Issue with chain slipping

PEHowland

I have just replaced the chain on my bike. The front crank is marked Shimano Nexave and appears to be the FC-T410 model (see http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-T410-1961_v1_m56577569830613253.pdf) with an 8-speed cassette on the rear (I don't know what model this is). I bought a new chain from the bike shop and they gave me a Shimano HG70 114 links 7/8 speed chain. I cut the chain to the same length as the old one and replaced it. However, now I notice the chain slips under load.

Is this a problem with the front crank or rear cassette, or is the chain the wrong model? When I fitted the chain, I noticed the links were slightly shorter than on the one I was replacing. I also notice that the Shimano Nexave page mentions the CN-IG51 chain, not the chain I was sold.

Any advice welcomed!

Thanks,

Paul


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pingpong

Is the cassette worn?

topdude

If the rear mech is adjusted correctly then most likely the cassette is too worn for your new chain.
Some cassette sprockets will be more worn than others so is the slipping only on the most used sprockets ?

PEHowland

The cassette doesn't look worn - no broken teeth and they all look in reasonable shape. However, the teeth on the front chain rings don't look so uniform. Could this be the cause? Also, is there a significant difference between the hyperglide (HG) chains that I have put on, and the IG range that the Shimano page seems to recommend for this chainwheel? I'm trying to figure out whether I need to buy another chain, or replace the chain rings or cassette...

Ambermile

Umm... do you have a stiff link in there somewhere? Happened to me with a HG chain.


Arthur


PS - hello - new member!

dazzawazza

Most likely the cassette doesn't work well with the new chain.
Recently I replaced the chain on my MTB commuter after 800 miles (mainly to extend the life of the cassette by swapping chains after certain miles), however when I received the SRAM chain it was a newer model from the original and there was chain slip immediately. I put the old chain back on and it was fine. So I have now left the set-up as it is until the chain has stretched too much. I will then replace both chain and cassette.
I will try swapping chains again, but next time will make sure they are identical models.
I would recommend checking the condition of your chain occasionally to prevent unnecessary damage to the front chain rings. Having to replace front chain rings, cassette and chain can get quite expensive.

alfablue

Often a new chain will reveal a worn cassette, they wear together so the old chain may "fit" the profile of the cassette while a new one will not. Some people reckon on changing the cassette every 2 to 3 chain changes, although if your old chain was used well past its "sell by" date, the casssette could be too worn already.

The chainring teeth are designed to be irregular in shape to promote shifting. One would expect a chainset to outlast a cassette or two (or three?) and several chains.

PEHowland

Thanks for the advice everyone. Can some also confirm that there is no difference between the HG and IG ranges of Shimano chains that might cause this?

Mr P

From Shimano website FAQs;
"All current HG cassette cogs are specially profiled to be HG or IG chain compatible.

Any Shimano IG chain will work with any HG cassette. If you use a HG chain with a 7-speed IG cassette (CS-IG50 and CS-IG60) the rear derailleur adjustment becomes more critical.

One significant compatibility issue is always to avoid using a HG chain with an IG-only crank set.
Why? The chain will release from the large (outer) chain rings too easily while in the larger rear cog. It may be possible that the chain drops off the outer ring without shifting the lever, when under full power."

PEHowland

Thank you everyone for your help. I replaced the rear cassette in the end and this did indeed solve the problem. I was surprised how subtle the wear on the old cassette was - although some of the teeth looked a little narrower than on the new one, it didn't look obviously worn. Anyway, lesson is now learned for next time. And I also plan to pay more attention to keeping the chain and gears clean each week. The combination of lube and sand here in Holland seems to make a wonderfully abrasive compound.

Paul