I really should have known this.

Dippydog3

Pedalling gently downhill I changed into the big ring and managed to throw my chain off to the outside. No worries, I said to my buddy, I will coast to the bottom of the hill, and then stop to sort it when I run out of speed on the next hill.

He then suggested to me I just flick it back on by using the front mech-, pedalling gently and shifting into the small ring. It worked, magic.

And, I have subsequently done this the other way if the chain is off towards the frame side.

Obvious trick really, but I have only been riding 47 years and have never seen anyone else do it, or read about it.

A sheltered life clearly.

sloppyschleckonds

Have you considered getting your front mech set up correctly?

Dippydog3

SloppySchleckonds wrote:

Have you considered getting your front mech set up correctly?

You can set your mech up as well as you like, but on bumpy roads chains can come off when shifting.

Unless you are perfect of course.

ugo.santalucia

Dippydog3 wrote:

Unless you are perfect of course.

Ideally you want to avoid shifting the front ring when you are going over a particularly rough patch. In the days of downtube shifters this came without saying as if you attempted the maneuver you would have found yourself on the pavement, while now with STIs it is possible, but still best avoided. Hence the importance of understanding the road ahead of you, which is pretty much everything in a race like Paris-Roubaix.

That said, if you have the limiting screws set up correctly but still drop the chain, I think you have a problem with chain tension... either the chain is too long or you are using a compact + big cassette setup with a short cage mech. Removing 1-2 links will give you more tension

Dippydog3

ugo.santalucia wrote:

Dippydog3 wrote:

Unless you are perfect of course.

Ideally you want to avoid shifting the front ring when you are going over a particularly rough patch. In the days of downtube shifters this came without saying as if you attempted the maneuver you would have found yourself on the pavement, while now with STIs it is possible, but still best avoided. Hence the importance of understanding the road ahead of you, which is pretty much everything in a race like Paris-Roubaix.

That said, if you have the limiting screws set up correctly but still drop the chain, I think you have a problem with chain tension... either the chain is too long or you are using a compact + big cassette setup with a short cage mech. Removing 1-2 links will give you more tension

Its very unusual for this to happen to me. The bike has been set up by a very professional mechanic. And it has the correct rear mech.

I wasn't telling the story for FD advice really, just that it seemed a good trick to know about if you didn't. It works when you have removed the chain for cleaning as well.

No chance in removing links. I run 11-32 at the rear so low tension is always going to be sub optimum in small small. Any fewer links and the rear mech catches on big big.

ugo.santalucia

Dippydog3 wrote:

No chance in removing links. I run 11-32 at the rear so low tension is always going to be sub optimum in small small. Any fewer links and the rear mech catches on big big.

Yeah, I moved it to this section for the benefit of those who don't know how a front mech operates.

Big-big (as well as small small) are combinations best avoided for a number of reasons (wrong chain angle leading to failure and the fact that the same ratio is available in a better combination on the other ring, probably somewhere in the middle of the pack) If you really want to use 34-11 and 50-32, then you are better off with a medium cage derailleur, that can keep thing under tension all the time. Otherwise avoid extremes

Dippydog3

ugo.santalucia wrote:

Dippydog3 wrote:

No chance in removing links. I run 11-32 at the rear so low tension is always going to be sub optimum in small small. Any fewer links and the rear mech catches on big big.

Yeah, I moved it to this section for the benefit of those who don't know how a front mech operates.

Big-big (as well as small small) are combinations best avoided for a number of reasons (wrong chain angle leading to failure and the fact that the same ratio is available in a better combination on the other ring, probably somewhere in the middle of the pack) If you really want to use 34-11 and 50-32, then you are better off with a medium cage derailleur, that can keep thing under tension all the time. Otherwise avoid extremes

It is a medium cage. Even with that, and avoiding the 34-11 and the 50-32 as much as possible, the simple fact is that due to the length of the chain it can come of sometimes on bumpy roads if you have an untimely shift.

ugo.santalucia

Dippydog3 wrote:

It is a medium cage.

You should have tension then...

I have occasionally changed front ring on some secteurs of Paris-Roubaix without issues, but you need to be careful and make sure you are on the new ring before putting power down again, or the chain will derail. I don't think you have anything as bad in terms of road surface, so it's really down to soft touch... good changing technique and it shouldn't happen

Dippydog3

ugo.santalucia wrote:

Dippydog3 wrote:

It is a medium cage.

You should have tension then...

I have occasionally changed front ring on some secteurs of Paris-Roubaix without issues, but you need to be careful and make sure you are on the new ring before putting power down again, or the chain will derail. I don't think you have anything as bad in terms of road surface, so it's really down to soft touch... good changing technique and it shouldn't happen

As a moderator by definition you must know more than me. Its a simple point really. If you have the right kit, and if you are careful then sods law will say that one day no matter how perfect your technique something will conspire to jump the chain off, even on my roads, which you havent seen.

This was just a little hint as how to get it back on without stopping. Not bike maintenance 101 or "my dad rides on rougher roads than yours"!

ugo.santalucia

Fine then... no need to get edgy... if you don't want advice, you won't get any. On fora people tend to give advice, sometimes beyond the request

Dippydog3

ugo.santalucia wrote:

Fine then... no need to get edgy... if you don't want advice, you won't get any. On fora people tend to give advice, sometimes beyond the request

fine then. No need to get edgy. A request for advice will normally be made obvious by the original statement being a question. If someone wants your advice they will ask for it.. On fora people tend to give advice even when it isnt wanted or needed. :twisted: