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Tricycle forks - curved or straight?

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Tricycle forks - curved or straight?

Old 04-29-12, 06:45 AM
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maddogandnoriko
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Tricycle forks - curved or straight?

I recently bought a used adult tricycle, I think it was cobbled together. Anyhow, went to grease the steering bearings and the fork threads were stripped. I proceeded to make it worse by forcing the nut on. The tires are 20" and the tube is 1", the forks are curved. I would like to apologize now for any incorrect terms I am using, it has been 20-25 years since I have been near a bicycle.

So obviously I am looking to fix my new toy, asap. Can I buy a used 'bmx' type kids bike and and put the straight forks on? If I do what will the ramifications be, if any? And what should I watch out for? I also know the brake set up will differ, but I have a set of cantilever brakes to switch with.

Thank you for your time,
Todd
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Old 04-29-12, 06:53 AM
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Forks are "raked" so the dropouts are somewhat forward of a line through the center of the steerer tube. Rake can be obtained in two ways, first by curving the fork blades as your now-defunct fork was made or second, by attaching the fork blades to the crown at an angle. Either method can give the same results.
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Old 04-29-12, 07:26 AM
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So essentially either will be the same? Just asthetics?
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Old 04-29-12, 07:34 AM
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Originally Posted by maddogandnoriko View Post
So essentially either will be the same? Just asthetics?
Yes. The amount of rake, measured in mm, for either type can vary depending on the designer's intent, but the conceopt is the same.
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Old 04-29-12, 07:44 AM
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I think that on a tricycle the amount of rake on the fork is less critical than when trying to balance on two wheels. Steerer compatibility and esthetics may be the deciding factors in this case.
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Old 04-29-12, 01:39 PM
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I'll guess you need a longer steerer tube on the fork, for the trike
than cannibalizing a Kids BMX bike offers.
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Old 04-29-12, 04:47 PM
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Fletsbob- I bought a junker an found this out the hard way, thanks for the help though.

I am shopping online for forks and am bufuddled by the numbers I am seeing. Maybe some one can help me out. I need 20" forks with a steerer length of 6 3/4 from top to bottom of race and 1" steerer tube O/D.

I looked at bike parts USA(and a few other shops) and saw numbers like these: 185x100x21.1x27.0BK.

Could someone please explain what those mean, so I can order the correct part?


Thank you for you for your patience,
Todd
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Old 04-29-12, 05:09 PM
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Bike shops will be helpful , walk into it and let them help.

100 is normal front fork tip width for the hub.

Other than that, no idea without seeing the dimensions on a blueprint graphic.

Last edited by fietsbob; 04-29-12 at 05:14 PM.
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Old 04-29-12, 07:41 PM
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Not sure what threads you stripped but think that a machine shop should be able to chase the threads.
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Old 04-30-12, 04:11 AM
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Originally Posted by HillRider View Post
Forks are "raked" so the dropouts are somewhat forward of a line through the center of the steerer tube. Rake can be obtained in two ways, first by curving the fork blades as your now-defunct fork was made or second, by attaching the fork blades to the crown at an angle. Either method can give the same results.
Or - as on BMX forks, simply mounting the dropout on the leading edge of the tube.

Originally Posted by maddogandnoriko View Post
185x100x21.1x27.0BK.
As fietsbob said, 100mm is the standard front hub OLD (over locknut dimension). I suspect that fork has a 185mm long steerer. The 21.1x27.0BK is likely the steerer diameter and thread pitch, but I'm not sure how those work. If you can verify it's standard BMX 1" threaded, and your current fork's steerer is shorter or equal to 185mm, you're good to go.

Last edited by Kimmo; 04-30-12 at 04:19 AM.
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