Why is FD with a 28.6mm clamp so hard to find?

Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

Marty wrote:
snip for clarity

"Why is FD with a 28.6mm clamp so hard to find?"

because most smart manufacturers there days use aluminum for their mtb
frames. aluminum mtb tube doesn't come that skinny.

Marty wrote:

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).
[...]
Any solutions out there?


How hard could this be, really? 1-1/8" (28.6mm) seat tubes are the
standard for steel frames and will probably be so for as long as we
all live. You have already discovered the advantage-- the ability to
mount the inner chainring closer to the bike's centerline and thus
keep the tread width of the pedals to a minimum.

Here's one for $13:
http://www.jensonusa.com/store/produ...erailleur.aspx

Nashbar offers one for $5 that does not specify diameter, but is more
than likely 28.6mm since it's a low-priced OEM item probably intended
for a steel bike.

Chalo

On May 10, 6:14*pm, Marty wrote:
Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. *I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

I've seen 35-28.6 eccentric shims before. JensonUSA.com used to carry
one. Been a while since I've seen it, but it's out there.

FWIW, I made one myself not long ago, for a 31.8 clamp. Plastic patch
kit box material is ~2mm thick, and I had a box with a side that was
about 3 inches long. The material is flexible enough to wrap around
the tube, but firm enough not to compress under the clamp. I put the
strip of box material between the 28.6 tube and the 31.8 clamp, with
the gap in the strip on the crank side. Worked spiffy.

Marty wrote:
Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

Make a shim that covers 1/2-2/3 of the tube. I've used a slice of
plastic tube (e.g. PVC).

On May 10, 7:14*pm, Marty wrote:
Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. *I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

It's not. Use a brazeon and 28.6 clamp, available at just about any
decent bike shop.

On May 10, 11:22*pm, Chalo wrote:
Marty wrote:

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).
[...]
Any solutions out there?

How hard could this be, really? *1-1/8" (28.6mm) seat tubes are the
standard for steel frames and will probably be so for as long as we
all live. *You have already discovered the advantage-- the ability to
mount the inner chainring closer to the bike's centerline and thus
keep the tread width of the pedals to a minimum.

Here's one for $13:http://www.jensonusa.com/store/produ...+Lx+M571+Front...

Nashbar offers one for $5 that does not specify diameter, but is more
than likely 28.6mm since it's a low-priced OEM item probably intended
for a steel bike.

Chalo


Close, but, need bottom pull.
--
Marty

On May 11, 6:38*am, "P. Chisholm" wrote:
On May 10, 7:14*pm, Marty wrote:





Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. *I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

It's not. Use a brazeon and 28.6 clamp, available at just about any
decent bike shop.- Hide quoted text -

- Show quoted text -

This is one solution that I thought of, but, who makes a mtb braze FD?
--
Marty

On May 11, 2:14*am, Marty wrote:
Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. *I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

Any kind of pliable plastic will do. i love the tops of poptop tubes
of Pringles potato crisps, what Americans call "chips". (Or "borrow" a
tupperware self-sealing top from your mom's kitchen.) To make an
asymmetric shim, just put more layers on one side. Each layer is
around 1mm. I have Pringles poptop shims in many places on my bikes; I
like them so much, I don't even take the rubber shims that come with
components out of the box, finding it faster and more satisfactory to
cut a Pringle-shim.

Cut the Pringle poptop shims wide enough so that any sharp edges you
will torque up cut into the plastic rather than your bike's paint or
ali.

Andre Jute
Novel solutions to easy problems

On May 10, 7:14*pm, Marty wrote:
Hi,

I have a Shimano MTB triple FD that works great with the rapid shift
brifters that I purchased to upgrade the wifes bike. *However, it
requires the use of a shim in order to clamp it on to the 28.6mm seat
tube. *WIth the shim in place, the FD sits so far to the right that I
cannot get the low end to swing far enough to cause the chain to drop
from the middle chainring to the small chainring (low set screw is all
the way up).

If I push the chainrings to the right with a wider BB spindle, my
chainline is gonna REALLLY suck. *I'm at about 50mm center of seat
tube to middle chainring with 113mm spindle length and I already don't
like the chainline.

What I'd like to have is a shim that is thick on one side so that the
FD can be clamped on, but be as far to the left as possible.

Any solutions out there?

Thanks.
--
Marty

I was able to get a hold of an eccentric shim and used it with the
thinner shim that came with the FD. This combination of shims moved
the FD to the left a few mm (at best). But, this few mm made a huge
difference. Actually, I was fairly amazed at what a big difference a
few mm can make in this case. Now I'm thinking of going from a 113mm
spindle width on the BB to 107mm to improve the chain line.

Thanks all for the feedback.
--
Marty