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Old 04-29-09, 11:36 PM   #1
rossmcloch
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replace r20 fork?

I trying to plan out my r20 upgrades and i'm getting stuck on replacing the fork. The fork will help decide what front wheel and brakes I get so I need to figure it out before ordering other parts.

I've heard mixed things about replacing the r20 stock fork. Some say it is a 'must replace' while others seem to leave it be. I would be replacing it with a sun ez sport recumbent fork (unless someone has another suggestion?). The fork will cost ~$60 but will also mean that my front wheel is slightly cheaper by not rebuilding it around the R20 stock hub.

Any thoughts?

If anyone has the sun ez sport fork, will it fit the stock fender/mudgaurd? What about a 451 wheel?

Maybe even a picture of how it looks?

Thanks for the help.
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Old 04-30-09, 12:14 AM   #2
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Originally Posted by rossmcloch View Post

Maybe even a picture of how it looks?

Thanks for the help.
Try Mr. Google.
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Old 04-30-09, 12:18 AM   #3
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Try Mr. Google.
well I meant on a r20...
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Old 04-30-09, 01:22 AM   #4
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Fork for Raleigh Twenty
http://www.tariksaleh.com/bike/twenty/twenty.html
http://www.sheldonbrown.com/raleigh-twenty.html
Another damn Twenty thread... with a twist.
http://www.flickr.com/photos/stevego...7602276418135/
http://www.phred.org/~alex/bikes/swift.html
http://home.comcast.net/~cheg01/r20.html
Got myself a Raleigh Twenty

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Old 04-30-09, 05:27 AM   #5
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The stock fork is usually derided because of five things - the width of the hub it takes, (narrower than a lot of hubs) the unusual nylon bushing fitment at the top (helps with vibration but very 'non-standard' if you want to upgrade the headset), the non-standard threading (same reasons of headset fitment), the relaxed rake of the fork (gives a laid-back and less responsive ride) and it's weight.

Opinion on what to do is divided, depending on what you want to do; here are some of the options you can think about:

1) Keep the stock fork. It worked when the original bike came out and there's nothing intrinsically wrong with it. Jur on these forums has documented somewhere a way to cold set them to liven up the ride - this is essentially a way of carefully bending the curvature of the rake to something a little less extreme. Keeping the original fork also means you can still utilise the handlebar quick-release that allows you to turn the bars 90 for a slimmer fold.

Notes on 1 and 2) Keeping the stock fork or adding a new rigid fork won't offer any suspension; if this is imperative, one fix is to build the front wheel around a Pantour suspension hub. This will be lighter (and easier) than fitting a full suspension fork, and offers plenty enough damping to cancel out the road buzz you tend to feel with smaller wheels.

2) Find another rigid 20" fork. The main benefit being you'll be able to find something a bit more sturdy and with a less lazy rake angle, and it will likely have a modern threading meaning you can fit a new headset. BMX forks, kids bike forks, recumbment forks and some adult trike forks will usually fit. However - the Twenty has a very long head tube and it's quite hard to find forks with a steerer long enough to fit. There are ways, included replacing the whole steerer, or adding quill extensions (or welding tubular extensions) that can solve this problem.

3) FIt a 20" suspension fork. There aren't that many out there compared to the wealth of choice for 26" wheels. But the economical RST solution is fairly popular and there are a few 'expensive' options if you look (as you have done) at recumbent forks which can be got in both ISO 406 and 451 flavours.

4) Convert a suspension seat-post into a suspended stem. I've not seen this done on a Twenty, but is a common aftermarket fix on Brompton bikes - and could be a good way to reduce vibration - if you have the tools and knowhow...



For what it's worth: I opted for a cheap suspension fork on my Twenty when I first restored it as I had come to believe it was what the bike would need (seeing Sheldon and Cheg's bikes) but the one I got was a little cheap (ie it dives a lot) and a lot heavy; In retrospect I think for a day-to-day road bike Twenty (as mine is) I'd have been better off keeping the standard fork and fitting a pantour hub. IMHO I think a susp fork is slight overkill unless your bike is going to be used for path/trail riding. Paved roads don't really require 2-3" of travel in your fork!
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Old 04-30-09, 11:06 AM   #6
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When I built my R20 I initially used the RST suspension fork. It would dive under even modest acceleration and braking, plus as stated above, it was heavy. I replaced it with the Sun EZ fork, which worked well, fit like a charm and it was quite a bit lighter. The 100mm axle spacing also gave me so many more wheelsets to chose from.

I agree that front suspension on a folder is not all that necessary. I had front susp. on my DT IX, but there is little difference in the ride of that bike and the ride of my BF NWT w/o suspension. In my experience the tires made more difference in the ride than having suspension on the front.
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Old 04-30-09, 06:47 PM   #7
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Originally Posted by LittlePixel View Post
The stock fork is usually derided because of five things - the width of the hub it takes, (narrower than a lot of hubs) the unusual nylon bushing fitment at the top (helps with vibration but very 'non-standard' if you want to upgrade the headset), the non-standard threading (same reasons of headset fitment), the relaxed rake of the fork (gives a laid-back and less responsive ride) and it's weight.

Opinion on what to do is divided, depending on what you want to do; here are some of the options you can think about:

1) Keep the stock fork. It worked when the original bike came out and there's nothing intrinsically wrong with it. Jur on these forums has documented somewhere a way to cold set them to liven up the ride - this is essentially a way of carefully bending the curvature of the rake to something a little less extreme. Keeping the original fork also means you can still utilise the handlebar quick-release that allows you to turn the bars 90 for a slimmer fold.

Notes on 1 and 2) Keeping the stock fork or adding a new rigid fork won't offer any suspension; if this is imperative, one fix is to build the front wheel around a Pantour suspension hub. This will be lighter (and easier) than fitting a full suspension fork, and offers plenty enough damping to cancel out the road buzz you tend to feel with smaller wheels.

2) Find another rigid 20" fork. The main benefit being you'll be able to find something a bit more sturdy and with a less lazy rake angle, and it will likely have a modern threading meaning you can fit a new headset. BMX forks, kids bike forks, recumbment forks and some adult trike forks will usually fit. However - the Twenty has a very long head tube and it's quite hard to find forks with a steerer long enough to fit. There are ways, included replacing the whole steerer, or adding quill extensions (or welding tubular extensions) that can solve this problem.

3) FIt a 20" suspension fork. There aren't that many out there compared to the wealth of choice for 26" wheels. But the economical RST solution is fairly popular and there are a few 'expensive' options if you look (as you have done) at recumbent forks which can be got in both ISO 406 and 451 flavours.

4) Convert a suspension seat-post into a suspended stem. I've not seen this done on a Twenty, but is a common aftermarket fix on Brompton bikes - and could be a good way to reduce vibration - if you have the tools and knowhow...



For what it's worth: I opted for a cheap suspension fork on my Twenty when I first restored it as I had come to believe it was what the bike would need (seeing Sheldon and Cheg's bikes) but the one I got was a little cheap (ie it dives a lot) and a lot heavy; In retrospect I think for a day-to-day road bike Twenty (as mine is) I'd have been better off keeping the standard fork and fitting a pantour hub. IMHO I think a susp fork is slight overkill unless your bike is going to be used for path/trail riding. Paved roads don't really require 2-3" of travel in your fork!
Thank you for all the info, you are always very helpful.

Does anyone know of a quick release stem that would allow me to keep the quick release on a new fork?
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Old 05-01-09, 04:34 AM   #8
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I've kept the stock fork.

I cold set the forks for a wider (10mm standard) hub and filed the fork ends to take the slightly ticker modern axles. For widening I just used a threaded bar and some nuts to "jack" the ends apart carefully.

I also straightened the fork blades a bit by sticking the curved bit in a soft jawed vice and squeezing them. This has the effect of lifting the front end a few mm (making for a more relaxed head tube angle, thought I doubt it makes any noticeable difference) and increasing the trail, again making for a more relaxed ride.

The headset bearings were replaced with a standard "aheadset" type set, using the original nut on the steerer to clamp down on the headset. I've added some locktite for peace of mind but it works a treat.

For "suspension" I run 50mm big apple tires on 406 rims. This brings the effective diameter to around 500mm, or just a little bit under the original 451 and 1 1/4" tire setup.

The 50mm tires at about 30-40psi soak up all the road buzz and most of the big stuff too. They roll pretty well too.
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Old 05-08-09, 09:02 PM   #9
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hi guys...how do you remove the nylon bushing in the head tube? it's rather difficult to get out...
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Old 05-08-09, 09:16 PM   #10
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Knock it out bit by bit from the opposite side, using a drift or a piece of rigid plastic tubing.
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Old 05-08-09, 09:56 PM   #11
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My P20's...



On the fixed gear I have since swapped out the 2.0 60 psi tyres for a 90 psi / 1.85 rear and 100 psi / 1.35 in the front and the ride is now faster and still reasonably comfortable although I do have to be a little more careful with potholes and will un-weight the bars a little when an evasive manoeuvre isn't possible.

The stock P20 fork is a little springier than the R20 fork and at some point I will be installing a new headset and fork since this really improves the bike's feel. A fork with v-brake mounts would be high on my list of possible forks as I don't know if there is a 20 inch fork that will take a disc brake.



Just built up my fixed gear's twin and went with a headset / stem replacement and 50mm suspension fork (Suntour) and with the 100 psi Schwalbes the bike has a very smooth / fast ride and eats up bad roads. The fork is quite heavy and does suck up some power on standing climbs but is otherwise working quite well. The head tube was cut down 15 mm and re-faced to accomodate the new fork and headset.

Being able to use a v-brake on the bike means the stopping power is now amazing and there is not an undue amount of dive with the fork under hard braking. I have yet to modify the rear brake.

I can also ride the bike with no hands which is something you can't do with a stock R20 / P20.
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Old 05-08-09, 10:00 PM   #12
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thanks jur, i was trying to pry it out using my finger nails, haha
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Old 05-09-09, 06:37 PM   #13
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How much weight do you save with the sun ez sport fork? The thing looks heavy. I would like to get a fork like the bike friday has or better yet a trigon carbon fork a Swift owner in Japan is running one..
I am still running the stock fork with a 1" Ritchtey thread-less headset. Would like to switch out the fork for two reasons : save weight and less rake.
Modding the drop outs was no problem for wider hubs, rake can be adjusted but I have not gotten around to it.

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Old 05-18-09, 11:13 AM   #14
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I just ordered a Formco Foundation Expert 24" Fork 1" Threadless (FK9078) 1 $146.62 from Jacks Bicycle and fitness.
It is carbon fiber and the head tube may need to be extended a bit...Will let you know how this goes!

NOTE:
Forks don't fit, unfortunately because it is areal fine looking product.

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Old 05-18-09, 11:45 AM   #15
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My new suspended Twenty has been logging some good miles and have to say I am really pleased with the SR fork (despite it's weight) as it really does make for an exceeding comfortable ride on our pothole ridden and rutted roads.

The one thing I really like is the ability to maintain a line through the roughest of roads and do not have to un-weight the bars much (if at all) as the suspension does it's job quite well and I am looking forward to some off road testing.

I can run the front tyre at 100 psi and have dropped the rear to 90 to smooth things out and my fixed folder runs a wider 85 psi in the rear to add some needed suspension.

On a conventional set up the riding position on a Twenty is fairly set back and the front wheel does not have to support much weight so a suspension there probably is not needed by most...they were designed to run 20 by 2.0 tyres which provide a great deal of suspension.

I also ride a pretty much stock Twenty and despite running much taller gearings the drop bar 20's are so much faster due to the better aerodynamics and a more centred position on the bike which balances the load on the wheels.

The new tyres on the fixed 20... 100 psi Comet up front and an 85 psi Phyte Odyssey in the rear. I was very surprised at how nice a ride the 1.35 Comet delivers at 100 psi and the Odyssey is a very fast rolling 1.85 tyre.

I still have to watch for potholes and ruts and the narrower front tyre is more likely to get caught in deep cracks.

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Old 05-18-09, 04:34 PM   #16
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This fork will fit, WITH ONE BIG CAVEAT

http://cgi.ebay.com/ws/eBayISAPI.dll...m=380120667448

It is 1", threaded, and the steerer tube is 9" long so the length is perfect, BUT

The tube circumference is a weeeee bit bigger than the stock fork, so it will rub against the bolts that hold the Raleigh 20 Heron emblem.

I believe if you file those little bolts or whatever they are called, remove some paint off the fork (mine was black), or spray a lot of lubricant, it will fit fine.
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Old 05-18-09, 11:52 PM   #17
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I'm sorry, i meant this link

http://cgi.ebay.com/NEW-SUN-EZ-Sport...3%3A1|294%3A50
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