32 to 36?

gerrit van wijk said:

I have 22-32-42 crank and a xt front derailleur (2000). I want to replace the 32 for a 36
chainring to get 22-36-42. Is the 6 teeth shift from 42 to 36 to small and will it cause bad
shifting? Would I need to replace the 42 for 44 to get an 8 teeth difference?

Of course it would work. I don't see why you'd want it, but it would work.

Quoted message said:

I also have an older shimano 'megarange something' front derailleur lying around which came on a
24-34-42 crank. With it's intended 8 teeth shift it might be needed to replace the xt derailleur
with this 'mega'

There is nothing about the design of either a front or rear derailleur that dictates a particular
jump size either for chainrings or cassettes. It is not "intended" for 8-tooth jumps. It is just
sold with that crank.

--

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. Johnson said:

There is nothing about the design of either a front or rear derailleur that dictates a particular
jump size either for chainrings or cassettes.

Most front derailleurs have bulges and dips inside the cage which are designed to align with certain
ranges of chainrings. Not every combination of rings will necessarily work.

~PB

"Pete Biggs" <pmelon{remove [email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

David L. Johnson said:

There is nothing about the design of either a front or rear derailleur that dictates a
particular jump size either for chainrings or cassettes.

Most front derailleurs have bulges and dips inside the cage which are designed to align with
certain ranges of chainrings. Not every combination of rings will necessarily work.

~PB

As a user of a bike with plain rings and front derailleur that works perfectly well on a 32-48
setup, I wonder why I would want a derailleur and chainring with "bumps and dips" to improve
shifting. It doesn't need improving.

I really do think that the best (front) shifting bike I own has plain rings and a Suntour Cyclone
front der. with abosolutely no bulges etc to be seen.

Certainly, some shifting components work better together than others, but, having "mixed and
matched" components from numerous bikes for longer than I care to remember, I have found no front
derailleurs that won't work with particular chainrings. Yes, the indexing of the shifter must
match and the radius of curvature should match the large ring for best performance, but that's
about it IMHO.

Andrew Webster.

"Pete Biggs" <pmelon{remove [email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

David L. Johnson said:

There is nothing about the design of either a front or rear derailleur that dictates a
particular jump size either for chainrings or cassettes.

Most front derailleurs have bulges and dips inside the cage which are designed to align with
certain ranges of chainrings. Not every combination of rings will necessarily work.

~PB

As a user of a bike with plain rings and front derailleur that works perfectly well on a 32-48
setup, I wonder why I would want a derailleur and chainring with "bumps and dips" to improve
shifting. It doesn't need improving.

I really do think that the best (front) shifting bike I own has plain rings and a Suntour Cyclone
front der. with abosolutely no bulges etc to be seen.

Certainly, some shifting components work better together than others, but, having "mixed and
matched" components from numerous bikes for longer than I care to remember, I have found no front
derailleurs that won't work with particular chainrings. Yes, the indexing of the shifter must
match and the radius of curvature should match the large ring for best performance, but that's
about it IMHO.

Andrew Webster.

Andrew Webster said:

Quoted message said:

Most front derailleurs have bulges and dips inside the cage which are designed to align with
certain ranges of chainrings. Not every combination of rings will necessarily work.

Quoted message said:

As a user of a bike with plain rings and front derailleur that works perfectly well on a 32-48
setup, I wonder why I would want a derailleur and chainring with "bumps and dips" to improve
shifting. It doesn't need improving.

It's not about special chainrings. I was referring to the profile of front derailleur cages and the
SIZE ranges of rings that they are designed to work with. I'm not suggesting that a different
derailleur be used, just that the existing one might not work well with just any rings.

~PB

Andrew Webster said:

Yes, the indexing of the shifter must match and the radius of curvature should match the large
ring for best performance, but that's about it IMHO.

If there is a dip instead of a plain or bulged section in the wrong place then it is possible
for the derailleur to contact the chain too late and not drag the chain far enough with
indexed shifting.

~PB

Pete Biggs said:

David L. Johnson said:

There is nothing about the design of either a front or rear derailleur that dictates a particular
jump size either for chainrings or cassettes.

Most front derailleurs have bulges and dips inside the cage which are designed to align with
certain ranges of chainrings. Not every combination of rings will necessarily work.

That depends on your definition of "work". I've had chainrings with pins and grooves, and those
without. There really isn't that much difference in how they shift.

--

David L. Johnson

__o | Arguing with an engineer is like mud wrestling with a pig... You _`\(,_ | soon find out the
pig likes it! (_)/ (_) |

David L. Johnson said:

Quoted message said:

Most front derailleurs have bulges and dips inside the cage which are designed to align with
certain ranges of chainrings. Not every combination of rings will necessarily work.

That depends on your definition of "work". I've had chainrings with pins and grooves, and those
without. There really isn't that much difference in how they shift.

I'm not referring to pins and grooves on the chainrings but to comptatibility between certain front
derailleurs (when used with indexed shifters) with certain sizes of middle rings.

~PB

Quoted post said:

Originally posted by Pete Biggs

I'm not referring to pins and grooves on the chainrings but to comptatibility between certain front
derailleurs (when used with indexed shifters) with certain sizes of middle rings.

~PB [/B]

I think what Pete is referring to here is the fact that derailleurs with deeper front cages (ie many MTB derailleurs, DA triple, etc) have such deep inner cage plates that thay will foul the middle ring unless set with excessive clearance above the outer ring. This will *not* help shifting to smaller rings.

It's reasonably inportant to match the number of teeth between the outer two rings fairly closely with the manufacturer's specs for best performance; if the outer ring is smaller this isn't usually a problem unless the derailleur is so low that the back edge of the cage fouls the chainstay...