Different threading for bottle bosses



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D. Keith Arbuck

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I picked up a 89/90 Bottecchia a short while ago and was installing some bottle cages on it the
other day. The bike came with bolts for the bottle cages; and the ones for the down-tube were
different from the ones on the seat-tube. I didn't think much about it since I was going to use a
different set of bolts anyway.

In installed the bottle cage on the seat-tube -- no problem. I went to install one for the down-tube
and the bolt wouldn't turn more than a 1/2 turn or so. I tried both bosses with the same results.
The bolt would "fit" into the hole, but would bind shortly after starting to tighten the bolt.
Obliviously the original bolts would work because they came already in the bosses. So I tried
putting the ones that came on the seat-tube in the down-tube -- same results as with my new bolts. I
then tried putting one of the original down-tube bolts in the seat-tube, it wouldn't go in there --
it will only fit in the down-tube bosses.

I know that the bottom bracket has "Italian" threading -- is it possible that bosses for the
down-tube are "Italian" threaded as well? If so, where can these be purchased from? The bolt heads
that came with the bike are too big to work with the bottle cages that I wanted to install.

Thanks in advance for your help. -Keith
 
T

Trent Piepho

Guest
In article <[email protected]>,
D. Keith Arbuckle <[email protected]> wrote:
>bottle cages on it the other day. The bike came with bolts for the bottle cages; and the ones for
>the down-tube were different from the ones on the seat-tube. I didn't think much about it since I
>was going to use a

Maybe the downtube bosses were damaged somehow and replaced? That would explain why they have a
different thread.

>
>I know that the bottom bracket has "Italian" threading -- is it possible that bosses for the
>down-tube are "Italian" threaded as well? If so, where can these be purchased from? The bolt heads
>that came with the bike are too big to work with the bottle cages that I wanted to install.

You might try taking the working bolts to a good hardware store, and see if you can find a nut that
fits them. That will tell you what size they are. Most water bottle bolts are metric M5, which is
about the same size as an
#10-32 screw. A #10-24 screw would be the same size, but have courser
threads, so maybe that's what you need? Or it could be some kind of Whitworth screw you'll
never find..

>
>Thanks in advance for your help. -Keith
 
J

Jeff

Guest
It is probably an M4.5. An M5 will start in the hole and then bind hard just when you think it
is going in. These are also used on Colnago C-40's. You will need a specialist fastener shop to
find them.

Jeffrey

"D. Keith Arbuckle" <[email protected]> wrote in message
news:[email protected]...
> I picked up a 89/90 Bottecchia a short while ago and was installing some bottle cages on it the
> other day. The bike came with bolts for the bottle cages; and the ones for the down-tube were
> different from the ones on the seat-tube. I didn't think much about it since I was going to use a
> different set of bolts anyway.
>
> In installed the bottle cage on the seat-tube -- no problem. I went to install one for the
> down-tube and the bolt wouldn't turn more than a 1/2 turn or so. I tried both bosses with the same
> results. The bolt would "fit" into the hole, but would bind shortly after starting to tighten the
> bolt. Obliviously the original bolts would work because they came already in the bosses. So I
> tried putting the ones that came on the seat-tube in the down-tube -- same results as with my new
> bolts. I then tried putting one of the original down-tube bolts in the seat-tube, it wouldn't go
> in there -- it will only fit in the down-tube bosses.
>
> I know that the bottom bracket has "Italian" threading -- is it possible that bosses for the
> down-tube are "Italian" threaded as well? If so,
where
> can these be purchased from? The bolt heads that came with the bike are
too
> big to work with the bottle cages that I wanted to install.
>
> Thanks in advance for your help. -Keith
 
D

D. Keith Arbuck

Guest
Jeffrey,

This is exactly what the bolt does. It will start, but then as you described "it will bind hard" --
you can tell there is no way that you can force this one in.

Since these are used on the C-40s, shouldn't shops that sell Colnago's have access to these bolts?

Thanks! -Keith

"Jeff" <[email protected]> wrote in message news:[email protected]...
> It is probably an M4.5. An M5 will start in the hole and then bind hard just when you think it is
> going in. These are also used on Colnago
C-40's.
> You will need a specialist fastener shop to find them.
>
> Jeffrey
 
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