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Old 04-10-06, 10:19 AM   #1
ppc
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Deflection in a cheap single-spring fork

From day one, I noticed the front wheel of my recumbent was always tilted a little to the left, and the boom a little to the right, indicating the bike was going sideway. A friend also told me the front wheel seemed to roll about a inch to the right of the rear wheel, which I confirmed by following him on my bike. When I tried to eyeball the bike carefully (without me on it of course), I couldn't see much of anything. I also brought the bike back to the manufacturer to have the frame checked out, and he couldn't see much either. So eventually, I filed the slight crab-like motion under the oh-well category and I've ridden the bike like that ever since.

Today however, I decided to change the preload on the POS Rockshox Judy TT fork that's currently on the bike, and while I was goofing with the (single) adjustment knob, I was pushing on the bike hard to test the fork's hardness, and that's when I noticed the wheel bending ever-so-slightly sideway as I pushed. It occured to me that, with a spring only in the left leg of the fork and the probably not-so-tight tolerances the fork was built with, it makes sense that the fork deflects to the right when it's under load, which would explain why I see my bike running sideway when I'm on it, but neither I or the manufacturer see a problem when I'm not.

So my question is : do you guys know if this is a common problem with cheap mono-spring forks ? I'm more than happy to get another one, especially since this one is generally sloppy and crummy, but I'd like to know if I should get another fork that has a spring in each leg. If I change the fork, I won't get anything fancy, it's just to soak up bumps on the road, but do you think I should avoid forks with only one spring?
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Old 04-10-06, 03:23 PM   #2
Avalanche325
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Gee. A few years ago, a Judy was top of the line.

I would think that the bike tracking funny would be an alignment problem in the rear. Did they LBS actually measure the frame for correct alignment? Is the rear wheel in the drops nice and square.

If the fork is deflecting, there is something wrong with it. These were the "standard" top end forks for several years for cross country. They have bushings that could be worn out.
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Old 04-10-06, 03:35 PM   #3
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Quote:
Originally Posted by Avalanche325
Gee. A few years ago, a Judy was top of the line.
That's a Judy TT though, it's the cheap model and it's definitely underwhelming. The preload does nothing at all, it feels mushy, and it bottoms out quite easily (although to be honest I'm not light). But it works well enough for my purpose, assuming it's not the cause of the tracking issue.

Quote:
I would think that the bike tracking funny would be an alignment problem in the rear. Did they LBS actually measure the frame for correct alignment? Is the rear wheel in the drops nice and square.
Actually, the bike manufacturer checked it out (I purchased the frame directly from them). They re-dished the rear wheel because it was a tad off, but aside from that, nothing wrong.

Quote:
If the fork is deflecting, there is something wrong with it. These were the "standard" top end forks for several years for cross country. They have bushings that could be worn out.
If the fork is the culprit, then it's a manufacturing defect, as it's been doing that from the start.
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