What size chainrings? 53/39 or 52/42?

[David Damerell]

Hunrobe <[email protected]> wrote:
>Personally, I'd do some serious gear inch calculations before I went to a 36 small ring but I don't
>live in the mountains.

Mountains, nothing - there's always a little steep hill, and there's always the day when you're
carrying as much luggage as you can.

I see no reason not to fit the smallest small ring you can, short of absurd setups where (large ring
x second largest sprocket) actually starts to pull away from (small ring x second smallest
sprocket). You're never going to ride up a hill and think "Gosh, I'm glad I didn't have any more
gears to fall back on!".
--
David Damerell <[email protected]> Distortion Field!

 

[Paul Kopit]

On 29 Apr 2003 14:45:42 +0100 (BST), David Damerell <[email protected]> wrote:

>When I get a 110mm BCD crank I'll change to 52/36.

You might consider 48/34 and a 12/32. The chain and rear derailleur cage can be shorter. You will be
less likely to drag the chain on the bridge of the front derailleur.

 

[Paul Kopit]

On Mon, 28 Apr 2003 20:15:51 -0400, Steve Palincsar <[email protected]> wrote:

>
>May well be, but 42/52 was NOT halfstep gearing.

Actually, I think they called 42/52 1½ step, which I never understood.
52/39 was called Alpine gearing.

 

[David Damerell]

Paul Kopit <[email protected]> wrote:
><[email protected]> wrote:
>>When I get a 110mm BCD crank I'll change to 52/36.
>You might consider 48/34 and a 12/32.

Acksherly, I brainoed when I meant 52/34 - which I've done at least twice today already. Of course
coaxing a fder into shifting that may be tricky, but if it can be done, it gives the lowest possible
gear on a 110mm BCD double. I won't want the 34x34 all that often, but from time to time...
--
David Damerell <[email protected]> Distortion Field!

 

[David Damerell]

Paul Kopit <[email protected]> wrote:
>On Mon, 28 Apr 2003 20:15:51 -0400, Steve Palincsar <[email protected]> wrote:
>>May well be, but 42/52 was NOT halfstep gearing.
>Actually, I think they called 42/52 1½ step, which I never understood.

Because a front shift is worth about half as much again as a rear shift?
--
David Damerell <[email protected]> Distortion Field!

 

[Baltobernie]

James <[email protected]> wrote in message news:[email protected]...
> Hi,
>
> I'm not a racer but do enjoy frequent fast club rides. At the moment, I'm considering fitting
> 'non-standard' size chainrings on my Ultegra 9-speed equipped roadbike.
>
> A few questions:
>
> 1. For double setups, why are there 2 popular big-ring sizes (53 or 52) when they only differ by 1
> tooth?
>
> 2. Likewise for front small-ring sizes (42 or 39).
>
> 3. When should riders choose 53/39, 53/42, 52/42 or 52/39? Are these chainring sizes arbitrarily
> chosen or is there a reasonable rationale behind the choice?
>
> 4. After some refining of my riding patterns, I think a 51(50)/36 may suit me very well. Where can
> I get such chainrings which are Shimano 9-spd compatible?
>
>
> All replies appreciated.
>
> Thanks.
>
>
> James
>

Dear James,

(1. & 2.) There are absolute limits on the size of the front chainrings, but the limiting factor is
usually the numerical difference between the big and little ring. Front derailleurs used to have
an upper limit of 10 teeth; that is, the mechanism could not reliably move the chain from 42
teeth to more than 52 teeth and back again.

(2.) Newer groupsets can cover a range of 12 or 13 teeth. (Similar advances have been made in the
rear derailleur.) What's the big deal over a couple of teeth? Well, humans have a very narrow
horsepower range, and having a wider ratio of potential gear choices usually makes for a more
pleasant ride. Now, if you ride on flat country, you should consider a very close <rear>
cluster, so that you can maximize your efficiency using small (one tooth) increments. For the
front, hilly OR flat, the larger the spread between the big and little ring is usually better.
You didn't mention the number of teeth on your present setup, but your LBS can tell you the
maximum range of your particular front derailleur.

(3.) I know of no currently available front derailleur that could handle a 50 by 36, a difference
of 14 teeth. Generally speaking, it is easier to shift among the 8-10 rear gears than between
the two or three front ones. I'd suggest that you ride (up) the steepest hill you're likely to
encounter on your rides, and choose the <rear> cluster that gives you the ability to climb
this hill, seated, with your little front ring. Maybe its a 12 x 19, maybe a 13 x 26.

There's nothing extravagant with having more than one rear cluster. In the old days, cyclists would
have a piece of plywood and nails holding each rear gear available. They would create a cluster
using gears and spacers for the particular ride or race that day. Today's more advanced (wider
range) groups make this largely unnecessary, but even I have two clusters; one for "normal" riding,
and one for our very flat centuries. A special socket, available at your LBS, is all you need to
easily change the rear cluster.

You know, of course, that your bike doesn't really have 16, 18 or twenty ratios. It may have that
many <gears>, but there is some duplication, or near-duplication. You can calculate all of these
ratios (called "gear-inches"), but using the Hill Method described above will yield acceptable
results. After all, one particular stretch of road may beg for a 52 x 18 on a particular day with a
particular wind, and you may have only a 17 or a 19 to select. But that's not nearly as bad as
dragging your ass home after a bad day, and flicking the right lever inward, only to find that
you're <already> in your lowest gear.

Leave your front chainrings alone, and experiment (or calculate) the optimum rear cluster for your
terrain, your abilities and your riding style.

Bernie

 

[Menno]

I'm using 50/38/26 (all TA 130mm) with a Ultegra 12-27 (9sp) cassette. Works fine with an Ultegra
front derailleur and a XT rear. The advantage of bigger jumps on the front chainrings is less
overlap on your total set of gears. And 26-27 enables you to do long and steep hills without much
training which is nice early in the season or when you carry panniers.

Menno

"Gary Mishler" <[email protected]> wrote in message
news:Ubvra.665424$3D1.367569@sccrnsc01...
> "Qui si parla Campagnolo" <[email protected]> wrote in message
> news:[email protected]...
> > Gary-<< What does TA have for Ultegra Triple?
> >
> > Ta makes a load of rings for 135mm, 130mm and 110mm cranks, all sizes,
> lots
> > with ramps and stuff for use as a triple...
> >
>
> I find this thread very interesting. I have often thought that my
52/42/30
> was bigger than I needed, especially the 52, and somewhat the 42.
>
> What would you recommend for a 130 mm Ultegra Triple? Currently I'm
running
> a 12-27 9 spd cassette that I'm happy with but I find that I'm *usually*
on
> the 15-19 cogs when on the 42 chainring and on the 17-21 cogs when on the
52
> chainring. Still sometimes with a good tailwind I get to 52/15 or 14 combinations, but usually
> never larger.
>
> I'm happy with my 30 inner ring, unless they should all three be changed
out
> as a set, then I could go a bit smaller.
>
> Thanks, Mish

 

[Paul Kopit]

On Tue, 29 Apr 2003 14:14:34 -0400, "baltobernie" <[email protected]> wrote:

>(4.) I know of no currently available front derailleur that could handle a 50 by 36, a difference
> of 14 teeth.

The derailleurs handle 53/39 or 14t w/o problem. A regular Campy front derailleur handles a 50/36
without a problem.

 

[Sheldon Brown]

James wrote:

>>3. When should riders choose 53/39, 53/42, 52/42 or 52/39? Are these chainring sizes arbitrarily
>> chosen or is there a reasonable rationale behind the choice?

They're fairly arbitrary. 42 was the smallest standard size that would=20 easily fit on the older
Campagnolo cranksets with the 144 mm bolt=20 circle, so folks got used to using that size.

When the 130 bolt circle became the new standard, 39 was the smallest=20 that could easily fit.

(There are 41/144s and 38/130s, but they sometimes require slight filing =

of the ends of the spider arms for clearance.

>>4. After some refining of my riding patterns, I think a 51(50)/36 may suit me very well. Where can
>> I get such chainrings which are Shimano 9-spd compatible?

It's hard to find any that aren't. 36 is not possible with the 130 mm=20 BCD (Bolt Circle Diameter)
so you would need something other than a=20 garden-variety "road" crankset.

The 110 mm bolt circle handles down to 34 (33) and is a good option if=20 you can find one.

Also, the venerable TA Cyclotouriste is still available, and will go=20 down to 26. It isn't a good
choice for a triple, but works great as a=20 double. I've got one on my Hetchins, 50-28, works fine
with 105 brifters=
=2E

An anonymous pessimist wrote:

> (1. & 2.) There are absolute limits on the size of the front chainring=
s,
> but the limiting factor is usually the numerical difference between the=
big
> and little ring. Front derailleurs used to have an upper limit of 10 t=
eeth;
> that is, the mechanism could not reliably move the chain from 42 teeth =
to
> more than 52 teeth and back again.

Most modern front derailers have much wider limits than that. I'm=20 running a plain vanilla Shimano
105 double front with my 50-28, and it=20 works just fine.

See also: http://sheldonbrown.com/gloss_ca-m.html#capacity

> (3.) Newer groupsets can cover a range of 12 or 13 teeth. (Similar adv=
ances
> have been made in the rear derailleur.) What's the big deal over a cou=
ple
> of teeth? Well, humans have a very narrow horsepower range, and having=
a
> wider ratio of potential gear choices usually makes for a more pleasant=

> ride. Now, if you ride on flat country, you should consider a very clo=
se
> <rear> cluster, so that you can maximize your efficiency using small (o=
ne
> tooth) increments. For the front, hilly OR flat, the larger the spread=

> between the big and little ring is usually better. You didn't mention =
the
> number of teeth on your present setup, but your LBS can tell you the ma=
ximum
> range of your particular front derailleur.

I agree with this recommendation. Using a wide range in front allows=20 you to have adequate low
gears, without having to suffer big jumps in=20 back. I don't, however put any stock in the rated
capacity of=20 derailers, which tends to be EXTREMELY conservative, as explained in the =

link above.

> (4.) I know of no currently available front derailleur that could hand=
le a
> 50 by 36, a difference of 14 teeth.=20

I know of no currently available front derailer that _couldn't_ handle=20 that range!

Sheldon "Don't Believe Everything The Manufacturers Say" Brown
+---------------------------------------------------------------+
| The poet Henry O'Meara (1848-1904) was my great-grandfather | I=92ve put his book "Ballads of
| America and Other Poems" | on the Web at: http://sheldonbrown.com/omeara |
+---------------------------------------------------------------+ Harris Cyclery, West Newton,
Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
shipped Worldwide http://captainbike.com http://sheldonbrown.com

 

[David L. Johnso]

On Tue, 29 Apr 2003 14:14:34 +0000, baltobernie wrote:

> (1. & 2.) There are absolute limits on the size of the front chainrings, but the limiting factor
> is usually the numerical difference between the big and little ring. Front derailleurs used to
> have an upper limit of 10 teeth; that is, the mechanism could not reliably move the chain from
> 42 teeth to more than 52 teeth and back again.

I managed to get a 1970 model Campy NR front derailleur to shift a 51/35 Campy Victory crankset.
There never was a 10-tooth limit on any derailleur made in the last 30 years. That was simply what
gave racers no gaps with a 14-18 5-cog cluster. Any larger a jump in the front, and there would be a
gap that would require using either the big-big or little-littel combination that we could not use
(the chain would jump off, or rub, depending). With the advent of 6-speed clusters a typical
straight block would give you close-ratio gears with no gaps with a 52/39, and at that time the
Campy bolt pattern was changed to accomodate the 39.
>
> (3.) Newer groupsets can cover a range of 12 or 13 teeth.

Nonsense. Those same front derailleurs will shift a triple with 20-25 tooth total jumps. No reason
they can't shift a double with a jump of that order.

> (4.) I know of no currently available front derailleur that could handle a 50 by 36, a difference
> of 14 teeth.

What?  False. They all handle this just fine. 14 teeth is precisely the jump between the stock 53/39
on darn-near every road bike made today.

> Leave your front chainrings alone,

Why? There is nothing sacred about the chainrings. Most of what you say is simply not true. Lots of
us are riding with chainrings you say we cannot use. Any current front derailleur can easily handle
as wide a jump as you would want to consider. I have used a 51/35, 48/30 (yes, 30-tooth inner ring
on a double, 94mm bolt pattern), and others have used similar ratios. Even back in 1970 I had larger
jups than 10. I got this 55-tooth big ring, and used a 55/42 on flat races.

--

David L. Johnson

__o | Some people used to claim that, if enough monkeys sat in front _`\(,_ | of enough
typewriters and typed long enough, eventually one of (_)/ (_) | them would reproduce the
collected works of Shakespeare. The internet has proven this not to be the case.

 

[David L. Johnso]

On Tue, 29 Apr 2003 14:37:59 +0000, Paul Kopit wrote:

> Actually, I think they called 42/52 1½ step, which I never understood.
> 52/39 was called Alpine gearing.

Back when it came out, Campy's 52/42 _was_ alpine gearing. Most cranks before that (TA was an
exception) typically were what we'd call half-step. I had a bike from about 1962 with a 52/47
Magestroni crankset that was fairly typical.

Tourist setups would have a granny added.

--

David L. Johnson

__o | A foolish consistency is the hobgoblin of little minds, adored _`\(,_ | by little statesmen
and philosophers and divines. --Ralph Waldo (_)/ (_) | Emerson

 

[David L. Johnso]

On Tue, 29 Apr 2003 18:34:38 +0100, David Damerell wrote:

> Paul Kopit <[email protected]> wrote:
>>On Mon, 28 Apr 2003 20:15:51 -0400, Steve Palincsar <[email protected]> wrote:
>>>May well be, but 42/52 was NOT halfstep gearing.
>>Actually, I think they called 42/52 1½ step, which I never understood.
>
> Because a front shift is worth about half as much again as a rear shift?

The drop from a 52 to a 42 is a 20% decrease. Put the other way, going from the 42 to a 52 is a 24%
increase. Now, that would be like a jump from a 14 to a 17 (plus, really 17 1/3) at the high end,
and a 24 down to a 19. Since clusters at that time were often 14-16-18-21-24 for hilly rides, that
would indeed be a step and a half. But if you had a straight block (14-15-16-17-18), it was almost
the entire block.

--

David L. Johnson

__o | It is a scientifically proven fact that a mid life crisis can _`\(,_ | only be cured by
something racy and Italian. Bianchis and (_)/ (_) | Colnagos are a lot cheaper than Maserattis
and Ferraris. -- Glenn Davies

 

[Sheldon Brown]

Paul Kopit wrote:
>=20
>>Actually, I think they called 42/52 1=BD step, which I never understood=
=2E
>>52/39 was called Alpine gearing.
>=20
> David L. Johnson wrote:

> Back when it came out, Campy's 52/42 _was_ alpine gearing. Most cranks=

> before that (TA was an exception) typically were what we'd call half-st=
ep.
> I had a bike from about 1962 with a 52/47 Magestroni crankset that was=

> fairly typical.

That's what came on my '61 Paramount, on an old Campagnolo Record=20 cranset (151 BCD). The early
front derailers had trouble shifting any=20 jump much bigger than that. Indeed, in the '50s, 49/46
was popular for=20 that reason.

The term "Alpine gearing" has a complicated history. Back in the '50s,=20 it generally referred to a
setup with a chainring of 36 teeth or=20 smaller, and/or to a freewheel with a big jump at the
bottom.=20 F'rinstance, my '57 OTB came with a 48/30 in front, and the freewheel=20 was 14-16-19-26.
The big 19-26 jump qualified it as an "Alpine"=20 freewheel. This concept has been revived by
Shimano in their=20 "Megarange" series, and it's actually quite a good setup.

In the '60s, however, marketeers appropriated the term and applied it=20 (inaccurately) to 52/40
14/28 setups. The term was thus debased and=20 lost all usefulness.

Sheldon "Alpine Once Meant Somthing" Brown +-----------------------------------------+
| Man invented language to satisfy his | deep need to complain. -- Lily Tomlin |
+-----------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

 

[Qui Si Parla Ca]

bernie-<< (4.) I know of no currently available front derailleur that could handle a 50 by 36, a
difference of 14 teeth.

Modern road fders are rated at 15t normally. A road fder would handle a 50/36
w/o problem. As Victory ones did two decades ago.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[David Damerell]

David L. Johnson <[email protected]> wrote:
>On Tue, 29 Apr 2003 18:34:38 +0100, David Damerell wrote:
>>Paul Kopit <[email protected]> wrote:
>>>On Mon, 28 Apr 2003 20:15:51 -0400, Steve Palincsar <[email protected]> wrote:
>>>>May well be, but 42/52 was NOT halfstep gearing.
>>>Actually, I think they called 42/52 1½ step, which I never understood.
>>Because a front shift is worth about half as much again as a rear shift?
>down to a 19. Since clusters at that time were often 14-16-18-21-24 for hilly rides, that would
>indeed be a step and a half. But if you had a straight block (14-15-16-17-18), it was almost the
>entire block.

Well, yes - the term "half-step" equally makes assumptions about the rear sprocket spacing.
--
David Damerell <[email protected]> Distortion Field!

 

[Risto Varanka]

David Damerell <[email protected]> wrote:
: Hunrobe <[email protected]> wrote:
:>Personally, I'd do some serious gear inch calculations before I went to a 36 small ring but I
:>don't live in the mountains.

: Mountains, nothing - there's always a little steep hill, and there's always the day when you're
: carrying as much luggage as you can.

It really depends. As anecdotical evidence comes, I doubt I have ever needed my smallest gear, in
over 5000 km of all-around riding. I'd be much more happy with a tighter-spaced cassette for more
exact gear ratios. Going for something quite different in my next vehicle

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/ varis at no spam please iki fi

 

[David L. Johnso]

On Wed, 30 Apr 2003 19:00:59 +0000, risto.varank wrote:

> It really depends. As anecdotical evidence comes, I doubt I have ever needed my smallest gear, in
> over 5000 km of all-around riding. I'd be much more happy with a tighter-spaced cassette for more
> exact gear ratios. Going for something quite different in my next vehicle

Why wait for the next bike (I presume the "vehicle" will be a new bike, not a station wagon)?
Replace the cassette for $30, and/or che chainrings for $20-$60, and ride what suits you.

--

David L. Johnson

__o | It is a scientifically proven fact that a mid life crisis can _`\(,_ | only be cured by
something racy and Italian. Bianchis and (_)/ (_) | Colnagos are a lot cheaper than Maserattis
and Ferraris. -- Glenn Davies

 

[Risto Varanka]

David L. Johnson <[email protected]> wrote:
: Why wait for the next bike (I presume the "vehicle" will be a new bike, not a station wagon)?
: Replace the cassette for $30, and/or che chainrings for $20-$60, and ride what suits you.

Good question. I think it's basically how my psychic self-regulation works. There's an inhibition on
spending money, but when I recognize the need for a new bike, this inhibition is lifted and I shell
out the money for everything I need or might need.

Getting a new bike just for new gearing doesn't usually make any sense at all The next thing will
basically have all custom selected components, apart from the frame which will be default if you can
even say that...

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/ varis at no spam please iki fi

 

[David Damerell]

<[email protected]> wrote:
>David Damerell <[email protected]> wrote: Hunrobe <[email protected]> wrote:
>>>Personally, I'd do some serious gear inch calculations before I went to a 36 small ring but I
>>>don't live in the mountains.
>>Mountains, nothing - there's always a little steep hill, and there's always the day when you're
>>carrying as much luggage as you can.
>It really depends. As anecdotical evidence comes, I doubt I have ever needed my smallest gear, in
>over 5000 km of all-around riding.

What _is_ your smallest gear? We're talking about a 36t inner here, which is at most a 36/34...
--
David Damerell <[email protected]> Kill the tomato!