Nov 6, 2002 12:43 PM
|I had my bike on the stand and noticed that when I turn the stem from the "center" position to either side, it feels like that there is a notch in the center postion of the races or cones. I have to use a little extra effort to turn the handlebar past the center forward position. Is this normal?
Thanks and regards,
|Not the way it's s'posed to be.||Spoke Wrench|
Nov 6, 2002 1:30 PM
|Your headset is indexed. The only real fix is a new headset.|
|Re: Not the way it's s'posed to be.||kilimanjaro|
Nov 6, 2002 1:45 PM
|Can you elaborate on why it is indexed in the center forward position and why is this bad? This is a beater that I am nursing along until I can afford to buy a new bike.
Thanks and regards,
Nov 6, 2002 2:26 PM
|Your bearings are brinnelled (sp?) from probably slight misadjustment & impact from miles of riding with the bottom race carrying the whole load. If you take the fork out, you'll see where the fork crown race has indentations where the bearings were riding.
You may be able to make a temporary fix, though. If your bearings are caged in a retainer-where a metal cage holds the bearings in a ring-replace them with loose balls of the same diameter. You'll need a few more bearings than are in the cages. If your headset had loose bearings-no retainer-try to find retainers of the correct diameter & spacing.
|Close, but not quite.||Kerry|
Nov 6, 2002 4:48 PM
|It's not the bearings that brinnel, it's the bearing race. And in all likelyhood, the race is fretted, not brinnelled. Brinnelling is denting, while fretting is eroding, and it is much more likely to see fretting in the bike headset application. The effect is the same - a series of divots in the race such that the bearings "drop into a hole" and give you the dreaded "index steering." The loose ball fix is the best approach short of replacing the HS.|
|But I'm backed up by a reliable source||Straightblock|
Nov 7, 2002 8:35 AM
|Sheldon Brown's website says:
"The dents that sometimes develop in headsets are often colloquially refered to as "brinelling" from the resemblance to the dents made by the Brinell Hardness Test."
OK, I was in a hurry, poaching on company time when I posted. Of course it's the races that brinell (or fret), specifically the bottom races which take the majority of the impact loads, but at least I got the fix right.
I went thru a couple of Tange headsets on my old team bike in the late 70's/early 80's & used the "loose balls" fix to get several thousand extra miles out of them. The ultimate fix? I replaced the Tange headset with a Super Record. The SR was still going strong when the frame cracked years later.
|I always heard it was brinnelling too||Kerry|
Nov 7, 2002 5:27 PM
|But I had it explained to me by a very knowledgeable mechanical engineer that a microscopic examination would show erosion (fretting) not denting (brinnelling). There it is. While I usually bow to Sheldon Brown on all things cycling, I've got to go with the ME on this one.|
|I've heard that "eroding" term before too.||Spoke Wrench|
Nov 9, 2002 5:37 AM
|Actually, there are some other terms that are commonly used inaccurately or imprecisely. My favorite is "alloy" when used as a synonem for "aluminum." Technically, while accurate, it's inprecise. You could accurately say that a steel bike has an alloy frame because steel is, by definition, an alloy containing iron and carbon.|
|re: how about this||ThirtyFive|
Nov 6, 2002 4:01 PM
|i had a friend with the same problem. i figured his headseat was toast, but in fact it was just too tight (threaded) and what he felt was acutally bearing bind. try that first its free....|
|re: how about this||Skidoo|
Nov 6, 2002 7:16 PM
|The Bicycling Magazine repair manual suggests that you can get by the indexed headset problem by detatching the handlebar and brake caliper from the stem and fork and spinning the fork around several times. They claim this can help by re-positioning the bearings, engaging the less worn bearing surfaces. Never tried it myself tho.|
Nov 7, 2002 4:49 AM
|Your headset is BRINNELED, meaning that there are indentations on the bearing races, most likely caused by over-tightening of the headset by a ham-fisted mechanic. Have you had your headset adjusted lately?|
Nov 7, 2002 10:14 AM
|I have not had the bike serviced for over a year, though I probably rode less than 1K miles in that period. In recent months I started to learn how to do my own maint (hubs, bb, truing wheels) so the frame is on the stand and noticed the index a few nights ago.
I will try all the above suggestions before getting a new headset.