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Old 07-23-07, 11:30 PM   #1
kraftwerk
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Will Swift forks work on a "twenty"?

Still in search of new forks for my " Twenty " . Wondering if the Swift fork would work? Is it 1" or 1 1/8"?
I located threadless 1" BMX forks but the head tube was only 7" or 8" when really I need 10" , (9.5" at the least...) I WOULD even use a THREADED HEAD Tube if it was long enough. I think the wonky stearing is the only flaw on the twenty which I am otherwise quite happy with.

Well-- it would also be nice if it didn't weigh a jillion pounds....
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Old 07-24-07, 12:44 AM   #2
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You could retain the stock fork and just replace the headset. I did that (for a while before i stuck in a suspension fork).

The Swift fork on my Xootr Swift is 1 1/8" so that wouldn't work.
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Old 07-24-07, 02:56 PM   #3
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Thanks Jur, What would we do w/o you!
I will put a head set on it, that sounds like a plan for now.
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Old 07-24-07, 05:13 PM   #4
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Threadless 1" headset is what you need.
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Old 07-25-07, 01:26 AM   #5
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Hmmmm, the forks on the twenty are threaded....
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Old 07-25-07, 05:32 AM   #6
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Hmmmm, the forks on the twenty are threaded....
Yes, but it's hard to find a new one with that thread; you'd have to get an old Raleigh headset, see Sheldon Brown's website for details. Keep the threaded top nut from your existing headset and replace everything else with a threadless one, and that'll work fine.
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Old 07-25-07, 10:25 AM   #7
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Cool that sounds perfect. Will keep using a quill stem. Now that I think of it nothing on my Twenty is original beyond the frame fork and head set.. old head set will go...besides the top nut.
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Old 07-25-07, 10:47 AM   #8
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Yeah, that'll help.
You've seen JUR's posts about bending his original R-20 fork to improve tracking, right? I did that too, and it really did help. I can now ride no-hands -- though not with quite as much confidence as on other bikes. Not sure whether I went too far, not far enough, or what.
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Old 07-25-07, 07:28 PM   #9
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Yes, but it's hard to find a new one with that thread; you'd have to get an old Raleigh headset, see Sheldon Brown's website for details. Keep the threaded top nut from your existing headset and replace everything else with a threadless one, and that'll work fine.
Ok so I follow this plan so far then I get a bit lost...
1) Keep old top nut because of stupid english imperial threading. Check!
2) erm...?

1" Threadless says 'ahead/star-fangled nut' and such to me, but I can't see how you combine this with the messy old threads that will be sticking out of the headtube, nor the original english threaded top nut. Have you still got the cheapo nylon thing in the top instead of a proper bearing? Or has this been junked? What's happening with the stem if it's sorta ahead but sorta quill too. I'm usually good with mechanics but I can't picture the way this works at all.

Can anyone make me a diagram or show a detail as I'm going to reinstall the original forks (Well some other original forks but they are R20) on mine at some point and will want to do something approximating this fix...
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Old 07-25-07, 07:49 PM   #10
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OK lemme see...

The original fork's threads are higher up on the steerer tube than normally on a threaded fork, in order for the original clamp to be installed, which sits between the top nut and the nylon bush.

This means that a threadless headset works just fine, it does not interfere with the threads which are higher up. In fact the original headset IS threadless, strictly speaking.

Now you will need to think carefully. Are you going to use the original bars with their quill? Or opt for something modern?

A modern setup can be easily achieved using a seatpost like this. (They used to have them in 1", maybe Caotropheus can help.) The thin end goes into the fork tube, the original clamp is applied to fix it in position. I think a 1" seatpost clamp might be used instead of the original. A shim with 28.6mm stem completes the setup. The original top nut is used to apply bearing preload and keep everything in place when the bars + quill are removed.

So, to re-cap:

1. Install 1" threadless headset. Nothing special.
2. Install 1" clamp (original or fancy eg Salsa, but file off internal lip). The original nutset keeps the clamp in place and sets bearing preload.
3. Install upside-down seatpost.
4. Install stem with shim.

You can remove the quill for folding, it won't slide down into the fork as the original design. To achieve that, use a 7/8" tube instead of upside-down seat post, with thicker shim.

Last edited by jur; 07-25-07 at 07:59 PM.
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Old 07-26-07, 05:04 AM   #11
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Thanks Jur - I think I'm a little clearer on it now. I was looking at your Twenty (pre susp forks) pix and it looks like you really went for it with custom machined alu parts. Or am I mistaken?
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Old 07-26-07, 06:23 AM   #12
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Correct. I have some pics still, I'll post them later tonight after TdF.
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Old 07-26-07, 07:08 PM   #13
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Here are some more details of my custom made parts:

An insert goes into the top of the fork steerer tube. Its purpose is to prevent collapse of the steerer when the clamp is done up, since I did not have an internal 7/8" piece in my setup.




A pic of the insert "inserted:

The top of the insert is the same diameter as the outside of the steerer, so in effect it lengthens the steerer tube. Just to make me feel better about "minimum insertion" stuff.

The rest of the setup is a 1 1/8" tube slid over the top of the steerer with insert, and a Salsa clamp holding the whole lot together.


I rode like that for a while, but the clamp was not strong enough to keep up bearing preload. So I modded the setup and turned it into a pure threadless setup. The top cap in the 3rd pic is screwed down with a looooooooooooong rod into a starnut which I inserted into the original steerer tube; it is lodged just below the insert. The rod holds bearing tension and makes me feel better on climbs while pulling hard on the handlebars.

So you see, all very complicated, my other idea is MUCH simpler and lighter and can be disassembled.

Last edited by jur; 07-28-07 at 11:48 PM.
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Old 07-26-07, 07:38 PM   #14
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Thanks for the info and pix!
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Old 07-26-07, 07:50 PM   #15
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I must say, I miss the original clean lines. Time to put the stock fork back in...?


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Old 07-28-07, 05:53 AM   #16
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Well I miss the clean lines on mine too... But when I put the old ones back in I'll have to get some 451 rims, and a whole bunch of new spokes too. ....
Can you expand a little on your 'straightening the fork rake in a vice' technique?
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Old 07-28-07, 10:33 PM   #17
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Can you expand a little on your 'straightening the fork rake in a vice' technique?
The vise in question is one of those woodworking ones with wooden jaws.

I loosely held the portion near the fork tip in the vise, and hauled away at the section near the crown. I sort of worked out where I wanted the bend to happen; the portion in the vise wasn't going to bend, and the portion near the crown being thicker wasn't goin to bend either. That left the section where maximum curvature was, to straighten out.



I carefully didn't put any strain on the steerer tube for fear of wrecking the crown bits.

To check alignment, I laid it on a flat surface and with a set square measured the distance to each fork tip from the flat surface, to make sure they ended up equal.



Check back later on this post. I intend to take a few pics to illustrate, and edit them in here.

[edit] images added.

The rake is now:



64mm - 31/2mm = 64mm - 16mm = 48mm.

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Old 07-29-07, 04:27 AM   #18
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One thing to consider is that, while the R20 frame is a gem, the forks are cheap. On an old bike, you can also get internal rusting. One of my worst crashes came when sprinting on an old bike with similar forks. Nothing worse than seeing the wheel twist to the right as you head for the pavement in slow motion!

I'm no framebuilder, but you definitely want to be careful with these kinds of mods. They say that steel warns before it fails, but that's not always true.
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Old 08-02-07, 11:11 PM   #19
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Okay, so I installed a Richtey WCS 1" threadless headset with fancy sealed bearings, and it looks fantastic! Glad to lose the q/r and original headset! Have not ridden it yet because i am also fixing the saddle. Jur your stock forks look newer than mine, I have the style with those chrome inserts near the fork crown... I like the look of the changed the rake, but Pm124 above has a good point considering the thin looking weld job this frame got at he factory...
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Old 08-03-07, 12:31 AM   #20
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re rusting: Would the general condition give a clue to internal rust condition? Also, perhaps if a fork was marginal internally due to rust, then hauling away to bend them would perhaps show the weakness.

Those forks with the chrome caps are a earlier, better version, I think... those chrome caps are called "thimbles" and are rare as hen's teeth. They can be sold to Raleigh Chopper restorers.

Fork options are extremely limited, unfortunately. I have actively considered shortening a surplus set of carbon forks. The main reason I didn't go ahead with it, was the dropouts spacing will be wrong.
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Old 08-05-07, 02:58 AM   #21
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One thing to consider is that, while the R20 frame is a gem, the forks are cheap. On an old bike, you can also get internal rusting. One of my worst crashes came when sprinting on an old bike with similar forks. Nothing worse than seeing the wheel twist to the right as you head for the pavement in slow motion!

I'm no framebuilder, but you definitely want to be careful with these kinds of mods. They say that steel warns before it fails, but that's not always true.

haha it's these sort of posts that flash through my mind when i'm doing over 30 down a hill, that and the last time i assembled my bike!!!!
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Old 08-05-07, 12:16 PM   #22
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"Those forks with the chrome caps are a earlier, better version, I think... those chrome caps are called "thimbles" and are rare as hen's teeth. They can be sold to Raleigh Chopper restorers."
This explains the theft of my pal's "thimbles" when he parked his bike on the street over-night in nyc.
We were scratching our heads about that.. actually more suprised to see the whole bike still there. Anyway, I am thinking of changing the the fork rake that looks like a good mod. and will lift the front end a wee bit... One thing: Since metal has "memory" i would be worried about it springing back unevely.
One tang before the other...
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Old 08-08-07, 08:49 PM   #23
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...Those forks with the chrome caps are a earlier, better version, I think... those chrome caps are called "thimbles" and are rare as hen's teeth. They can be sold to Raleigh Chopper restorers...
I guess my forks are the 'earlier' version, as I have the chrome caps on them. My R20 has a date stamp on the rear dropout, however: 03-19-1979. Would this be considered an early R20? Also, just out of curiousity, what are the caps worth?

Also, Jur, thanks for the information on the headset. I put in a 1" threadless Aheadset and it fits and works perfectly. Instead of using a starnut, I keep enough tension on the headset by using the nut on the original threaded forks. It's kind of strange because I have both a threaded and threadless setup on the same bike!
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Old 08-08-07, 09:04 PM   #24
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'79? Then I must be mistaken... mine has the other plain fork crown version and it dates from '76. I have no idea about the thimbles' worth; I picked up the rarity info from a Chopper restorer website that littlepixel pointed me to once.

I also used an Aheadset.
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Old 08-08-07, 11:08 PM   #25
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'79? Then I must be mistaken... mine has the other plain fork crown version and it dates from '76...
Well, I made an assumption. The left, rear dropout reads: 19197903 I assume this is a date code (March 19, 1979). However, on my original SA 3 (it's no longer on the bike; I've replaced it with the SA 8), it says 2 73, which seems like a date code for the hub's manufacture. Which assumption would most likely be correct?

Re: worth, I've found the answer to my question (just out of curiousity, not because I wanted to sell them). There are some thimbles on ebay for 11.99.

By the way, Jur: how did you get the chainguard on with the larger rear cog (you too are using an SA 8, from the looks of it)? You must have had to cut it to get it to fit, right?

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