Question: is a 34/50 compact crank to small to work well on flats using a nine speed 12/26 cog?



In article
<[email protected]>,
"Qui si parla Campagnolo" <[email protected]> wrote:

> [email protected] wrote:
> > Guys,
> >
> > Question is a 34/50 compact crank to small to work well on flats using
> > a nine speed 12/26 cog?
> >
> > We have healthy hills in the Ozarks, but certainly not "Alpine"
> > inclines.

>
> Well, gearing is really 'personal' but I use a 50/39 with a 13-23 rear
> and ride around on the flats in the 14/15/17 cog most of the time.
> 50/12 is a gigantic gear and most cannot ride on the flats in a 53/12,
> at say 90 rpm, anyway....so the 50t should be fine..


What sprocket cassette? My 13-23 has a 16 tooth sprocket:
13,14,15,16,17,18,19,21,23.

--
Michael Press
 
Michael Press wrote:
> In article
> <[email protected]>,
> "Qui si parla Campagnolo" <[email protected]> wrote:
>
> > [email protected] wrote:
> > > Guys,
> > >
> > > Question is a 34/50 compact crank to small to work well on flats using
> > > a nine speed 12/26 cog?
> > >
> > > We have healthy hills in the Ozarks, but certainly not "Alpine"
> > > inclines.

> >
> > Well, gearing is really 'personal' but I use a 50/39 with a 13-23 rear
> > and ride around on the flats in the 14/15/17 cog most of the time.
> > 50/12 is a gigantic gear and most cannot ride on the flats in a 53/12,
> > at say 90 rpm, anyway....so the 50t should be fine..

>
> What sprocket cassette? My 13-23 has a 16 tooth sprocket:
> 13,14,15,16,17,18,19,21,23.
>
>


I suspect Peter is referring to a 13,14,15,17,19,21,23 7SP FW. I have
one of those (a Regina) on my vintage Motobecane, which began life as a
5SP.
 
On Fri, 19 May 2006 07:47:40 -0400, John Forrest Tomlinson wrote:

> On Fri, 19 May 2006 00:00:37 -0400, Matt O'Toole
> <[email protected]> wrote:
>
>>On Thu, 18 May 2006 23:58:38 +0000, Michael Press wrote:
>>
>>> I
>>> go faster by tucking than I could turning a higher high
>>> gear.

>>
>>This is true. I gain on others when I tuck and they're pedaling,
>>even if they're much stronger than I,

>
> Even on the flats and in a tailwind? Wow.


What do you think?

Matt O.
 
On Fri, 19 May 2006 15:07:07 -0400, Matt O'Toole
<[email protected]> wrote:

>On Fri, 19 May 2006 07:47:40 -0400, John Forrest Tomlinson wrote:
>
>> On Fri, 19 May 2006 00:00:37 -0400, Matt O'Toole
>> <[email protected]> wrote:
>>
>>>On Thu, 18 May 2006 23:58:38 +0000, Michael Press wrote:
>>>
>>>> I
>>>> go faster by tucking than I could turning a higher high
>>>> gear.
>>>
>>>This is true. I gain on others when I tuck and they're pedaling,
>>>even if they're much stronger than I,

>>
>> Even on the flats and in a tailwind? Wow.

>
>What do you think?


I don't think so -- pedalling is faster.

JT

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Some years before when these 110 bcd cranks were only available in CX
models I used to install a 50 on my winter training bike (using the 135
bcd I always do).

If you can get a chain-ring to try out it might give you the answer.
You do notice the difference but I would think in most cases you won't
lose any top end. How often do you get spun out in your current big
gear? My 53*12 only gets spun out when I hit a 10% section of a nearby
climb (descent). In other terrain, I would be able to spin out a tad
sooner and it motivated me to spin higher, smoother etc. Based on that
experience, unless you often have situations where your 52 or 53 * 12
it just right. I found that I was many times able to use the same
cassette cog and used leg speed to make up the difference. That was my
objective anyway. If your top gear is a 52 or 53 * 13 then you are
getting a bit of an increase with a 50 * 12. The only thing to be
concerned about in *that* case is the slightly bigger gap comparing the
difference of a 14 to 13 and a 13 to 12 shift in cogs while riding
(shifting to your biggest gear).

The bottom line is that the older cranks at 144, 135 and even 130 were
used at a time when 6 and 7 cogs in the back meant some riders would be
shifting the front more often than one needs to with 9 or 10 cogs. It
is more common now to use the same ring for the majority of the ride.
Some guys (now) never use the ring unless they are flying along in a
group and others never use the small ring unless there are hills. It
now makes a lot of sense to have a larger gap between the front rings.
Before the 110s became widely available, I had considered changing from
a 53/39 and 12/25 to a 55/39 and 13/25. When I first looked in to this,
I wanted to get my 16 tooth cog while racing. I found that a 53 13 was
not big enough for a lot of racing (that of course depends on who what
and where, etc. but that is what I found). When 10 speed came out, I
got to use a 12/25 with the 16 so that took away most of my need to
solve that problem. Now with the 110s, I can get even tighter cogs with
a 12/23 (like I said, 50*12 is enough for me) and still climb these
steep long grades in the Sierras. Since I have enough 12/25 cassettes
and all 135 bcd cranks, it does not seem worth it until I am buying a
new crank anyway.

I hope that helps. I think you will be happy with your idea. The 50/34
seems the most flexible unless you can't get a dedicated "compact"
front derailleur in which case you might want to get a 36/50. Do make
sure you get the most recent ramp and pin scheme for your rig since
that makes a difference in shifting performance and you may (likely)
need that with the larger gap that the chain has to jump with the
compact (for the 50/34 anyway).
 
On 20 May 2006 15:00:04 -0700, "Chris M" <[email protected]>
wrote:

>I hope that helps. I think you will be happy with your idea. The 50/34
>seems the most flexible unless you can't get a dedicated "compact"
>front derailleur in which case you might want to get a 36/50. Do make
>sure you get the most recent ramp and pin scheme for your rig since
>that makes a difference in shifting performance and you may (likely)
>need that with the larger gap that the chain has to jump with the
>compact (for the 50/34 anyway).


There are two sides to the problem: upshifting the 16 tooth gap from
34 to 50 (vs. the 14 tooth gap 39 to 53 the standard derailleur is
designed for); and preventing the chain from falling off the rings
into the frame when downshifting.

As for upshifting, standard derailleurs/shifters "work," but generally
not very efficiently IME. Having experimented with a number of
combinations (using Shimano drivetrain) I have found the best
combination is FSA rings, Dura Ace shifters, and FSA C-16 compact
derailleur. Instant, crisp, and perfect. As opposed to hesitation and
delay with such combos as Ultegra shifters and derailleur.

As for downshifting, you definitely should install a chain catcher.
Forget the brand names: buy one for $4 at:
http://www.biketoolsetc.com/index.cgi?id=716814898195&c=Components&sc=Chain Guides&tc=Chain Catcher
 
Doug Taylor wrote:
> On 20 May 2006 15:00:04 -0700, "Chris M" <[email protected]>
> wrote:
>
>
>>I hope that helps. I think you will be happy with your idea. The 50/34
>>seems the most flexible unless you can't get a dedicated "compact"
>>front derailleur in which case you might want to get a 36/50. Do make
>>sure you get the most recent ramp and pin scheme for your rig since
>>that makes a difference in shifting performance and you may (likely)
>>need that with the larger gap that the chain has to jump with the
>>compact (for the 50/34 anyway).

>
>
> There are two sides to the problem: upshifting the 16 tooth gap from
> 34 to 50 (vs. the 14 tooth gap 39 to 53 the standard derailleur is
> designed for); and preventing the chain from falling off the rings
> into the frame when downshifting.
>
> As for upshifting, standard derailleurs/shifters "work," but generally
> not very efficiently IME. Having experimented with a number of
> combinations (using Shimano drivetrain) I have found the best
> combination is FSA rings, Dura Ace shifters, and FSA C-16 compact
> derailleur. Instant, crisp, and perfect. As opposed to hesitation and
> delay with such combos as Ultegra shifters and derailleur.
>
> As for downshifting, you definitely should install a chain catcher.
> Forget the brand names: buy one for $4 at:
> http://www.biketoolsetc.com/index.cgi?id=716814898195&c=Components&sc=Chain Guides&tc=Chain Catcher


Personal anecdote ... I have never had a chain drop issue with my 50/34.
I have, however, since my crank is an old Ritchey 110bcd double from
7/8sp era and I run 9sp, had chain skate between the rings. I use a
Campagnolo road double front derailleur and Shimano barcons (which is
probably why I don't have chain drop). STI might be a problem but I
have not encountered it on the STI systems I've retrofitted with compact
cranks, standard derailleurs withstanding.

Robin Hubert
 
What is EPO?


Ozark Bicycle wrote:
> [email protected] wrote:
> > > You can hold 30 MPH for an hour by yourself? Wow.
> > >
> > > Matt O.

> >
> > I have no idea...I haven't tried...but as I mentioned else where if I
> > could dope for a year or two who knows what's possible :)
> >

>
> Ride like a Pro - use EPO ;-)
 

> My 48/34 x 11-28 setup allows me to ride in the big ring almost all the
> time, except on the steepest grades.


I'd agree...I'd take it another step...maybe a 44/34 with a 11-30.
That would keep me in the big ring 95% of the time. I only have one
hill where a ratio of 1.25 is ideal. Sure I can make it up in a ~1.5,
but I spin too little which eventually gives me that lower knee pain
after a week.

Randolf