Chainring gap sizes for SunTour front der's?

On my vintage XT cranks, I want to run 26/36/46 or 48t rings. With a
modern LX front derailleur (571 model), the cage gets too close to the
top of the middle ring with 46 and 48 rings (it's OK on a 50t).

Looking at the older (early '90s) SunTour triple front mechs, it appears
that the inner/outer cages are closer in profile (or "drop"). Anyone
happen to know what the preferred chainring gap sizes are for the older
(non-micro) SunTour front derailleurs (X-1, XC-LTD/COMP/PRO)?

--
Mark Chandler
Superior, CO
http://www.MileHighSkates.com

On my vintage XT cranks, I want to run 26/36/46 or 48t rings. With a

modern LX front derailleur (571 model), the cage gets too close to
the
top of the middle ring with 46 and 48 rings (it's OK on a 50t).

Looking at the older (early '90s) SunTour triple front mechs, it
appears
that the inner/outer cages are closer in profile (or "drop"). Anyone

happen to know what the preferred chainring gap sizes are for the
older
(non-micro) SunTour front derailleurs (X-1, XC-LTD/COMP/PRO)?

For several years I ran a Deore DX triple front derailleur with the
deep inner cage on 48-45-20 chainrings. The front derailleur was
mounted at least 1/2 inch above the outer chainring. Didn't matter.
Shifted just fine.

I currently use a Sora double front derailleur to shift 45-42-20
chainrings. Its about 1/4 inch above the outer chainring. No problem
with the inner cage hitting the middle chainring. But its mounted a
bit higher than the experts recommend because the chain will drag the
underside of the front derailleur when in the 45x28 cog. Front
derailleur shifts fine.

I'd suggest you just use the front derailleur you have and stop
worrying about made up problems and ride the bike. Or if the imaginary
problems are too great to overcome, then get a double front derailleur
and mount it as close to the top of the outer chainring as you want.

wrote:

For several years I ran a Deore DX triple front derailleur with the
deep inner cage on 48-45-20 chainrings. The front derailleur was
mounted at least 1/2 inch above the outer chainring. Didn't matter.
Shifted just fine.

I currently use a Sora double front derailleur to shift 45-42-20
chainrings. Its about 1/4 inch above the outer chainring. No problem
with the inner cage hitting the middle chainring. But its mounted a
bit higher than the experts recommend because the chain will drag the
underside of the front derailleur when in the 45x28 cog. Front
derailleur shifts fine.

Have you ever thrown the chain with the front mechs set so high above
the chainring?

I'd suggest you just use the front derailleur you have and stop
worrying about made up problems and ride the bike. Or if the imaginary
problems are too great to overcome, then get a double front derailleur
and mount it as close to the top of the outer chainring as you want.

Gee, thanks (I think).


--
Mark Chandler
Superior, CO
http://www.MileHighSkates.com

M. Chandler wrote:
wrote:

For several years I ran a Deore DX triple front derailleur with the
deep inner cage on 48-45-20 chainrings. The front derailleur was
mounted at least 1/2 inch above the outer chainring. Didn't
matter.
Shifted just fine.

I currently use a Sora double front derailleur to shift 45-42-20
chainrings. Its about 1/4 inch above the outer chainring. No
problem
with the inner cage hitting the middle chainring. But its mounted
a
bit higher than the experts recommend because the chain will drag
the
underside of the front derailleur when in the 45x28 cog. Front
derailleur shifts fine.

Have you ever thrown the chain with the front mechs set so high above

the chainring?

I'd suggest you just use the front derailleur you have and stop
worrying about made up problems and ride the bike. Or if the
imaginary
problems are too great to overcome, then get a double front
derailleur
and mount it as close to the top of the outer chainring as you
want.

Gee, thanks (I think).


I use the Third Eye chain watcher or the N Jump Stop chain watcher on
all of my bikes with triples. So no I don't throw the chain. Its
cheap insurance.

wrote:

I use the Third Eye chain watcher or the N Jump Stop chain watcher on
all of my bikes with triples. So no I don't throw the chain. Its
cheap insurance.

I was wondering if you were throwing the chain over the big ring because
of the large gap.


--
Mark Chandler
Superior, CO
http://www.MileHighSkates.com

M. Chandler wrote:
wrote:

I use the Third Eye chain watcher or the N Jump Stop chain watcher
on
all of my bikes with triples. So no I don't throw the chain. Its
cheap insurance.

I was wondering if you were throwing the chain over the big ring
because
of the large gap.


I throw the chain to the outside every year or two. Scattered among
the three bikes I regularly use. And some of the bikes have the front
derailleur cage 1-2 mm above the outer chainring. So I don't think
having the front derailleur mounted high makes much difference. At
least not in my experience.