Chain and sprocket wear

Discussion in 'Australia' started by Uncas, Jan 28, 2017.

  1. Uncas

    Uncas Making space for lost time

    Jan 2, 2014
    Safe distance West of Brisbane
    Hi All,

    Just seeking some feedback on longevity and replacement of sprockets and chain. I ride a 650 single on and off road, don't flog things and clean the chain after each ride. After 35,000 Km the front sprocket teeth are visibly thinned and curved. The rear sprocket looks pretty good with only slight thinning and curve. I have never taken the chain off to test wear but have been impressed that I have only had to adjust it twice in some 5 years (although this is in comparison to pre o-ring chains in the 1980s which wore comparatively quickly).

    I am tempted to just replace the front sprocket (tight-arse syndrome). However am aware of the adage that both sprockets and chain should be replaced together, as they wear together, but not sure if this is fact or marketing?

    So, if you also ride a big thumper, don't flog it but do maintain it I am very interested to hear your thoughts and experiences on:
    - at what Km you replaced chain and or sprockets?
    - have you ever just replaced a front sprocket? And did this cause more problems than it solved etc?
    - are there any key signs that a sprocket is at the end of its service life?

    Appreciate any feedback and responses.
  2. enookway

    enookway Are we having fun yet?

    Jan 3, 2008
    Leeton NSW
    35,000km is impressive for any chain and sprocket set.
    If the rear sprocket looks OK, grab the chain at the rear of the sprocket (3 o'clock position) and pull it rearwards. If can only be pulled up half a tooth height or less then then chain still has plenty of life in it.
    Front sprockets are 3 times smaller than rears so theoretically wear 3 times faster, so you can replace 2 or even three fronts for one rear and a chain.
    A worn front will also accelerate chain wear, so when the teeth on a front start to become asymmetrical (visibly worn on one side), replace just the front. That's what I do anyway
    Lots more opinions to follow, just don't mention chain lube:rofl
    davorallyfan, Rumble and lnewqban like this.
  3. Bing267

    Bing267 Wannabe Adventurer

    Apr 13, 2015
    Toowoomba Queensland Australia
    35000km, well done, just replaced mine,DR 650, front, rear and chain had done 18000km, front wasn't bad, rear was starting to curve, chain shot, will keep front as spare. Don't mind spending $$ to have piece of mind. Do mostly dirt. Cheers
  4. Scrubmonkey

    Scrubmonkey Been here awhile

    Feb 8, 2016
    Australia, QLD
    I replaced the chain and rear sprocket on the drz about 9k ago. I put a new front sprocket on a few thousand before that and its started to hook but hasnt reached near the flat part ontop of the teeth yet. I do ride it moderately hard and oil it every other ride unless its in the sand then ill go over it with a tooth brush and a rag for a more thorough clean. Never adjusted it yet (rk chain i think it was and super sprox sprockets) so will replace front only and keep running it. Though will be swapping rear sprocket soon. I forget the measurments but you can measure the max service length of the chain. Hang it up with a weight to make it taught and measure betseen the pins 18 links apart i think it was.
  5. gavo

    gavo Slacker

    Jan 5, 2010
    Gympie QLD
    35000 is a pretty good run. I've replaced just the front or just the rear sprocket or even just the chain no probs.
    I tend to do new chain and sprockets before a big trip or a very remote trip just for peace of mind but my current set will go till they break.
    Also I some times change the front for different riding.
    Don't ask how I got this colour and I have a DR 650.:-)
  6. Toy Rolex

    Toy Rolex Been here awhile

    Feb 14, 2013
    I have broken a chain and the resulting mess was very very expensive.

    Change the lot before it is to late.
  7. Portly

    Portly Plodder

    May 25, 2011
    North coast NSW Aus
    I run two fronts to one rear and chain.
    I rotate the fronts every eight to ten thousand and get 25 to 30,000 from a set.
    You will generally know when the chain is nearly shot as frequency of adjustment will increase.
    My issue seems to be when the O rings go and the chain dries out and I get a rusty looking dust coming from the inside of the chain.
    On brands I find the JT rears last longer than Supersprox
    glitch_oz, Scrubmonkey and lnewqban like this.
  8. lnewqban

    lnewqban Ninjetter

    Jan 22, 2012
    The important thing is to determine how much wear each link of the chain has.
    Measure the admissible elongation by sections of chain.

    If the factory lubrication is gone from one or several links, the pitch of the chain grows for that section and those rollers hit the sprockets in a destructive way.
    The pins for those links may become dangerously weak and they stop pivoting freely.

    If the chain is evenly worn but still within spec, I would just replace the front sprocket.

    Please see these:

  9. GodSilla

    GodSilla I did that.

    Sep 21, 2006
    GodSowncountry Australia
    35K? Just replace the lot. Then replace the front every 5 to 10k, depending on wear.
    davorallyfan likes this.
  10. ferals5

    ferals5 Grumpa

    Jan 6, 2011
    Goulburn, Australia
    ??? 525 v's 520 chain there is a huge difference in km covered. 520 I only get 10k of hard yakka, 525 it's 25k+

    replace the lot.
  11. Blakduk

    Blakduk Don’t be too practical.

    Sep 30, 2007
    FFS. 35,000 kms on the FRONT sprocket? On a big single? Holy Mackeral that's a lot. It would have stuffed the chain by now for sure.

    Dirtbike riders often do 3 fronts, 2 chains to one superhardened rear sprocket. The reason I like the soft stock front sprockets is that they are relatively cheap and there is less chance of wearing out the gearshaft splines, which are very hardened.

    I will use two front sprockets, then replace the chain, but usually do the rear sprocket too as I often just buy the kit. Consequently I have a lot of half worn sprockets, chains and chain guides in the garage. Some for bikes that have looooong gone!

    The thing you should remember is that a sprocket will start to wear a chain before the sprocket looks worn to a casual glance.

    Having had a chain brake on a TE610 while overtaking a caravanner on a country road, leads me to suggest you should err on the side of reliable. I didn't smash a case, but others have and had very expensive repairs.
  12. Uncas

    Uncas Making space for lost time

    Jan 2, 2014
    Safe distance West of Brisbane
    Thanks guys, some great responses and info here. I did some of the tests inmates have suggested (could only pull the chain about 2mm off the rear sprocket at 3 o'clock) which did not indicate excessive wear - then did some further google research.

    For those like me who didn't know - the standard pitch for a 520 chain, pin centre to pin centre is 15.88 mm or 5/8" for our American friends. I then tightened the top of the chain, counted out 24 intervals and then measured outside pin to outside pin. This should measure 381 mm or 15" for a new 520 chain. I returned three readings of 382.5 to 383 mm. Empirical data on acceptable chain wear was difficult to locate on the internet but I found a couple of sites which suggested 2% as the upper service limit.

    So, at present I have just over 0.5% of chain wear! Which does suggest to slap another front cog on and all sweet for another 20K. However, will do a bit more research on acceptable chain wear as this does seem to be the crux of things.

    Thanks again for responses, have learnt heaps of relevant information and also some irrelevant such as an inch measurement was based on the width of a man's thumb at the base of the fingernail - surprisingly accurate too!

    Happy and safe riding to all.
  13. Warin

    Warin Retired

    Aug 30, 2012
    Its the Kings thumb you have to use!

    And a yard is from the tip of his nose to the outstretched fingers.
    A foot is ...well a foot.

    As others have said .. check the chain in various places over it length .. and it should be checked when in tension ... just pull a one end of the measured section. If your happy with it .. just get a new sprocket. I'd also look at getting a chain /sprocket set if you have the room on a shelf, that way your ready to run when the things ware out and that can happen rapidly.
    lnewqban likes this.
  14. JohnG.

    JohnG. Long timer

    Mar 18, 2006
    Cooma N.S.W.
    35,000 is impressive for a big trailie venturing on dirt.
    Currently have 52,000 on a mostly tar ridden vstrom 1000.
    Previous Aprilia managed 62k...
    Always adjust at the 'tight spot' that develops towards the end of a chains life and lube the crap out of it.
    then replace it all just before the front sproc starts loosing teeth lol
    having said that I 'flipped over' the rear sproc on the Aprilia and got 112k from it!! Seriously hard metal!
  15. wairau

    wairau get in behind!

    Mar 29, 2011
    Taranaki, NZ.
    after 35k you dont need any advice mate. you should be giving it.

    whatever you're doing, its working.
    GodSilla likes this.
  16. Uncas

    Uncas Making space for lost time

    Jan 2, 2014
    Safe distance West of Brisbane
    Ha, I am doing even better with my 1999 1.8 litre, 4 cylinder manual 4WD, which is up to 180,000 Km on the original clutch plates! Common theme is a lack or stick or mechanical sympathy depending non which way you look at things.
    anydavenow likes this.
  17. JMick

    JMick Been here awhile

    Feb 23, 2014
    FNQ, Oz
    Got 245,000 kms out of the original clutch on my '99 2.8 TD Rodeo, although it was starting to slip a bit on really steep hills towards the end. It has spent most of its life towing heavy trailers and heavily loaded, so a pretty good run. On the downside I seem to get less than 2 years out of windscreens for it.

  18. bigbrad

    bigbrad Long timer

    Feb 3, 2015
    Margate Beach
    My current 06 4wd Triton has original clutch and at 370 000 klm is doing just fine with no slippage or burning.

    My previous Gq patrol managed 620 000 klm before it needed a new clutch.

    I must be a pansy driver
    Tomdog and DeLewis like this.
  19. wassie

    wassie Life is too short for traffic.

    Apr 21, 2011
    Brisbane QLD
    Just changed the front sprocket on the XR650R after 10000km, chain and rear good for at least 5000km I reckon
    davorallyfan likes this.
  20. gateman

    gateman Long timer

    Apr 12, 2009
    Norther NSW, Australia
    Im interested to know what a life span might be for a KTM1190 or 1290.
    Say 70% road based.
    Any comments?
    Blakduk likes this.