Mystery Problem

[Moab]

Okay, so I think I have found the problem but out of interest sake I want to see the opinions of you technoboffins on the hub:

 

On Saturday whilst riding my bike started making an awful sound! A lekker grinding sound which I eventually worked out was coming from the RD. My gears were jumping as well . The noise only happened when I was not peddaling  and the chain went slack. Whilst riding a long (800m) and steep downhill I saw that my chain also went slack during these times.

 

So, what do you think is the prob and what caused it.

 

Btw.... I was riding hectically dusty roads on the weekend whilst out exploring if that helps.

 

Okay, I get popcorn now and watch.....

Di CPD2009-05-21 00:21:40

[droo]

Freehub gritty and jammed. Or just jammed, could also be something stuck between the big sprocket and the spokes or hub. Remove muck and relube...

[Moab]

Freehub gritty and jammed. Or just jammed' date=' could also be something stuck between the big sprocket and the spokes or hub. Remove muck and relube...[/quote']

 

But would that cause chain slack and jumpy gears? (Sorry, I not techno weenie yet )

[AndreZA]

where does the chain go slack, on top or below the chain stay? Above then you freewheel wants to keep on turning and thus "feeding" more chain to the cranks but because you are not pedaling you are not taking up the slack.

 

 

 

Sorry, I do not know why the gears are jumping.

[Moab]

where does the chain go slack' date=' on top or below the chain stay? Above then you freewheel wants to keep on turning and thus "feeding" more chain to the cranks but because you are not pedaling you are not taking up the slack.

Sorry, I do not know why the gears are jumping.[/quote']

 

Is da top. Okay, so I need to clean the freewheel hub then?

 

What I figured: Jockey wheels. They are a bit wobbly. Think the gears need tweeking / service.

[droo]

Hmmm... in that case maybe a combination of laterally loose and sticky clutch. Either way, the remove freewheel / remove gunk / relube should do the trick. What make of hub is it?

 

 

[Moab]

Hmmm... in that case maybe a combination of laterally loose and sticky clutch. Either way' date=' the remove freewheel / remove gunk / relube should do the trick. What make of hub is it?
[/quote']

 

Thanks. So... here is my dumb q for the week: i suppose i should have bought the cassette remover tools today? suppose I need to remove that before i clean?

 

Sorry, but not 100% sure of what to do here

[AndreZA]

Not just a cassette remover tool for that job. You need to remove the cassette and axle to get to the freewheel.

[droo]

First take the wheel off and spin the freewheel. If it's tight or gritty, and / or has lateral play, I'm right. If not, then my advice won't be any good anyway... Your jockey wheels are unlikely to be causing the problem IMO, the top one is supposed to have a bit of lateral float to make up for any inaccuracy in the shifter indexing mechanism. You may have caught your rear mech on a rock and knocked the alignment out though, so have a look at that too, as well as cable tension, before buying tools.

[Moab]

First take the wheel off and spin the freewheel. If it's tight or gritty' date=' and / or has lateral play, I'm right. If not, then my advice won't be any good anyway... Your jockey wheels are unlikely to be causing the problem IMO, the top one is supposed to have a bit of lateral float to make up for any inaccuracy in the shifter indexing mechanism. You may have caught your rear mech on a rock and knocked the alignment out though, so have a look at that too, as well as cable tension, before buying tools.[/quote']

 

Thanks Droo. I will look at that as soon as I get home - so much for riding at the bike park today. I will also try to get a hold of a cassette remover and chain whip to give everything a good ole clean.

[droo]

You'll also, as Mampara said, have to take the axle out in most cases to get the freehub body off before cleaning it. A bit of a PITA, and possibly worth a trip to the LBS if you haven't set a bearing before and don't have lots of patience and free time.

[Moab]

You'll also' date=' as Mampara said, have to take the axle out in most cases to get the freehub body off before cleaning it. A bit of a PITA, and possibly worth a trip to the LBS if you haven't set a bearing before and don't have lots of patience and free time.[/quote']

 

thanks guys. if i dont get it right tonight then i will pop into one of the stores down the road and see if they can help me out tomorrow. has to happen this week!!

[Moab]

Okay, so after a quick clean of the freehub I still have the problem. Now, tonight I am going to do a more thorough attempt but also want to service the hub. Its a Mavic Crossland. Any advice? Also, would the crossland be an adjustable cone hub or a cartridge hub?

Or can someone tell me step by step what I need to do?

My email addy is dianelogie@mweb.co.za if you have any great ideas! (I am outta here at 4:30 to do this. )

 

[Moab]

Okay, so.... I had a mechanic service my freehub. He said it was fine, he gave it some tlc and off I went on a ride. Only to have the problem again . But now I have looked carefully: the noise starts and the chain drops when the chain is on the lower sprockets of the cassette. Then on Saturday I also noticed that my bottom bracket needs replacing. Any further ideas as to what my bike's problem is?? I am racing Babbas on Sunday and cant do any repairs this week, so anything has to happen next week before the Monster but I need to find the blinking problem!! And I am hoping that riding with the mystery problem does not cause more damage.

 

So, any ideas as to what this mystery could be?

 

Thanks

[gremlin]

If you still got the plastick cover that clips between the Casette and spokes, have a look at this and maybe remove. I had this before as soon as you start to free wheel that the chain goes slack, it was the plastick pushing against the cassette that caused this. After I removed this it was 100%.

[droo]

Ahhhh... the joys of the Mavic freehub. PM MoreTrails, he's pulled his one apart often, and seems to be quite good at getting it back together too...