27" to 700c

[Julian]

Hi

I'm thinking of swapping my 27" wheels for 700c size. At the same time I would want to fit new gears
with a triple chainring, as I need a few more low gears. Are all the currently available gears
indexed, or will I be able to continue using my downtube mounted levers? I currently have five-speed
gears, are all the modern offerings eight speed or more? Five would probably be enough, with a
triple. In case you're wondering, I'm pretty sure my current side pull brakes have enough drop and
my 531 frame will accommodate a 130mm oln as it's designed for 126mm and will easily spring the
extra 4mm. TIA (take the dots from bicycle-chien to reply)
--
Julian

[Peter Clinch]

Julian wrote:

> Are all the currently available gears indexed, or will I be able to continue using my downtube
> mounted levers?

Most stuff with a lever has a switch on the side which you can flip so the lever works on simple
friction rather than indexing: there's nothing particularly special about the derailleur that is
"indexed", this is controlled by the shifters themselves (or at least in the systems that I use,
including 9 speed mid-level swishness Shimano), so I wouldn't think that'll be a problem.

> five-speed gears, are all the modern offerings eight speed or more? Five would probably be enough,
> with a triple.

You *might* find a 6 if you hunt, if you can find a 5 it's probably made of cheese or Precambrian
(or both). The main problem may well be do you have enough lateral space for a current block without
excessively dishing the wheel.

Pete.
--
Peter Clinch University of Dundee Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net p.j.clinch@dundee.ac.uk
http://www.dundee.ac.uk/~pjclinch/

[Zog The Undenia]

Julian wrote:

> Hi
>
> I'm thinking of swapping my 27" wheels for 700c size. At the same time I would want to fit new
> gears with a triple chainring, as I need a few more low gears. Are all the currently available
> gears indexed, or will I be able to continue using my downtube mounted levers?

The indexing is in the levers [1], not the mech. So the answer is yes - provided they pull enough
cable to move the mech over its full range.

I currently have
> five-speed gears, are all the modern offerings eight speed or more?

5, 6 and 7 speed parts are all quite easily available. It's unlikely that even 7 speed cassettes
will become difficult to obtain in the near future - and the 9 speed Shimano mechs are all backwards
compatible.

Five
> would probably be enough, with a triple. In case you're wondering, I'm pretty sure my current side
> pull brakes have enough drop and my 531 frame will accommodate a 130mm oln as it's designed for
> 126mm and will easily spring the extra 4mm.

Don't do this. Cold set it once and for all, or have a frame builder do it for a very small fee.
Stretching the back end every time you fit a wheel can break it over time.

[1] very old subscribers may remember a primitive indexing system in the rear mech, which initially
made sense because cable elasticity was a major obstacle, but in practice this system didn't
work brilliantly. Pre-stretched cable inners and incompressible outers eventually made it
possible to put the indexing in the levers where it stays reasonably clag-free and gives a
positive feel. Oh yeah, and funky shaped HG sprockets with a floating top jockey wheel running
very close to them help a lot :-)

[Nc]

"Peter Clinch" <p.j.clinch@dundee.ac.uk> wrote in message
news:3FF0587A.9030902@dundee.ac.uk...
> Julian wrote:
>
> > Are all the currently available gears indexed, or will I be able to continue using my downtube
> > mounted levers?
>
> Most stuff with a lever has a switch on the side which you can flip so the lever works on simple
> friction rather than indexing: there's nothing particularly special about the derailleur that is
> "indexed", this is controlled by the shifters themselves (or at least in the systems that I use,
> including 9 speed mid-level swishness Shimano), so I wouldn't think that'll be a problem.

Highly unlikely to be a problem, if you like down-tube levers, you can use them.

You may find it advantageous to change the gear mechanisms at the same time. At which point you
might question whether this is a cheap upgrade and look at the price of a new machine in the sales.
(I've already decided that if the wheels on my cheap 27in bike become un-replaceable, it will be
better to get a new bike.)

> > five-speed gears, are all the modern offerings eight speed or more? Five would probably be
> > enough, with a triple.
>
> You *might* find a 6 if you hunt, if you can find a 5 it's probably made of cheese or Precambrian
> (or both).

Depleted uranium cheese, combining the weight of uranium with the strength of ripe brie.

> The main problem
may well be do you
> have enough lateral space for a current block without excessively dishing the wheel.

You might have enough space on the wheel for 7 speed block. My cheap bike started out with 5-speed
on the rear and how has 7 speed screw-on block. Frame is a 1970's 10-speed racer.

However, if fitting new wheels, the chances are anything will have a modern cassette system of hub
unless you search out a wheel builder who has a stock of decent screw-on hubs. That means 7 speed is
the effective minimum, and 8 or 9 are more common. Consult Sheldon Brown on possible combinations,
spacers, etc.. to allow unusual combinations.

Nigel

[Julian]

In message <bspt7n$e0e$1@news5.svr.pol.co.uk>, Zog The Undeniable <ggg@hhh.net> writes
>
>Five
>> would probably be enough, with a triple. In case you're wondering, I'm pretty sure my current
>> side pull brakes have enough drop and my 531 frame will accommodate a 130mm oln as it's designed
>> for 126mm and will easily spring the extra 4mm.
>
>Don't do this. Cold set it once and for all, or have a frame builder do it for a very small fee.
>Stretching the back end every time you fit a wheel can break it over time.
>
Wow, didn't know that! Thanks for the warning.
--
Julian

[Julian]

In message <bsps8v$6bgn$1@ID-100732.news.uni-berlin.de>, NC <ncliffe@talk21.com> writes
>
>You may find it advantageous to change the gear mechanisms at the same time. At which point you
>might question whether this is a cheap upgrade and look at the price of a new machine in the sales.
>(I've already decided that if the wheels on my cheap 27in bike become un-replaceable, it will be
>better to get a new bike.)
>
Yes, I'm aware that I might exceed the price of a new bike, but I'm fond of the Reynolds 531 frame I
have because it fits me well and I like the steel feel. If I could find a new bike with suitable
gears, the correct size, with tubing of similar (non-aluminium) quality and at the right price then
I guess I would probably be persuaded. I'm not keen on second hand though.
--
Julian

[Pete Biggs]

Julian wrote:
> In message <bspt7n$e0e$1@news5.svr.pol.co.uk>, Zog The Undeniable <ggg@hhh.net> writes
>>
>> Five
>>> would probably be enough, with a triple. In case you're wondering, I'm pretty sure my current
>>> side pull brakes have enough drop and my 531 frame will accommodate a 130mm oln as it's designed
>>> for 126mm and will easily spring the extra 4mm.
>>
>> Don't do this. Cold set it once and for all, or have a frame builder do it for a very small fee.
>> Stretching the back end every time you fit a wheel can break it over time.
>>
> Wow, didn't know that! Thanks for the warning.

You didn't know it because it's not true. See www.sheldonbrown.com/frame-spacing.html

~PB

[Just Zis Guy]

On Mon, 29 Dec 2003 16:27:27 +0000, Julian
<julian@v.e.l.o.d.o.g.demon.co.uk> wrote:

>I'm thinking of swapping my 27" wheels for 700c size. At the same time I would want to fit new
>gears with a triple chainring, as I need a few more low gears. Are all the currently available
>gears indexed, or will I be able to continue using my downtube mounted levers?

I changed my 531 framed bike to 135mm OLN (cold-set by my bike mechanic) and 8-speed at he back, no
problems. You can get even get indexed downtube levers. You might have toruble getting the brakes
adjusted if you change to 700c, you may need new calipers. Or you may get away with it.

Guy
===
May contain traces of irony. Contents liable to settle after posting.
http://chapmancentral.demon.co.uk (http://chapmancentral.demon.co.uk/)

[Zog The Undenia]

Pete Biggs wrote:

> You didn't know it because it's not true. See www.sheldonbrown.com/frame-spacing.html

Well, the great SB does say "If, however, you want to do it right, and your frame is steel, cold
setting is the better way to go."

Steel doesn't fatigue as readily as other metals, but the force involved in springing a frame apart
is almost certainly over its safe fatigue limit, so it will break eventually with repeated removal
and refitting of the wheel. Maybe 10 years, maybe 100 years, but it's an unnecessary risk.

[Pete Biggs]

Zog The Undeniable wrote:
> Well, the great SB does say "If, however, you want to do it right, and your frame is steel, cold
> setting is the better way to go."

Yes, and I think it's perfectly reasonable to cold set if springing is difficult - just for the sake
of convenience as much as anything else. I cold set my 126 frame, but I don't believe it's always
worth the bother, cost and even the vaious slight risks.

> Steel doesn't fatigue as readily as other metals, but the force involved in springing a frame
> apart is almost certainly over its safe fatigue limit

Sometimes very little force is required - so little that I can't believe any damage is done. Exact
actual frame sizes vary and some locknuts fit in easier than others. In fact, sometimes stays have
to be sprung out a bit in normal course (maybe if frame was made a bit on the small side?). It's not
normal practice to get the frame spread in these cases just to make the wheel fit easier and people
don't seem to have problems.

> , so it will break eventually with repeated removal and refitting of the wheel. Maybe 10 years,
> maybe 100 years, but it's an unnecessary risk.

I would guess nearer 500 or 1000 years because (up to) 2mm (on each) side is so little. I think Mr
Brown is being unusually cautious in case someone has some bad luck and blames it on him. It's
amazing (and alarming!) how far a steel stay needs to be pushed out before the elastic limit is
reached and it permanently bends at all. I know that's not quite the same thing but it provides a
vivid insight into what this material is like.

~PB