Worn chainring causing slippage?
 

After wearing out three chains I today replaced the chain and Deore 9 spd cassette.

To my surprise, there is slippage when riding in the large 44t chainring on the SLX crankset. Do chainrings wear out like sprockets and should I replace it?

I can't get it to slip in the middle or small chainring.

All advice welcome!

Thanks.

i would think that they do, although i don't know that i've ever had one slip. of course, i keep changing them for other reasons, so they rarely get more than 10,000 miles on them.

my best guess is that after it has survived three worn out chains it might well be worn out too. i might think about buying the small one too, unless you rarely use it.

Chainring wear to the point od slippage does happen, but it's a long slow process. It's more common on mtn bikes than the road, especially on the middle ring. (the granny fares a bit better being steel, and usually used less).

Unlike cassettes which may slip even when they look pretty good, worn chainrings usually have visibly shark finned teeth, and are obviously worn looking long before they slip.

One test to predict slippage is to pull the chain out from the ring at the front (1/2 way around the wrapped side). If you can pull the chain out so there's almost 1/4" gap underneath, get out the butter because it's toast.

What else could cause slippage in thîs scenario?

The freehub ratchet could slip. Andy.

A picture of the chainring would be useful. :)

I started to get some slips on the large chain ring of my road bike after 60 kmiles. This ring was one with symmetrical teeth so I could flip it over which let me continue to use it for another 35 kmiles before it again started to slip when I'd push down hard when starting from a stop. The somewhat more common problem with worn chain ring teeth is 'chain suck' where the chain isn't released cleanly at the bottom of the ring.

If it happens on only the large chainwheel it is possible but very unlikely that the pawls could be at fault. If you have worn out the large chainwheel and 3 chains you may want to consider adapting to a higher rpm, as the large chainwheel should be ridden at relatively low pedal pressure. Those gears are used for maintaining speed rather than acceleration, and tromping on the pedals has no benefits.

Huh...?.. Say What?

Thank you all.

I located a very-gently-used replacement chainring for $25 and, after installing it, everything is again sweetness and light. No more slipping. Comparing the almost-new and the old, I see that some teeth have had about 1/16 of an inch shaved off. It's not a dramatic shark's fin but there is clearly a fair bit of missing metal.

So I can answer my own question. Yes, it is possible to wear out a front chainring resulting in slippage and, in future, I'll probably be replacing it when I replace the cassette.

As your own experience shows, that's much sooner than necessary.

how's that?

Did I stutter? My statement is accurate, though the guidelines I stated are often not followed. Yes, racers will get out of the saddle in a relatively high gear to accelerate, but that is the exception, and occurs for only a short period.

Your right, I misread your OP and missed the fact that this was your first cassette replacement. However, this puts you in a very small minority, and generally you can replace multiple cassettes before needing a new ring.

You might consider sourcing a replacement when the time approaches, but holding off actually switching until it's necessary.

What race was this, the Tea Cozy Classic Cat.6?

That "short period" occurred over & over & over until the dead weight was dispensed with and over every rise until the big accelerations came to select the final group who then really jumped on it for the line in every race that I've been in.

Big Ring + Big Effort = Big Speed. Repeat as necessary.

-Bandera

This sounds very similar to a situation I am facing.

I had a tune up a month or two back. He commented of difficulty with my FD adjustment.

He put on a SRAM 9 speed chain and said he could not find slipping in the cassette.

I put on a new cassette a few hundred km later (I noticed slipping immediately after the tune up).

My issue is now this:

I almost exclusively ride in in the big ring. Since the tune up I have had consistent problems with my chain dropping to the middle ring, and then I have issues getting the chain back to the big ring. This did not change with cassette replacement.

I plan to do a complete adjustment on the FD this weekend to get it tuned, in case he messed up. I hope this solves it.

But I worry it may not since I never had it happen before.

Could it be:

Chain incompatibility? I have never used SRAM chains (honestly cannot recall my previous chain).

Worn big ring? I will check for shark fining.

Bike details

I am also on my third chain and second cassette.

The freehub body was new last year (so several thousand km).

The bike has about 10,000 km. It have Tiagra STI shifters, Tiagra FD, XT RD, low end Deore cassette (11-32), Andel crank (175mm) and I cannot recall brand of chain ring (26t-36t-48t(maybe 46t)). I have never had a problem shifting FD between big and mid rings, though some issues getting into small ring previously. I never used it so was not worried.

I feared you might be pointing out (rightly) that I should pay more attention to chain lubrication (maybe using a fine product like Chain-L) and replace the chain before it stretches too much in the hope that this will prevent premature wear of the chainring.

I'm sure you are just too darned modest to say this so I will. Or maybe you don't think that at all.

Definitely will have a chainring in stock for future needs.

It's not modesty -- nobody ever accused me of that -- it's tactfulness.

I don't like to tout my own stuff unless fed a very straight invitation to do so. I prefer that folks come to it on their own, or via endorsement from others who can't be accused of shilling for me.

But, yes, some chain care might change the ratio of chainring vs. cassette wear. But IMO the jury is still out on the way to extract the most bang for the buck from drive trains. Some religiously replace chains and preserve the sprockets, others simply run until dead, and some, like myself, rotate multiple chains on the same drive train, then run until dead.

IME all the methods yield comparable costs per mile and possibly the only wrong approach is to run chains slightly too long, then replace them when it's too late for the sprockets anyway.