Bicycle Mechanics - What if I don't replace a pitted race/cone?
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
06-16-08, 12:32 PM
I just bought a used Trek Kids mountain bike with 24" wheels on Craigslist for $35. I'm planning on giving this to my daughter. The bike is generally in good shape, but I thought I would overhaul everything. Last night I disassembled the front hub. I was just going to get new bearings and repack with grease, but I found a little pitting. Each cone has a slight scratch it it. The race on one side has some corrosion on it. I know the proper course of action is to get a new hub since this one has some corrosion. However, my daughter doesn't put many miles on her bike, and I'm wondering what harm there may be in just repacking the hub with new grease and bearings? Is there any harm to riding on a pitted race or cone?
If this were my bike, I certainly would get new hubs because I am relying on my bike for transportation. My daughter, on the other hand, still does most of her riding up and down our driveway.
Clean them out good. The metal from those pits went somewhere and you want to be rid of it. Consider replacing the ball bearings. Even pitted races will last longer with new BBs. When you go to the LBS for BBs, take a cone with you too. They might have a replacement in stock.
06-16-08, 02:35 PM
You just won't be able to get them adjusted perfectly. You'll have to choose between too loose and "crunchy". I usually pick a little too loose.
06-16-08, 02:41 PM
Agree with adjusting a bit loose. As with a pothole in the road it will get worse, as the bearings will hit the imperfection and a bits metal will get broken off. The problem will eventually accelerate as there is more foreign material and more damage. Given the limited use I would say just have her ride it and look for a replacement wheel at a garage sale or used bike dealer, or pitch it when done.
06-16-08, 03:10 PM
I've repacked many a hub in that condition. Unless she's going to use the heck out of it, I think you'll be fine. Just check and repack more often. I've usually been able to adjust to the proper setting in this condition, i.e. no play at the rim, with negligible "crunchiness".
06-16-08, 03:35 PM
She will go .003 % slower.
06-16-08, 08:25 PM
If it starts to feel crunchy then just back it off a hair even if it's not to the right preload.
Yes, technically it'll all wear faster. But given the "miles" that will likely be put onto this bike it'll easily last until she needs the next size up bike and will likely last one or two more young'uns after her before it's an issue.
06-16-08, 08:29 PM
i agree with dmf, well nothing it will happen, the bike probably will be usable for years anyways. THe whole concept between ppitted parts is that they roll quite ROUGH, so theorically the bike wont go that smooth. I might do all that DMF said and other guys but for sure u can ride that thing as it is anyways. Safety concerns? I set of pitted cones in the rear wheel wont make u have an accident anyways. A set of worm out brake pads will!!!!
06-16-08, 09:18 PM
She will go .003 % slower.
The correct way to quantify it is how many watts it's losing vs a properly adjusted hub with perfect components.
06-17-08, 12:34 PM
When I find pitted cones that are either not availale or I'm too lazy to chase down I mount the cone on the axle and lock it in place with it's lock nut. I've had good luck chucking uti up in my lathe and polishing out the pits if they aren't too deep with 600 grit cloth backed sanding belt material wrapped around a dowl or metal rod. You could do the same with a drill press.
06-17-08, 02:03 PM
Thanks for all the advice. I was mainly concerned about the hub seizing and causing her to do an end-over. If the only problem is that she goes 0.003% slower, that should be OK. :) I'll just get by with it as is for now.
06-17-08, 03:25 PM
Thanks for all the advice. I was mainly concerned about the hub seizing and causing her to do an end-over.No chance of that happening unless you leave out half the balls on each side. ;)
06-17-08, 10:13 PM
Even severely pitted cones are almost impossible to notice when you're on the bike, even though they feel pretty rough when spun in your hands. I don't think your daughter will notice. There's also absolutely no safety issue even with poor adjustment, as long as you tighten the locknuts onto the cones enough.
Joshua A.C. New
06-19-08, 12:04 AM
Pitted bearing races are a leading cause of bicycle fires.
Powered by vBulletin® Version 4.1.12 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.