Lots of interesting stuff snipped >"Gary Smiley" <[email hidden]> wrote in message when I ride the bike, it veers slightly back and >>forth, similar to a car with a misaligned front-end.
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philcycles said:
Here's the key. I'll bet the headset is too tight. this is called a Dutch roll and comes from too tight head bearings. It's more common on motorcycles than bicycles.
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"A Muzi" <[email hidden]>
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OK, it's certainly likely at that shop and may account for some of his symptom, but the mechanic _admitted_ installing a fork with different rake. . .
Mike Jacoubowsky said:
Andy: Since the fork was purchased from Nashbar, it's
unlikely that the shop
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mechanic "admitted" (as in takes blame for) installing a fork with a different rake since he didn't apparently buy the fork from the place that installed it. Part of this story involves the pitfalls of not doing everything in one place at one time, since finger-pointing can drag out solutions.
I'm sorry , I missed the Nashbar part. Yes I agree that ideally one person doing the whole job would be better. Hopefully someone who could both match the fork and adjust the headset ( Or not flip a part over in that headset?)
At any rate there's probably more to this than the headset. I guess we'll have to wait for the diagnosis at Harris.
-- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971
Thanks for all your help. First of all, the bike is a 1999 KHS Aero Comp. It had a generic carbon fork, and unfortunately I scrapped it when I replaced it so I'll never get the measurements. As I mentioned I replaced it with an Easton EC30 carbon fork. I did loosen the headset a bit, and it moves freely, but when I ride it it feels like the wheel is stuck in some kind of groove in the road (although not as extreme). I thought that maybe my tire might be too grippy, but when I swapped the wheel with one from another road bike I got the same symptoms. It's driving me crazy- I used to like my bike, but now I feel uncomfortable with it. I guess the next step is to have someone actually look at it. Here's what I'm going to do: Since I live in the Boston area, I'm going to take it to Sheldon. (But not today - it's snowing like crazy.)
It may be that the bearing cage is installed upside-down. This can cause the fork to swing freely until you load it with body weight at which time it starts binding.
I was thinking of that - maybe the crown race was improperly installed, or something. But that's what it feels like - a gyroscopic feel- left for 2 seconds, then right for 2 seconds or so, back and forth. It's rideable, but it's not pleasant.
A crooked race(s) seems most likely to me. Can you adjust the headset so that it swings freely without binding, yet has no play when the front brake is applied and the bike rocked fore and aft, or when bouncing the front wheel on the ground?
A change in the axle/crown length would modify the handling a little bit, but there isn't a huge variation between forks... not enough to cause what you are describing, IMO.
Fork problem has been resolved- I brought it to Harris Cyclery. The new fork was OK - no rake problems - but they installed a new headset (properly, I might add) and the bike now runs like the precision instrument it was intended to be. Didn't cost much, either. Thanks everybody.
"Gary Smiley" <[email hidden]> wrote in message news:[email hidden]...
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Here's the story: I have a road bike (853 steel frame, carbon fork). I had a bike-rack mishap- the skewer on my car-top bike rack released, causing my bike to tip over and bending (thereby ruining) the aluminum dropout on my carbon fork. I found a replacement- an Easton EC30 fork that I bought from Nashbar, and I had it professionally installed. Here's the problem: something is wrong- when I ride the bike, it veers slightly back and forth, similar to a car with a misaligned front-end. It's kind of like a gyroscopic force is pushing my front wheel from side to side. I checked the wheel for trueness and it's true. So, for example, if I feel a slight force pushing my wheel to the right, I will apply an opposite force to the left, and vice versa. I can't ride "no-hands" any more. I brought it back, and the mechanic said that it had a different rake, and that the front wheel was now closer to my downtube, and that the bike would now be more "twitchy", more like a real racing bike. But I disagree- the rake is the same (based on the fact that my wheel is in the same position (relative to my downtube) as it was before. Any ideas? Is my (threaded) headset screwed up? (It turns freely). Something is "off". Should I take it to a different mechanic?
