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I was overhauling the hubs of my mountain bike and cones on the front hub are badly pitted. I'm not sure how the inside of the hub body looks, but I'd suspect it's not in good shape either. (The bike is 3 and a half years old.)

A couple questions:

1. Is there a way I can test for pitting in the hub body (like the way a ballpoint pen can feel pits on cones)?

2. If the hub body is ok, can I go to a shop with my axle and buy a cone or set of cones?

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1. Shine a flashlight up in that junx. Use the pen on the cup of the hub and fell for any pits.
2. If you want the easiest solution, take your axle and cones to Yojimbos. They might have a replacement for ya on the spot. I had an axle to replace one and they were the only ones that had a replacement in seconds.
2b. West town has a lot of spare parts like cones. Go to an open shop class and see if you find parts.
3. Drink more beer! "It is the cause of and solution to all of life's problems."
Thanks Homer!

Ryan L said:
1. Shine a flashlight up in that junx. Use the pen on the cup of the hub and fell for any pits.
2. If you want the easiest solution, take your axle and cones to Yojimbos. They might have a replacement for ya on the spot. I had an axle to replace one and they were the only ones that had a replacement in seconds. 2b. West town has a lot of spare parts like cones. Go to an open shop class and see if you find parts. 3. Drink more beer! "It is the cause of and solution to all of life's problems."
lol, fell = feel. Silly internets!

As always, Sheldon Brown has the answer.


R.I.P. Sheldon
Thanks Michael. I don't see how I overlooked checking his site.

Michael said:
As always, Sheldon Brown has the answer.


R.I.P. Sheldon
Dredging up an old thread...

A great tool for inspecting bearing cones and wheel races is a Jeweler's Loupe. IMHO you can't see anything but the most severely pitted of parts with the naked eye -at least not with my old & crappy eyes! With a Loupe you can see EVERYTHING. One can often find cheap Loupes at a dollar store for a dollar (plastic lens with black plastic housing) which is great for working on greasy/filthy bikes because you don't want to ruin nice optics by using them on the workbench with bikes.

I usually throw away used ball bearings (or save them to throw at cages) because they aren't worth the trouble cleaning them up even if you know they are good (just put them in yesterday) much less you can't really inspect them very well even with a loupe. I usually buy them in bulk but your local LBS will most probably sell them to you individually -buy a few extra for droppage.

I hate to disagree with Sheldon on the cone pitting issue. There is no such thing as "perfect" races or cones. Look at them with enough magnification and you'll see micro imperfections -even on brand new ones. Ball bearings, especially the grades commonly used in bicycle bearings, will not be perfect either and you can clearly see the imperfections and micro-pitting even when new. It's just a matter of tolerances and knowing what you can get away with.

This is a grade-100 ball bearing (about 2-3 orders of magnitude better than your standard grade-3 bicycle loose ball bearing).


Still not perfect!

Instead of costing $.04/each for grade-3 expect to pay about $5-10/each for grade-100 bearings. Just keep adding zeros behind it as the grade goes up ;)

Slightly bad pitting will usually make it very difficult if not impossible to get the bearings properly tensioned in the wheel. Either they will be "crunchy" or have a tiny bit of wiggle. You probably won't be able to feel it when riding but it will be there. A barely-pitted cone will eventually lead to pre-mature bearing wear and eventual failure -perhaps as much as 50% lifespan for very minor pitting or in a few hundred miles if it is even worse. Keep an eye on them an when they start getting loose and needing re-adjustment every few miles then pull them apart, clean, inspect, replace balls, and repack.

Often it is less work in the end to just find the correct cones. I think I've bothered Jon at The Bike Lane a half dozen or more times in the past 6 months to source for me hard to find cones for the various basket-case wheels of vintage rebuild projects I've taken on. My latest disaster is a 1950's Raleigh Sports with very difficult to find cones and one of the fronts has a tiny little but visible with 30x magnification pit on one of them but I'm going to give it a try and see how many miles I can get out of it. If I have to rebuild it every 500 miles or so it'll still be less trouble than trying to find a suitable used replacement that isn't in worse shape than the one I have since nobody is making replacements any more.

If anyone out there happens to have a vintage NOS Sturmey-Archer front hub cone or a used one in good shape shoot me a message.

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