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Old 05-02-09, 10:20 PM   #1
Sixty Fiver
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She lives... another P20 build

Forrest and Grace are a pair of P20 folders I got a few years ago and while Forrest has become infamous for being one of a handful of folding fixed gears (and the only one in these parts) Grace's path was a little different.

I built her up with a dual drive on her SA 3 speed and other than replacing her fenders she remained pretty much stock... she was very utilitarian.

I sold her last year and while she was in Toronto she was mugged and then given back to me and she has just been sitting around in a rather sad and forlorn condition.

Forrest...



Grace... before the mugging.


I love Forrest and we have travelled many glorious miles but every once in a while I'd like to go a little faster than his gearing allows and perhaps descend into the valley and be able to climb out with a little more ease.



So to that end I have gathered up a new suspension fork (cause we're gonna run some high psi slicks), a new Nitto technomic stem, new Tange headset, Shimano 600 cranks, drop bars and levers, bar tape, and a new bottom bracket.

I got her up and running tonight by using her old stock wheels and am stuck in 3rd as her shifter cable was destroyed (but I have spares at my shop).

On Monday I will retap her bb and install the new cranks and might just get the drop bars installed.

Stay tuned.
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Old 05-03-09, 03:38 AM   #2
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Sixty Fiver,

Nice bikes...these P/R20s really grow on you don't they?

Q1: Are you going to cut the BB shell down to 73 or 68mm?

Q2: With the dual drive set up you do, what type of RD do you use?



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Last edited by stevegor; 05-03-09 at 03:40 AM. Reason: Add
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Old 05-03-09, 11:27 AM   #3
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I used a Suntour VX on the dual drive and used Shimano 3/32 cogs and spacers.... it was a bit of a job to fit the derailer as a few little mods to the drop out were needed... a dual drive might be included in this build too.

I discovered that an easily obtained 70mm Shimano cartridge fit the fixed P20 bb really well (after re-tapping) and did not have to cut down the bb on the fixed gear.

The P20 has a 72 mm shell width and the 73 mm cartridge bb can accommodate that... R20's are fitted with the 76 mm shell.

Last edited by Sixty Fiver; 05-04-09 at 11:06 PM.
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Old 05-03-09, 02:52 PM   #4
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Nice looking bikes. Grace was mugged and then returned? How does that work?
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Old 05-03-09, 03:02 PM   #5
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Nice looking bikes. Grace was mugged and then returned? How does that work?
I sold her to a friend who packed her up and took her to Toronto and while there some tweakers tried to jack her wheels but could not get through the locks...they broke the indicator spindle, took the qr levers, wheel nuts, destroyed the computer, and bent the crank arm.

When my friend returned she only did so to finalize her move back east and gave Grace back to me to I could rehabilitate her.

I am just about ready to head down to the shop to start working on her some more as I don't have all the bits I need here at home.
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Old 05-04-09, 03:53 PM   #6
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thats a shame that they wrecked the bike
suppose its an excuse to build it differently
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Old 05-04-09, 03:58 PM   #7
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I got her up and running yesterday and she was purring like a kitten although those steel wheels and cottered crank really have to go... she is loaded up on the longbike so I can haul her down to begin her makeover.

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Old 05-04-09, 05:31 PM   #8
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Quick question...I am getting ready to order wheel parts for my R20. I am planning on using CR18 rims (unless something else is highly recommended) and a old Sturmey Archer AG hub I have laying around. Do I need spoke washers and any recommendation on spoke brands? I am planning on SS spokes. I am keeping the bike pretty much stock looking for the time being. I do have some Kool Stop pads which will get swapped in after I get the wheels done. The OEM steel rims are pretty rough and I don't want to chew the pads up before I get the new rims on there.

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Old 05-04-09, 11:05 PM   #9
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Snapped a few pics when I got home...

Gotta love the longbike...



Re-tapped the bb and used a 73 / 113 bb and fitted a Shimano 600 crank with a 52 tooth ring... I have a 110mm that should allow me to keep the chain ring on the outside of the spider.

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Old 05-04-09, 11:59 PM   #10
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Quick question...I am getting ready to order wheel parts for my R20. I am planning on using CR18 rims (unless something else is highly recommended) and a old Sturmey Archer AG hub I have laying around. Do I need spoke washers and any recommendation on spoke brands? I am planning on SS spokes. I am keeping the bike pretty much stock looking for the time being. I do have some Kool Stop pads which will get swapped in after I get the wheels done. The OEM steel rims are pretty rough and I don't want to chew the pads up before I get the new rims on there.

Aaron
DT spokes are the standard by which all other spokes are measured... I happen to have a massive stash of old Berg spokes in stainless / butted which are equally as good and have been used for countless wheel builds.

If you use the same gauge spokes a spoke washer should not be needed and the CR18 seems like a good choice and one that I have considered for Grace's new wheel set.

In test driving her after the crank upgrade I was so very pleased on how smooth she had become and I did not feel like I was pushing a taller gear as despite gaining 8 teeth up front I had also lost at least a pound of rotating weight at the cranks.

With the 52:16 I get a gear ration of 45.5 / 60.7 / 80.9 and with a 15 (I have one of these) I would get 48.6 / 64.8 / 86.3 but since my 15 is a 1/8 I would need a new chain...I am still considering reinstalling the dual drive to really expand the range and improve climbing ability and could use a barcon to handle the rear shift.

I can't wait to overhaul the front end and get the new fork and drop bars installed...I will be picking up new wheels tomorrow and might even get them laced up... I have a Shimano 105 hub for the new front wheel.
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Old 05-05-09, 05:12 AM   #11
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Sixty Fiver,

You may remember my R20, "The Wasp" as LittlePixel named it, well... I was using 451mm wheels, but swapped them to my wife's Magenta R20 and am currently rebuilding mine with 406mm rims, a SA 8 spd hub with a 25t cog and a 48t chainring. I'm having problems with the chain as it gets very tight at one point and a bit slack at the opposite point, I don't think the chainring is a biopace and the hub is centred correctly into the frame.....can you shed any light on this, please?

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Old 05-05-09, 09:35 AM   #12
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I think we love our 20's because of the challenges they offer up and once the swearing ois over we can really enjoy our rides.

The dropouts on 20's seem to work best with odd numbered cog and chain ring combinations due to the stay length and short dropout... the stock gearing is a 46:15.

The 52:18 I started with could not be adjusted for chain line as the axle was either too far forward or could not go far enough back and a 16 tooth cog put the axle at the most forward (safe) point.

I modified the rear dropouts on my fixed folder to lengthen the dropout a few mm so I could run a 14 / 16 flip flop and get proper chain adjustment...and the Stronglight crank I have is extremely precise (round).

You may have a really out of round chain ring or cog that is causing undue variations in your chain tension and Sheldon Brown wrote an excellent instructional piece on how to loosen the stack bolts to adjust the position of the chain ring.

And then some chain rings are just really bad and need to be replaced.

A Biopace is actually fairly easy to set up as the variance in the chain ring is exact and there's no guessing... I was thinking that a Biopace ring would not be a bad idea for the folder and may just have to hook one up to play with it.

Some road frames have those 1/2 length horizontal dropouts which are very similar to 20's and in turning a few into single speeds I have had a few challenges in finding gear combinations that work.
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Old 05-05-09, 03:08 PM   #13
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ooh fluted straight arm cranks....sooperb

Ive got 52 15 on my city bike. was built for getting along a flat road to work.
but not all the roads are flat in town. So was thinking of changing to a bigger cog. Ive got a box full of SA cogs
come to think of it. Ive got 52 15 on my Puch Mini sprint too. But it feels low geared. Its got an old Shimano hub. Are they the same ratios as a SA hub?
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Old 05-05-09, 09:03 PM   #14
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Back from the shop...

Replacing the headset was a snap although I did have to trim the head tube by 15 mm to accommodate the steerer on the suspension fork and the Tange headset. A spare bmx wheel I had will have to serve until I get the new wheels built... our potholes are big but I don't think I need a 48 spoke front wheel.

Mind you... on the way home I felt no need to dodge anything and was riding at some pretty good speed.

I took her out for a few test spins as I was building her and went for coffee and got half a dozen "cool bike" comments and a few guys at the shop took her for a spin and understood why I like my folders...one of them also building up a Phillip's Twenty so was really paying attention to what I have been doing.

That saddle has to go...



Picked up Tektro levers to work with the new V-brake and the stopping power is off the hook and there is very little dive to that fork (Sr Suntour). The rear brake continues to be all but useless so I am going to use a drop bolt and use a shorter reach brake... or get brake bosses brazed on.



The stem is a Nitto Technomic that I picked up new at a gear swap for $6.00 and it is still far from it's limit... it is ten inches long.



Headset is a Tange and things are smooth as silk and I did something I have never been able to do on Twenty today... I rode no handed.



So now I need to build those new wheels and hope that my Schwalbe Marathons don't get back ordered.
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Old 05-05-09, 09:05 PM   #15
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grifter - Shimano hubs seem to have bigger jump to both their high and low positions...
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Old 05-06-09, 02:55 AM   #16
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I'll have to look up the ratios for the Shimano hub. Havent been to Sheldon Browns for ages. Ive got a few of the Shimano hubs. Got one on my Huffy roadster.

I got a 48 spoke front wheel from my last job. I noticed when selling a customer a wheel that it had been reduced from 25 to 5. So I bought the other one that was in stock.

I got this V brake adaptor from Ebay. Its a heavy steel plate. Ive seen other models that are machined alloy.
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Old 05-06-09, 10:25 AM   #17
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That V brake adaptor looks like a possible solution to the rear braking issue on the 20...

I put on a new old saddle and my old Shimano 600 racing pedals (clips and straps) this am and the bike looks like like it lost 5 pounds... I am looking forward to taking the bike out later.

On my little spin home last night I estimated I was hitting 20 plus mph (90 + rpm spin)...Twenty's really go so much faster when you redistribute your weight evenly over the bike, get off the back wheel, and get much more aero.

With lighter wheels and faster tyres I expect to be able to hit 25 mph plus even though she will never be a lightweight (the frame and fork are too heavy)... my fixed folder was down 24 pounds before I reinstalled the factory fenders which is good for a bike that started life at 36 pounds.
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Old 05-07-09, 08:39 PM   #18
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What a difference a day makes...







Laced up a temporary rear wheel with an Alex C1000 single wall (they are stiff as hell) so I can ponder wheel choices while I rock the new higher psi Marathons, replaced the saddle and pedals, and now need to install that drop bolt and a rear brake that works before I tear her down for a bead blast and powdercoat.

Her frame is pretty scruffy and I am leaning toward a deep copper.

I have a gorgeous 1954 SA AW that I will use for the new wheel set as these are just that much better than later model hubs and this hub and wheel will then replace the rear wheel on my daughter's commuter.

The ride on the 100 psi Marathons is excellent... they are smooth and fast, the bike just devours potholes and bumps, and like every small wheeler... she's really agile.
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Old 05-07-09, 09:09 PM   #19
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that is one nice bike......
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