Bicycle Mechanics - Notchy steering.
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12-03-02, 09:00 AM
My steering started to get all notchy, somtimes stiffening up as I turn. A few rotations of the bars seems to free up the stiffness.
Its not the headset adjustment.
I took it to a good bike shop, and the mechanic did an eyeball measure of the forks. He thinks that the forks are bent to one side through some inpact damage. The resultant sideways stress on the headset is causing the bearing to bind.
He said he had done that to some hard-ridden commuter bikes, they just wear out after a few years, one curb or pot-hole too many.
The forks can be bent back (cold-set) but its not worth the work, so he said keep riding it until it feels unsafe, then get another bike.
Has anyone else ever had such a problem ?
No, but forks can be replaced,rather than buying whole bike.Someone more qualified like a local framebuilder, could also check the forks for alignment. Sure the HS is not indexed?
12-03-02, 10:06 AM
That def sounds like the headset. A bent fork wouldn't magically be fixed if you twist the handlebars around. Look at your bearings in ur headset cups
Sure sounds like somebody brinnelled that headset. This commonly happens when some ham-fisted mechanic over-tightens the bearings, dimpling the races with the bearings. Maybe it was the same mechanic that's giving you his opinion? If he didn't at least mention the possibilty of the headset being brinnelled, I'd bet he's covering his @$$.
It sounds like the headset is too tight to me too. At the same time, I recognize that MichaelW knows his stuff. If he says that it isn't the headset, then I have to believe it.
I had a similar problem with a bent steering tube a while back. Bent forks make for a wobbly ride, but a notchie feeling usually comes from the head - either the bearings or the steering tube or the headtube.
Any chance you have a bad bearing? Even one bad ball bearing can cause misery.
12-04-02, 07:02 AM
Originally posted by D*Alex
Sure sounds like somebody brinnelled that headset.
Shucks! D*Alex beat me to using the fancy word! Brinnelling was my first thought.
If an arm on the fork is bent, I don't think it would show up as notchy steering. It would just pull to one side or the other. I guess it is possible the symptom you describe could occur if the steerer tube were bent a little. Try just cleaning and repacking the headset bearings. That doesn't cost anything and might smooth things out enough to feel better. While you are at it examine the cups carefully for signs of brinnelling/dimpling. If there is any you need a new headset. I wouldn't jump to replacing the fork.
Can you take your hands off the bars and ride in a straight line?
It seems strange that a qualified mechanic would tell you the fork is bent and tell you to ride it until it feels unsafe. In my book, it's unsafe now. Fork failure could end your biking career forever.
Take Pokey's advice and get a frame builders opinion.
A new fork is an inexpensive fix.
12-04-02, 08:52 AM
What it sounds like is an ovalized ball in the lower headset cup. Brinnelling occurs all the time in the lower race in the back of the race nearest the frame, it seems that's where the stress loads up under impact. I see this more often on road and commuter bikes more often than mountain bikes. The shocks help the ATB's and road bikes aren't steered as radically as mountain bikes generally steering in the same spot, therefore pounding or binnelling the race and or crushing the ball bearings.
Since the headset gets tight then loosens up that is most often an oval bearing, it moves, another takes its place until it's the oval bearing's turn again. After that most common is a bad headset, then ovalized head tube, then bad fork.
I would replace the headset and that would check everything but the fork (if your head tube is oval I wouldn't instal the headset, return it and go bike shopping). While the fork is out of the bike, it is easy to guage it to see if it is straight, your bike shop will have the guage.
12-04-02, 05:43 PM
Dimples in the headset race are not caused by brinelling.
12-05-02, 04:30 AM
Thanks for the input. An ovalised ball sounds credible, given the way the steering frees up after waggling the bars. Ill change the bearings, and check for brinnelling as well.
BTW the mechanic is a fairly good one , and he just gave a roadside opinion, there wasnt time for him to strip the headset and check. He did have one interesting headset in his shop on a 1930s Bains International bike It was a Chater-Lea threadless headset integrated into specially "bulged" headtube lugs, just like the current crop of road bikes.
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