Mystery noise on my big bear - suggestions please.

[Woody]

Hi folks,

I've just reached 2,000 miles on my Woosh Big Bear, approx half covered in France, in a very hilly part of Limousin, and the rest in a much flatter region of Spain near Alicante. My experience has been very good generally, and apart from a few minor niggles, the bike has performed well.

Just as I started writing a review to post here - wouldn't you know it - it's started to make a noise that's driving me nuts.

The noise is quite a loud crack which varies in volume - audible from off the bike as I pass someone - and seems quite random in nature.

I've had the bike serviced recently but it's still doing it. I also took the rear wheel to a bike mechanic locally (in France) last week and he took the bearing apart, re-greased it and put it back together - no difference.
Thinking that there can't be many likely causes I just took the bottom bracket apart - but there's not really any way to service it - so I gave it a coat of grease and reassembled it - no difference.

The noise happens whether the electrics are on or off and also even when I'm free-wheeling, though I think it's more frequent when I'm pedalling. It does not occur at any particular part of the pedal stroke nor is it rhythmical in nature. I would say that it's a mechanical noise - hence my focus on wheel bearing and bottom bracket.

I don't think it's anything to do with the head set - it does it in a straight line and doesn't seem to do it more when I'm turning. I also don't think it's anything to do with the brakes.

Thought it might be one of the pedals but it still does it with my feet off them!

Thinking it could possibly be a broken spoke, I just tried playing a tune on them and they're all fine.

My first instinct was the bottom bracket - I had a similar noise while I was in Spain - but that was much more rhythmical in nature and was solved by simply tightening the bb up.

What I can't work out is that if it's the bb again would it make a noise when I'm not pedalling? If it's not the bb what else could it be?

Any suggestions most welcome,

Cheers,

Phil

 

[Croxden]

I had this once, trying locate where the sound came from had me doing acrobatics whilst trying keep going straight.

Mine was from the saddle or seat post, that area I forget now. Remove/refit the saddle and seat post and see if it makes a difference.

 

[trex]

it could be from the freewheel skipping. On the Big Bear, it's a Shimano TZ21

 

[Woody]

I had this once, trying locate where the sound came from had me doing acrobatics whilst trying keep going straight.

Mine was from the saddle or seat post, that area I forget now. Remove/refit the saddle and seat post and see if it makes a difference.

That's spooky! Just had the same thought and tried standing on the pedals - if anything it made it worse. So unfortunately it's not that. Cycled a mile uphill and it cracked about twenty times, coming back it did it about 5 times - and not so loud. I'm almost sure I can feel it through the pedals - but I could be fooling myself. You are right though it is driving me nuts!

 

[Woody]

it could be from the freewheel skipping. On the Big Bear, it's a Shimano TZ21

Hadn't thought of that, but would it make the noise both while pedalling and also while coasting?

 

[trex]

it's possible.
You said while coasting, that rules out chain, bottom bracket and crank arms.
The freewheel still turns while coasting.

 

[flecc]

The freewheel bearings could be breaking up, and that could cause loud cracking sounds both when it's not rotating it's bearings when under load or when it's freewheeling.

Multi-sprocket freewheels are inherently less strong than cassette mounted sprocket assemblies and their bearings can fail from time to time.
.

 

[Woody]

The freewheel bearings could be breaking up, and that could cause loud cracking sounds both when it's not rotating it's bearings when under load or when it's freewheeling.

Multi-sprocket freewheels are inherently less strong than cassette mounted sprocket
assemblies and their bearings can fail from time to time.
.

Thanks guys, that makes a lot of sense. Also explains why the noise doesn't correspond to any position of the cranks/pedals.

One of the slight niggles that I mentioned is that I find the Bear slightly under-geared on occasion, so I have been thinking about changing the freewheel for something with a smaller cog for top gear. From memory the Bear has a 14 tooth - so I could look for a suitable freewheel and hopefully solve the noise issue too.

Any ideas where to find a 7 speed freewheel with a range from 11 or 12 to 28? Don't know the technical term but it's a screw on type freewheel. I'd like to get a decent quality one - don't want to have to change it every 2,000 miles!

 

[flecc]

The thread is standard and it's just called a freewheel. Check with Cyclezee, they've got some 11 to 32 ones on this page which should be ok.

Of course I can't say for certain it is the freewheel causing your problem, it just seems a likely suspect.
.

 

[Alan Quay]

I had a similar situation (albeit a totally different bike), and it was worn pedal bearings.

 

[Woody]

Thanks Flecc I'll get in touch with them.

Thanks Mike, pretty sure it's not the pedal bearings - I've had them go on other bikes, and they're really noisy at the start of the power stroke usually, whereas this noise is seemingly random.

It may take me a while to get the freewheel and fit it - but it's got to be worth a try as I want a different ratio anyway.

 

[Nealh]

D8veh has some 11-30 & 11-32 freewheels on Fleabay.

 

[RobF]

Sounds to me like a broken axle.

The bike still works after a fashion because the quick release holds everything together.

The seven speed freewheel is notoriously unreliable and has largely been replaced by the freehub system, which has eight or more speeds.

http://sheldonbrown.com/free-k7.html

 

[Woody]

Just came across this dormant thread on 11 tooth freewheels.

http://www.pedelecs.co.uk/forum/threads/dnp-epoch-freewheels-and-gearing-question.13139/

Don't much like the sound of the potential of the freewheel case splitting on the dnp freewheel. Is this still an issue?

Found a Shimano 13 - 28 freewheel on Amazon (supplied by woolly hat) which might do me otherwise.

Thanks RobF, it's not a broken rear axle, had the hub apart - plus there's no quick release.
Changing the whole hub in order to use a cassette would be an option but more hassle than changing the freewheel. Think I'll try that first.

 

[Cyclezee]

The thread is standard and it's just called a freewheel. Check with Cyclezee, they've got some 11 to 32 ones on this page which should be ok.
.

That link has now changed to this one http://www.cyclezee.com/e-bike-parts.html and the 7 speeds are 11to 30t

 

[RobF]

Changing the whole hub in order to use a cassette would be an option but more hassle than changing the freewheel. Think I'll try that first.

Makes sense.

The freehub is deemed to be vastly superior, but a new freewheel will get you useful extra service life - hopefully more than 2,000 miles this time.

 

[Deleted member 4366]

Those DNP freewheels are used by many forum members including myself. I've never heard of any problems or failures. The stories you hear are probably from the distant past and hopelessly out of date.

 

[flecc]

Multi-sprocket freewheel failures have been most likely with the cheap single bearing variety, the one inboard bearing not providing much support when the the outboard small sprockets are under load.

Shimano had the similar budget Cadet range at one time, but they seem to be out of stock from many sources with no indication of more coming, so maybe they've discontinued them.
.

 

[Woody]

Having decided to change the freewheel for a DNP 11T-30T I've been looking for a DNP removal tool in case I ever want to get it off again.
I have an Icetoolz 09X3 tool which fits the Shimano freewheel on the bike. I have read that this may not work for DNP freewheels as they need a long reach tool.
Struggling to find the right tool - other than from the U.S. with a $25 postage charge!
Any ideas of where I might get what's needed?

Thanks,

Phil

 

[Cyclezee]

Having decided to change the freewheel for a DNP 11T-30T I've been looking for a DNP removal tool in case I ever want to get it off again.
I have an Icetoolz 09X3 tool which fits the Shimano freewheel on the bike. I have read that this may not work for DNP freewheels as they need a long reach tool.
Struggling to find the right tool - other than from the U.S. with a $25 postage charge!
Any ideas of where I might get what's needed?

Thanks,

Phil

We have the long reach removal too, £7.50 including
delivery.

Drop me an email if you want one.

We also have the DNP 11 to 30t freewheel.