Crunching/Clanking from down there ...

[Shaun]

Never come across this before, but on the way home tonight I was about 5 miles into my 6 mile journey home when I got a loud crunching/clanking sound from my pedals/chain/bottom bracket/deraileur? - best way to describe how it felt was like stones stuck in the chain!

It smoothed-out for a short while, then started-up again, then smoothed till I got home. Don't think it was chain slip, and checked all spokes on back wheel were good and tight.

I couldn't replicate it when I was off the bike messing with it in the back yard, but just wondered if this rings any bells for some of you more experienced boys and girls?

I just don't want to knacker the bike riding it if it needs immediate attention.

Unfortunately my LBS man has gone on holiday this week, so if anyone can shed any like I'd appreciate it.

Cheers,
Shaun

 

[snorri]

If it ran smoothly for the last mile, it doesn't sound as if anything is damaged. Perhaps your gear change is a bit out of adjustment, but I would not like to advise without having seen your bike.

 

[Smokin Joe]

Do the gears still shift ok?

What happens when you spin the cranks with the chain off, if it is still noisy or rough running you could have a bearing breaking up, or if you are using a non-cartridge bb the bearing cage could have done the same.

Check the hanger isn't bent.

And check that you haven't actually got something caught in the chain.

Difficult to diagnose strange sounds, it is just a process of going through everthing that moves one at a time till you pin it down.

 

[Tynan]

bracket bearing is my guess

as a seasoned veteran of running a set to complete disintegration

 

[gkerr4]

sounds to me like a BB too - although i recently bought a brand new specialized langster and there was clonking and clanking from the BB area on the first ride!!

I took it to bits that night, cleaned and re-greased where applicable (although the standard of initialassembly was awful! - who does that - specialized or the bike shop?) re-assembled and tightened up and then it was silent!

I'd say check everything for tightness and / or regrease things. - see how you get on.

 

[Twenty Inch]

bracket bearing is my guess

as a seasoned veteran of running a set to complete disintegration

That was my first thought too.

 

[Shaun]

Thanks all, I'll look into it. I did wonder if it might be the BB, but wouldn't want to tackle that on my own.

I'll give it a run up the street and see if it starts up again; if so, it's a run down to the LBS.

 

[XTCRider]

I had a clanking noise coming from down there too, thought my BB was on its way out. Took it to a LBS and they checked my BB and it was fine. Turned out to be just a loose crank bolt. So it might be worth LBS having a look if they are trustworthy as there might not be anything major wrong

 

[aberdeenian]

I've had mysterious clanking before too on my mountain bike. Checked the chain, check the derailler was straight, all that good stuff. Eventually spotted that there was half a tree caught in between the wheel and the luggage rack. Now it's always the first thing I check for.

 

[gkerr4]

have a go yourself!!
it's just a bike you know - fairly simple machines, have been for years! - it's no nuclear submarine in complexity terms!

get stuck in and feel the satisfaction of fixing your own bike!!

 

[Shaun]

I would, but I just don't have the time

Anyway, dropped it into LBS today and he confirmed it was the BB and charged me £25 to replace it. All done and ready for me passing by at 5pm

 

[gkerr4]

that sounds pretty decent actually - despite what I just said - £25 all-done is very good.

glad you are back on the road!

 

[yenrod]

It came across as one or more bearings cracking...those that where were smoothed down hence the quietness...and so you did the obvious thing.