34.9mm adapter on 32mm tube?

[[email protected]]

Hi All,

I have a 34.9mm Shimano front derailleur adapter to use a braze-on
fron der. But the frame has a 32mm seat tube. Any reason to not use
some rubber left over from reflector clamps, etc as a shim?

Joseph

 

[Chalo]

joseph santaniello wrote:
>
> I have a 34.9mm Shimano front derailleur adapter to use a braze-on
> fron der. But the frame has a 32mm seat tube. Any reason to not use
> some rubber left over from reflector clamps, etc as a shim?

The mount will flex-- perhaps problematically, perhaps not-- when
loaded, as when shifting. Most rubber materials exhibit some degree
of creep, meaning your clamp force will diminish over time and
eventually might allow the derailleur to slip.

It's probably fine, but it would be a better idea to use a small piece
of 1-3/8" diameter aluminum tubing with a .058" or .065" wall
thickness, and cut a pair of semicircular shims out of it. If your
part of the world uses metric tubing, a trashed aluminum bike frame
might be the most likely source of such tubing.

Chalo

 

[Peter Cole]

[email protected] wrote:
> Hi All,
>
> I have a 34.9mm Shimano front derailleur adapter to use a braze-on
> fron der. But the frame has a 32mm seat tube. Any reason to not use
> some rubber left over from reflector clamps, etc as a shim?
>
> Joseph

I did this on one bike, but I slit a bit of rigid plastic tubing.

 

[[email protected]]

On Mar 20, 9:00 pm, A Muzi <[email protected]> wrote:
> [email protected] wrote:
> > I have a 34.9mm Shimano front derailleur adapter to use a braze-on
> > fron der. But the frame has a 32mm seat tube. Any reason to not use
> > some rubber left over from reflector clamps, etc as a shim?
>
> Try it but generally a metal or Delrin liner is more rigid.
> --
> Andrew Muziwww.yellowjersey.org
> Open every day since 1 April, 1971

So perhaps trimming one of the reflector brackets rather than using
the rubber?

This is for my TT bike which only has a fornt der to keep the chain
from falling off. It will be essentially always in the big ring.
Constant tension on the cable, but not frequent torque, as shift will
be infrequent.

Joseph

 

[A Muzi]

[email protected] wrote:
> I have a 34.9mm Shimano front derailleur adapter to use a braze-on
> fron der. But the frame has a 32mm seat tube. Any reason to not use
> some rubber left over from reflector clamps, etc as a shim?

Try it but generally a metal or Delrin liner is more rigid.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Mike Jacoubowsky]

<[email protected]> wrote in message
news:79f896fa-74a1-45fc-afe2-a8613466c65a@e23g2000prf.googlegroups.com...
| Hi All,
|
| I have a 34.9mm Shimano front derailleur adapter to use a braze-on
| fron der. But the frame has a 32mm seat tube. Any reason to not use
| some rubber left over from reflector clamps, etc as a shim?
|
| Joseph

Back in the day you'd take care of it with the plastic that tressostar
handlebar tape was wrapped around. You might be able to use the equivalent
from a roll of Velox rim tape.

I would advise, strongly, against using a piece of rubber as the shim. If
the derailleur were to slide around the tube, the consequeces can be dire.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

 

[Pikachu]

In article
<79f896fa-74a1-45fc-afe2-a8613466c65a@e23g2000prf.googlegroups.com>,
"[email protected]" <[email protected]> wrote:

> Hi All,
>
> I have a 34.9mm Shimano front derailleur adapter to use a braze-on
> fron der. But the frame has a 32mm seat tube. Any reason to not use
> some rubber left over from reflector clamps, etc as a shim?
>
> Joseph

A braze-on front derailleur clamp in the correct 32mm size is $3.99 from
Nashbar and less than $10 from your LBS. Is it worth the time, effort
and sometimes agitation to cobble together a solution yourself?

Pikachu

 

[[email protected]]

On Mar 21, 1:54 pm, Pikachu <[email protected]> wrote:
> In article
> <79f896fa-74a1-45fc-afe2-a8613466c...@e23g2000prf.googlegroups.com>,
>
>  "[email protected]" <[email protected]> wrote:
> > Hi All,
>
> > I have a 34.9mm Shimano front derailleur adapter to use a braze-on
> > fron der. But the frame has a 32mm seat tube. Any reason to not use
> > some rubber left over from reflector clamps, etc as a shim?
>
> > Joseph
>
> A braze-on front derailleur clamp in the correct 32mm size is $3.99 from
> Nashbar and less than $10 from your LBS.  Is it worth the time, effort
> and sometimes agitation to cobble together a solution yourself?
>
> Pikachu

I live in Norway. The cheapest I can get one online delivered is $36.
The LBS may have one (probably not), but they will want at least as
much, and it is 30km away. With gas, parking and tolls that trip by
car would cost about $15. I could ride, but it is a boring ride
through gravel strewn suburbs. I want to go the other way! And today!

It probably will come back to bite me in the ass, but I'd much rather
putz about in my shed for 1 hour than sitting in traffic.

Joseph

PS: Of course there was a monster snow storm last night (and now) so
my ride is postponed who knows how long. And I'll probably end up
driving past the LBS in a day or so anyway, and maybe they would have
traded an unopened 34.9 I had for a 32 if I had been patient...