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-   -   vintage twenty with upgrades? (http://www.bikeforums.net/folding-bikes/878382-vintage-twenty-upgrades.html)

foldup68 03-17-13 10:24 AM

vintage twenty with upgrades?
 
Looking to buy a 70,s twenty or stowaway and i want to upgrade the gears new seat handlebars to bring it up to date. but still keep the old look. anyone have any ideas what type of gearing to put on there i was thinking about making her a 18 speed as it will be for touring.:) Thanks folks. help much appreciated.

LittlePixel 03-18-13 07:06 AM

1 Attachment(s)
Sounds like a great project - quite ambitious...

You'll have trouble making it a full 18 speed with a traditional 9 rear/2 front derailleur setup because of the width of the rear dropouts - I have a modded twenty with a rear derailleur only (you'll need to figure out a way to fit a hanger also - there are shimano bolt-on hangers that will work, but you'll need to drill the dropout for a fixing bolt) and can only use six of the seven on my cassette, because the smallest, outermost sprocket is so near the chainstay and dropout that when the chain is running on it it fouls the stay. I believe this can be resolved by removing a sliver of the stay and filleting it but this is a proper frame-builder's job in such a load-specific area of the bike.

Front derailleur is doable if you can find one that will fit between the bottom-bracket and top tube (or fit a braze on) but you have to be aware the shorter wheelbase of the bike can lead to a greater likelihood of chain-drops due to its shorter wheelbase making greater angles for the chain to run at in the most extreme gear combinations.

Less hassle would be to go for an seven eight or nine-speed rear planetary hub (Alfine, Spectro, SA9, Nexus et al) - it's heavier but chain-line issues would be a lot less / zero with its single sprocket. You'd probably need to cold-set the stay so the rear dropout is stretched from the stock width (120mm? I can't quite remember) to 135mm - easily done without harming the bike too much. In theory then you could fit a front derailleur then- or perhaps even better a Schlumpf Mountain-drive Bottom Bracket to double the amount of ratios.

Hope that's some help; keep us up to date with the project - would love to see progress / see pictures.

http://bikeforums.net/attachment.php...hmentid=305195

foldup68 03-18-13 09:06 AM

thats some great info! thanks very much!!:thumb: what like is your gearing setup for hills?:rolleyes:

foldup68 03-18-13 09:16 AM

i like the set up on the photo single chain ring at front sounds easier.... maybe replace it with a larger one if needed for hills!
i hate hills as stay in scotland!!!:cry:

foldup68 03-18-13 09:25 AM

2 Attachment(s)
here is a photo of the setup i could go for. maybe this is someones bike from the forum. it looks great:)
!http://bikeforums.net/attachment.php...hmentid=305223http://bikeforums.net/attachment.php...hmentid=305224

foldup68 03-18-13 01:05 PM

was looking at this set up Shimano Deore 9 Speed Cassette 11/32 and a 52 front? would this work.

sreten 03-18-13 01:18 PM

Quote:

Originally Posted by foldup68 (Post 15400553)
i like the set up on the photo single chain ring at front sounds easier....
maybe replace it with a larger one if needed for hills!
i hate hills as stay in scotland!!!:cry:

Hi, No point making hills harder with a bigger front chainring ;), rgds, sreten.

The more you want mod a Twenty the much harder it gets.
e.g. This is much easier to customise and needs far less :

http://www.sportsdirect.com/dunlop-t...ng-bike-933006

The Tourney derailleur will accommodate a big low bottom gear,
I can't tell if it comes with a wide range cassette or not, it looks
like it does come with a big bottom gear (32?), it's hard to say.

foldup68 03-18-13 01:23 PM

what do you reccomend sreten?

foldup68 03-18-13 01:25 PM

maybe 22/32/44 set up

sreten 03-18-13 02:22 PM

Quote:

Originally Posted by foldup68 (Post 15401697)
what do you reccomend sreten?

Hi,

I'm not recommending anything other than a Twenty can't
be upgraded to modern specification without some very
serious work being involved, you can't just slap on modern
components, your talking a serious (expensive) rebuild.

The bike I linked to has some nice bits at a silly price.

The only reason to fit a Tourney type derailleur on a
budget bike is to accommodate a big (low) bottom gear.

To me it looks like one might be fitted, but if not you
could certainly change the rear freewheel cassette.

A 9 speed rear will need a splined hub, I don't know
what sort of hub is is used, freewheel or splined.

(But I'd assume freewheel, and your best option
is to go 2 or 3 speed on the crank. 2 speed can
be done on any 5 spoke crank, drilling, tapping
and spacers, but will only give lower gears.)

IMO walk before you can run, and customise a bike
with changing parts, rather than rebuilding one.

Racks, mudguards, tyres, handle bars, (barends),
grips, seat, front brake shoes come to mind.

Pannier systems front and back.

Probably ditch the probably nice folding pedals,
and look at the gearing options you really need.

rgds, sreten.

fettsvenska 03-18-13 02:48 PM

1 Attachment(s)
Here is my Twenty...

http://bikeforums.net/attachment.php...hmentid=305263

This took a lot of work and a lot of $$$ and I didn't even change the gearing. One thing to be aware of is that if you change the cranks, you will need to have a mechanic re-face the bottom bracket shell and re-tap the threads in the bottom bracket. Back in the day when Raleigh was making the Twenty they had their own proprietary 26 TPI threading. Most (maybe even all) modern bottom brackets use 24 TPI. A mechanic will need to shave a few millimeters off each side of the bottom bracket shell (down to 68mm) and then then re-tap the threading to 24 TPI. Also, understand that re-tapping the threads to 24 TPI will make them weaker. However, since you will be making the shell narrower, the newly tapped threads will go deeper into the bottom bracket shell. I hope I explained that well enough. The late, great Sheldon Brown does a much better job explaining things than I do. Look up his website and see what he has to say.

I use Primo Comet tires on my Twenty and I love them.

BassNotBass 03-18-13 03:12 PM

Quote:

Originally Posted by fettsvenska (Post 15402096)
... you will need to have a mechanic re-face the bottom bracket shell and re-tap the threads in the bottom bracket. Back in the day when Raleigh was making the Twenty they had their own proprietary 26 TPI threading. Most (maybe even all) modern bottom brackets use 24 TPI...

The only alternative that I know of is buying Phil Wood stainless steel cups (1.370 x 26 tpi, RH/LH thread) and fitting a cartridge BB... certainly not cheap but no special machining/tapping involved.

wahoonc 03-18-13 03:48 PM

Quote:

Originally Posted by BassNotBass (Post 15402197)
The only alternative that I know of is buying Phil Wood stainless steel cups (1.370 x 26 tpi, RH/LH thread) and fitting a cartridge BB... certainly not cheap but no special machining/tapping involved.

You can also buy a Velo-Orange "threadless" bottom bracket. Depending on the version of the Twenty you might have to still shave the bracket down or maybe not, there were some interesting quality control issues.

Aaron :)

Diode100 03-18-13 04:36 PM

The Twenty clones, Dawes, etc., come with a standard bottom bracket, don't they ?

sreten 03-18-13 05:07 PM

Quote:

Originally Posted by Diode100 (Post 15402609)
The Twenty clones, Dawes, etc., come with a standard bottom bracket, don't they ?

Hi, the same, but non-standard would be more accurate, rgds, sreten,

Sixty Fiver 03-18-13 05:33 PM

Quote:

Originally Posted by foldup68 (Post 15396945)
Looking to buy a 70,s twenty or stowaway and I want to upgrade the gears new seat handlebars to bring it up to date. but still keep the old look. anyone have any ideas what type of gearing to put on there i was thinking about making her a 18 speed as it will be for touring.:) Thanks folks. help much appreciated.

I have converted many 20's to a 73mm bottom bracket and 24 tpi threads and have had no reported issues and have been riding my own P20 for well over 5 years with a 73mm cartridge bb... the Phillip's has a stock 72- 73mm bottom bracket so no facing was required but the threads needed to be re-tapped.

The rear spacing is problematic in several ways as the frame is 115mm and will accept a modern IGH with no issues while using a derailleur equipped wheel poses some issues. The frame needs to be cold set and the rear seat stays are rather beefy and will interfere with the chain when it runs on the outermost cog.

Spacing a new hub requires that you add spacers to the drive side to give the chain the room it needs so a 126mm hub needs a 130mm spacing or you can go beyond that and modify the stay so that it offers adequate clearance.

If you are a guy like me and work in a frame shop, you cut out the rear triangle and replace it with a modern one with 130mm spacing, a proper dropout hangar, and cable guides and stops, build a new fork, and powder coat it.

http://www.ravingbikefiend.com/bikep...estpowder1.JPG

I have chronicled the entire saga here... I run a triple with a 48/52 half step and 40 tooth granny and built up a custom 7 speed freewheel.

Forrest - 1973 Phillip's 20

Sixty Fiver 03-18-13 05:35 PM

Quote:

Originally Posted by Diode100 (Post 15402609)
The Twenty clones, Dawes, etc., come with a standard bottom bracket, don't they ?

The Dawes has a standard BSA / ISO bottom bracket and standard sizing throughout so upgrading these is much easier save for the wheels as the stock 500A they came with is obsolete... a 451 is an excellent modern replacement wheel size for these.

I have one of these in the works now... it will be getting an SA 8 speed cassette / drum brake in the rear and a standard double up front.

fettsvenska 03-18-13 07:51 PM

Groovy!

Quote:

Originally Posted by Sixty Fiver (Post 15402842)
I have converted many 20's to a 73mm bottom bracket and 24 tpi threads and have had no reported issues and have been riding my own P20 for well over 5 years with a 73mm cartridge bb... the Phillip's has a stock 72- 73mm bottom bracket so no facing was required but the threads needed to be re-tapped.

The rear spacing is problematic in several ways as the frame is 115mm and will accept a modern IGH with no issues while using a derailleur equipped wheel poses some issues. The frame needs to be cold set and the rear seat stays are rather beefy and will interfere with the chain when it runs on the outermost cog.

Spacing a new hub requires that you add spacers to the drive side to give the chain the room it needs so a 126mm hub needs a 130mm spacing or you can go beyond that and modify the stay so that it offers adequate clearance.

If you are a guy like me and work in a frame shop, you cut out the rear triangle and replace it with a modern one with 130mm spacing, a proper dropout hangar, and cable guides and stops, build a new fork, and powder coat it.

http://www.ravingbikefiend.com/bikep...estpowder1.JPG

I have chronicled the entire saga here... I run a triple with a 48/52 half step and 40 tooth granny and built up a custom 7 speed freewheel.

Forrest - 1973 Phillip's 20


BassNotBass 03-19-13 04:29 AM

Quote:

Originally Posted by wahoonc (Post 15402355)
You can also buy a Velo-Orange "threadless" bottom bracket. Depending on the version of the Twenty you might have to still shave the bracket down or maybe not, there were some interesting quality control issues.

Aaron :)

Damn that's pretty slick. Thanks for the tip.

wahoonc 03-19-13 04:07 PM

Quote:

Originally Posted by BassNotBass (Post 15404567)
Damn that's pretty slick. Thanks for the tip.

I have used it to rescue a frame that had bad threads in the BB, it was a Reynolds 531 but wasn't worth paying to have a new BB brazed in. It does work with Twentys, I have seen blog posts where it was done. It is also a decent work around if you have a Raleigh Sports and want to upgrade the crank but don't want to mess with the odd ball threading.

Aaron :)

social suicide 03-20-13 05:58 AM

I used the $140 SA XRF8-W IGH in my R20. It is the 120mm version. I used a UN72 with Phil Wood cups and an Origin8 46 tooth crankset up front. No issues with the rear hub, except noisy and I still don't like the twist grip shifter after almost 2000 miles. I have to watch it in the turns, the cranks are a little long. I had to make a little 1/4 inch tab to get the chainguard to fit.
My butt bought that seatpost when I wasn't looking!:innocent:
http://farm6.staticflickr.com/5053/5...bbf7f47fef.jpg

kraftwerk 03-26-13 09:45 PM

Quote:

Originally Posted by BassNotBass (Post 15402197)
The only alternative that I know of is buying Phil Wood stainless steel cups (1.370 x 26 tpi, RH/LH thread) and fitting a cartridge BB... certainly not cheap but no special machining/tapping involved.


that's what I did, & used an UN 72 bottom bracket..

Forrest seems like a great build! Loved reading about it.

fietsbob 03-27-13 12:22 AM

IGH fan a sturmey 8 speed is best suited to small wheels. 19/21/25t cog ..

The Recent Bromptons use a Plastic thread BB they may fake their way through the thread pitch mismatch.


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