double or triple

in message <[email hidden]>,
Chris Armstrong

(') said:

I bought a road bike a couple of years ago and bought one with two
front chainrings. This was a bit of a mistake as not being very fit, I
really struggle to get up some hills that I manage relatively easily
on my mtb. I have been offered a swap for a cyclocross bike - which
sounds fun- but this also has two front chainrings. Does anyone know
if I am just swapping like for like, or will I find the cyclocross
bike generally a bit more low geared than than the roadbike. I know
the science all depends on how many teeth there are but I am just
wodering if there is a general rule of thumb.
Any advice appreciated.

It's not the number, it's the size. Or, to put it differently, don't
count the rings, count the teeth. If you use a 'compact double'
chainset, your smaller ring is going to be the same size as the granny
ring on a 'road triple' chainset. Which means, driving the same
cassette, you will have the same bottom gear. You will have a lower top
gear, of course, but that may not matter so much to you.

You can easily swap the chainset either of your new crosser or your old
road bike to a triple, if that's what you want to do; or you can change
individual rings on your existing chainset, although if the jump from
the smaller to the bigger ring is too great your front deraileur
mechanism will struggle, and you may need a longer cage on your rear
deraileur.

Alternatively you can change the cassette - the cluster of cogs on your
back wheel - to one with larger cogs, which will equally lower your
bottom gear. In this case you will need a longer cage rear deraileur.

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

Hobbit ringleader gives Sauron One in the Eye.

Hi

Quoted message said:

in message <[email hidden]>,
is there a general rule of thumb.[?]

Quoted message said:

Any advice appreciated.

Yes, I struggle too. I use a triple on all my road bikes. And
even some road pros like Roberto Heras and David Millar have used
triples in major stage races with long steep climbs. On the Angrilu climb
of a Vuelta stage I believe Heras used a triple with a 30 tooth inner ring
on the front and a 26 tooth big cog on the back.

If you fit a triple chainset you will need to change the bottom bracket
and both the front and rear derailleurs. If you are using Shimano STI
shifting/brake levers you will have to change the left hand lever for a
triple compatible. If you are using Campag ergo shifting/brake levers then
you don't need to change the left lever as they are both triple and double
compatible.

Here's what I use:

On my winter training bike (which I ride more than any other bike) I have
the following set up: Sugino fuse 500 triple c/set 50 x 36 x 28 and 13-28
9 speed Campag cassette.

Pinarello racing bike: Campag Racing T c/set 52 x 42 x 30 and 13-26 9
speed Campag cassette. (I'm going to swap the 42 c/ring for a 39 and maybe
the 13-26 for a 13-28).

My heavy touring bike uses a typical MTB set up.

HTH

Bin

Simon Brooke <[email hidden]> wrote:

: It's not the number, it's the size. Or, to put it differently, don't
: count the rings, count the teeth. If you use a 'compact double'
: chainset, your smaller ring is going to be the same size as the granny
: ring on a 'road triple' chainset.

A little bigger actually. A 110 PCD chainset (ie a "compact" one) can
take a 34 tooth inner ring as the smallest. Road tripes tend to have
a 32 or a 30 as the smallest ring from stock and you can fit a 28.

Arthur

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
Don't get me wrong, perl is an OK operating system, but it lacks a
lightweight scripting language -- Walter Dnes

Chris Armstrong <[email hidden]> wrote:

: mtb. I have been offered a swap for a cyclocross bike - which sounds
: fun- but this also has two front chainrings. Does anyone know if I am
: just swapping like for like, or will I find the cyclocross bike
: generally a bit more low geared than than the roadbike.

You'll probably find the 'cross bike has a smaller top gear and may
or may not have a smaller bottom gear depending on how it's been setup.

36/48 is common for cross, which would give lower gears, but some run
38/48 I think, which won't be noticably lower (at least at the front)

Arthur

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
Don't get me wrong, perl is an OK operating system, but it lacks a
lightweight scripting language -- Walter Dnes

Arthur Clune said:

Simon Brooke said:

It's not the number, it's the size. Or, to put it differently, don't
count the rings, count the teeth. If you use a 'compact double'
chainset, your smaller ring is going to be the same size as the
granny ring on a 'road triple' chainset.

A little bigger actually. A 110 PCD chainset (ie a "compact" one) can
take a 34 tooth inner ring as the smallest. Road tripes tend to have
a 32 or a 30 as the smallest ring from stock and you can fit a 28.

s/28/24/

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/> I
thought I saw his name on a jar of marmalade the other day, but
when I looked more closely, I saw it read 'thick cut'.

I have put a stronglight impact double 46/36 on my audax bike with 11
to 34 cassette .Since I have a long arm rear changer already there was
no need to change anything else.I think you will find this chainset
with 48/34 also, or pick your own rings.
Mine was from Settle.
TerryJ

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

Quoted message said:

I have put a stronglight impact double 46/36 on my audax bike with 11
to 34 cassette .Since I have a long arm rear changer already there was
no need to change anything else.I think you will find this chainset
with 48/34 also, or pick your own rings.
Mine was from Settle.

I was going to suggest the OP fit an 11-34 and mtb rear mech., not only a
longer cage but also a longer body to keep the top jockey wheel off the
larger cogs.
That's what I do with a 39-53 chainset and it suits me although (obviously)
there are bigger gaps between gears.

Pete

Peter B <[email hidden]> wrote:

: I was going to suggest the OP fit an 11-34 and mtb rear mech., not only a
: longer cage but also a longer body to keep the top jockey wheel off the
: larger cogs.

Each to their own, but I *hate* cassettes like that. They work fine offroad
where you can't be too subtle in your gear choice anyway, but ever there
I'd find 11-28 preferable.

On road, it'd drive me nuts.

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
Don't get me wrong, perl is an OK operating system, but it lacks a
lightweight scripting language -- Walter Dnes

Quoted message said:

Each to their own, but I *hate* cassettes like that. They work fine offroad
where you can't be too subtle in your gear choice anyway, but ever there
I'd find 11-28 preferable.

road, it'd drive me nuts.

But it depends where you ride.In most of lincolnshire you dont need
low gears and close ratios are more comfortable, but in the pennines
you are either going up or down, and need a wide variety.And it seems
the poster wants low gears, and I was just showing that you do not
necessarily have to go for a triple.
Indeed I find my set up of 2x7 11 to 34 is very good.If I make a
change it might be to revert to DT changers, which worked well with
less fuss than my new sti levers.
TerryJ

"Arthur Clune" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Peter B <[email hidden]> wrote:

: I was going to suggest the OP fit an 11-34 and mtb rear mech., not only

a

Quoted message said:

: longer cage but also a longer body to keep the top jockey wheel off the
: larger cogs.

Each to their own, but I *hate* cassettes like that. They work fine

offroad

Quoted message said:

where you can't be too subtle in your gear choice anyway, but ever there
I'd find 11-28 preferable.

On road, it'd drive me nuts.

Yep, I use an 11-25 usually. It gets me up any hill I'm likely to encounter
in Leicestershire/Rutland/Warwicks/Northants but would leave me walking up
hills in the Peak District so the cheap answer is to borrow the cassette and
mech from my mtb for those occasional trips.
In hindsight maybe I should have bought a bike with a triple even though
the lower gears would have been redundant most of the time (which is why I'm
loathe to shell out to retrofit a triple).

Pete

in message <[email hidden]>, Peter B

(') said:

"Arthur Clune" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Each to their own, but I *hate* cassettes like that. They work fine

offroad

Quoted message said:

where you can't be too subtle in your gear choice anyway, but ever
there I'd find 11-28 preferable.

On road, it'd drive me nuts.

Yep, I use an 11-25 usually. It gets me up any hill I'm likely to
encounter in Leicestershire/Rutland/Warwicks/Northants but would leave
me walking up hills in the Peak District so the cheap answer is to
borrow the cassette and mech from my mtb for those occasional trips.
In hindsight maybe I should have bought a bike with a triple even
though the lower gears would have been redundant most of the time
(which is why I'm loathe to shell out to retrofit a triple).

My solution has been to go for a 13-26 cassette, but a medium cage
deraileur that will accommodate up to 13-29. So far 53/39 front and
13-26 rear has been fine for every hill I've tried it on (including
more than half way up the highest rated climb in Britain) but if I need
something lower it's easy to change.

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

;; It appears that /dev/null is a conforming XSL processor.

I said:

Yep, I use an 11-25 usually.

Actually I think it's 12-25, not that it has any bearing on climbing but it
does bring the ratios closer.

Quoted message said:

It gets me up any hill I'm likely to
encounter in Leicestershire/Rutland/Warwicks/Northants

The above is with a 39-53 up front and the hills are the same ones I used to
climb successfully with a 7 speed 13-23 and 42-53 up front. Not sure if it's
part of the ageing process or the fact that the more lower gears there are
to hand the more lower gears will be used!

Simon replied:

Quoted message said:

My solution has been to go for a 13-26 cassette, but a medium cage
deraileur that will accommodate up to 13-29.

Seems sensible.

Pete