tandem front derailleur question

[Ron Vance]

Bought a new tandem frame. Bought a new Ultegra triple front derailler, but there is a water bottle
cage hole on the stoker steat tube right where the clamp needs to go to clear the big chain ring.
I'm thinking that maybe I can carefull file off the bottle cage fitting. It appears to have been
drilled and a threaded piece pressed
in. There is a round "cap" around it. It is not brazed. Another thought is that there may be a
style of front derailleur that clamps lower on the seat post. Help please!

 

[David Ornee]

"Ron Vance" <[email protected]> wrote in message
news:[email protected]...
> Bought a new tandem frame. Bought a new Ultegra triple front derailler, but there is a water
> bottle cage hole on the stoker steat tube right where the clamp needs to go to clear the big chain
> ring. I'm thinking that maybe I can carefull file off the bottle cage fitting. It appears to have
> been drilled and a threaded piece pressed
> in. There is a round "cap" around it. It is not brazed. Another thought is that there may be a
> style of front derailleur that clamps lower on the seat post. Help please!

Ron, Remove the water bottle holder and get your FD working first. There are other water bottle
holders that may work on the seat tube further up, by using clamps around the water bottle holder
ears. I suggest that you also consider a hydration pack like Camelbak for your stoker.

David Ornee, Western Springs, IL

 

[David]

"Ron Vance" <[email protected]> wrote in message
news:[email protected]...
> It appears to have been drilled and a threaded piece pressed
> in. There is a round "cap" around it. It is not brazed. Another thought is that there may be a
> style of front derailleur that clamps lower on the seat post.

If you have the type where the clamp is above the mechanism (bottom-swing), then you probably need
the kind where the clamp is below the mechanism (top-swing).

 

[John Everett]

On 15 Jun 2003 20:28:46 -0700, [email protected] (Ron Vance) wrote:

>Bought a new tandem frame. Bought a new Ultegra triple front derailler, but there is a water bottle
>cage hole on the stoker steat tube right where the clamp needs to go to clear the big chain ring.
>I'm thinking that maybe I can carefull file off the bottle cage fitting. It appears to have been
>drilled and a threaded piece pressed
>in. There is a round "cap" around it. It is not brazed. Another thought is that there may be a
> style of front derailleur that clamps lower on the seat post. Help please!

As it's a new frame, why not ask the manufacturer/framebuilder what they/he had in mind?

Also, is the fitting a RivNut? See: http://www.bollhoff-rivnut.com/ If so it can be drilled out
without damaging the frame (if you're careful).

John "Always Glad to Help a Relative" Everett

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

 

[Eric Salathe]

Ron Vance:
> Bought a new tandem frame. Bought a new Ultegra triple front derailler, but there is a water
> bottle cage hole on the stoker steat tube right where the clamp needs to go to clear the big
> chain ring.

I am hesitant to criticize someones new bike, but this is an agregious design flaw. Who made this?
Do they understand other critical design issues? I wouldn't accept this frame.

Dave Ornee writes:
> I suggest that you also consider a hydration pack like Camelbak for your stoker.

Generally speaking, treating ones tandeming partner as equiptment is not likely to achieve a
desirable result.

Eric Salathe

 

[Helmut Springer]

Eric Salathe <[email protected]> wrote:
> I am hesitant to criticize someones new bike, but this is an agregious design flaw. Who made this?
> Do they understand other

The frame might be designed for today's MTB chainrings, 44t. If the stocker's saddle tube is short
and the frame has the lateral tube that most frames have today room is tight...

--
MfG/Best regards helmut springer

 

[Ron Vance]

Some clarifications:

John Everett is correct, it's a rivnut. This is what's in the way, since I did not put on the cage.
A second water bottle is less important than getting the derailleur to work right.

FYI, it's a Tsunami that I bought from Chuck's Bikes last fall. I also had to cut my own seat clamp
notch on the captain's seattube, since the mfgr forgot to. QA/QC is not too good, but the price at
the time was low.

Will a bottom pull derailleur work on a road triple as someone suggested? I have not examined a
bottom pull before.

 

[Eric Salathe]

Eric Salathe <[email protected]> wrote:
> > I am hesitant to criticize someones new bike, but this is an agregious design flaw. Who
> > made this?

Helmut Springer:
> The frame might be designed for today's MTB chainrings, 44t. If the stocker's saddle tube is short
> and the frame has the lateral tube that most frames have today room is tight...

...then you don't put bottle bosses on the seat tube.

This is only to expand on the flaw and look at how it may have happend. One would hope, as you say,
that it was designed with small rings in mind, not that the maker never thought about how to mount a
front derailleur. To design a tandem around 44T rings is the flaw that raises doubts. I think you
will find it quite unusual among frames from companies and builders with tandem experience.

Eric Salathe

 

[Helmut Springer]

Eric Salathe <[email protected]> wrote:
> To design a tandem around 44T rings is the flaw that raises doubts. I think you will find it quite
> unusual among frames from companies and builders with tandem experience.

For an MTB tandem that can use top swing derailleurs one might call it wasted space if there are
none. 44/11 equals 53/13 and most cassettes start with an 11. YMMV (mine actually does).

--
MfG/Best regards helmut springer

 

[David]

"Helmut Springer" <[email protected]> wrote in message
news:[email protected]...
> For an MTB tandem that can use top swing derailleurs one might call it wasted space if there are
> none. 44/11 equals 53/13 and most cassettes start with an 11. YMMV (mine actually does).

I use 48 with my XTR FD (BS, but comes in TS too), and I'd expect it will handle more. Is there no
top-swing FD that will handle 53?

 

[David Ornee]

"Eric Salathe" <[email protected]> wrote in message
news:[email protected]...
>
> Dave Ornee writes:
> > I suggest that you also consider a hydration pack like Camelbak for your
stoker.
>
> Generally speaking, treating ones tandeming partner as equiptment is not likely to achieve a
> desirable result.
>
> Eric Salathe

I was not suggesting that you treat your tandem partner as equipment. I suggest that a hydration
pack could be a positive alternative. My stoker (and life partner for over 33 years) considers the
hydration pack a positive alternative. We have been riding tandem together for 8 of those 33 years.
We have had many refinements along the way. We both are very pleased to use hydration packs even
though we have suitable arrangements for water bottle holders.

David Ornee, Western Springs, IL

 

[Rob Cohen]

Ron Vance wrote:
> Bought a new tandem frame. Bought a new Ultegra triple front derailler, but there is a water
> bottle cage hole on the stoker steat tube right where the clamp needs to go to clear the big chain
> ring. I'm thinking that maybe I can carefull file off the bottle cage fitting. It appears to have
> been drilled and a threaded piece pressed
> in. There is a round "cap" around it. It is not brazed. Another thought is that there may be a
> style of front derailleur that clamps lower on the seat post. Help please!

I had this problem on a bike I just built up. Here is how I solved it. Rather than using a clamp-on
derailleur, I purchased a braze-on unit and a 'problem-solver' clamp for braze-on derailleurs. I
attached the band of the clamp as high as I could without interfering with the bottle braze-on, but
still needed the derailleur about 5 mm higher. I machined out the derailler attchment hole on the
adapter to form a vertical slot, giving me the height adjustment I needed. I used a Dremel-type
tool, but you could easily file the soft aluminum.

Good luck. I can take a picture if you need it, but I think it is pretty self-explanatory.

Rob

 

[John Everett]

On 16 Jun 2003 15:00:21 -0700, [email protected] (Ron Vance) wrote:

>Some clarifications:
>
>John Everett is correct, it's a rivnut. This is what's in the way, since I did not put on the cage.
>A second water bottle is less important than getting the derailleur to work right.
>
>FYI, it's a Tsunami that I bought from Chuck's Bikes last fall. I also had to cut my own seat clamp
>notch on the captain's seattube, since the mfgr forgot to. QA/QC is not too good, but the price at
>the time was low.
>
>Will a bottom pull derailleur work on a road triple as someone suggested? I have not examined a
>bottom pull before.

Your Ultegra is a bottom pull derailleur. If the cable come up from the bottom bracket it's a bottom
pull. If (like many MTBs) the cable comes down from the seat clamp area it's a top pull.

I think you're referring to a top swing derailleur. On these the mounting clamp is located below the
pivot point. Unfortunately most of these are MTB specific derailleurs. This presents a couple of
problems. Most top swing derailleurs are designed for Shimano's "compact drive" systems, so the
cages are contoured to mate up with 46 or 48 tooth big rings The outer cage plate can be modified
via a few minutes at a bench grinder, but this only solves one problem.

The other problem is that Shimano (in their infinite wisdom) has designed their MTB and Road
derailleurs to use different cable pulls. Thus modifying a top swing MTB derailleur to match up with
a 52 or 53 tooth ring would still not match up with an STI shifter.

One person who may be able to identify a Shimano derailleur that might solve the problem is Sheldon
Brown, but he hasn't weighed in on this thread yet. He has a couple of extensive pages on front
derailleurs (derailers) on his site. See:

http://sheldonbrown.com/harris/derailers.html#front and:

http://sheldonbrown.com/derailer-adjustment.html

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

 

[John Everett]

On 16 Jun 2003 15:00:21 -0700, [email protected] (Ron Vance) wrote:

>Some clarifications:
>
>John Everett is correct, it's a rivnut. This is what's in the way, since I did not put on the cage.
>A second water bottle is less important than getting the derailleur to work right.
>
>FYI, it's a Tsunami that I bought from Chuck's Bikes last fall. I also had to cut my own seat clamp
>notch on the captain's seattube, since the mfgr forgot to. QA/QC is not too good, but the price at
>the time was low.
>
>Will a bottom pull derailleur work on a road triple as someone suggested? I have not examined a
>bottom pull before.

Ron:

Second response to the same posting. I just now may have solved your problem by going down to the
garage and looking at my touring bike. It has a top swing, bottom pull front derailleur and STI
levers. It's RSX equipped and the part number of the clamp-on front derailleur is FD-A410.

The only concern is that the bike has a 46 tooth big ring. I compared the arc of the outer cage
plate to the 105 derailleur you sent me a couple of years ago (it's still laying around in the
parts bin) and to my best estimate it's identical, therefore should work fine with outer rings as
large as 53 teeth.

Bottom line...unless someone can identify another Shimano top swing, bottom pull, clamp-on, triple
road derailleur I'd order an FD-A410 and keep the bottle cage mount.

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

 

[Eric Salathe]

Ron Vance wrote in message news:<[email protected]>...
> Some clarifications:
>
> John Everett is correct, it's a rivnut. This is what's in the way, since I did not put on the
> cage. A second water bottle is less important than getting the derailleur to work right.

Since it is doubtful the rivnut is adding any reinforcement to the hole, you might be comfortable
drilling of filing it out so you can mount the front derailleur (I haven't done this, but have heard
that drilling alone sometimes just causes the rivnut to spin in the frame so you may need to get
creative).

Tandems don't usually have seat-tube water bottle mounts since you can usually fit two on the
lateral tube. In addition to the front derailleur, you can get interference from a long shock
seat post. You can probably find somewhere to clamp on another bottle or share some of your water
with your stoker. Or, stop occasionally and get off the bike somewhere interesting where you can
get a drink....

> FYI, it's a Tsunami that I bought from Chuck's Bikes last fall. I also had to cut my own seat
> clamp notch on the captain's seattube, since the mfgr forgot to. QA/QC is not too good, but the
> price at the time was low.

http://www.chucksbikes.com/frames.htm

For that price, I too might be willing to fiddle around a bit to get it to work.

> Will a bottom pull derailleur work on a road triple as someone suggested? I have not examined a
> bottom pull before.

You mean "bottom swing", which presumably is what the Tsunami folk had in mind. It won't work for
two reasons:

1) An MTB derailleur will not work with indexed road STI
<http://www.sheldonbrown.com/harris/derailers.html#front>
2) There are no bottom pull derailleurs that accept large chainrings.

You need a "road" front derailleur. Also, get a chain watcher; it's the only way to make the front
shifting work reliably.

Eric Salathe

 

[Eric Salathe]

Helmut Springer <[email protected]> wrote in message
news:<[email protected]>...
> Eric Salathe <[email protected]> wrote:
> > To design a tandem around 44T rings is the flaw that raises doubts. I think you will find it
> > quite unusual among frames from companies and builders with tandem experience.
>
> For an MTB tandem that can use down swing derailleurs one might call it wasted space if there are
> none. 44/11 equals 53/13 and most cassettes start with an 11. YMMV (mine actually does).

Yes, but since "milage varies", a 26-inch wheel tandem that cannot use larger than a 44T ring is not
going to be a very versatile bike and thus is not a good design. Most MTBs, whether single or tandem
spend a lot (all) of time on the road. Many of people would be spun out at 25 mph with this setup,
which is not a lot of fun.

MTBish 44/11 is not roadish 53/13 -- an MTB has smaller wheels. So, 26x1-1/4" (559-32) wheels
(24.5" diameter) with 44/11 is 98 gear inches. 700x32C (622-32) wheels (27" diameter) with 53/13 is
110 gear inches. Big difference! And 53/13 is not typical tandem gearing, more like 54/12, or 121
gear inches.

Eric Salathe