How to tell when your drive chain is gone?
 

Good afternoon. Having a few issues with my drive chain. The story is as follows:

• Tightened up my chain two weeks ago, it required a surprisingly large amount of tightening compared to other times, and therefore the tightening bolts are 75% towards the end of the shaft thingy.
• The chain started making clicking sounds when the bike was walked, and a starnge 'whirring' sound when ridden; the speed of the 'whirring' was relative to the speed of the bike.
• Passed my MOT a week ago, but looked at my bike today after coming home and the chain is very tight, and the wheel hasnt moved at all.
• Slackened off the chain tighteners, walked the bike and gained even more slackness without adjustment.

It has done over 8000miles over three years and wasnt a posh one to begin with. Has my chain died? And if so why?

Many thanks, Tom.

Sounds like your chain may have a tight spot?

Slowly rotate the rear wheel and check the chain tension at the same place (mid way between the sprockets on the lower chain run) and look for variations in chain tension. If you find them, your chain needs replacing.

If you're going to continue using the chain, you need to tension it on the tightest spot - note that this is a temporary fix and that the rest of the chain will be slack with the risk of the chain jumping off the sprocket. If you do otherwise, you'll risk snapping the chain, potentially holing the crankcase in the process. There's also the risk of the too tight chain pulling on the bearing that supports the output shaft that carries the front sprocket. If the bearing fails, you risk the gear shafts moving and locking up. I've seen both of the above and have also seen rear sprockets pulled off the carrier, trashing the wheel in the process.

Personally I'd replace both the chain and sprockets ASAP.

Cheers Steve, looks like I am going to be replacing the lot.

When your chain starts doing inexplicable stuff (needing a lot of tightening all of a sudden, after which it then appears to need loosening; making weird noises) it's time for replacement. Past time, in fact. There are official, reliable ways of checking, but the difficulty adjusting it properly is, in my experience, foolproof.

I don't replace sprockets until they're obviously worn, but this comes up for debate all the time here, so take this under advisement.

The real question is: what in the world have you done to your chain to cause it to wear out so quickly? And what are you going to do differently from now on? No reasonable chain should go that fast (unless a non-o-ring chain, which is worth using only in dire emergencies); it'll be well worth your while to figure this part out. I can't even imagine changing out chains and sprockets every 8,000 miles.

There are lots of chain-care threads here, including lots of contradictory opinions and suggestions. Certain basics will be obvious, with the rest up to you to sort through and adapt to suit your preferences (and belief systems).

Hope that helps.

Mark

Hi Mark,

It was a non o ring chain, came as standard with the bike, I presume as it is a 125cc commuter bike.

The new one Im getting is a 'better' one, or so Im told. The sprockets havnt worn out though, but its good practice to change them with the chain, or so Im told.

Cheers for the help.

Exactly what happened with my on my dr in the French alps.:rolleyes2:

had to carry on going on my way to west coast of Italy.

had no probs all the way... just a clicking sound.

doh and did another 1000 miles with it like that.doh

had a guy in France wanting to buy it coz i had it advertised for sale.

he took it for a ride and came back saying there was some thing wrong with the gear box/.. :welcome:


i was even showing him the tight spot on the chain while bike was on a stand, and back wheel turning by hand.

oh well.

guess i will be changing the chain at some point. hahaha

Chains don't cost a lot so unless you are out in the middle of nowhere I would replace it if it the problems can't be smoothed over.

I assume you have been lubing the chain regularly ?

Yea.

i was lubing quite a bit and managed to loosen the tight spot a little by soaking in diesel.

I think it may have got rusty if the diesel soaking works. If I were you I would change the chain, and only change any sprocket if it shows wear or damage.

Like said, if it needs tightening on a weekly basis then it's ready for the bin.

"whirs and clicks" can be quite normal. They can be anything from chain rollers, gearbox bearings, chain guides etc etc etc.

How are your sprockets ?? Sharp ? Shark toothed ???

You can measure chain wear but you need to remove it.

Lay it down in a straight line and try and push all the links together but keep the chain in a straight line. Measure the length in this state.

Then pull the chain apart as far as you can and measure it again. The number should be in mm, not cm. Your chain manufacturer will have the proper service limit.

Once a chain starts needing constant adjustment it only gets worse and worse. I know people who have ridden 20,000 miles (on 1000cc sports bikes too) on a chain like this. They take links out rather than pay for a new one. It's not something I'd do but they manage.

Be wary of the clicking sound if you are a long way from nowhere, it could mean imminent failure of a link, which can cause bad things.

Replace it with an O or X ring chain, keep it clean and lubed and with new sprockets should last for ages. I have been getting 30,000km on a good chain.

Cheers
TS

This makes me think you probably have a seized link or links as well as a tight spot. They are not the same thing. If you have seized links you should replace chain asap.

Hi
It would be worthwhile to check the front and rear sprocket too. In addition to checking the state of the teeth, you should also verify that they are not loose. This is not obvious when you arer stopped unless you specifically check for it.

I might be wrong here, but I think a small amount of play in the front sprocket is OK.

Cheers