New Chainrings

[Chislenko]

So what is the concencus?

Fitted some new chainrings and everything works fine on the workstand.

However in real life when out on a ride chain does not want to go onto the big ring.

Old rings were circa ten years old and quite worn, could it be just harder to catch on new properly shaped teeth, mech gap looks fine. Chain is new by the way.

Cable tension looks good, tried limit screw and yes then it would go up to big ring but over the other side and off so put the limit screw back.

Doesn't seem a happy medium.

Before I lift the mech a bit anybody got any better ideas?

Edit: Fitted many new chainrings in the past and never had to move the mech so maybe clutching at straws!

 

[Ajax Bay]

Same size (teeth) big ring?

 

[Chislenko]

Same size (teeth) big ring?

Yes, straight swap, 50_34 old and new.

 

[Ajax Bay]

Then my only suggestion is to be rigorous about the vertical clearance of the FD cage above the top teeth of the 50: 1mm. Correct setting of the upper limit screw should both allow the shift to succeed (inner plate function) AND to mitigate the risk of the chain coming off outwards: but you know all this. Assume new chain is correct speed. A narrower one (eg 11sp) will be a scintilla more likely to do what you've described, till you get it 'mummy bear'.

 

[Sittingduck]

H limit screw should be set right, happy medium as you say. It should be perfectly possible to adjust it gradually so that it will definitely move across enough but not too much as to ditch the chain off the edge. Is there sufficient cable tension?

 

[Chislenko]

H limit screw should be set right, happy medium as you say. It should be perfectly possible to adjust it gradually so that it will definitely move across enough but not too much as to ditch the chain off the edge. Is there sufficient cable tension?

Tension looks fine, I have finely adjusted the limit screw on the stand again last night (and ok on stand) so will give it another go on the road today and see how it is behaving!

 

[Chislenko]

Then my only suggestion is to be rigorous about the vertical clearance of the FD cage above the top teeth of the 50: 1mm. Correct setting of the upper limit screw should both allow the shift to succeed (inner plate function) AND to mitigate the risk of the chain coming off outwards: but you know all this. Assume new chain is correct speed. A narrower one (eg 11sp) will be a scintilla more likely to do what you've described, till you get it 'mummy bear'.

Everything is like for like, 9 speed chain and genuine Sora rings as per what came off. Just waiting for the rain to go off (could be a long wait!) and I will go and give it another test ride.

 

[Chislenko]

Update.

Very fine adjustment of the limit screw has it working just fine out on the road.

Never had any problems previously when changing rings, just bunged them on and they have performed with no adjustments.

You live and learn!

 

[fossyant]

You probably just needed a fraction of adjustment, that's all. I set my mech's quite close to the big ring (vertically)