Cassette, Lockring & Freehub issues

[RodTi]

Yello all,

 

 

So after getting a bit cocky on the "What will snap first" poll/thread See here- and having mentioned to the wife a while back that "I'm hardly spending money on my bike these days" - I've been brought back down to earth. With a bump.

 

 

Replaced my chain about 3 weeks ago.

Was naturally nervous I needed to change the whole cassette as well - and maybe the blades.

 

Was very happy when all went well.

Until yesterday.

 

Uphill - and especially in the smaller cogs at the back - serious slippage started happening on several of the rings, all at once?

Which kinda surprised me - going from smooth riding to cluster-@#$% in the matter of a day...

 

Rode on - and on the way back, burning the downhills, even noticed slippage on the smallest at the back, whilst on big blade in front - whilst descending??

Lots of noise too - but was hard to judge with the usual wind blasts etc. on the way down...

So I resign myself to the fact that I need to replace the cassette.

 

And then the following happened:

 

I take the rear wheel off this morning - to take it in to the LBS.

As I remove it - I hear the sound of metal hitting tiles - look down, and notice the Lockring on the floor, together with the two smallest cogs... Third on the list, appears to be loose as well?

 

Dressed for work already - so don't want to get too greasy/dirty - so leave it be, and simply put them back on, and take it in.

 

LBS replaces my Lockring - tells me to try it out tonight and see if slippage occurs again...

 

Questions:

 

1.) How common is it for a lockring to work its way loose?

2.) If the lockring loosens - do the cogs normally simply slide off?

3.) Could this be the sole reason for slippage - and a simple case of tightening the lockring?

4.) Chances I'm going to have to replace the cassette - should I not do this in any event?

5.) Might there be a problem with my freehub unit - and if so - does this entail a new hub/wheelset, or can this be repaired individually?

 

I'm really ignorant when it comes to wheelset issues - so I'm not even sure I've asked the right questions here - but any suggestions will be appreciated!

[Christopher Brunsdon]

Interesting. I did look at the lock ring when replacing my cassette and the only way I can see it working itself loose is if it was never tight.

 

Then again becuase of the grooves I can easily understand the ring getting damaged it not tight (so I don't think your LBS was wrong). I've also kept my old lock ring should this also happen to me.

 

Just waiting for JB to comment

[RodTi]

Interesting. I did look at the lock ring when replacing my cassette and the only way I can see it working itself loose is if it was never tight.

 

Then again becuase of the grooves I can easily understand the ring getting damaged it not tight (so I don't think your LBS was wrong). I've also kept my old lock ring should this also happen to me.

 

Just waiting for JB to comment

 

CB - the LBS techie said it happens occasionally, that the lockring works its way loose...

I've had the cassette on for about 2 years now, without any problems so far - so I guess it's possible?

 

Just hope this doesn't mean there's a problem with the freehub...

[Christopher Brunsdon]

Personally I would but it down to the lock not being tight enough. A quick google confirms this but there was mention of using spacers on certain hubs.

 

Perhaps thats the issue and what can cause the ring to come loose.

[patham]

Just to add that I borrowed a lockring tool & chain whip to remove an old cassette last w/e, only to find out that I could take it off with fingers only.

 

However the shifting has always been flawless, so slippage and lockring tightness may or may not be related. Who knows - but I made sure the new one is not going anywhere..

[Johan Bornman]

My thinking is that someone forgot to tighten the lockring. It requires 40NM of torque, which means it ain't going anywhere once tightened. Human error. It cannot happen by itself.

 

Can the rest come off if the lockring is loose? Yes, they will.

 

Don't suspect your freehub, suspect the last person to tighten the lockring.

 

Do you need to replace the cassette? No, not from this incident in anyway. Other reasons maybe but not this.

 

I think this is the cause of your gear slipping. However, putting a new chain on an old casssete, where the cassette is worn beyond spec, presents with similar problems - slippage under pressure. However, it will slip only in one or two of your favourite gears (i.e. most worn) gears and almost never in the smallest.

 

Tighten your cassete, have a beer and go ride.

[DirtyFrank]

Just to add that I borrowed a lockring tool & chain whip to remove an old cassette last w/e, only to find out that I could take it off with fingers only.

 

However the shifting has always been flawless, so slippage and lockring tightness may or may not be related. Who knows - but I made sure the new one is not going anywhere..

 

Are you riding Mavic Crossmax wheels/hubs perhaps?

[Christopher Brunsdon]

Are you riding Mavic Crossmax wheels/hubs perhaps?

 

Those where the hubs I read that need spacers.

 

Anyway, buying a chain wip & cassette tool is only R200 bucks and worth the effort as its quicker to pick up a loose lock ring with the tools than having to wait for it be loose enough for your fingers.

[RodTi]

My thinking is that someone forgot to tighten the lockring. It requires 40NM of torque, which means it ain't going anywhere once tightened. Human error. It cannot happen by itself.Can the rest come off if the lockring is loose? Yes, they will.Don't suspect your freehub, suspect the last person to tighten the lockring.Do you need to replace the cassette? No, not from this incident in anyway. Other reasons maybe but not this.I think this is the cause of your gear slipping. However, putting a new chain on an old casssete, where the cassette is worn beyond spec, presents with similar problems - slippage under pressure. However, it will slip only in one or two of your favourite gears (i.e. most worn) gears and almost never in the smallest.Tighten your cassete, have a beer and go ride.

 

Thanks JB - I'm hoping that you're right about the cassette!

 

I think it should be ok, for the simple reason that for the weeks/rides after having replaced the chain, I had no issues - only for everything to go pear yesterday afternoon.

This would appear to support the idea that the lockring being loose was behind the problems.

 

Obviously, if slippage occurs now - I'll take the plunge...

 

Re human error - might have been the very LBS who gave me the free lockring replacement this morning? They serviced my wheels a few months back - and presumably would have removed the cluster to do the hub?

 

Regardless - bygones now.

[Thermophage]

Are the bicycle torque wrenches even rated to 40 Nm?

[RodTi]

Are you riding Mavic Crossmax wheels/hubs perhaps?

 

 

Nope - I remember reading that they had some issues.

 

Cane Creek Zonos SS.

[RodTi]

Those where the hubs I read that need spacers.

 

Anyway, buying a chain wip & cassette tool is only R200 bucks and worth the effort as its quicker to pick up a loose lock ring with the tools than having to wait for it be loose enough for your fingers.

 

True - although, a loose lockring is hopefully something that won't happen to me again!

[bikemonster]

Are the bicycle torque wrenches even rated to 40 Nm?

 

Prolly not, but a "real" torque wrench will be.

 

More important, 40Nm is a fair old twist. You can, within reason, lean on the lockring tool. With the lockring, you need to tighten it up good and proper to stop it coming undone.

 

With things like the allen head bolts that hold bars to stem, the torque wrench is more to prevent you from over-tightening than to ensure that you do it up tight enough.

 

Then again, who needs a torque wrench? Tighten until it it goes loose, then a 1/4 turn back.

[Thermophage]

Yeah...the 1/4 turn back is NNB...

Over torquing bolts/etc can actually (in some cases) cause them to loosen more easily.

But a decent torque wrench is a lifetime investment anyway

[Stretched@Birth]

Question - Why were the old screw on style "clusters" replaced with cassettes? The screw on ones could not come loose, as they were tightened by your pedalling... This did make them fairly difficult to remove. Would be interested to know why the change occurred.

[RodTi]

Question - Why were the old screw on style "clusters" replaced with cassettes? The screw on ones could not come loose, as they were tightened by your pedalling... This did make them fairly difficult to remove. Would be interested to know why the change occurred.

 

Blame Shimano!