masi61

I'm working on a friend's Giant mountain bike and initially didn't notice any problem with the headset. But after mounted in my workstand and with the front wheel removed I noticed that it turns in a notched manner, like little detents are in the cups that make the fork want to stop in spots almost like an index shift lever. I think the term is Brinnelling, I'm not sure where the term came from or if I'm spelling it right. Could someone please advise: am I half baked on the use of this term, and second, what is the best course of action for dealing with this symptom. I've heard that you can do away with the caged bearings and repack the headset with free ball bearings of the same size, like one more than you had before. I tried that once with a Shimano 105 headset that was doing the same thing but found it unsatisfactory and ended up replacing the headset.

TallRider

This is also known as "indexed steering" and is not a nice thing. With wheels, they're always turning. But with headsets, most of the time the handlebar is pointed in one direction, and the bearings are planted in one spot on the bearing races. Over time (especially if some dirt gets in, headset not re-greased, etc) bearings wear depressions in the bearing races.

You can replace the caged bearings with loose bearings. This helps somewhat b/c there's more bearings, and they're not lined up in the same spot as before. However, as you've discovered, it's not a total cure.

The overall picture is that indexed-steering isn't a huge problem unless it's really obvious to the point where it affects steering. You can ride with a bit of this, and not have a problem.

Also, adjust the headset as loose as possible where you still have no play (and I mean no play). A headset that's too tight contributes to brinneling, and you also have a more obvious indexed-steering effect if the headset races are already brinneled.

Rev.Chuck

Sometimes they only get indented fore/aft. Take it apart and if it looks like this, remove the cups and reinstall them turned 90 degrees.

masi61

Tim said:
"the overall picture is that indexed-steering isn't a huge problem unless it's really obvious to the point where it affects steering. You can ride with a bit of this, and not have a problem."

That was the impression I had too, that for an inexpensive mountain bike, I could regrease the headset and be sure to tighten it just enough to remove all the play being careful not to overtighten...
One thing that made assessing this condition more difficult was all of the cables - 4 of them that are stiff enough to keep the fork from flopping from side to side.

masi61

I would love to try this: unfortunately I don't have a headset press or drift for driving out the cups other than a really big round, tapered general purpose "punch". In the future I will try this proposed solution though.

genericbikedude

if you're going to overhaul the headset, you may as well rotate the cups as chuck suggested

San Rensho 

Have to disagree. Too loose, is what causes the brinnelling. When a headset is properly tightened, the forces it encounters are distributed evenly on all the ball bearings. When its loose, one or two ball bearings take all the force and transfer it to one very small point on the cup or race, causing the ding in the metal.

When in doubt, leave it tight, especially after servicing when things will settle in and eventually get loose.

AndrewP

The name comes from Brinell who developed a method of metal hardness testing over 100 years ago. This involved pressing a ball bearing into the surface being tested with a certain force, then measuring the diameter of the indent under a microscope gave a measure of the hardness.

TallRider

Note that I emphasized the "no play" point. This is the case for any bearings. If you tighten it just to the point where there is really no play, it's ideal. Your critique would only be true if the bearings were too loose.

Although you're probably right about headsets being too loose, not too tight, as the biggest cause of brinneling.

Your point about "settling in" is good too - this is especially the case for newly-pressed-in headsets, but also for repacked headsets, to a lesser extent. However, my preference is here not to overtighten, but rather to tighten properly, and then check periodically to see if things have loosened up by "settling in". If they have, then adjust the headset a bit tighter.

operator

Brinelling is the wrong term to use at any rate, as it implies something a cause that isn't actually happening.

white lobster

Ever tried cranking down as hard as you dare on the adjustable cone of a cheapo steel headset and then turning the handlebars back and forth a couple of times? If the steel is soft enough, you can sometimes flatten out some of those ridges. I wouldn't try it with a 105 headset, but it definitely does the trick on WalMart style kid's bike headsets.

Turning the cups often does the trick, but it can also end up moving the indexing notch a few degrees off of center. As long as you're going straight, it's fine, but it definitey does make for a big no-hands surprise if you try to turn!

cascade168

I just did this with a bike that I did not have the correct size headset on hand for and I was really surprised at how well it worked. Obviously, there is no guarantee that this will work every time, but it's definitely worth the couple of bucks that 25 5/32" bearings will cost you. It went from pretty clunky to smooth. Loose bearings, baby ;-)

knjc68

Several right answers there but, even if the bearings are adjusted just right, the actual bearing surfaces are so small that they are absorbing / transfering quite a bit of force into a pretty small area. Every time a big bump is hit, or a big rider using a long-or-tall stem stands up & really cranks, it puts a lot of prerssure on those itty bitty surfaces. The extra ball helps, like was mentioned, because it moves the balls out of the "dents" that have been formed in the race.
If it's a big issue, replace it with a roller-bearing headset. They have more contact surface &, in my experience, rarely give any problems.

HillRider

The real cure is to replace a loose (or retainer caged) ball headset with a cartridge bearing type. The inherent design of the cartridges avoids the forces that cause "brinelling" or, more properly, fretting corrosion, which causes the pockmarks in the races.