Raleigh Twenty Bottom Bracket Shell

I have a Raleigh Twenty that I haven't ridden for the past three years
because it needed bottom bracket attention.

Newly motivated, I attacked the cotters today with a drill and managed
to get the cranks and most of the bottom bracket out. I reckon some
penetrating oil will get me past the right-side cup hurdle.

I'm going to be switching to a cotterless setup. I would like to take
the bottom bracket from 76mm down to 68mm, as I reason that:

1. I'll be able to cut more BSC threads into virgin shell if I go down
that small.

2. If the threading doesn't work out I can always use a YST threadless
bottom bracket. They appear to only be available in 68mm.

Has anyone taken a Twenty bottom bracket down that far, or is 73 the
limit?

---
Lars Lehtonen
Los Angeles, CA
swap.bikeboom.com

Has anyone taken a Twenty bottom bracket down that far, or is 73 the
limit?

---
Lars Lehtonen

Many, many years ago I used a Raliegh Twenty BB shell for a recumbent
project. After filing it down to 68mm width and retapping it for
"standard" English threads, it worked fine.

I think you'll be OK- you might want to saw off a slice off of each
side, then mill the sides after tapping.

Jeff

"Lars Lehtonen" wrote in message
...

I reckon some
penetrating oil will get me past the right-side cup hurdle.


If that isn't enough, get a large grade 5 bolt that will just fit through
the axle hole, and a nut to match. Put the bolt through from the inside,
screw the nut down tight on the outside, then crank on the nut. The tighter
the net gets the more grip it will have on the cup (I'm assuming it has LH
threads - if not, a buffing wheel mandrel for use in hand-held drills has
left-hand threads and is about the correct size).