The life of a chain

[Kamboskid]

Hi everyone,

 Apologies if this question has been asked before, I shall be replacing my chain as it would appear the adjustment is as far as it can go, therefore iy has to be changed, the bike has covered a total of 33,400kilometres, and never done any drag starts or wheelies and generally it has been ridden with restraint and respect, but in the last 16,000 km has been in 2 up mode.
 I feel that the distance covered is less than I anticipated and would have thought 40- 45 thou was possible, any thoughts or insight appreciated?

[Art]

There is no way a drive chain can stretch that much. If the drive chain slack cannot be taken up by the adjusters then either the drive chain is too long or the sprockets are too small, you may need to remove a link in the chain. The drive chain should be 120 links long, which equates to 75" to 76" depending on wear, yes drive chains are measured in imperial units. The front sprocket should have 16 teeth and the rear sprocket 43 teeth. Note due to the 2010 to 2014 overlap in production and registrations some SC58's have been fitted with a smaller 41 tooth SC64 replacement rear sprocket.

If you're checking chain wear by comparing the chain adjuster index mark against the chain wear label on the swinging arm then that is an unreliable method of checking chain wear because many of those labels have been applied incorrectly. The correct way, and in my opinion the only way, to satisfactorily measure chain wear is by measuring the chain. Do this by applying some tension to the upper chain run so that all slack is taken out of the lower chain run, then measure across the centres of 17 link pins on the lower chain run. This is easiest done by covering a ruler in masking tape and placing two pencil marks 257 mm apart and comparing that to the distance between the centres of 17 link pins.

The numbers- A new straight out of the box CBF 1000 drive chain such as the DID 530 VX3 will measure 254 mm across 17 link pins. DID’s, and most other drive chain manufacturers, service limit is +1% stretch which means that a measurement in excess of 256.5 mm would indicate a replacement chain is due. At your own risk and assessment if the sprockets are showing little sign of wear and there are no issues with the drive chain such as binding, seized links, failed 'X' rings etc you could leave the chain a little longer to say 1¼% or even 1½% stretch (257 or 258 mm across 17 pins) but you do this at your own risk of any future chain failure. If you're unclear between the difference in 'worn' and 'worn out' or you ride it like you stole it then stick to the chain manufacturers service limit of 1% stretch (256.5 mm across 17 pins).

[Kamboskid]

Hi Art,

 Thanks for the detailed reply, as it happens I did in fact change the size of the rear sprocket to improve the economy as the bike is used specifically as a tourer, the chain was a tad overlong so it was shortened by a couple of links, but I am surprised it needs to be changed after ( I think) a relatively low distance covered esp as its in km, not miles! Having said that it is a heavy bike, but 33,500 km only equates to 20,000 miles which in anyone's book is low IMHO!

[Art]

I'd expect 25-40,000 miles (40-65,000 Km) from a chain, of course that do depend on riding style and regular maintenance by way of cleaning, adjustment and lubrication. How many of us get down and dirty and clean the drive chain?

I'm assuming here you changed the rear sprocket without replacing the drive chain and front sprocket, this will accelerate chain wear because the rollers on the part worn chain will not mesh properly with the teeth of the new rear sprocket and will need to bed in. Chain wear is further accelerated because as the meshing of the chain and rear sprocket improves the meshing of the chain and front sprocket worsens, the chain is forever wearing in to properly mesh with one or other of the sprockets. I understand the reasoning for fitting a smaller rear sprocket but it will always be a false economy if the chain and both sprockets are not replaced as a kit.

[Kamboskid]

Hi Art,

 Once again your wisdom prevails, it never occurred to me that uneven wear would result because of my action. It now makes sense to me, thank you for clearing that up.

 Now a new chain should last a fair bit longer I am hoping or do you think the same thing will happen again and replacing the original rear sprocket makes more sense? Appreciate your comments!

[Art]

Replace chain, front and rear sprocket as a kit - always.

Its not so expensive, less than £100 from Hunters of Newcastle

Note the 2006-2010 SC58 CBF1000 kit comes as 16 tooth front, 43 tooth rear, 120 link chain. If you want to preserve your modified gearing order a 2011-2016 SC65 CBF1000 kit which comes as 16 tooth front, 41 tooth rear, 120 link chain. As before you may need to cut one or two links from the chain, measure twice cut once.