chain-line and usable cogs on 10spd?

[damyth]

What's the "recommended" maximum number of "usable" cogs on a 10 spd
cassette for a given (double) chainring, from a chain line perspective?

Would it be 9, 8, or some other number?

 

[[email protected]]

damyth wrote:
> What's the "recommended" maximum number of "usable" cogs on a 10 spd
> cassette for a given (double) chainring, from a chain line perspective?
>
> Would it be 9, 8, or some other number?

7-8-9-10 speed cassettes have all used the same 130 mm rear dropout
spacing for at least 15 years now. So they all have the same
chainline. The time honored saying of avoiding the big-big and
small-small still applies until the rear dropouts get wider. Or
chainstays get much shorter. And running the big-big or small-small
combinations works too. You just might have some accelerated wear on
the parts. Not a big deal really.

 

[Leo Lichtman]

<[email protected]> wrote: (clip) And running the big-big or
small-small combinations works too. (clip)
^^^^^^^^^^^^^^^^^
They are useless combinations, since they both give you "middle" gearing
that can be achieved better with other combinations.

 

[Jasper Janssen]

On 17 Oct 2005 16:36:32 -0700, [email protected] wrote:

>7-8-9-10 speed cassettes have all used the same 130 mm rear dropout
>spacing for at least 15 years now. So they all have the same
>chainline. The time honored saying of avoiding the big-big and
>small-small still applies until the rear dropouts get wider. Or
>chainstays get much shorter. And running the big-big or small-small
>combinations works too. You just might have some accelerated wear on
>the parts. Not a big deal really.

The cogs are only a little tighter together than the rings, though, so cog
10 on the big ring and cog 9 on the small ring are not all that different
in chain-unline.

Jasper

 

[Jasper Janssen]

On Mon, 17 Oct 2005 23:48:35 GMT, "Leo Lichtman"
<[email protected]> wrote:

>They are useless combinations, since they both give you "middle" gearing
>that can be achieved better with other combinations.

Yeah, that's by design because you can't effectively use them for other
reasons. If you *could* use them with impunity, you could choose your
rings and cassette in such a way so that there would be no overlap.

Jasper

 

[Michael Press]

In article <[email protected]>,
Jasper Janssen <[email protected]> wrote:

> On Mon, 17 Oct 2005 23:48:35 GMT, "Leo Lichtman"
> <[email protected]> wrote:
>
> >They are useless combinations, since they both give you "middle" gearing
> >that can be achieved better with other combinations.
>
> Yeah, that's by design because you can't effectively use them for other
> reasons. If you *could* use them with impunity, you could choose your
> rings and cassette in such a way so that there would be no overlap.

24-38-52; 12-19,21,23.

24 38 52
23 1.04 1.65 2.26
21 1.14 1.81 2.48
19 1.26 2.00 2.74
18 1.33 2.11 2.89
17 1.41 2.24 3.06
16 1.50 2.38 3.25
15 1.60 2.53 3.47
14 1.71 2.71 3.71
13 1.85 2.92 4.00
12 2.00 3.17 4.33

Still plenty of overlap.

--
Michael Press

 

[Dave Thompson]

[email protected] wrote:
<snip>.................... And running the big-big or small-small
> combinations works too. You just might have some accelerated wear on
> the parts. Not a big deal really.
Maybe not a big deal, but a *very expensive* deal if you're running the
top-end Campy or Shimano stuff. I'm still trying to figure out why riders
are willing to pay so much for such a small return in 'peformance'.

 

[John Forrest Tomlinson]

On Mon, 17 Oct 2005 21:17:44 -0700, "Dave Thompson"
<[email protected]> wrote:

>[email protected] wrote:
><snip>.................... And running the big-big or small-small
>> combinations works too. You just might have some accelerated wear on
>> the parts. Not a big deal really.
>Maybe not a big deal, but a *very expensive* deal if you're running the
>top-end Campy or Shimano stuff. I'm still trying to figure out why riders
>are willing to pay so much for such a small return in 'peformance'.

Because they want to beat other riders who have the same stuff.
Top-end Campagnolo and Shimano are racing groups.

JT

****************************
Remove "remove" to reply
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[Qui si parla Campagnolo]

damyth wrote:
> What's the "recommended" maximum number of "usable" cogs on a 10 spd
> cassette for a given (double) chainring, from a chain line perspective?
>
> Would it be 9, 8, or some other number?

I recommend that in the large ring, use the smallest 7, in the small
ring, use the largest 7...so as to not wear stuff out too quickly.

 

[Qui si parla Campagnolo]

Dave Thompson wrote:
> [email protected] wrote:
> <snip>.................... And running the big-big or small-small
> > combinations works too. You just might have some accelerated wear on
> > the parts. Not a big deal really.
> Maybe not a big deal, but a *very expensive* deal if you're running the
> top-end Campy or Shimano stuff. I'm still trying to figure out why riders
> are willing to pay so much for such a small return in 'peformance'.

or no return. DA, Record/Chorus chains and cogs and such offer no
benefit, costing more. We sell Ultegra 10s cogs, 105 level 9s chains,
Veloce 9s and 10s cogs....A few want the most expensive but $150+ for a
cogset, $60+ for a chain, yikes.

 

[[email protected]]

Dave Thompson wrote:
> [email protected] wrote:
> <snip>.................... And running the big-big or small-small
> > combinations works too. You just might have some accelerated wear on
> > the parts. Not a big deal really.
> Maybe not a big deal, but a *very expensive* deal if you're running the
> top-end Campy or Shimano stuff. I'm still trying to figure out why riders
> are willing to pay so much for such a small return in 'peformance'.

How expensive do you think it is? How much more quickly does the
small-small or big-big combination wear the chain than the others? 1%
more wear? 10% more wear? What about when you use the next to
smallest or biggest cogs? How much extra wear do they cause than using
the perfectly straight chain position gears?

Lets say you use the small-small or big-big combinations whenever that
gear is the one you need. Lets say instead of getting 3000 miles from
a Campagnolo 9 speed chain, the ones I use, I only get 2500 miles.
2500/3000=.8333. 1-.8333=.1667. 16.67% extra wear. Quite a bit.

Lets say I ride 6000 miles a year. So that would be 2 chains if not
using the small-small or big-big combinations. Or 2.4 chains if I use
the small-small or big-big combinations and get the accelerated 16.67%
wear. I buy my 9 speed Campagnolo chains from Nashbar on sale for $20
each. These are the Record 9 speed chains. So the extra wear would
cost me $8 extra per year.

A similar scenario can be done for cassettes. Lets say 9,000 miles use
from a Campagnolo 9 speed ti/steel Record cassette when not using the
small-small or big-big combinations. I had a Record ti/steel 9 speed
cassette in the late 90s and I think it lasted about this long. Lets
assume the same 16.67% accelerated wear. 83.33% * 9,000 = 7,500 miles.
Using the same 6,000 miles riding per year, we use .67 of the cassette
if not using the big-big or small-small combinations. We use .8 of the
cassette if we use the big-big or small-small combinations whenever we
want. An extra .13 of the cassette is used in a year of riding. Lets
assume a price of $200 for a Record ti/steel 9 speed cassette. I can't
find anyone selling them anymore and this $200 is a little less than
the 10 speed ti/steel cassette. So the extra cost per year is $200 *
..13 = $26.

So Dave Thompson thinks an extra $34 of chain and cassette wear per
year is very expensive if using the top end stuff.

 

[Jasper Janssen]

On Tue, 18 Oct 2005 03:00:05 GMT, Michael Press <[email protected]> wrote:
>In article <[email protected]>,
> Jasper Janssen <[email protected]> wrote:
>
>> On Mon, 17 Oct 2005 23:48:35 GMT, "Leo Lichtman"
>> <[email protected]> wrote:
>>
>> >They are useless combinations, since they both give you "middle" gearing
>> >that can be achieved better with other combinations.
>>
>> Yeah, that's by design because you can't effectively use them for other
>> reasons. If you *could* use them with impunity, you could choose your
>> rings and cassette in such a way so that there would be no overlap.
>
>24-38-52; 12-19,21,23.
>
> 24 38 52
>23 1.04 1.65 2.26
>21 1.14 1.81 2.48
>19 1.26 2.00 2.74
>18 1.33 2.11 2.89
>17 1.41 2.24 3.06
>16 1.50 2.38 3.25
>15 1.60 2.53 3.47
>14 1.71 2.71 3.71
>13 1.85 2.92 4.00
>12 2.00 3.17 4.33
>
>Still plenty of overlap.

16-30-56; 12-19,21, just to limit myself to currently available (if not
exactly conventional[1]) gear.

2.6 4.9 9.2
2.4 4.5 8.5
2.2 4.2 7.9
2.1 3.9 7.3
2.0 3.7 6.9
1.8 3.5 6.5
1.7 3.3 6.1
1.7 3.1 5.8
1.5 2.8 5.2

Of course, it would be better to have some overlap to be able to avoid
doubleshifts when necessary, but without chainline considerations, you do
need less overlap than you might otherwise need.


Jasper

[1] The cassette is a standard 9er, the cranks would consist of a 110/74
with a Mountain Tamer Quad Plus doing the middle and low, and just the
high gear on the 110 -- which means you get slightly bad Q factor and
chainline (the equivalent of having a quad, in fact), but chainline
considerations were eliminated from this thought experiment and a few mm
of Q-factor won't usually kill you.

 

[Leo Lichtman]

ytgdse wrote: (clip) Lets say you use the small-small or big-big
combinations whenever that gear is the one you need.(clip)
^^^^^^^^^^^^^^^^^
The point I think you are missing is that those two combinations are NEVER
ones you need. There are combinations in the middle which give you
essentially the same ratios, but which are better for power transfer and
chain/sprocket wear. The only time I ride with the chain in either of those
two positions results from inattention--a string of upshifts or downshifts
that are quickly made, without noticing that the limit was being reached.
The MAIN disadvantage of riding like that is that the next shift will
probably fail, so you will HAVE to make a chainring shift, which probably is
more than you wanted, so you end up doing a double shift.

As others have pointed out, the excess wear is probably not really very
important. To me it's kind of an esthetic thing--why do it wrong when you
could do it "right?"

 

[[email protected]]

Leo Lichtman wrote:
> ytgdse wrote: (clip) Lets say you use the small-small or big-big
> combinations whenever that gear is the one you need.(clip)
> ^^^^^^^^^^^^^^^^^
> The point I think you are missing is that those two combinations are NEVER
> ones you need.

I guess if you define NEED as meaning only a different numerical gear,
then you could be right. I define NEED as the right gear at the right
time. Like when I was riding with some friends and the pace picked up.
I was leading the chasing group in the small-small combination (42x13)
at 29 mph after quickly clicking down a cog at a time. Taking the
seconds to shift to the big ring and then upshift 2-3 cogs on the back
to get to the next correct gear in the progression was not an option.
Unless I wanted to get run over by the tandem following me. Not
something I wanted to do.


There are combinations in the middle which give you
> essentially the same ratios, but which are better for power transfer and
> chain/sprocket wear. The only time I ride with the chain in either of those
> two positions results from inattention

Or the pace picks up instantly and you go by shifting the rear
derailleur to a smaller cog or you get left.

--a string of upshifts or downshifts
> that are quickly made, without noticing that the limit was being reached.
> The MAIN disadvantage of riding like that is that the next shift will
> probably fail, so you will HAVE to make a chainring shift, which probably is
> more than you wanted, so you end up doing a double shift.

I can get my 42x13 up to 30 mph on the flat. That is as fast as I can
maintain (for a brief period) on the flat so there is no need for
another shift. I don't have to make a shift to the big chainring.


>
> As others have pointed out, the excess wear is probably not really very
> important. To me it's kind of an esthetic thing--why do it wrong when you
> could do it "right?"

In some instances it is right to use the small-small combination or
big-big combination. For the big-big, if you are racing up the hill
staying with the group, or keeping the pace you want, being able to
quickly shift to the big-big will keep you moving. Dropping to the
small ring and then dropping the rear derailleur to a smaller cog will
lose you all your momentum.

There are more than a few instances where not using the small-small or
big-big combinations would make you a danger in group riding. The
sudden drop in speed by double shifting as you suggest makes your speed
drop too much for people riding behind you. Very unsafe way to ride.

 

[Booker C. Bense]

-----BEGIN PGP SIGNED MESSAGE-----

In article <[email protected]>,
Jasper Janssen <[email protected]> wrote:
>On Tue, 18 Oct 2005 03:00:05 GMT, Michael Press <[email protected]> wrote:
>>In article <[email protected]>,
>> Jasper Janssen <[email protected]> wrote:
>>
>>> On Mon, 17 Oct 2005 23:48:35 GMT, "Leo Lichtman"
>>> <[email protected]> wrote:
>>>
>>> >They are useless combinations, since they both give you "middle" gearing
>>> >that can be achieved better with other combinations.
>>>
>>> Yeah, that's by design because you can't effectively use them for other
>>> reasons. If you *could* use them with impunity, you could choose your
>>> rings and cassette in such a way so that there would be no overlap.
>>
>>24-38-52; 12-19,21,23.
>>
>> 24 38 52
>>23 1.04 1.65 2.26
>>21 1.14 1.81 2.48
>>19 1.26 2.00 2.74
>>18 1.33 2.11 2.89
>>17 1.41 2.24 3.06
>>16 1.50 2.38 3.25
>>15 1.60 2.53 3.47
>>14 1.71 2.71 3.71
>>13 1.85 2.92 4.00
>>12 2.00 3.17 4.33
>>
>>Still plenty of overlap.
>
>16-30-56; 12-19,21, just to limit myself to currently available (if not
>exactly conventional[1]) gear.
>
>2.6 4.9 9.2
>2.4 4.5 8.5
>2.2 4.2 7.9
>2.1 3.9 7.3
>2.0 3.7 6.9
>1.8 3.5 6.5
>1.7 3.3 6.1
>1.7 3.1 5.8
>1.5 2.8 5.2
>
>Of course, it would be better to have some overlap to be able to avoid
>doubleshifts when necessary, but without chainline considerations, you do
>need less overlap than you might otherwise need.
>
>

_ This gets vastly easier if you give up the relatively widely spaced
12 and 13 and use something like a 14-25 ( Not custom, shimano
sells an Ultegra and 105 version. ). Of course if you switch
to the junior racing 15-25, I think you could even do it with
a 130/74 crank. It's silly game to play, but you get much
closer spacing with bigger gears on the back.

_ Booker C. Bense

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[Ron Ruff]

[email protected] wrote:
>
> 7-8-9-10 speed cassettes have all used the same 130 mm rear dropout
> spacing for at least 15 years now.

True

> So they all have the same
> chainline.
>
Not true. Dropout spacing is not the issue. The ctc width of a 7 speed
cluster is 30mm. For Shimano 10 it is 35.5mm, for Campy 10 it is
37mm... they are more than 1 gear wider overall.

I'd recommend avoiding the two most extreme cogs with a double. With a
triple I'd avoid two cogs with the center ring and three cogs with the
big and small rings. For brief periods or "emergency" situations
though, you can use them all.

AFAIK there have been no tests done to determine the effect of
chainline on wear.

 

[Leo Lichtman]

<[email protected]> wrote: I guess if you define NEED as meaning
only a different numerical gear, then you could be right. I define NEED as
the right gear at the right time. (clip)
^^^^^^^^^^^^^^^^
I concede that you are right. I further wish to state that you were able to
see where our differences were, and clearly explain what I was missing.

 

[Mark Hickey]

[email protected] wrote:

>How expensive do you think it is? How much more quickly does the
>small-small or big-big combination wear the chain than the others? 1%
>more wear? 10% more wear?

It's a LOT more than that.

The best anecdotal evidence I have is the fact the timing (left) chain
on my old tandem lasted for many years, probably racking up 15-20,000
miles, and still measured like new. That was on a bike with smallish
timing rings, which actually increases the tension on the chain to
much more than that of my "normal road bike" which wore out chains
much faster.

My MTB (which has to put up with bad chainline pretty often) goes
through chains even quicker, though the direct comparison to my road
bike is difficult since I spend so much time in smaller rings (that
is, nearly all of the riding I do is in a smaller ring on the MTB).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

 

[Mark Janeba]

Jasper Janssen wrote:
> On Tue, 18 Oct 2005 03:00:05 GMT, Michael Press <[email protected]> wrote:
>
>>In article <[email protected]>,
>>Jasper Janssen <[email protected]> wrote:
>>
>>
>>>On Mon, 17 Oct 2005 23:48:35 GMT, "Leo Lichtman"
>>><[email protected]> wrote:
>>>
>>>
>>>>They are useless combinations, since they both give you "middle" gearing
>>>>that can be achieved better with other combinations.
>>>
>>>Yeah, that's by design because you can't effectively use them for other
>>>reasons. If you *could* use them with impunity, you could choose your
>>>rings and cassette in such a way so that there would be no overlap.
>>
>>24-38-52; 12-19,21,23.
>>
>> 24 38 52
>>23 1.04 1.65 2.26
>>21 1.14 1.81 2.48
>>19 1.26 2.00 2.74
>>18 1.33 2.11 2.89
>>17 1.41 2.24 3.06
>>16 1.50 2.38 3.25
>>15 1.60 2.53 3.47
>>14 1.71 2.71 3.71
>>13 1.85 2.92 4.00
>>12 2.00 3.17 4.33
>>
>>Still plenty of overlap.
>
>
> 16-30-56; 12-19,21, just to limit myself to currently available (if not
> exactly conventional[1]) gear.
>
> 2.6 4.9 9.2
> 2.4 4.5 8.5
> 2.2 4.2 7.9
> 2.1 3.9 7.3
> 2.0 3.7 6.9
> 1.8 3.5 6.5
> 1.7 3.3 6.1
> 1.7 3.1 5.8
> 1.5 2.8 5.2
>
> Of course, it would be better to have some overlap to be able to avoid
> doubleshifts when necessary, but without chainline considerations, you do
> need less overlap than you might otherwise need.
>
>
> Jasper
>
> [1] The cassette is a standard 9er, the cranks would consist of a 110/74
> with a Mountain Tamer Quad Plus doing the middle and low, and just the
> high gear on the 110 -- which means you get slightly bad Q factor and
> chainline (the equivalent of having a quad, in fact), but chainline
> considerations were eliminated from this thought experiment and a few mm
> of Q-factor won't usually kill you.

Ummm.. is there a rear derailleur that will wrap that much chain?
(49T difference)? Or is that, as I gather, beside the point?

Mark

 

[Jasper Janssen]

On Tue, 18 Oct 2005 20:36:23 -0700, Mark Janeba
<[email protected]> wrote:
>Jasper Janssen wrote:

>> [1] The cassette is a standard 9er, the cranks would consist of a 110/74
>> with a Mountain Tamer Quad Plus doing the middle and low, and just the
>> high gear on the 110 -- which means you get slightly bad Q factor and
>> chainline (the equivalent of having a quad, in fact), but chainline
>> considerations were eliminated from this thought experiment and a few mm
>> of Q-factor won't usually kill you.
>
>Ummm.. is there a rear derailleur that will wrap that much chain?
>(49T difference)? Or is that, as I gather, beside the point?

If you're going for Mountain Tamers and the like anyway, you might as well
mod your rear derailer with a super-long cage and an extra strong chain
tension spring, since you'll sure as hell need to make a custom front
derailer cage. Or you could do it by mounting two rear derailers in
series, just need to fabricate the mount and a 'cablesplitter' that will
allow one cable from the shifter to operate both RDs.

But if chainline considerations weren't around, you might see people
actually making these -- setups not that dissimilar are used on recumbent
trikes where chainline considerations are moot; although admittedly those
usually go for quad or quint chainwheels within the 16-156 range.

Jasper