Front Mech and Chain Ring Questions.

[IanT]

Lately, the gears on my Carerra TDF have become noisy - with the chain rubbing the front derailleur. After diligently watching numerous YouTube tutorials and, armed with my Haynes Bike Book and downloaded Shimano servicing info, I set about adjusting the front mech.

I'm confident that the height and alignment are now both correct (which they were not before - as fitted from new, it was angled distinctly inward). After adjusting both limit screws and cable tension, the shifting is better - although, I notice that the shift from the small to the large chainring, the shift you sometimes have to stop pedalling for the shift to happen. It's odd, because, with the bike in the workstand, the shift is seamless. I can only imagine that the frame flexes, when loaded - altering the cable tension?


One thing has got me wondering, though, is the front outer chainring. It appears that a few of the teeth are slightly squared-off. Now, the bike has only covered about 200 miles from new - so I'm sure it's not wear. I do know that some chainringa have a ramped section to ease shifting - so I wonder if this is what I'm seeing? I have attached a photo of the offending few teeth and would be very grateful for any opinions or advice.

Thanks.

Ian.

 

[heliphil]

changing under load is always slower / more tricky and the chain ring teeth are machined to help the chain slip off more easily to help with the changes....

 

[IanT]

Thanks heliphil.

 

[lukesdad]

Nothing wrong with your chain rings. the shifting problem would have been due to cable stretch so you should really of just needed to adjust on your barrel adjusters. Not tinkering with the stop screws. If I understand you right if you stop pedalling the shift wont happen, do you just mean taking of pressure and pedalling slower ?

 

[IanT]

Thanks for the response Lukesdad - think it's sorted.

Took the bike out for a quick 14 miler to give it a proper test and the gears are now quiet and very slick.

As you say, cable stretch was an issue, but I maintain that the limit screws were not helping. I think they had probably been set with the cage skewed because the inner was set with what looked like just a few threads left before it popped out and the outer felt like it had been tightened with an impact wrench!!! They are now much more evenly balanced.

Whilst doing the adjustments last night, I did re-tension the cable (having disconnected it to move the front mech). To be honest, I think the little ride up and down my road was not letting the gears get into their stride - so was not a fair test of the changing.

What I was noticing last night was that you had to stop pedalling and then re-start for the chain to move up from the inner chain ring to the outer. But, having been out on it tonight, the gears are probably the best they have been at any time. So, panic over.

Thanks again for the responses and advice on this.

Cheers,

Ian.

 

[lukesdad]

Glad you ve got it sorted, it pays to do one thing at a time and start with the simplest option first

 

[byegad]

Now you know how to set one up properly keeping it sweet is going to be easy.