Chain/ sprocket life

samsbike
samsbike Posts: 942
edited June 2012 in Commuting general
Just went into my LBS and got my rear wheel fixed and asked about a new chain. I need a new one in about 300 miles which is fine, however he also said that a new chain for a 9 speed will last about 1000 miles. Is that right? Do they really only last that long?

My chain on my old cannondale mtb, lasted a lot longer than that.

Comments

  • BigLights
    BigLights Posts: 464
    well, my chain on my commuting Sirrus usually needs replacing each service (about every 8-9 months) which is roughtly 2,000 miles, if that helps.
  • dav1
    dav1 Posts: 1,298
    I get 1500 - 2000 miles out of a SRAM PC870, and go through three chains per cassette. This requires regular cleaning and relubing.

    Offroad my SRAM PC971s last 1000-1500 miles.
    Giant TCR advanced 2 (Summer/race)
    Merlin single malt fixie (Commuter/winter/training)
    Trek superfly 7 (Summer XC)
    Giant Yukon singlespeed conversion (winter MTB/Ice/snow)

    Carrera virtuoso - RIP
  • Moodyman
    Moodyman Posts: 158
    About 1600 miles from a KMC X8 93 - good, strong middle of the road chain.

    But I'm a heavy rider and my commute is quite hilly. I'm mad on maintenace though - chain gets cleaned & oiled every week. If you clean/lub less, then 1000 miles seems about right.

    Also,what speed you running? 7/8 speed chains tend to be stronger (mine is 8 spd). 9/10 speeds less so.
  • samsbike
    samsbike Posts: 942
    Its a nine speed
  • simon_e
    simon_e Posts: 1,707
    Are you sure 8 speed chains are stronger, Moodyman? For those on 8 speed and lower, avoid the PC830, it's not half as durable as the PC850 and up.

    Chain life varies based on several factors. A strong lad who goes stomping up offroad climbs in a wet, Scottish winter will place greater strain on it than a granny who pops to the shops in Norfolk only on dry days; also, wear will be faster with worn chainrings and cassette or if you don't lube the chain regularly.

    I read a recommendation recently that for optimum cassette & chainring life to swap your chain sooner - 0.5% stretch (1/16" measured over 12 links) rather than 0.75%.

    SRAM PC951, PC971 or KMC X9 would be ideal.
    Aspire not to have more, but to be more.
  • pdw
    pdw Posts: 315
    I got somewhere between 3 and 4,000 out of my last 105 10 speed chain. Daily commuting in all weather on a flat route. Never cleaned, but regularly lubed. Was a bit under .75% stretch when I changed it, and had no trouble putting a new chain on the old cassette.
  • Moodyman
    Moodyman Posts: 158
    Simon E wrote:
    Are you sure 8 speed chains are stronger, Moodyman?

    Al other things being equal, 7/8 speed chains are stronger than 9/10/11 speed.

    This is because they're thicker. The freehub body has a limited space. So to cram all the extra sprockets on at the back, manufactureres make the gap between each ring tighter. This means chains have to be narrower to fit the narrow sprockets. Narrow chains, means less metal, meaning weaker.

    Another thing...higher speed chains have to run over greater gear combinations - (front chain ring vs cassette) - so there is more twist-ability built into them. This also makes them weaker.

    Hence, why single speed chains are said to be the strongest because they just run round & round
  • Daz555
    Daz555 Posts: 3,976
    I don't keep any sort of track of miles but I just replaced the cassette, chain and front rings on my commuter. They only lasted 16 years. :mrgreen:
    You only need two tools: WD40 and Duck Tape.
    If it doesn't move and should, use the WD40.
    If it shouldn't move and does, use the tape.
  • simon_e
    simon_e Posts: 1,707
    Moodyman wrote:
    Al other things being equal, 7/8 speed chains are stronger than 9/10/11 speed.

    This is because they're thicker. The freehub body has a limited space. So to cram all the extra sprockets on at the back, manufactureres make the gap between each ring tighter. This means chains have to be narrower to fit the narrow sprockets. Narrow chains, means less metal, meaning weaker.
    I realise they are narrower but, as the load is generally placed along the length of the chain, is rivet/roller width really a source of weakness or higher wear? Are the side plates thinner? TBH since I'm not going to downgrade my STIs, cassette and so on to get a 'stronger' chain it's irrelevant to me (though I'm still interested to know the answer).
    Moodyman wrote:
    Another thing...higher speed chains have to run over greater gear combinations - (front chain ring vs cassette) - so there is more twist-ability built into them. This also makes them weaker.
    I don't see how a 10-speed chain has to work with a greater gear combination than 8-speed. They both could be used on a bike that has 52x25 and 30x11 (big/big, small/small), for example, and the freehub is the same width.
    Aspire not to have more, but to be more.
  • corshamjim
    corshamjim Posts: 234
    I just measured the (10-speed) chain on my Trek for the first time. I haven't ridden it all that much (maybe 1,000 miles or less) but it seems it's already stretched. :cry:

    Oh well, I'll keep replacing the chain until the sprockets/chainwheels are worn then put an 8-speed setup on there.

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