New 7-speed cassette to replace old 6-speed on shimano 105 hub?

Hi

I've bought a ten year old Mercian audax bike and I'm off touring in the
Alps soon. The current gears are not ideal for loaded touring in the
mountains, so I'd like to change the cassette and the chainrings (42/52 -
38/48).

Currently I have a ~10 year old shimano 105 hub with a 6-speed cassette
(I think 14-24 teeth). The rear axle appears to be 137mm.

I'm wondering if anyone knows if a new shimano 7-speed cassette is likely
to fit on this hub without changing anything.

Thanks
Rob

Rob Shields wrote:
Hi

I've bought a ten year old Mercian audax bike and I'm off touring in the
Alps soon. The current gears are not ideal for loaded touring in the
mountains, so I'd like to change the cassette and the chainrings (42/52 -
38/48).

Currently I have a ~10 year old shimano 105 hub with a 6-speed cassette
(I think 14-24 teeth). The rear axle appears to be 137mm.

I'm wondering if anyone knows if a new shimano 7-speed cassette is likely
to fit on this hub without changing anything.

Thanks
Rob

Is the cassette held on by a lockring or held on by screwing on the
smallest cog?(I'm guessing it's uniglide)
If the later, short answer is no but you can probably retrofit a HG
freehub to the hub that will accept a 7s cassette.

On Thu, 30 Jun 2005 05:59:11 -0700, Qui si parla Campagnolo wrote:

Is the cassette held on by a lockring or held on by screwing on the
smallest cog?(I'm guessing it's uniglide)
If the later, short answer is no but you can probably retrofit a HG
freehub to the hub that will accept a 7s cassette.

It's a regina extra-BX cassette like this one:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7163863498

It has a freewheel built in and simply screws on to the hub.
Is it still possible to retrofit a free hub ?

Cheers
Rob

Rob Shields wrote:
On Thu, 30 Jun 2005 05:59:11 -0700, Qui si parla Campagnolo wrote:

Is the cassette held on by a lockring or held on by screwing on the
smallest cog?(I'm guessing it's uniglide)
If the later, short answer is no but you can probably retrofit a HG
freehub to the hub that will accept a 7s cassette.

It's a regina extra-BX cassette like this one:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7163863498

It has a freewheel built in and simply screws on to the hub.
Is it still possible to retrofit a free hub ?

Cheers
Rob

It's a freewheel, not a cassette. It is freewheel only and with spacer
swapping left to right followed by a wheel red0sh, you can screw on a
7s freewheel. BUT there are 6s freewheels out there that have a wide
range of gearing, Like 14-28.

On Thu, 30 Jun 2005 06:42:29 -0700, Qui si parla Campagnolo wrote:

It's a freewheel, not a cassette. It is freewheel only and with spacer
swapping left to right followed by a wheel red0sh, you can screw on a
7s freewheel. BUT there are 6s freewheels out there that have a wide
range of gearing, Like 14-28.

You're quite right, it's a freewheel. I was confused.

I've found a
nice looking 6-speed freewheel that should work:
http://www.wiggle.co.uk/Default.aspx...D=530000 6534

That will save me re-dishing the wheel

Thanks for your help
Rob

I've found a nice looking 6-speed freewheel that should work ...
That will save me re-dishing the wheel

I changed my 6 speed freewheel to a 7 speed freewheel without
redishing. I could have used the old shifters in friction mode but
decided to spend the $30 to get indexing. It was a very simple change
and the extra gear is appreciated. With a new rear derailler ($25-$30)
you could get some pretty low gears too (but I didn't go this route.)

see: http://sheldonbrown.com/k7.html
and http://sheldonbrown.com/harris/freewheels.html#7

Joe LoBuglio Wrote:
I've found a nice looking 6-speed freewheel that should work ...
That will save me re-dishing the wheel

I changed my 6 speed freewheel to a 7 speed freewheel without
redishing. I could have used the old shifters in friction mode but
decided to spend the $30 to get indexing. It was a very simple change
and the extra gear is appreciated. With a new rear derailler ($25-$30)
you could get some pretty low gears too (but I didn't go this route.)

see: http://sheldonbrown.com/k7.html
and http://sheldonbrown.com/harris/freewheels.html#7

The big-small sprocket distance is only a little over 3 mm more for a
vs. a 6 so re-dishing would not be imperitive, merely optimal

--
meb

On Thu, 30 Jun 2005 13:11:17 -0700, Joe LoBuglio wrote:

I changed my 6 speed freewheel to a 7 speed freewheel without
redishing. I could have used the old shifters in friction mode but
decided to spend the $30 to get indexing. It was a very simple change
and the extra gear is appreciated. With a new rear derailler ($25-$30)
you could get some pretty low gears too (but I didn't go this route.)

see: http://sheldonbrown.com/k7.html
and http://sheldonbrown.com/harris/freewheels.html#7

Is a 7-speed block wider than a 6-speed one? There isn't enough room for a
wider block without re-spacing the wheel to the left.

Rob Shields wrote:
Is a 7-speed block wider than a 6-speed one? There isn't enough room for a
wider block without re-spacing the wheel to the left.

meb Wrote:

The big-small sprocket distance is only a little over 3 mm
more for a 7 vs. a 6 so re-dishing would not be imperitive,
merely optimal.

Sheldon's site says about 7 speed freewheels: "These will generally
work on hubs made for 6-speed freewheels, sometimes with the addition
of a washer or two."

If you don't need the washer and don't use a washer than your rim
location is unchanged so redishing would not be needed. The difference
would be that the chainline of your smallest cog is 3 mm outboard (I am
using meb's number here). The chainline of your largest cog would
remain unchanged.

If you didn't need the washer but used one anyway you'd probably want
to split the difference and move everything in by 1.5 mm. This would
keep your middle cog as it was. You could redish the wheel 1.5 mm or
just live with one that is 1.5 mm off.

It costs about $20 bucks to find out.

Joe

Rob Shields Wrote:
On Thu, 30 Jun 2005 13:11:17 -0700, Joe LoBuglio wrote:

I changed my 6 speed freewheel to a 7 speed freewheel without
redishing. I could have used the old shifters in friction mode but
decided to spend the $30 to get indexing. It was a very simpl
change
and the extra gear is appreciated. With a new rear deraille
($25-$30)
you could get some pretty low gears too (but I didn't go thi
route.)

see: http://sheldonbrown.com/k7.html
and http://sheldonbrown.com/harris/freewheels.html#7

Is a 7-speed block wider than a 6-speed one? There isn't enough roo
for a
wider block without re-spacing the wheel to the left.

Yes.

5.3 mm c-c between cogs vs. 5.0 mm c-c between cogs, you see
difference of 3.5 mm in the cassette. I believe the carrier siz
difference is less than 3.5 mm though. Both generally use the sam
droppout width.

For a freewheel, the 7 threads onto the six, but you may or may no
need fiddle with spacer and rder and dish

--
meb