2 x 9

<Taka> wrote

Quoted message said:

Hello Everyone,

I am thinking about running a 2x9 (2 front rings).
If I have a choice between a long cage and short cage rear derailleur,
which should I choose?

Do you have an old mech you can try to begin with?

Quoted message said:

Does it depend on how many teeth my front rings have?

I recently tried keeping an old Exage mech when I changed from 7sp 13-24
to a 9sp 11-34 cassette. It actually worked fine with friction shifters.
When I tried a 9sp indexer it was only the cable tension on the rachet that
prevented it getting on the 9th sprocket. Clearly there is an enormous
amount of tolerance in these systems.

Quoted message said:

What would be a good mix between speed and uphill useability? How does
36/48 sound? Would it be possible to shift easily with this?

That's only a jump of 12. I know someone that has gone for 22/42 in one
jump. Compact sets are 34/48. A road set is often 39/52.

in message <[email hidden]>, Taka <Taka> (''😉

Quoted message said:

Hello Everyone,

I am thinking about running a 2x9 (2 front rings).
If I have a choice between a long cage and short cage rear derailleur,
which should I choose?
Does it depend on how many teeth my front rings have?

It depends on the difference between your highest overall gear and your
lowest overall gear. I run 53/39 at the front and 13-26 at the rear, so
could get away with a short cage; but in fact I use a medium cage so
that I can stick a 13-29 on the back when I feel particularly weedy or
the hills are just too big.

Quoted message said:

What would be a good mix between speed and uphill useability? How does
36/48 sound?

Reasonable for a touring bike, or a utility. You'll be short of gears at
the top end, unless you're a master spinner.

Quoted message said:

Would it be possible to shift easily with this?

Yes.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; So, before proceeding with definitive screwing, choose the
;; position most congenital.
-- instructions for fitting bicycle handlebars

Taka said:

Hello Everyone,

I am thinking about running a 2x9 (2 front rings).
If I have a choice between a long cage and short cage rear derailleur,

Medium cage as well with Campag.

Quoted message said:

which should I choose?
Does it depend on how many teeth my front rings have?

Partly, but more on the rear sprockets. What freewheel or cassette?

Quoted message said:

What would be a good mix between speed and uphill useability? How does
36/48 sound? Would it be possible to shift easily with this?

Shifting will be good but you might want more range, say 36/50. Depends
on cassette and what you like.

Note. Standard Shimano "road" cranksets can't take an inner ring smaller
than 38 teeth (39 for Campag). You need a "compact" chainset for smaller.

~PB

Simon Brooke said:

in message <[email hidden]>, Taka <Taka>

('') said:

Hello Everyone,

I am thinking about running a 2x9 (2 front rings).
If I have a choice between a long cage and short cage rear
derailleur, which should I choose?
Does it depend on how many teeth my front rings have?

Quoted message said:

Quoted message said:

What would be a good mix between speed and uphill useability? How
does 36/48 sound?

Reasonable for a touring bike, or a utility. You'll be short of gears
at the top end, unless you're a master spinner.

Surely it depends on the rear cluster as well....

52 front, 13 rear is the same ratio as 48 front, 12 rear.
Many modern cassettes seem to come with either 11T or 12T as the smallest
size, whereas it used to be 13T was the smallest commonly available size.

- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Taka <Taka> wrote:

: What would be a good mix between speed and uphill useability? How does
: 36/48 sound? Would it be possible to shift easily with this?

Go with 34/48 if you want the low gears.

Is this Shimano or Campag? Usually you'll be fine with a short cage
rear mech, but if you want the option to run big rear cogs as well
you may want the longer cage (or medium cage campag) rear.

Arthur

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
The struggle of people against power is the struggle
of memory against forgetting - Milan Kundera

Simon Brooke <[email hidden]> wrote:

: Reasonable for a touring bike, or a utility. You'll be short of gears at
: the top end, unless you're a master spinner.

Why? I run 38/48 12-25 (on a compact crank so I can swap in the 34 for hard
rides) and haven't had issues with 48x12 (=52x13) as a big gear.

The only time I use a bigger gear is racing (especially TT'ing when I tend
to pedal slower than normal) and even then it's on 52x12 which is only
acutally one gear bigger.

For non-racing use, I think 48x12 is plenty big enough, and has the extra
benift that for most people a 48 big ring is much more usuable than a 52.

Arthur

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
The struggle of people against power is the struggle
of memory against forgetting - Milan Kundera

in message <[email hidden]>, Arthur Clune

(') said:

Simon Brooke <[email hidden]> wrote:

: Reasonable for a touring bike, or a utility. You'll be short of gears
: at the top end, unless you're a master spinner.

Why? I run 38/48 12-25 (on a compact crank so I can swap in the 34 for
hard rides) and haven't had issues with 48x12 (=52x13) as a big gear.

Fairy snuff. Mind you, in another thread someone has recently pointed out
that the efficiency of chain drives degrades fairly sharply as the cogs
get smaller... (note desperate scrabble for justification here)

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; For in much wisdom is much grief; and he that increaseth
;; knowledge increaseth sorrow.." - Ecclesiastes 1:18

Arthur Clune said:

Taka <Taka> wrote:

: What would be a good mix between speed and uphill useability? How does
: 36/48 sound? Would it be possible to shift easily with this?

Go with 34/48 if you want the low gears.

Is this Shimano or Campag? Usually you'll be fine with a short cage
rear mech, but if you want the option to run big rear cogs as well
you may want the longer cage (or medium cage campag) rear.

Arthur

Thanks everyone.

So even 36/50 doesn't sound unreasonable.
I will probably be running 32/11 in the back (sorry, it's a
mountainbike! I forgot to add that to my original post).

Thank you!
Taka

Quoted message said:

I am thinking about running a 2x9 (2 front rings).

Why? What's wrong with a triple? (The OP's bike is an MTB, but both my
road bikes have triples.)

--
Peter Headland

Peter Headland said:

What's wrong with a triple?

Nothing much wrong with a triple, but there can be reasons to prefer a
double if one doesn't need quite as broad a range of gears.

In the 7-speed days, a typical mountain bike transmission was 46/36/24 with
a 12-28 cassette. 9-speed cassettes are more commonly 11-32, 11-34 or
12-34. The bigger sprockets can be nice to have because they delay the
shift to the granny gear, but some riders find that they have no need of
the very lowest gears, or are unable to make use of them (because rear
wheel traction or the tendency of the front wheel to lift limits their
climbing before their strength does).

By reducing the size of the middle ring slightly, a 2x9 system can give a
range of gears as broad as a typical 7-speed triple with fewer gear
duplications, less front-end shifting, less chain suck, lower Q, and a
little less weight. A shorter rear mech keeps the chain further from the
ground and is slightly less vulnerable to damage.

Road riders are choosing compact doubles for similar reasons.

James Thomson

Simon Brooke said:

in message <[email hidden]>, Taka <Taka> (''😉

Quoted message said:

Arthur Clune said:

Taka <Taka> wrote:

: What would be a good mix between speed and uphill useability? How
: does 36/48 sound? Would it be possible to shift easily with this?

Go with 34/48 if you want the low gears.

Is this Shimano or Campag? Usually you'll be fine with a short cage
rear mech, but if you want the option to run big rear cogs as well
you may want the longer cage (or medium cage campag) rear.

Thanks everyone.

So even 36/50 doesn't sound unreasonable.
I will probably be running 32/11 in the back (sorry, it's a
mountainbike! I forgot to add that to my original post).

Ah! That makes a difference. Is it a mountain bike which is being /used/
as a mountain bike, or is it a mountain bike which is mainly used on
roads? If the former, a 48 tooth ring may be quite large, both in terms
of what you can usefully pedal and in terms of what the front mech and
chain stay will accommodate. If the latter, nevertheless make sure that
it will actually fit before parting with your cash.

Thanks for the warning!

Ah, it will be a mountain bike to be used XC and on roads.
I wanted disc brakes and some suspension (front only) so decided to
make a sort of hybrid based on a MTB frame.

Taka said:

There's nothing wrong with a triple, except that I never use the
granny ring!

You would sometimes if the inner rear sprockets were smaller. Having a
"closer" cassette while retaining the triple would allow you to ride at an
ideal cadence more of the time to dramatically improve the road riding.
And get everything customised nicely and you'll be on the middle ring most
of the time, resulting in less front-shifting than you would do on a
compact double.

Quoted message said:

I also think it looks better without the 3rd ring.

And that's more important than how it goes?

~PB

in message <[email hidden]>, Taka <Taka> (''😉

Quoted message said:

Simon Brooke said:

in message <[email hidden]>, Taka <Taka>

('') said:

On 31 Jul 2005 10:00:48 GMT, "Arthur Clune" <[email hidden]> wrote:

>Taka <Taka> wrote:
>
>: What would be a good mix between speed and uphill useability? How
>: does 36/48 sound? Would it be possible to shift easily with this?
>
>Go with 34/48 if you want the low gears.
>
>Is this Shimano or Campag? Usually you'll be fine with a short cage
>rear mech, but if you want the option to run big rear cogs as well
>you may want the longer cage (or medium cage campag) rear.

Thanks everyone.

So even 36/50 doesn't sound unreasonable.
I will probably be running 32/11 in the back (sorry, it's a
mountainbike! I forgot to add that to my original post).

Ah! That makes a difference. Is it a mountain bike which is being
/used/ as a mountain bike, or is it a mountain bike which is mainly
used on roads? If the former, a 48 tooth ring may be quite large, both
in terms of what you can usefully pedal and in terms of what the front
mech and chain stay will accommodate. If the latter, nevertheless make
sure that it will actually fit before parting with your cash.

Thanks for the warning!

Ah, it will be a mountain bike to be used XC and on roads.
I wanted disc brakes and some suspension (front only) so decided to
make a sort of hybrid based on a MTB frame.

OK. Well, to accommodate big tyres, the chain stays on mountain bikes are
spaced wide apart, which pushes them into space which on a road bike is
used for the chain rings. Many mountain bike chain stays have a notch or
dent to accommodate the chain ring, and the position of this notch or
dent determines the size of the largest chainring you can fit.
--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; killing [afghan|iraqi] civilians is not 'justice'

Taka said:

I also think it looks better without the 3rd ring.

Bikes often look better without their riders but that doesn't stop people.

DavidR said:

With a wide range cassette a double ought to be sufficient. The
difficulty has been finding suitable chain sets but I now notice TA
do an 'Escape' series with 86mm BCD. This allows a double with,
say, 28/42 which would be perfect for a 11-34 cassette.

That's the Stronglight Escape.

The 86mm bolt circle has been more-or-less obsolete since the mid eighties,
and I can't see chainrings being easy to find in the longer term. A Compact
Drive 94mm bolt circle will allow a 29t ring, and Ritchey made a special
28t. It's also possible to use a 110/74, 130/74, or 135/74mm triple as a
double with chainrings in the inner and middle positions. A typical road
triple with the big ring removed makes a 42/30 double, leaving the outer
position free for a chain guard / bash ring.

James Thomson

Pete Biggs said:

Taka wrote:

Quoted message said:

Quoted message said:

There's nothing wrong with a triple, except that I never use the
granny ring!

Quoted message said:

You would sometimes if the inner rear sprockets were smaller.

Quoted message said:

Having a "closer" cassette while retaining the triple would allow
you to ride at an ideal cadence more of the time to dramatically
improve the road riding.

Close ratio cassettes don't make much sense on a bike like Taka's that's
going to be ridden off road. Bigger jumps between gears are often a benefit
where cadence has to vary more widely with more variable terrain and rugged
surfaces. Closer spacing between gears simply means more frequent multiple
shifts, and more frequent middle-granny shifts at the front. Notice how
with increasing numbers of sprockets, mtb cassettes have generally gone for
more range, while road cassettes have generally kept the same range with
smaller jumps. There are exceptions, of course.

It can be nice to have two sets of wheels for a bike like Taka's - a light
pair with road tyres and a close ratio cassette, and a sturdier pair with
fat tyres and an mtb cassette.

Quoted message said:

And get everything customised nicely and you'll be on the middle
ring most of the time, resulting in less front-shifting than you would
do on a compact double.

Since Taka's talking about an mtb frame, the middle ring is likely to be
limited to 36t or smaller by chainstay clearance. With a 26" wheel, that's
not a very big top gear. The big ring tends to give a better range for road
riding on an mtb.

James Thomson

James Thomson said:

"Pete Biggs" <[email hidden]>

Quoted message said:

Taka wrote:

Quoted message said:

Quoted message said:

There's nothing wrong with a triple, except that I never use the
granny ring!

Quoted message said:

You would sometimes if the inner rear sprockets were smaller.

Quoted message said:

Having a "closer" cassette while retaining the triple would allow
you to ride at an ideal cadence more of the time to dramatically
improve the road riding.

Close ratio cassettes don't make much sense on a bike like Taka's
that's going to be ridden off road.

It's going to be ridden on road as well. Taka didn't say how much was on
and off. Note that I specifically mentioned "road riding" so the OP can
make their own decision.

Quoted message said:

Bigger jumps between gears are
often a benefit where cadence has to vary more widely with more
variable terrain and rugged surfaces.

Fair enough if doing /lots/ of that sort of stuff.

Quoted message said:

Closer spacing between gears
simply means more frequent multiple shifts, and more frequent
middle-granny shifts at the front.

More frequent rear shifts are no big deal on road or gentle off road, and
the front shifts won't be too frequent if rings and cassette are chosen
carefully.

Quoted message said:

Notice how with increasing numbers
of sprockets, mtb cassettes have generally gone for more range, while
road cassettes have generally kept the same range with smaller jumps.

A "road" cassette could be fitted.....

Quoted message said:

There are exceptions, of course.

It can be nice to have two sets of wheels for a bike like Taka's - a
light pair with road tyres and a close ratio cassette, and a sturdier
pair with fat tyres and an mtb cassette.

Nice idea.

Quoted message said:

Quoted message said:

And get everything customised nicely and you'll be on the middle
ring most of the time, resulting in less front-shifting than you
would do on a compact double.

Since Taka's talking about an mtb frame, the middle ring is likely to
be limited to 36t or smaller by chainstay clearance. With a 26"
wheel, that's not a very big top gear. The big ring tends to give a
better range for road riding on an mtb.

I find that on MTBs when the middle ring is 32T but I reckon 36T would be
pretty good actually. With a cassette that goes down to 12T, it would be
great for road cruising speeds, leaving the big ring for fast stuff only.
Even more the case if a 11-x cassette was used.

It's only slightly lower than the 39T middle with 13-28 cassette that I
love using on my 700c road bike. In fact it would be more like
traditional touring gears, so would be nice when it comes to moderate
climbs to save going down to the granny.

~PB

James Thomson said:

That's the Stronglight Escape.

The 86mm bolt circle has been more-or-less obsolete since the mid
eighties, and I can't see chainrings being easy to find in the longer
term.

Stronglight "86mm pcd plain alloy rings from 28 to 52 tooth" are available
from Settle Cycles. Stock up?

The "plain" bit doesn't sound great, though. No ramps and pins?

~PB

Pete Biggs said:

Stronglight "86mm pcd plain alloy rings from 28 to 52 tooth" are
available from Settle Cycles. Stock up?

The "plain" bit doesn't sound great, though. No ramps and pins?

I used them for years on my old tourer and never had any trub changing gear
at the front, save that a 20T gap was a bit much for the mech to cope with.
28-44 worked fine.

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
It is impossible to eat a banana without looking like a tw*t.