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Discussion Starter · #1 ·
I built up an On One Inbred 29er recently, and have not ridden it for a while. Took it to work this morning and it was really wierd...you know when you take the front wheel off the bike and spin it really fast while holding the QR, if you lean the wheel it kinda pulls you in the direction of the lean? The gyro effect I think? Well my bike handles like that for some reason...the wheel hardly wants to remain straight while riding, tiny movements of the bars, and the front wheel wants to keep turning rather than come back in line...to the point it was kinda scary at speed, I could hardly keep it in a straight line!?! I checked the stem bolts, and they are not overly tight (with the wheel off the ground you can turn the bars without resistance). I checked the QR skewers were tight and that the wheels were properly seated. I found the that the rear wheel was a bit loose, so I released it, jiggled the wheel around a bit to make sure it was seated and did it up nice and tight, and this helped for a while. It did not cure it, but it helped, but it came back shortly after, so I think it has something to do with the rear wheel, even though it really feels like it is coming from the front?? I did not have time to muck about with it any more as I had to get to work. What do you guys think? I am baffled...it did not do this last time I rode it about a month ago.
 

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Haven't got the fork on backwards, have you? :)

Sounds like a tight headset to me. Will the front end turn/fall sideways under it's own weight when you lift the front end?
 

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Discussion Starter · #3 ·
^ haha...Nope!

And yes, I thought the headset was too tight as well, but it is not. Bars fall to the side on their own when wheel is lifted, no resistence from the stem/topcap at all, nice and smooth. Still baffled.
 

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Have you checked your cable routing? Possibly one of the lines is cut too short? Or did you zip tie the cables together instead of letting them hang normal? Maybe your using a weighted bar end on one side and not the other? One handlebar maybe clogged with mud adding extra weight to that side?

Otherwise I'm stumped. I'd pull off the fork and make sure your headset bearings aren't upside down. I'd also check your crown races....making sure you have one on the forks steer tube. And another above the top headset. if it only did it on the trail my first thought would be the tires squirming due to tire pressure or too narrow of a rim.

Post a picture of your bike. Maybe we can visually see the problem.
 

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1*14*29*2.1 & 1*1*29*2.4
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what fork did you use? Is it swinging side to side or just one side? If you have wheel flop oyu may have put too long a fork on or not enough rake.
 

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Sounds like a tight headset to me.
That ^^ is exactly what it sounds like, but since you said it moved freely with the wheel off the ground it could be 1 or more of the HS parts are incorrectly installed as drz suggested.
This could cause the HS to seem to move freely as described but bind under load.

That is where I would start anyway.
 

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Headset is my first.
:thumbsup:

That's what I'm going to with as well. Pretty common.

One can easily overtighten the headset cap before tightening up the stem bolts. Yup, the wheel will seemingly turn fine in the stand or while holding it on the garage floor even with an overtightened headset cap - until you get on the bike and ride. Then you feel the gyroscopic action of a seized headset from the top bolt on the cap being too tight. Chris King headsets are notorious for this if you even as so much as think of an extra little tighten on the headset cap hex bolt.

I'd say, loosen the stem bolts, loosen the headset cap bolt and try again. Keep doing it until you get it right. You won't believe how "loose" that top cap bolt has to be to get it right. In fact, I just went through this myself the past few days as I built up a new Karate Monkey on Friday and thought everything was loose as a goose until I got on the bike. It took me 2 more tries to get it right and remove any gyroscopic odd handling.
 

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I think you are experiencing the early effects of the magnetic pole reversal which will go into full effect this Friday. What is your latitude?
 

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Discussion Starter · #10 ·
Hey guys, thanks for all the advice...seems it was the headset bearings....took the headset apart last night and cleaned it...there was a lot of water and grit mixed in with the grease (been super wet here lately, and I left the bike sitting while dirty for a few weeks as well). One of the bearing cups has some pressure marks, but only in one area, about a quater of the surface area, so I am guessing some grit was lodged in there. Not enough to stop the bars from moving side to side normally when the wheel was off the ground, but when under pressure, clearly enough to mess with the system! I cleaned things up and it is all good now...will be keeping an eye on the head set bearings and making sure they are clean...was amazed at how much crud had gotten in there with all this wet weather we have had (riding to work along the train tacks at the moment is more like swimming in places! Also noticed a slow leak in the rear tire which I think excacerbated the handling problem a bit, so sorted that as well! Thanks again for the tips guys!
 
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