Is this worn?

bill_gates

Looking for some help.

Symptoms are that on the front drivetrain,it is sometime a bit reluctant to shift into the big ring although I've had new cables this week which did make a good improvement, it's just not feeling quite right yet!

Do these teeth look worn, front rings are about 12-months old exactly with approx. 1200 miles on them with predominantly dry and a very minor amount of winter miles but alway lovingly cleaned and maintained.

Chain is not stretched currently and I've regularly swapped when it shows signs of being 0.75% on the chain-check tool.

trailflow

No. They are fine.

Did you install the cables yourself ? are the front derailleur limit screws are set up properly ? If you put the chain the small front ring and biggest cog at the rear. You want the deraileur cage positioned as close as posible to the chain without rubbing.

If the gap is too big. Shifting will feel sluggish.

dowtcha

They are fine, some teeth will look worn but this is the way they are made to help with smooth shifting from inner to other ring. Check limit screws on front derailleur.

bill_gates

Is there a tool for measuring teeth on chainrings or sprockets or a general rule of thumb. New cable was done by the LBS and they ar usually pretty good at indexing, high/low setup.

keezx

No, there isn't...
Comes down on expierience

Monty Dog

Chainring is barely worn - they are worn-down when they resemble a row of pointy shark's teeth. The poor shifting will be due to a poorly aligned / adjusted front mech

doug5_10

As above, the paint's barely been rubbed off, chainrings last for 10k miles plus.
If its shifting up into big ring that's specifically the problem, cable tension should be your first port of call. TBH, I would just go through all possibilities, a full FD adjustment and indexing takes 5 mins.

diamonddog

Monty Dog wrote:

Chainring is barely worn - they are worn-down when they resemble a row of pointy shark's teeth. The poor shifting will be due to a poorly aligned / adjusted front mech

^^This or cable tension

keef66

I just replaced the middle ring on my 105 triple chainset. I reckon it had done about 10,000 miles, much of it in crappy weather, and I was treating it to a new chain and cassette so I thought I might as well replace it too. (the inner and outer rings get much less use). When I had the thing in pieces, out of curiosity I compared the old and new rings, and found barely any visible sign of wear. I fitted the new one anyway, but I'm keeping the old one since it's apparently still OK.

So chainrings can indeed last a lot longer than chains and cassettes!

bill_gates

What sort of distance cycled on a brand new cable would be realistic for stretch to appear

My LBS installed d a new cable on Monday (It's now Saturday) and I've done approx. 6o miles this week since then but now the terrible shifting at the front has returned. I almost need two hands to make the shift and the big ring just does;t seem to want to 'grab' the chain.

kajjal

As well as the above useful advice, Oil the pivots on the front mech, if they are sticking the shifting will be unreliable at best. After a few minutes of gear changes it will free up if that is your problem.