Raleigh 20 Insanity

wrote:
It's a replacement fork for a Sun "EZ Sport CX" or "EZ Sport AX"
recumbent. These are recumbents sold by J&B Importers, one of the
US's
biggest bike industry wholesalers. Virtually all shops have an
account
with them and can get this part. It's not in the catalog and I had to
call down to the Florida location and get it shipped from there.

Yeah, this fork might not work. The EZ-Sport has a pretty shallow head
angle, and the offset (rake) may be correspondingly large. On a more
upright head angle, it might result in too little trail. The EZ's tend
to have minimal offset (rake), though... so it might work.

A while back, I bought a couple forks from a builder in Seattle that
were designed for folders or recumbents. They were designed for 20"
wheels, and came with 15" long, 1" threadless steerer tubes. They were
built by Bicycle Specialties in Seattle:
http://www.sandsmachine.com/bp_bspec.htm

Jeff

In message . com,
" writes
A friend and I are doing a full scale conversion of a Raleigh 20. For
the bottom bracket, we're doing the Raleigh-threaded Phil cups & UN72
thing. However, we've run into a problem: the cups can't thread in far
enough to engage the UN72 cartridge fully. They run into the ends of
the chainstays inside the BB shell,

Martyn Aldis wrote:
I don't think so as the stays are flattened and MIG/MAG welded to the
outside of the shell. It could be the weld you have hit or

(bn) and beyond that they may be out of
thread (the bike is not currently in front of me, otherwise I'd
measure).

(ma) maybe more likely especially if you have got the wrong
width -

(bn) Anyone know if there have there been different
outside widths of
Shimano BB cartridges that don't have the threaded part integrated with
the bearing part? Any advice?

(ma) What length of shell was the UN72 made for? It should
be the one
intended for a 73mm shell I think. These are made for the older mountain
bikes that had extra wide shells. See
http://www.sjscycles.com/store/cat21.htm
just over half way down listed as:
Shimano UN72/3 73mm shell Sealed B/B
I have never done the above conversion preferring the option of using
the existing cups, a Japanese spindle and 6mm balls. I think Sheldon's
site says what English size to use if you can't get metric balls easily.
(1/4" will not do). You have to take a couple of mm off the non-drive
side of the shell to get the lock ring on. This option is cheap, and
easy and less risky than trying to cut threads (should you really need
to do that for the UN72). However, my way does not give you a sealed
bottom bracket if that matters.
Other points about R20 conversion.
I suggest you either take off the very top bit of the head tube with the
slot in it or put a reinforcing ring around and then, in either case,
reface and ream out for your headset. I did not do any of these things
on one of mine and split the head tube at the corner of the slot.

Concerning the fork with canti bosses, I think the 406mm BMX wheel
should only be used with fairly fat ty(i)res unless you go for very
short cranks. For a skinny (28mm) or medium (37mm) tyres the 451mm rim
works far better as you get a decent bottom bracket height and if you
don't want to braze on bosses at the correct height, front and rear, or
are going for drop bars you can use a longish but effective double pivot
brake like the Alhonga 714. I've found these work very well with reverse
levers specifically the Tektro RX4.1.

The later 20s sold in the UK had a reasonable taper fork with a proper
end to take a mudguard (fender) stay. I have got over the 26 tpi thread
problem on the fork by using an ahead set upper bearing held down and
adjusted by the original nut and lock nut over a couple of spacers. A
conventional quill stem or internal expander type stem extender can then
be used (not an ahead stem or clamp-over extender). I'm not sure if any
of these late type forks made it to North America.

Velocity do nice narrow 451mm rims to suit 28mm tyres and Sun do CR18s
still I think. For tyres there are now Schwalbe Stelvios in 28 - 451 as
well as IRC Roadlites but for a bit smoother ride I prefer Comets in 35
- 451. Of course supply of either (or most likely all) could dry up at
any moment and then those of us with a considerable investment in 451s
will be unhappy. I hope the Bike Friday 451 market is large enough to
keep the tyre manufacturers interested.

I don't think I would venture out around here on Sheldon's skinny tyre
fixed wheel as shown on his Twenty page unless the new fork (not shown
in the picture) has lifted it up a good bit. We have so many odd slopes
where roads join that pedal grounding would be certain.

Well done overall!

Raleigh cups and indeed standard bicycle bearing parts in
general are designed for 1/4" balls.

I'm curious - in UK are 6mm balls as common as 1/4"? Even
inside metric cartridges the actual balls are inch
dimensioned here and in Japanese bearing cartridges. Anyone
know about EU in that regard?

I also wondered about his diagnosis of the chainstays
hitting the cups. Twenties can have a steep lip at the end
of a shallow thread. That would as you note be better
addressed with a longer cartridge.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi wrote:
Unpiloted taps are what
you'll find in 1.370 x 26tpi at most bike shops.)

Chalo wrote:
I have worked in a few bike shops, and I have been welcome at the
workbenches of a handful of others. I have never wrenched in a shop
that kept Raleigh-specific thread cutting tools.

I imagine that the shops in possession of such esoteric tools are
mostly those that were fully equipped 30 or more years ago. Most bike
shops in business today were established long after Raleigh's oddball
26tpi threads had met a long-overdue and richly-deserved fate.

You're right, I'm out of date as Sheldon also observed. 30
years ago nearly every Raleigh dealer had 'em.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

In message , A Muzi
writes
Well done overall!
Thanks for that. I hope the OP comes back with how they get on with the
UN72 / Phil Wood rings method as this information could be useful for
R20 and Moulton Mk3 although I don't know that UN72s are readily
available.
I'm curious - in UK are 6mm balls as common as 1/4"? Even inside metric
cartridges the actual balls are inch dimensioned here and in Japanese
bearing cartridges. Anyone know about EU in that regard?

Engineering suppliers in the UK have no trouble getting metric sizes and
the reason I used 6mm was it came to mind as a small step down from 1/4"
and our local supplier could get them next day.

I've not tried to get 64th interval inch (15/64" is suggested on
Sheldon's page about fitting cotterless spindles to Raleigh cups:
http://sheldonbrown.com/raleigh26.html ) but 16th interval have been no
problem from the same suppliers.

Although the spindles I have are Japanese they do not work with the
Raleigh cups I have and 1/4" balls.

The fact I got metric ball bearings next day must mean they are in
general use outside the bicycle world.
--

Martyn Aldis, e-mail
================================================== ============================

"Martyn Aldis" wrote in message
...
In message , A Muzi
writes
Well done overall!
Thanks for that. I hope the OP comes back with how they get on with the
UN72 / Phil Wood rings method as this information could be useful for
R20 and Moulton Mk3 although I don't know that UN72s are readily
available.


I have good results with Phil Wood cups and a 73x113 mm UN72 Bottom Bracket on
my Raleigh 20. The cups may have cut some new threads on the way in, it took
some force to get them in all the way, but they clamp the bottom bracket well
enough to keep it locked in and quiet.

The bike is shown he http://cheg01.home.comcast.net/r20.html

The first picture shows the flatland version with a 7 speed 451 rear wheel,
Primo Comet 406 front, and bullhorn bars and a stem shifter
..
The second picture is the hills version with a Sachs Dual Drive 3x7 Hub, Maxxis
Hookworm 406 front, and Bike Friday split mountain bars with barends and grip
shifters.

UN72 bottom brackets are not made any more but they still turn up on ebay and in
mailorder catalogs from time to time. I have a spare waiting for mine to wear
out (unless I get another R20 frame first...). The Phil Wood rings are
exorbitantly expensive, but they work. It used to bother me that the rings cost
more than the complete bike I started with, but I'm satisfied with the outcome
after the first 1000 miles.