat treated version. Do a first pass at heat treating and you have a hard, strong part, but one that may be distorted from the treatment, and which is brittle. Temper the part and you still have the distortion, but the steel is still strong and has better toughness. Not sure about case hardening stuff. You'd have to get to dimension, case harden, then grind smooth (the case-hardening will leave a rough surface). If you get enough case depth, you can grind and polish. Then you have a tough inner core and a hard strong case. But this takes really, really good process optimization, especially if the part is at all complex (a bearing race would have some complex heat transfer and cooling characteristics) . And the part has to be big enough or you end up through-hardening it anyway. I think most bike bearings are too small to case harden. A taper-mount bottom bracket axle gets into the feasible range for case hardening.

Still, grinding races in the old days involved super rigid ultra-high-quality bearings on both the chuck spindle (That held the bearing race) AND the spindle holding the grinding wheel. I can see that if you got the bearing in a good drill press, you might smooth out some rough spots. I'd probably bite the bullet and buy a bearing!

CliffordK

Do you have the materials testing equipment? Manufacturing?

I'll try to do some more documentation, and perhaps start a YouTube channel.

I've started to get some long-term testing in, with some successes, and I presume some failures. I have a few hubs to tear down to inspect.

I do wonder a bit about the target hardness and tempering. Would it actually be possible to crack a properly adjusted cone?

Of course, a small shop might be able to make the perfect cone, but it may not adapt well to mass production. Likely a reason why we see varying quality of cones with different hub models.

WizardOfBoz

I just grew up working in a manufacturing plant, and have an interest (and some engineering degrees).

Bearing quality varies greatly, and slight differences in heat-treatment and/or metallurgy can give wildly different results in terms of strength, hardness, toughness, dimensional stability, and so forth.

It would be pretty easy to over-harden or under-temper a bearing in a home environment resulting in a brittle cone (or vice versa, to get a soft bearing that wears prematurely). Consequences of bad bearings nowadays means that the top folks have process down to the nth degree. Unfortunately, marginal companies in unregulated economies, or unscrupulous folks in any economy can make cr**.

CliffordK

I'm not sure I've ever seen an issue I could attribute to an over-hardened cone cracking.

I have seen too soft cones just mash.

Any badly damaged cones seem to be due to abuse, including riding with loose parts and broken bearings.

I'm not quite sure what causes pitting, but it does seem to involve malleable changes to the metal.

I am a bit surprised that we're not seeing ceramic cones for loose bearings, although it does appear that Campagnolo does sell one ceramic cone.

https://www.modernbike.com/campagnol...earing-os-hubs