Oink

Managed to take off the cotter-pinned cranks of my Raleigh Twenty, not before ruining the thread on one of the pins and completely destroyed the other one with saw/hammer/drill. I had every intention to run the original parts to the ground but I now I want to get rid of cotter pins.

For months, I read with interest pretty much every article on the subject and scouting ebay for possible parts, and then I stumbled upon a forgotten set of SKF cartidge BB from my Moulton FX8. It is English (1.37 x 24 tpi) has 116mm axle length and detachable two plastic sleeves.

I recall Vince and his *** story (https://www.bikeforums.net/folding-bikes/123152-raleigh-twenty-s.html) where he mentioned, "...you just screw them in and as the TPi is not so very different (26 and 24) it goes in quite easily, towards the end the going gets a bit tougher but that's it..." I am just about to do that and wonder if anyone care to give any last minute info/warning/tip I should be aware of before I do this. The only shortcoming is the possibility of ruining the pastic sleeves, then I will pay the $50 to get the proper 26tpi lock ring. I assume they would work with the SKF.

A single Stronglight chainring and cranks, again, from the Moulton will replace the original... I hope to run the other parts of the Twenty unmodified for the time being.

Thanks

alecw35

lock ring? On a cartridge bb....should just be just 2 cups and the cartridge.
unless its got lockrings so you can move the cranks across for a better chain line.

I always recomend modding the frame to take standard inexpensive parts.
I modded my 20, Grifter and old Raleigh Cruiser at home with normal tools for no cost

LittlePixel

So how does one convert from 24 to 25tpi with home tools? I'd really like to go this route but the cost of a tap and die set is as much if not more than getting a pair of phil wood rings...
Interested in some tips here in London!

Oink

My terminology was wrong. I meant "cups" when I said "sleeves". Sorry. Also, isn't 25tpi as much a standard as 26tpi?

phatatude

If I remember right Alec used a hardened steel 24tpi cup to mod his BB. He said it took a while (threading it in, and then backing it out. Taking it further in each time.) My flippin 20's are a bit too rare (In the middle of the U.S.) to try this method, but in theory it should work, heck, he did it.

If you are lookin for other options, there is the Pristine line of BB. There are two with plastic cups, and one is pretty slick, it is for if you have cross threaded you bb. The way it works is it has plastic cups with NO threads, so its threads are cut as it goes in. Im thinking about one of these on the next R-20 I do. I just dont know if I am going to have to buy a special bb tool for them...

R-20's : Sometimes ya just gotta wing it!

check the progress, and post
https://web.mac.com/phatatude/Green_S...enty_Blog.html

alecw35

yeah just took bb cups out of a modern bike and gently but firmly screwed them in a bit ...then out.
every thing must be clean.
oil all the parts.
clean them
then oil some more.

I work at a bike shop thats got the bb cutting tool.
think its by Park or Var...got light blue handles so likely to be Var...
so I do my frames there.

If I was to fit a bb at work i would likely run the tap through.
be £10 or so to fit the bb.
cant see why other shops cant do that.
alloy frames ussually need cleaned up.
so the shops should have the tool.

also got the proper tool to take bb cups out.
but ussually tap them out with a small chissel

LittlePixel

Sorry - that was a typo. I meant 24 to 26...

LittlePixel

I wonder if one was to dremel in some vertical grooves around this old BB cup one might get more of a 'tapping' effect as the removed swarth would have somewhere to go? Just thinking out loud here!

Is working at an LBS as fun as it appears?

You should advertise the service for the rabid twentynauts!

alecw35

Oh not seen many 20s about here.
The shop sells a Dahon. It looks ok. Strange rear mech on it.

Yeah you could slot the BB cup.
I Just screw them in a bit...then take them out and clean the cup and BB shell off.
I have done forks as well. Either to take modern headsets. Or to miss out the handle bar clamp.

One man come in and said that he'd got a shopper bike from a skip..er dumpster.
He was wanting to sell it...or part ex it for a new bike. But it was a curved tube frame...not a 20.

Can be fun in a bike shop. Just a job most of the time.
And you get all the small kids ringing all the bike bells...can get annoying.

Oink

Talking about standards. Should one worry about the shell width of the twenty. The PhilWood cups look like they can be screwed right into the shell. With the wider shell and a standard sized BB, I am a bit concern about the BB moving loose laterally. Am I worrying too much? It would be a good time to trim the shell!

I wonder how many Twenty's are being worked on right now. I came across mine last September quite by chance, going cheap. I haven't even ridden it due to a broken pedal. Thought it would be a good compliment to the Moulton FX8 I ride daily. Now I realised that all the Twenty parts are non standard, down to the 451mm wheels instead of the 406mm I have a few lyring around.

LittlePixel, the typo never crossed my mind. I seriously was thinking "Not another standard!"

alecw35

Good thing is that the 20 takes normal 9/16th inch pedals.
So you can fit most pedals to it.

Sammyboy

The Phil Wood cups do indeed screw right in, holding the cartridge in place with no play. Not only that, but they allow you to hack the chainline a bit, cos you can move the whole cartridge within the BB shell.

phatatude

Im not sure whether the *** or the Pristine use a fastening tool that grabs on their insides or around their outer edges, but if i is on the inner edge, you can grind off the outer edge that stops it from continuing into the BB shell. If you did that you would essentually have an adjustable set up like the Phil Wood option(allowing you to adjust your chainline). (Im not sure this clear to anyone but me )... At this point the only concern would be the length of the axle. You'd have to make sure it would clear the R-20's BB shell...

R-20's - If it was easy, everyone would have one...

Come check the progress...
https://web.mac.com/phatatude/Green_S...enty_Blog.html

sahadev

Phatatude,

I tried that on the UN-72 BB I put in my R20. For whatever reason it seemed to make no difference. The fixed cup screwed in to the spot where it would have stopped with the retaining ridge intact and went no further. I had cleaned the threads on the cup and inside the BB shell several times, but it wouldn't budge any further. There appeared to be plenty of extra threads inside the BB shell, although I couldn't see clearly enough to tell how usable they were. Luckily the chainline came out fine by moving the chainring to the other side of the crank spider.

phatatude

Maybe its also a function of how wide the cups are to then? I did the Phil Wood conversion, and the cups where more narrow than the UN7's cups. That might be an advantage of trying this with a plastic cup. It may tend to keep going, especially if your treads arent the cleanest further into your shell...

So you had your BB shell rethreaded sahadev? What width UN73 did you use? And what are you running in the rear? (gears?internal?hub width?) Im just asking because I used a UN72 that is 113mm wide, and it seems to be perfect for a single speed on a 115mm wide hub flipflop. But I cant see using the 113 UN72 for any hubs that are wider than 115mm. You wouldnt be able to move the chainline far enough over without your cranks making contact with the BB shell.

R-20's - The thinkin' man's bike... and woman

Come check the progress...
https://web.mac.com/phatatude/Green_S...enty_Blog.html

Sammyboy

If sahadev used a UN72, then he had to have Phil Wood rings too, unless there are some mysterious 26TPI UN72s out there that we don't know about...

Oink

The Phil Wood 26dpi cups are sounding more and more interesting. But I am going to try jamming/force screwing in the 24tpi plastic cups first. I have to take the bike to a shop soon. I have had no luck taking the fixed cup (drive side) off the frame. Don't have that 16mm (5/8in) open wrench. It is also left-hand thread. right?

phatatude, no, I can't cut off the lip to make the cups go inside the shell. The fastening notches are on the lips.

phatatude

Good catch Sammyboy...

My bad... I missunderstood you Sahadev... I thought you were saying you used the method of grinding off the edge of a UN73 or some other cartriage.
I am able to move my setup right and left... hmmm

Still curious what the width of your UN72 was, and what the width is at your rear (of your bike )
Im thinking a 115 would be a primo size axle for most apps.


R-20's - Step 1: Unfold, Step 2: Pedal Step 3: Smile...

Come check the progress...
https://web.mac.com/phatatude/Green_S...enty_Blog.html

LittlePixel

I put the whole frame in a vice and rotated it - you get very good leverage if you're using the frame as the spanner and it pops off in no time.

Also - it's worth noting a Phil Wood Cartridge will fit nicely in there if money is no object; Sizes are plentiful: See here:

https://www.philwood.com/SpecStainlessBB.htm

Oink

Thanks for that tip. Will definitely try it before I lug along half a Twenty in my bike trailer in sub zero temperature, dodging broken glass and what-have-you that have just begun to surface on the road after 5 months in snow! It is not decent cycling season yet.

The problem is that expensive Phil Wood, with expensive shipping, customs clearance fee, uncertain customs, taxes etc etc, can become a traumatic experience both financially and mentally, eventhough we are in the same free trade zone with Harris Cyclery!

jur

Ever wonder why Phil Wood make cups with 26tpi? Is it just for us in the unlunatic fringe?

sahadev

To the best of my recollection, I used a 68x113 UN-72. I cold set the rear dropout to 125mm to accept a SA8 hub. The BB was used from eBay. As it turns out the cups did not match. The drive side was 26TPI and screwed in just fine. The adjustable side turned out to be 24TPI(measured by a machinist). No wonder I couldn't get it to go all the way in!! The machinist recut the threads on the cup, and not the BB shell, starting in the middle of the threads and working out to the edges. After that it screwed in just fine and feels very solid.

The chainline, thank God, basically resolved itself. I am running an inexpensive triple crank that allowed me to move the large chainring to the position of the middle chainring, and removing the smallest ring. With this setup the alignment is within a mm or two of being perfect. I haven't measured to verify this - I'm eyeballing it.

***

I just re- read some of the posts above re the UN-72. All this time I have been working under the assumption that UN-72 threading was 26TPI. I went back to SB's pages and lo and behold, they aren't!! I read the information incorrectly(or incompletely). It is amazing how we get an idea in our head, right or wrong, and it assumes a life of its own. So why on earth did the drive side cup screw in easily? If it really is 24TPI, that would explain why it stopped and would not go further in.

Good Lord...I feel foolish and relieved, all at the same time!

Sammyboy

I think that misconception comes from the fact that people are so keen to get them for R20 restorations. In fact, their only advantage is the fact that having no "fixed cup" means that with the right cups, they can fit in a shell that's wider than they are.

Jur - I think it is just for us. They're in the business of making small runs of things, so it probably doesn't hurt them to make a run of 26 tpi cups now and then. I know of no other use for them than old Raleighs, which probably assumes Phil BBs get bought for bikes which would never normally use them!

bryano

I also read everything about how to deal with 26tpi BB for my 20 upgrade. Since I was going fixed-gear, I didn't trust the cross-threading plastic cups option. Phil options seemed pretty pricey, so I was lucky to find a BB spindle that worked with original 26tpi cups--a square tapered one stamped TA37. I don't know what brand bike it orig came from, or when, so not sure what luck you'll have finding one. Note that it had to go in backwards and there's a cm gap btwn non-drive-side crank and cup.

bryano

MISTYPED-- "TA37" should be TA374