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  #1  
Old 09-01-2014, 12:34 AM
FlashUNC FlashUNC is offline
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Steel fork alignment question...

Assuage my needless paranoia. Any shade tree mechanic suggestions on how to check a steel fork alignment? I swear one leg looks further forward than the other.

Fwiw, the bike tracks fine.
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Old 09-01-2014, 12:58 AM
rustychisel rustychisel is offline
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It probably is [off aligned] as steel forks are shaped by hand to semi-precise curvature. If the curvature is different the correct alignment can still be achieved.

The proof is in the riding, but remove fork, knock off crown race, place fork on flat surface - the glass top to my study desk is ideal - and eyeball closely to see if it rocks slightly or sits square upon the fork crown.
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Old 09-01-2014, 01:10 AM
HillDancer HillDancer is offline
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This method is imprecise because dropouts are not always parallel, but it will reveal gross disparities. Attach bolts & nuts to each dropout and see if the bolts align at their ends.
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Old 09-01-2014, 01:56 AM
FlashUNC FlashUNC is offline
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Thanks guys.

The bike tracks flawlessly and its probably only my bike hypochondria setting in.
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Old 09-01-2014, 01:58 AM
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Scooper Scooper is offline
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The quickest way is to put it in a fork jig and measure the distance of each dropout from the base. If they're not the same, cold set one or both of the blades to the correct offset. The Park Tool FFG-2 fork end alignment gauge set is then used to ensure the dropouts are lined up parallel to each other.

I've got the jig and the gauge here across the bay.

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Old 09-01-2014, 02:08 AM
JLP JLP is offline
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I'd bring it to a frame builder with a surface plate and some v-blocks. You can easily check that the dropouts are aligned with each other with Park dropout tools, but that doesn't mean it's not twisted or off to one side. If you can find a builder you trust and bring them just the fork, it shouldn't be too hard.

Kind of curious what the pros say when they jump in.

Joe
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Old 09-01-2014, 06:51 AM
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oldpotatoe oldpotatoe is offline
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Quote:
Originally Posted by FlashUNC View Post
Assuage my needless paranoia. Any shade tree mechanic suggestions on how to check a steel fork alignment? I swear one leg looks further forward than the other.

Fwiw, the bike tracks fine.
Have a LBS slap some 'H' tools on it to see.
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  #8  
Old 09-01-2014, 10:30 AM
ultraman6970 ultraman6970 is offline
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Check the drop out alignment first.

Did you check the frame using a string?

Wow, a dude here has the jig and the tool. Dont have all the tools but a fork jig would be nice to have, not hard to built but aluminum profiles pieces arent cheap at least here :/

Quote:
Originally Posted by FlashUNC View Post
Assuage my needless paranoia. Any shade tree mechanic suggestions on how to check a steel fork alignment? I swear one leg looks further forward than the other.

Fwiw, the bike tracks fine.
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  #9  
Old 09-01-2014, 11:41 AM
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EricEstlund EricEstlund is offline
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There is fork visual symmetry, and fork functional alignment. In an ideal world you have both. The H tools can tell you about the drop out faces being in phase, but doesn't necessarily indicate total fork alignment.

If the bike tracks well you may have a little visual asymmetry but a still aligned fork.
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  #10  
Old 09-01-2014, 11:41 AM
8aaron8 8aaron8 is offline
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If it's tracking straight you should probably leave it alone. The mandrels used to bend fork blades, as said earlier, are not perfectly exact, so the blade may be bent a mm or 2 higher on one. The only issue with using the fork jig to test alignment is that the adjustable jig has too many variables to test for. You have to make sure that both the clamp for the steer tube and dummy axle are in alignment, as they slide side to side a bit, then you have to make sure that the height of the dummy axle on both sides are equal, which without a surface gauge can be difficult. Finally, you have to be sure that the fork is sitting square in the jig after all the aforementioned has been checked. Using a surface plate with square blocks is a better bet. With all that said start with the dropout alignment first.
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  #11  
Old 09-01-2014, 11:42 AM
8aaron8 8aaron8 is offline
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Quote:
Originally Posted by EricEstlund View Post
There is fork visual symmetry, and fork functional alignment. In an ideal world you have both. The H tools can tell you about the drop out faces being in phase, but doesn't necessarily indicate total fork alignment.

If the bike tracks well you may have a little visual asymmetry but a still aligned fork.
Well said
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  #12  
Old 09-01-2014, 12:31 PM
ultraman6970 ultraman6970 is offline
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Take the fork out and put it over a counter top, just flat the fork crown against the counter and check if the blades are even. If the bike is not trailing anywhere and all is ok I would not worry about it that much.

I built myself a tool the check drop out alignment with stuff from home depot. if the dropouts are off even with 2 rods or two axles and bolts you will notice the difference right away.

If you need to stress the fork to one side I would advice you to put a hub in the fork so when you pull it back both blades move together. Just in case forks are super hard to work with too, hope you know hulk
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  #13  
Old 09-01-2014, 01:29 PM
Tandem Rider Tandem Rider is offline
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First, use a pair of H tools on the tips.

Second, a perfectly dished wheel should sit exactly centered under the brake centerbolt. Flip the wheel to verify this.

Next, a visual sighting along each side of the steerer tube to the rim edge furthest from the crown will verify pretty close symmetry and alignment.

Last, assuming everything looks good so far, reassemble and ride, if the bike tracks correctly as well then all is good.
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  #14  
Old 09-01-2014, 08:49 PM
Craig Ryan Craig Ryan is offline
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If you get two V blocks, a flat surface, a 90 square, and a good measuring device (height gauge), and play with those in every conceivable way you will learn a lot about forks. As Eric pointed out, the tips being lined up don't mean much alone. I would be far more comfortable just riding it than trying to tweak some irregularity I wasn't sure was there to begin with. That is if it hasn't been crashed and bent in some fashion.
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  #15  
Old 09-01-2014, 11:31 PM
unterhausen unterhausen is offline
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I agree with what Eric said above. Before I bought an Anvil, I was puzzling out how to convince myself that the fork was straight using the instruments I had available to me. And the truth is that you can make a fork that works perfectly well that has horrible cosmetics. I think the main mistake that builders make is bending the blades clocked to the crown. This will be obvious if you look, but will not affect the function at all. No fixture will fix that issue.
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