JoelF

Hi! I am Joel and for the moment I based in Malawi, Africa as a volunteer. But I am born and raised in Sweden and going back in January. A few weeks ago I bought lugs in a local bicycle store just because they were so cheap. Around 7$ for a complete set.

The problem is that the bikes sold here are the kind that would be called vintage/retro in western countrys. Copys of old Raleighs. So I wonder if anyone ever tried to put a british BB in a Raleigh shell? Sheldon says it will bind after a few threads are engaged. But before I ruin a fine BB I'd like to hear some other results.

cycle_maven

I've done it, but I filed and ground off all of the threads but the outer 3 rows on the British BB. The three rows hold the BB in the Raleigh shell just fine- if the Raleigh 26 TPI shell were re-tapped to the British 24 TPI, then there would be only 3 rows of threads left anyway- better to ruin a BB than a BB shell...


(courtesy RHM)

Hilarystone

Its very easy to retap a Raleigh 26tpi shell to 24tpi - the tap does not simply cut the metal away it squeezes the 26tpi threads into the 24tpi so you are left with a perfectly good thread. I have done this job many times and have never had any troubles. You then need to reduce the shell width by 1mm each side as the Raleigh shell is 70 rather 68mm wide - this is best done with a BB facing tool but can be done with a broad flat file witrh care.

garage sale GT

If the bike in question is a local copy of a roadster, it is possible the bottom bracket is 76mm wide.

wrk101

I tried it, and similar to Sheldon, it only went in a couple of threads before stopping. I ended up refurbing the original BB instead.

Roll-Monroe-Co

Good luck finding the tap in Malawi.

3alarmer 

This seems contrary to every machining practice
I have ever learned, but if it really works, would
in many instances here in Sacramento, California
prove to be a significant benefit in the sort of
work I do in the local Bike Coop.

However, I remain a little dubious (forgive me
please) and would appreciate it if you would
take a moment to answer a couple of questions.

How many times is "many times" (roughly)?

While I am sure that is fairly easy to run
the 24tpi tap through the BB, I am less
confident that:

My concern is that I will send these souls
out into the world with BB's that will be
a continuing source of misery and aggravation
because they will not remain in adjustment.

So when you say you have never had any
troubles, what exactly does that mean?

Have you done this on a number of your own
bicycles and ridden them significant miles
and had no problems? Have you done this
in a professional capacity and are living
in a local enough environment that you
would be aware of any problems experienced
by your clients?

Again, the questions are not meant as a
challenge or in any way to impugn your
mechanical abilities or standards. It just
really does appear too good to be true.

I shall have to try it as an experiment on
a junker, but certainly I have access to
both taps and facers for BB's (and Loctite
in several formulations.)

Thanks and regards,
Michael Larmer

JoelF

Some intresting and good answers so far.

@ Roll-Monroe-Co: I don't think I will even try. Might do it when I come home.

@ garage sale GT: It's 75mm wide, roughly, I only have a plastic ruler to measure with. But i think I will cut it down when home again...

Hopefully I will get a good result so I can post a thread of it later

bbattle

Bike mechanic re-tapped an old Sprite and we installed a Shimano BB with no trouble. Take it slow, and use lots of Tap Magic.

Anyone tried one of these threadless BB? https://store.velo-orange.com/index.p...-brackets.html

Mr IGH

I did it exactly one time one my own bike (a Raleigh Record) worked fine for several years until I sold the bike. Tapped several 26TPI Raleighs to 24TPI at the LBS, never had a return or complaint.

"worked fine" = stayed in adjustment and worked trouble free including salty Chicago winters

In later years when I didn't have access to taps, I used the old cups and a old fashion Sugino 3T nutted spindle. It's one of those recipes that works. Loose balls, widest spacing, allows standard tapered cranks on an old Raleigh without tapping.

Wogster

Just because a bike is a copy of an old Raleigh doesn't mean that the shell is Raleigh threaded. Just like a copy of a French bike may not be French threaded and a copy of an Italian bike may not be Italian threaded. Now if you have a set of lugs the shell is most likely a little over 70mm wide and has no threads cut, it can be faced to either 70mm or 68mm and the threads cut.

One way to repair an old Raleigh is to remember that an English BB is a hair under 35mm across, and Italian BB is 36mm across, and English Raleigh shell is 76mm wide, so a permanent solution is to grind 2.5mm off either side, then face it to 70mm and chase it with an Italian thread die, and fit an Italian threaded BB in it. Phil Wood makes a Raleigh threaded BB, but the %$%# BB will be the most expensive part of the bicycle.....

cycle_maven

I did have to cut the shell width down to 73 mm (mountain bike standard) from 76 mm, though. I did it with care and a flat file, checking squareness a lot. The cartridge bottom bracket has held up well so far- maybe 1000 miles. The whole process was considerably cheaper than re-tapping the shell- cost a $10 BB and some time with a file and a grinder.

rhm

There are many threads in the Folding Bikes forum devoted to hotrodded Raleigh Twenties. One of the chief concerns is what to do about the BB, and one of the favorite fixes is to tap it English. I'm not about to do my homework on this, but my recollection is that for every ten posts that say "I did it, and it worked great!" there's one that said "I had my LBS do it to mine, and they screwed up the job!" or some such thing.

I believe Raleigh cut the threads only as far as they were needed; so if you cut your BB shell down by 2 mm, you will get 2 mm of shell that have no thread in them at all; so when you tap it, this area will get perfectly good new threads.

After running the tap through once, with a lot of oil, cutting some metal away and pushing a lot into a new position, I suspect it would be good idea to clean it thoroughly and apply some JBweld to the new threads, then running the tap through again.