XTR BB on a road bike? Is the Mfg full of it?

[Jens Kurt Heycke]

I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
up to accomodate a 56 chainring, it can't swing inwards far enough on
reach all the rear cogs with the small chainring. The FD arm hits the frame
and
can't go any further, so when you're in the small chainring, the chain rubs
the
FD in the 2 biggest rear cogs.

I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
Does this sound like reasonable solution?

It seems to me that I will end up with a bigger Q factor and a bad chainline
and maybe some other consequences I haven't thought of yet?

thanks in advance

- Jens

[daveornee]

Jens Kurt Heycke Wrote:
> I've got a Aegis T2 TT bike with a shifting problem: when you slide th
> FD
> up to accomodate a 56 chainring, it can't swing inwards far enough on
> reach all the rear cogs with the small chainring. The FD arm hits th
> frame
> and
> can't go any further, so when you're in the small chainring, the chai
> rubs
> the
> FD in the 2 biggest rear cogs.
>
> I've tried a few solutions: an extra BB spacer, a Campy (instead o
> Shimano)
> derailleur. Nothing quite seems to work. Now Aegis tells me th
> solution is
> to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> Does this sound like reasonable solution?
>
> It seems to me that I will end up with a bigger Q factor and a ba
> chainline
> and maybe some other consequences I haven't thought of yet?
>
> thanks in advance
>
> - Jens

If the 3 mm difference allows you to use cross chained combination
that you must have then go for it.
However, you might want to check if other combinations could give yo
the same desired gearing without so much cross chaining.
I would also check to see if you can get the desired results by makin
small adjustments in height and angle of the front derailer. Th
larger radius of the TT Chain Wheel makes this a challenge as the Fron
Derailer isn't optimized for this combination.

Does your fron shifter allow you to trim it's position?

I have modified the radius of my front derailers... just slightly.. o
our tandems that use 54 teeth chain wheels so I can get the positio
just a faction of a milimeter lower and can use any combination withou
chain rub... as long as I have trimmed the position

--
daveornee

[daveornee]

Jens Kurt Heycke Wrote:
> I've got a Aegis T2 TT bike with a shifting problem: when you slide th
> FD
> up to accomodate a 56 chainring, it can't swing inwards far enough on
> reach all the rear cogs with the small chainring. The FD arm hits th
> frame
> and
> can't go any further, so when you're in the small chainring, the chai
> rubs
> the
> FD in the 2 biggest rear cogs.
>
> I've tried a few solutions: an extra BB spacer, a Campy (instead o
> Shimano)
> derailleur. Nothing quite seems to work. Now Aegis tells me th
> solution is
> to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> Does this sound like reasonable solution?
>
> It seems to me that I will end up with a bigger Q factor and a ba
> chainline
> and maybe some other consequences I haven't thought of yet?
>
> thanks in advance
>
> - Jens

If the 3 mm difference allows you to use cross chained combination
that you must have then go for it.
However, you might want to check if other combinations could give yo
the same desired gearing without so much cross chaining.
I would also check to see if you can get the desired results by makin
small adjustments in height and angle of the front derailer. Th
larger radius of the TT Chain Wheel makes this a challenge as the Fron
Derailer isn't optimized for this combination.

Does your fron shifter allow you to trim it's position?

I have modified the radius of my front derailers... just slightly.. o
our tandems that use 54 teeth chain wheels so I can get the positio
just a faction of a milimeter lower and can use any combination withou
chain rub... as long as I have trimmed the position

--
daveornee

[Jens Kurt Heycke]

Thanks Dave. I've clarified some things below.

"daveornee" > wrote in
message ...
>
> Jens Kurt Heycke Wrote:
> > I've got a Aegis T2 TT bike with a shifting problem: when you slide the
> > FD
> > up to accomodate a 56 chainring, it can't swing inwards far enough on
> > reach all the rear cogs with the small chainring. The FD arm hits the
> > frame
> > and
> > can't go any further, so when you're in the small chainring, the chain
> > rubs
> > the
> > FD in the 2 biggest rear cogs.
> >
> > I've tried a few solutions: an extra BB spacer, a Campy (instead of
> > Shimano)
> > derailleur. Nothing quite seems to work. Now Aegis tells me the
> > solution is
> > to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> > Does this sound like reasonable solution?
> >
> > It seems to me that I will end up with a bigger Q factor and a bad
> > chainline
> > and maybe some other consequences I haven't thought of yet?
> >
> > thanks in advance
> >
> > - Jens
>
> If the 3 mm difference allows you to use cross chained combinations
> that you must have then go for it.

But I don't want to use cross-chained combinations. Just to clarify:
the chain rubs the front derailleur when I'm on the _small_ chainring
and the large cogs (i.e. 23, 25) in the back. IOW, inside chainring
to inside rear cogs -- the opposite of cross-chaining.


> However, you might want to check if other combinations could give you
> the same desired gearing without so much cross chaining.
> I would also check to see if you can get the desired results by making
> small adjustments in height and angle of the front derailer. The
> larger radius of the TT Chain Wheel makes this a challenge as the Front
> Derailer isn't optimized for this combination.
>
> Does your fron shifter allow you to trim it's position?

Yes. I use aerobar shifters, with friction shifting on the front. The
problem is not derailleur adjustment, it's that the seat-tube, with its
funky aero shape, stops the derailleur arm from going inward enough to
fully center over the small chainring.


>
> I have modified the radius of my front derailers... just slightly.. on
> our tandems that use 54 teeth chain wheels so I can get the position
> just a faction of a milimeter lower and can use any combination without
> chain rub... as long as I have trimmed the position.
>

I'm not sure what you mean by "modifying the radius"


thanks again for your thoughts

Jens

[Jens Kurt Heycke]

Thanks Dave. I've clarified some things below.

"daveornee" > wrote in
message ...
>
> Jens Kurt Heycke Wrote:
> > I've got a Aegis T2 TT bike with a shifting problem: when you slide the
> > FD
> > up to accomodate a 56 chainring, it can't swing inwards far enough on
> > reach all the rear cogs with the small chainring. The FD arm hits the
> > frame
> > and
> > can't go any further, so when you're in the small chainring, the chain
> > rubs
> > the
> > FD in the 2 biggest rear cogs.
> >
> > I've tried a few solutions: an extra BB spacer, a Campy (instead of
> > Shimano)
> > derailleur. Nothing quite seems to work. Now Aegis tells me the
> > solution is
> > to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> > Does this sound like reasonable solution?
> >
> > It seems to me that I will end up with a bigger Q factor and a bad
> > chainline
> > and maybe some other consequences I haven't thought of yet?
> >
> > thanks in advance
> >
> > - Jens
>
> If the 3 mm difference allows you to use cross chained combinations
> that you must have then go for it.

But I don't want to use cross-chained combinations. Just to clarify:
the chain rubs the front derailleur when I'm on the _small_ chainring
and the large cogs (i.e. 23, 25) in the back. IOW, inside chainring
to inside rear cogs -- the opposite of cross-chaining.


> However, you might want to check if other combinations could give you
> the same desired gearing without so much cross chaining.
> I would also check to see if you can get the desired results by making
> small adjustments in height and angle of the front derailer. The
> larger radius of the TT Chain Wheel makes this a challenge as the Front
> Derailer isn't optimized for this combination.
>
> Does your fron shifter allow you to trim it's position?

Yes. I use aerobar shifters, with friction shifting on the front. The
problem is not derailleur adjustment, it's that the seat-tube, with its
funky aero shape, stops the derailleur arm from going inward enough to
fully center over the small chainring.


>
> I have modified the radius of my front derailers... just slightly.. on
> our tandems that use 54 teeth chain wheels so I can get the position
> just a faction of a milimeter lower and can use any combination without
> chain rub... as long as I have trimmed the position.
>

I'm not sure what you mean by "modifying the radius"


thanks again for your thoughts

Jens

[S R Sharp]

Jens Kurt Heycke wrote:
> I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
> up to accomodate a 56 chainring, it can't swing inwards far enough on
> reach all the rear cogs with the small chainring. The FD arm hits the frame
> and
> can't go any further, so when you're in the small chainring, the chain rubs
> the
> FD in the 2 biggest rear cogs.
>
> I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
> derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
> to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> Does this sound like reasonable solution?
>
> It seems to me that I will end up with a bigger Q factor and a bad chainline
> and maybe some other consequences I haven't thought of yet?
>
> thanks in advance
>
> - Jens

Grind some material off the back of the derailleur where it contacts the
frame.



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[S R Sharp]

Jens Kurt Heycke wrote:
> I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
> up to accomodate a 56 chainring, it can't swing inwards far enough on
> reach all the rear cogs with the small chainring. The FD arm hits the frame
> and
> can't go any further, so when you're in the small chainring, the chain rubs
> the
> FD in the 2 biggest rear cogs.
>
> I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
> derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
> to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> Does this sound like reasonable solution?
>
> It seems to me that I will end up with a bigger Q factor and a bad chainline
> and maybe some other consequences I haven't thought of yet?
>
> thanks in advance
>
> - Jens

Grind some material off the back of the derailleur where it contacts the
frame.



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[Jeff Starr]

On Wed, 13 Oct 2004 08:25:59 -0700, "Jens Kurt Heycke"
> wrote:

>I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
>up to accomodate a 56 chainring, it can't swing inwards far enough on
>reach all the rear cogs with the small chainring. The FD arm hits the frame
>and
>can't go any further, so when you're in the small chainring, the chain rubs
>the
>FD in the 2 biggest rear cogs.
>
>I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
>derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
>to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
>Does this sound like reasonable solution?
>
>It seems to me that I will end up with a bigger Q factor and a bad chainline
>and maybe some other consequences I haven't thought of yet?
>
>thanks in advance
>
>- Jens
>
>

Hi, I thought the Octalink was different on the road and mtb cranks,
but I don't know for sure. I suppose a road triple BB would bring it
out too far?


Life is Good!
Jeff

[Jeff Starr]

On Wed, 13 Oct 2004 08:25:59 -0700, "Jens Kurt Heycke"
> wrote:

>I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
>up to accomodate a 56 chainring, it can't swing inwards far enough on
>reach all the rear cogs with the small chainring. The FD arm hits the frame
>and
>can't go any further, so when you're in the small chainring, the chain rubs
>the
>FD in the 2 biggest rear cogs.
>
>I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
>derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
>to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
>Does this sound like reasonable solution?
>
>It seems to me that I will end up with a bigger Q factor and a bad chainline
>and maybe some other consequences I haven't thought of yet?
>
>thanks in advance
>
>- Jens
>
>

Hi, I thought the Octalink was different on the road and mtb cranks,
but I don't know for sure. I suppose a road triple BB would bring it
out too far?


Life is Good!
Jeff

[daveornee]

Jens Kurt Heycke Wrote:
> Thanks Dave. I've clarified some things below.
>
> <SNIP>> If the 3 mm difference allows you to use cross chaine
> combinations
> > that you must have then go for it.
>
> But I don't want to use cross-chained combinations. Just to clarify:
> the chain rubs the front derailleur when I'm on the _small_ chainring
> and the large cogs (i.e. 23, 25) in the back. IOW, inside chainring
> to inside rear cogs -- the opposite of cross-chaining.
>
> <SNIP>
> Yes. I use aerobar shifters, with friction shifting on the front. The
> problem is not derailleur adjustment, it's that the seat-tube, wit
> its
> funky aero shape, stops the derailleur arm from going inward enough to
> fully center over the small chainring.
>
> <SNIP>
> I'm not sure what you mean by "modifying the radius"
>
>
> thanks again for your thoughts
>
> Jens[/color]

Sorry, I misread and it was my mistake. I get your issue now on th
little ring/large cog area.
What I did with modifying the radius was a little careful bending an
grinding of the "offending" parts of the cage (Shimano calls it th
CHAIN GUIDE UNIT). I made the cage have a slightly larger radius so
could lower it a very small amount (~1 mm) and it doesn't catch an
teeth of the large ring when passing just over them. I bent the cag
just a bit (much less than 1 mm) so it would clear. The cage I use
had a radius optimized for a 53 tooth large ring. I made the radiu
much closer to a 54 tooth ring (You may need to go further or d
something else completely different) in the area of the outer plat
that would have contacted the big ring teeth when shifting down toward
the small ring.
XTR Splines are the same as DURA ACE and Ultegra.... to answer anothe
poster's question.
If you have already used 1.5 mm worth of spacing and it hasn't cleare
the issue, I don't know if I would push towards the XTR BB unti
someone can demonstrates that it really works

--
daveornee

[daveornee]

Jens Kurt Heycke Wrote:
> Thanks Dave. I've clarified some things below.
>
> <SNIP>> If the 3 mm difference allows you to use cross chaine
> combinations
> > that you must have then go for it.
>
> But I don't want to use cross-chained combinations. Just to clarify:
> the chain rubs the front derailleur when I'm on the _small_ chainring
> and the large cogs (i.e. 23, 25) in the back. IOW, inside chainring
> to inside rear cogs -- the opposite of cross-chaining.
>
> <SNIP>
> Yes. I use aerobar shifters, with friction shifting on the front. The
> problem is not derailleur adjustment, it's that the seat-tube, wit
> its
> funky aero shape, stops the derailleur arm from going inward enough to
> fully center over the small chainring.
>
> <SNIP>
> I'm not sure what you mean by "modifying the radius"
>
>
> thanks again for your thoughts
>
> Jens[/color]

Sorry, I misread and it was my mistake. I get your issue now on th
little ring/large cog area.
What I did with modifying the radius was a little careful bending an
grinding of the "offending" parts of the cage (Shimano calls it th
CHAIN GUIDE UNIT). I made the cage have a slightly larger radius so
could lower it a very small amount (~1 mm) and it doesn't catch an
teeth of the large ring when passing just over them. I bent the cag
just a bit (much less than 1 mm) so it would clear. The cage I use
had a radius optimized for a 53 tooth large ring. I made the radiu
much closer to a 54 tooth ring (You may need to go further or d
something else completely different) in the area of the outer plat
that would have contacted the big ring teeth when shifting down toward
the small ring.
XTR Splines are the same as DURA ACE and Ultegra.... to answer anothe
poster's question.
If you have already used 1.5 mm worth of spacing and it hasn't cleare
the issue, I don't know if I would push towards the XTR BB unti
someone can demonstrates that it really works

--
daveornee

[Robin Hubert]

S R Sharp > wrote in message >...
> Jens Kurt Heycke wrote:
> > I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
> > up to accomodate a 56 chainring, it can't swing inwards far enough on
> > reach all the rear cogs with the small chainring. The FD arm hits the frame
> > and
> > can't go any further, so when you're in the small chainring, the chain rubs
> > the
> > FD in the 2 biggest rear cogs.
> >
> > I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
> > derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
> > to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> > Does this sound like reasonable solution?
> >
> > It seems to me that I will end up with a bigger Q factor and a bad chainline
> > and maybe some other consequences I haven't thought of yet?
> >
> > thanks in advance
> >
> > - Jens
>
> Grind some material off the back of the derailleur where it contacts the
> frame.
>

I have done this when building Aegis bikes. For some reason they
haven't figured out the derailleur tab position. If you look closely
you can see which part touches the frame, and you can grind it down.

The other option of using a sligthly longer spindle isn't all bad.
Both might even have to be done to accomplish the goal. The
difference in q-factor and chainline is negligable. We're talking
about 1.5mm on either side ....

Robin Hubert

[Robin Hubert]

S R Sharp > wrote in message >...
> Jens Kurt Heycke wrote:
> > I've got a Aegis T2 TT bike with a shifting problem: when you slide the FD
> > up to accomodate a 56 chainring, it can't swing inwards far enough on
> > reach all the rear cogs with the small chainring. The FD arm hits the frame
> > and
> > can't go any further, so when you're in the small chainring, the chain rubs
> > the
> > FD in the 2 biggest rear cogs.
> >
> > I've tried a few solutions: an extra BB spacer, a Campy (instead of Shimano)
> > derailleur. Nothing quite seems to work. Now Aegis tells me the solution is
> > to use an XTR BB 112.5 instead of the Ultegra 109.5 I'm now using.
> > Does this sound like reasonable solution?
> >
> > It seems to me that I will end up with a bigger Q factor and a bad chainline
> > and maybe some other consequences I haven't thought of yet?
> >
> > thanks in advance
> >
> > - Jens
>
> Grind some material off the back of the derailleur where it contacts the
> frame.
>

I have done this when building Aegis bikes. For some reason they
haven't figured out the derailleur tab position. If you look closely
you can see which part touches the frame, and you can grind it down.

The other option of using a sligthly longer spindle isn't all bad.
Both might even have to be done to accomplish the goal. The
difference in q-factor and chainline is negligable. We're talking
about 1.5mm on either side ....

Robin Hubert