swap 5 speed freewheel for 7 speed - possible?

Alan Paterson said:

Forgive what's doubtless a real duh question, but can I remove
the 5 speed freewheel block from my old Dawes Warwick ('70s
vintage) and replace it with a modern 7 speed, like the ones on
ebay? I recognise that even if I can I'll need to adjust the derailleurs
- but is it basically possible...or impossible, or possible but you'll
need a new chain or......?

It's possible, but rather more involved than just changing the block.

The hub thread is standard, so a 7-speed freewheel will fit.

The first problem is that it will overhang the end of your axle, requiring
you to add spacers to the axle between the drive side cone and locknut, and
shift everything leftward on the axle in order to have enough axle
protruding at either end to support the wheel in the dropouts.

You'll then need to re-dish the wheel to centre the rim between the
locknuts.

You'll then find that your hub is too wide for the frame. You can either
spring the frame and pop the wheel in, or cold set (bend) the rear triangle
to accommodate the broader hub.

When that's done, you'll need a new chain.

James Thomson

James Thomson said:

Alan Paterson said:

Forgive what's doubtless a real duh question, but can I remove
the 5 speed freewheel block from my old Dawes Warwick ('70s
vintage) and replace it with a modern 7 speed, like the ones on
ebay? I recognise that even if I can I'll need to adjust the
derailleurs - but is it basically possible...or impossible, or
possible but you'll need a new chain or......?

It's possible, but rather more involved than just changing the block.

The hub thread is standard, so a 7-speed freewheel will fit.

The first problem is that it will overhang the end of your axle,
requiring you to add spacers to the axle between the drive side cone
and locknut, and shift everything leftward on the axle in order to
have enough axle protruding at either end to support the wheel in the
dropouts.

You'll then need to re-dish the wheel to centre the rim between the
locknuts.

You'll then find that your hub is too wide for the frame. You can
either spring the frame and pop the wheel in, or cold set (bend) the
rear triangle to accommodate the broader hub.

When that's done, you'll need a new chain.

Yes to the chain business, but when I put a 7 speed block onto my 126 mm OLN
rear wheel, I just put a 1mm thick washer each side of the axle, which
spread the dropouts far enough to give clearance. No need for redishing.

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
World Domination?
Just find a world that's into that kind of thing, then chain to the
floor and walk up and down on it in high heels. (Mr. Sunshine)

James Thomson said:

You'll then find that your hub is too wide for the frame. You can either
spring the frame and pop the wheel in, or cold set (bend) the rear triangle
to accommodate the broader hub.

The method I use to spring the frame which gives accuracy and control
over the brute force methods is now up at
http://www.cycling.raven-family.com/Cold%20Setting%20Rear%20Triangle.html

(Sorry about the image file sizes; Nvu doesn't resize the image file
when you resize the image and I haven't got round to doing it manually)

Tony

Dave Larrington said:

Yes to the chain business, but when I put a 7 speed block onto my
126 mm OLN rear wheel, I just put a 1mm thick washer each side
of the axle, which spread the dropouts far enough to give clearance.
No need for redishing.

Alan's Dawes is almost certainly 120mm oln.

James Thomson

"Tony Raven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

James Thomson said:

You'll then find that your hub is too wide for the frame. You can either
spring the frame and pop the wheel in, or cold set (bend) the rear

triangle

Quoted message said:

Quoted message said:

to accommodate the broader hub.

The method I use to spring the frame which gives accuracy and control
over the brute force methods is now up at
http://www.cycling.raven-family.com/Cold%20Setting%20Rear%20Triangle.html

That's better than just pulling on them, but there's no way of ensuring that
the spread is the same (from the centre-line) on both sides. You are hoping
that the two sides bend equally, and given the manufacturing techniques and
tolerances it is improbable.

The minimum tool to do this the correct way is a pair of large bars with
blocks drilled sized to fit the head-tube and seat-tube, both to fit between
the bars, and a spreader mechanism at the end of the bars. The blocks and
spreader should be mounted on pins, with a hole for the seat-tube block, and
slots for the head-tube block and spreader. If you wish to get really fancy
you can arrange independant screws for each side of the spreader; and make
the right side go out farther - the recent fad of more than 5 cogs would
suggest that as a useful modification to frame design.

Ah well, so much for that idea! Many thanks for replying.
"James Thomson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Alan Paterson said:

Forgive what's doubtless a real duh question, but can I remove
the 5 speed freewheel block from my old Dawes Warwick ('70s
vintage) and replace it with a modern 7 speed, like the ones on
ebay? I recognise that even if I can I'll need to adjust the derailleurs
- but is it basically possible...or impossible, or possible but you'll
need a new chain or......?

It's possible, but rather more involved than just changing the block.

The hub thread is standard, so a 7-speed freewheel will fit.

The first problem is that it will overhang the end of your axle, requiring
you to add spacers to the axle between the drive side cone and locknut,

and

Quoted message said:

shift everything leftward on the axle in order to have enough axle
protruding at either end to support the wheel in the dropouts.

You'll then need to re-dish the wheel to centre the rim between the
locknuts.

You'll then find that your hub is too wide for the frame. You can either
spring the frame and pop the wheel in, or cold set (bend) the rear

triangle

Quoted message said:

to accommodate the broader hub.

When that's done, you'll need a new chain.

James Thomson

jtaylor said:

That's better than just pulling on them, but there's no way of ensuring that
the spread is the same (from the centre-line) on both sides. You are hoping
that the two sides bend equally, and given the manufacturing techniques and
tolerances it is improbable.

The minimum tool to do this the correct way is a pair of large bars with
blocks drilled sized to fit the head-tube and seat-tube, both to fit between
the bars, and a spreader mechanism at the end of the bars. The blocks and
spreader should be mounted on pins, with a hole for the seat-tube block, and
slots for the head-tube block and spreader. If you wish to get really fancy
you can arrange independant screws for each side of the spreader; and make
the right side go out farther - the recent fad of more than 5 cogs would
suggest that as a useful modification to frame design.

Yes you can do that and really you need a frame measuring jig as well to
do it properly. But either way your proposal is complex, expensive and
most people will not go to those lengths. OTOH the technique I use is
cheap, easily sourced and IME the tolerances are such that it does end
up bending equally and accurate within a mm which manual brute force
does not achieve, while being pretty effortless to do. YMMV

Tony

James Thomson said:

It's possible, but rather more involved than just changing the block.

The hub thread is standard, so a 7-speed freewheel will fit.

The first problem is that it will overhang the end of your axle, requiring
you to add spacers to the axle between the drive side cone and locknut, and
shift everything leftward on the axle in order to have enough axle
protruding at either end to support the wheel in the dropouts.

You'll then need to re-dish the wheel to centre the rim between the
locknuts.

You'll then find that your hub is too wide for the frame. You can either
spring the frame and pop the wheel in, or cold set (bend) the rear triangle
to accommodate the broader hub.

When that's done, you'll need a new chain.

You may also need a new longer axle. They're quite cheap and a standard
size, though.

Thanks for all responses..certainly enough to put me off pursuing the idea.
I'll just keep my eyes out for the right 5-speed block.
"Zog The Undeniable" <[email hidden]> wrote in message
news:41f931eb.0@entanet...

Quoted message said:

James Thomson said:

It's possible, but rather more involved than just changing the block.

The hub thread is standard, so a 7-speed freewheel will fit.

The first problem is that it will overhang the end of your axle,

requiring

Quoted message said:

Quoted message said:

you to add spacers to the axle between the drive side cone and locknut,

and

Quoted message said:

Quoted message said:

shift everything leftward on the axle in order to have enough axle
protruding at either end to support the wheel in the dropouts.

You'll then need to re-dish the wheel to centre the rim between the
locknuts.

You'll then find that your hub is too wide for the frame. You can either
spring the frame and pop the wheel in, or cold set (bend) the rear

triangle

Quoted message said:

Quoted message said:

to accommodate the broader hub.

When that's done, you'll need a new chain.

You may also need a new longer axle. They're quite cheap and a standard
size, though.