Big Chainring Shifting woe fix.

[Paul Milner]

Back in the mid-70's, when dinos ruled the earth. the current fad of the time was drilling out parts
and cutting anthing off that seemed superfluous(sp?). This included the filing off of every other
chainring tooth. It gave a little extra room for the chain to catch on the rings. All of a sudden,
even poor shifting front deraillers worked better. Some times a lot better. I myself have
filed/ground off each tooth above the spider arms on a Rans Rocket. 5 teeth max. It really helps the
chain to engage quicker And if you are having the same type of problem on the big cog in the back,
the same thing helps. Paul Milner

 

[Alpha Beta]

I just paid 20$ for 54 teeth chainring. I'd like to try and fill some teeth down. Buy I just bought
it -- what if it is a disaster.

"Paul Milner" <[email protected]> wrote in message
news:[email protected]...
> Back in the mid-70's, when dinos ruled the earth. the current fad of the time was drilling out
> parts and cutting anthing off that seemed superfluous(sp?). This included the filing off of every
> other chainring tooth. It gave a little extra room for the chain to catch on the rings. All of a
> sudden, even poor shifting front deraillers worked better. Some times a lot better. I myself have
> filed/ground off each tooth above the spider arms on a Rans Rocket. 5 teeth max. It really helps
> the chain to engage quicker And if you are having the same type of problem on the big cog in the
> back, the same thing helps. Paul Milner

 

[Ben Fox]

Another fix for big ring shifting is to bend about 5 teeth in towards the middle ring ,has the same
effect, but can be bent back if you want. Ben Fox "Paul Milner" <[email protected]> wrote in
message news:[email protected]...
> Back in the mid-70's, when dinos ruled the earth. the current fad of the time was drilling out
> parts and cutting anthing off that seemed superfluous(sp?). This included the filing off of every
> other chainring tooth. It gave a little extra room for the chain to catch on the rings. All of a
> sudden, even poor shifting front deraillers worked better. Some times a lot better. I myself have
> filed/ground off each tooth above the spider arms on a Rans Rocket. 5 teeth max. It really helps
> the chain to engage quicker And if you are having the same type of problem on the big cog in the
> back, the same thing helps. Paul Milner

 

[Paul Milner]

"Alpha Beta" <[email protected]> wrote in message
news:<[email protected]>...
> I just paid 20$ for 54 teeth chainring. I'd like to try and fill some teeth down. Buy I just
> bought it -- what if it is a disaster.
>
>
> "Paul Milner" <[email protected]> wrote in message
> news:[email protected]...
> > Back in the mid-70's, when dinos ruled the earth. the current fad of the time was drilling out
> > parts and cutting anthing off that seemed superfluous(sp?). This included the filing off of
> > every other chainring tooth. It gave a little extra room for the chain to catch on the rings.
> > All of a sudden, even poor shifting front deraillers worked better. Some times a lot better. I
> > myself have filed/ground off each tooth above the spider arms on a Rans Rocket. 5 teeth max. It
> > really helps the chain to engage quicker And if you are having the same type of problem on the
> > big cog in the back, the same thing helps. Paul Milner

Hello Alpha-Beta, I have done this procedure many, many times over the course of some 30 years of
mechanicing. It has never(!) had any bad effects. I wouldn't worry about a 54 tooth chainring giving
you any shifting problems. The shifting problems start to appear around 57 teeth. FYI, many bikes in
the 70s and 80s came with every other tooth on the big chainring(52t) gone anyway. Only helped to
make for better shifting.

 

[Dave Miller]

On Sun, 2 Mar 2003 21:50:09 -0600, "Ben Fox" <[email protected]> wrote:

>Another fix for big ring shifting is to bend about 5 teeth in towards the middle ring ,has the same
>effect, but can be bent back if you want. Ben Fox
I'm actually willing to try this but have a followup question.

At good o'le Georgia Tech I was taught that contact (in this case chaing and ring) starts with 3
points of contact and the items "collapse" as much as needed to support the contact.

All that to ask "With fewer contact points (teeth) won't the remaining teeth AND the chain wear out
quicker as each is taking more contact?

 

[Paul Milner]

Dave Miller <> wrote in message news:<[email protected]>...
> On Sun, 2 Mar 2003 21:50:09 -0600, "Ben Fox" <[email protected]> wrote:
>
> >Another fix for big ring shifting is to bend about 5 teeth in towards the middle ring ,has the
> >same effect, but can be bent back if you want. Ben Fox
> I'm actually willing to try this but have a followup question.
>
> At good o'le Georgia Tech I was taught that contact (in this case chaing and ring) starts with 3
> points of contact and the items "collapse" as much as needed to support the contact.
>
> All that to ask "With fewer contact points (teeth) won't the remaining teeth AND the chain wear
> out quicker as each is taking more contact?
Hi Dave, What you say is true, however, remember that there are a lot of teeth on a chainring to
wear down. If a chainring is missing a few teeth, it will still last for years. Paul