Shimano mountain f/d and road shifter compatibility

Hello, I just read in the Quality Bicycle Products (QBP) catalog, that one
should not mix a mountain front deraiileur and a road front shifter. Why is
that?

My specific question: does this guideline still apply to bar-end shifters
(D-A 9-speed) and mountain front derailleurs (XT M751 or LX M571)? Thanks
in advance for your input.

On Mon, 23 May 2005 22:11:55 -0400, Jeff S. wrote:

Hello, I just read in the Quality Bicycle Products (QBP) catalog, that one
should not mix a mountain front deraiileur and a road front shifter. Why is
that?

The amount of cable-pull per shift is different.

My specific question: does this guideline still apply to bar-end shifters
(D-A 9-speed) and mountain front derailleurs (XT M751 or LX M571)? Thanks
in advance for your input.

It would if the bar-end shifters are indexed. Can you use them in
friction mode? If so, they'd work fine. There is also at least one
mountain-sized derailleur that will work with road shifters. Check
Sheldon Brown's site for details.

--

David L. Johnson

__o | Do not worry about your difficulties in mathematics, I can
_`\(,_ | assure you that mine are all greater. -- A. Einstein
(_)/ (_) |

Jeff S. wrote:
Hello, I just read in the Quality Bicycle Products (QBP) catalog, that one
should not mix a mountain front deraiileur and a road front shifter. Why is
that?

They use a different amount of cable travel per shift.

My specific question: does this guideline still apply to bar-end shifters
(D-A 9-speed) and mountain front derailleurs (XT M751 or LX M571)?

Not a problem with bar-end shifters, 'cause they aren't indexed for the
front derailer. This is only an issue with indexed front shifters, such
as STI.

Sheldon "No Worries" Brown
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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

Thanks for the quick response. That is as I expected, but you just need to
be certain when re-configuring a drivetrain. My Jamis Aurora has a Truvativ
'Touro' (130/74 w/ 52/42/30) and I want to go to a Sugino XD to go 110/74.

My latest thinking (always subject to change with a new brain synapse) is
48/36/26 or 24 with a 12x23 9-sp. cassette and M751 or M571 28.6 mm bottom
pull traditional swing f/d and a 105 triple r/d. Now to sort out the
chainrings and bb length (Grant says 107/110 and QBP says 113/118). I will
do this with moustache bars rather than the stock Biomax bars.

Thanks again.


"Sheldon Brown" wrote in message
...
Jeff S. wrote:
Hello, I just read in the Quality Bicycle Products (QBP) catalog, that
one
should not mix a mountain front deraiileur and a road front shifter.
Why is
that?

They use a different amount of cable travel per shift.

My specific question: does this guideline still apply to bar-end
shifters
(D-A 9-speed) and mountain front derailleurs (XT M751 or LX M571)?

Not a problem with bar-end shifters, 'cause they aren't indexed for the
front derailer. This is only an issue with indexed front shifters, such
as STI.

Sheldon "No Worries" Brown
+-----------------------------------------------------------------+
| This message has been sent to you using recycled electrons |
| exclusively. Please do not discard them after use, |
| send them along and help conserve these irreplaceable |
| sub-atomic resources for future generations. |
+-----------------------------------------------------------------+
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

Jeff S. wrote:
Hello, I just read in the Quality Bicycle Products (QBP) catalog,
that one
should not mix a mountain front deraiileur and a road front shifter.
Why is
that?

My specific question: does this guideline still apply to bar-end
shifters
(D-A 9-speed) and mountain front derailleurs (XT M751 or LX M571)?
Thanks
in advance for your input.

Cuz it doesn't work. The arms of the MTB front ders are of a different
dimension and the resulting STI(road) and MTB front der is not
compatible.

NOT for friction barend shifters, of course. These are compatible tiwht
anything, jus about.

On Tue, 24 May 2005 00:18:28 -0400, Jeff S. wrote:

Thanks for the quick response. That is as I expected, but you just need to
be certain when re-configuring a drivetrain. My Jamis Aurora has a Truvativ
'Touro' (130/74 w/ 52/42/30) and I want to go to a Sugino XD to go 110/74.

My latest thinking (always subject to change with a new brain synapse) is
48/36/26 or

Oh, so you have a road derailleur, and feel the need to switch to mountain
because of the 48? Not necessary, actually. I use a road derailleur with
a 46/30 front, and have no problems shifting. Mine's Campy, but Shimano
can also be set up to work fine this way. It is a little fussier, but not
impossible.

--

David L. Johnson

__o | What is objectionable, and what is dangerous about extremists is
_`\(,_ | not that they are extreme, but that they are intolerant.
(_)/ (_) | --Robert F. Kennedy

Jeff S. wrote:
Thanks for the quick response. That is as I expected, but you just
need to
be certain when re-configuring a drivetrain. My Jamis Aurora has a
Truvativ
'Touro' (130/74 w/ 52/42/30) and I want to go to a Sugino XD to go
110/74.

Why? You can put any size chainring down to 38 teeth on the middle and
outer spots on your current crank. The 74mm bcd inner spot is the
exact same on the two cranksets so your low gear is identical. What
exactly do you imagine you are getting by switching cranks?


My latest thinking (always subject to change with a new brain
synapse) is
48/36/26 or 24 with a 12x23 9-sp. cassette

And your current 130mm bcd crank will take 48-38-24. Close enough to
your proposed 48-36-24 to not make one bit of difference. You are
obviously just picking chainring sizes because they have a nice dozen
teeth difference between them. You are not trying to get a certain
shifting pattern. So 38 or 36 teeth on the middle ring will make no
difference to you.

wrote:
Jeff S. wrote:
My Jamis Aurora has a Truvativ
'Touro' (130/74 w/ 52/42/30) and I want to go to a Sugino XD to go
110/74.

Why?

The Sugino XD is $70 at Lickton's (the first response from Froogle).
Three chainrings probably add up to about that much, maybe more. So it
might be cheaper to get the cranks rather than 3 chainrings.

On the other hand, if the new cranks also require a new BB, he might be
better off with 3 new rings.

--
Dave
dvt at psu dot edu

Jeff S. wrote:

be certain when re-configuring a drivetrain. My Jamis Aurora has a
Truvativ
'Touro' (130/74 w/ 52/42/30) and I want to go to a Sugino XD to go
110/74.

Russell Seaton asked:

Why? You can put any size chainring down to 38 teeth on the middle and
outer spots on your current crank. The 74mm bcd inner spot is the
exact same on the two cranksets so your low gear is identical. What
exactly do you imagine you are getting by switching cranks?

Good point!

My latest thinking is 48/36/26 or 24 with a 12x23 9-sp. cassette

You'd be better off leaving the cranks alone, and going with one of my
"Century Special" 13-30 cassettes. The 52/13 top gear is _exactly_ the
same as your proposed 48/12. The 30/30 low gear is 10% lower than your
proposed 24/23.

This setup would provide much better shifting in front, because you'll
be using the chainring sizes the front derailer was designed for.

It will also give longer chain/sprocket life due to the larger sprockets
involved.

http://harriscyclery.com/9

Sheldon "Save Your Money" Brown
+-----------------------------------------------+
| The wayfarer |
| Perceiving the pathway to truth, |
| Was struck with astonishment. |
| It was thickly grown with weeds. |
| "Ha," he said, |
| "I see that none has passed here |
| In a long time." |
| Later he saw that each weed |
| Was a singular knife. |
| "Well," he mumbled at last, |
| "Doubtless there are other roads." |
| --Stephen Crane |
+-----------------------------------------------+
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

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In article ,
David L. Johnson wrote:
On Mon, 23 May 2005 22:11:55 -0400, Jeff S. wrote:

Hello, I just read in the Quality Bicycle Products (QBP) catalog, that one
should not mix a mountain front deraiileur and a road front shifter. Why is
that?

The amount of cable-pull per shift is different.

My specific question: does this guideline still apply to bar-end shifters
(D-A 9-speed) and mountain front derailleurs (XT M751 or LX M571)? Thanks
in advance for your input.

It would if the bar-end shifters are indexed. Can you use them in
friction mode? If so, they'd work fine. There is also at least one
mountain-sized derailleur that will work with road shifters. Check
Sheldon Brown's site for details.


_ The Dura Ace front bar end shifter is not indexed, so you can use
any fromt derailleur you want with it. I don't know of any bar
end shifter that has indexing on the front.

_ Booker C. Bense

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