RIPPED OFF DERAILLEUR CAGE

[Oscdav]

Can anyone tell me please how the hell I ripped off the cage from my rear derailleur. It is (was), a pretty new SHIMANO ZEE M640 Shadow+ (short cage). Have a 42t Blingring up front and a 10 ring sprocket on rear and a 10 chain.
The bike is a 2010 FS COMMENCAL with a MARZOCHI ROCCO rear suspension; recent Bafang BBSHD conversion.
I was at the very beginning of a steep climb, hitting it suddenly whilst sitting and peddling at speed, resulting in an almost immediate (and expensive) metallic crunching sound.
I have an idea that the rear suspension might have bottomed out. Though there is no sign of the bottom of the cage having hit the ground!
Don't want to make that mistake again if I can avoid it
Cheers all! Oscdav.

 

[Kuorider]

The Commencal has a lot of suspension travel ,on full bottoming out it's possible that your short cage was unable to keep the chain tight enough to avoid the slack chain loop bunching up before the lower jockey wheel or leaving a fold of chain between the jockey wheels and locking everything up with the resultant failure. With the chain jamming and you + the bafang pulling it up against the sprocket, the cage would be pulled apart, thus no lower witness marks on the cage. Any damage to those carbon stays?

 

[tommie]

As above,
probably chain jumping out of line, getting stuck around one of the jockey wheels maybe and then the torque of the HD ripping everything apart.

So now how about a Rohloff or decent IGH??

Derailleurs are so 19th century!!

 

[Deleted member 4366]

The most common cause for mashed derailleur is when bottom gear end-stop isn't set, so you pull the derailleur into the spokes. Look for marks on the spokes to identify that as a cause. Which gear were you in when it happened?

 

[Oscdav]

Yes guys, This bikes suspension has a large amount of travel. Any one of your first 2 disaster scenarios make a lot of sense to me now. There was a chain stay on the bike and I stupidly took the damn thing off because of the original chain not being long enough to take the Blingring. Should had let be and bought a new longer chain and let the chainstay be!
I love this bike.Though walking home, pushing this old horse as well was a real workout that I don't ever want to repeat! The guy I bought it from here in Norway was a downhill freak. Bit heavy, but bomb proof wheels, large brake discs etc. I only use it for single track riding in rough terrain here.Too old for downhill!
Lots of slippy, wet rocks and pine tree roots that really test the skills.
Suppose I have been lucky until now. But I did hit this large, steep incline suddenly and at high speed and at high speed. Had just dropped down the gears Dave; was 2nd smallest cog.That also seems a very likely cause. Will check for tell tale signs later. Sorry, but not sure what is meant by "bottom gear stop end."
The Roholf looks tasty! But again' what is IGH?

Regards, Oscdav.

 

[Deleted member 4366]

There's two screws on the rear derailleur, often marked H and L. They set a stop at each end of the travel to prevent the chain being pulled past the end gears. At the high gear end, your chain comes off, but at the low end, the derailleur travels until it hits a spoke and goes bang.

There's loads of Youtube vids on how to adjust a derailleur. It should have been done by the shop or factory, but often it gets missed.

It can also happen if you fall off your bike or lay it in the car on the wrong side, which can bend the derallieur so that the adjustment is no longer valid. The result is the same as above.

 

[Oscdav]

Ok, those 2 screws..., now I know what you mean Dave.
I need to get up to speed on bike tech terms!
Also had a few falls, which could have affected the blade. Which also affects me 'cause I don't fall enjoy those too much either

 

[Benjahmin]

IGH = internal geared hub.

 

[Kuorider]

I would have expected an out of adjustment end stop to have shown up sooner, I never though for a second that someone undertaking a Commencal E build would have missed this basic adjustment. Inspection of the damaged parts may provide an clearer answer.
When you rebuild consider changing to a 7 speed set up with a long arm changer. Very few e bikes need 10 gears. An 11-38 cassette should cover most requirements. Refit that chain guide and take care with the chain length. Your bike is a fast downhill charger and needs careful setting up.
A hub gear will need a good tension arm controlling the chain so you will still have a vulnerable component in the mix. It will add a bit to your unsprung weight and swinging like a big pendulum on that light back end will upset your handling on the surfaces you are riding on. Commencal build them the way they do for good reasons.
IGH is Internal Geared Hub.

 

[Danidl]

As above,
probably chain jumping out of line, getting stuck around one of the jockey wheels maybe and then the torque of the HD ripping everything apart.

So now how about a Rohloff or decent IGH??

Derailleurs are so 19th century!!

Sandals are so 1st century, Dining plates , table forks and knives are so 18th. century, ( whats wrong with a plank of timber and a dagger.?.) but we still use them.
The Derailleur is the more efficient mechanism by say 8% than the internal hubs. Maybe not as robust in a crash, but cheaper, wider ranging , lighter, and efficient.

 

[Danidl]

There's two screws on the rear derailleur, often marked H and L. They set a stop at each end of the travel to prevent the chain being pulled past the end gears. At the high gear end, your chain comes off, but at the low end, the derailleur travels until it hits a spoke and goes bang.

There's loads of Youtube vids on how to adjust a derailleur. It should have been done by the shop or factory, but often it gets missed.

It can also happen if you fall off your bike or lay it in the car on the wrong side, which can bend the derallieur so that the adjustment is no longer valid. The result is the same as above.

Another thing that can happen is that the chain wedges just inside the largest sprocket and the back wheel locks solid...

 

[tommie]

Sandals are so 1st century, Dining plates , table forks and knives are so 18th. century, ( whats wrong with a plank of timber and a dagger.?.) but we still use them.

Yes, all still very useful but useless if you want to change bike gears with them!!

The Derailleur is the more efficient mechanism by say 8% than the internal hubs. Maybe not as robust in a crash, but cheaper, wider ranging , lighter, and efficient.

I have two mid-drive BBSxx bikes, one with the Alfine 8 and the other with a 7 speed derailleur. Stopped in the middle of a hill? The IGH is simplicity itself, couple of clicks and you`re off, no faffing around trying to get the chain up onto the right cog, the same with an emergency stop. Chains and cogs will last longer as the IGH will always have the chain engaging on the cogs in a perfect straight line, not so with a wide cassette. As for weight, its negligible there`s only a few grams in it.
Only one downside that i can see is the present price, upwards of £1k for the latest Rohloff is too rich for me, the Alfine 8 all in at £220 inc. wheel is much more acceptable, i`ve had it two years now along with the BBS02, so far so good.
The IGH out on the road makes cycling much more enjoyable and relaxing over the clunk-click-graunch of a derailleur .................. all imo of course.

 

[Deleted member 4366]

I have two mid-drive BBSxx bikes, one with the Alfine 8 and the other with a 7 speed derailleur. Stopped in the middle of a hill? The IGH is simplicity itself, couple of clicks and you`re off, no faffing around trying to get the chain up onto the right cog, the same with an emergency stop. Chains and cogs will last longer as the IGH will always have the chain engaging on the cogs in a perfect straight line, not so with a wide cassette.

That's right for when you've stopped on a hill, which is quite common with an IGH. It's a different story, though, if you want to keep pedalling up a steep hill. With a BBS02, you'd very soon have an expensive pile of scarp rather than something that could change gears if you try and change while pedalling or with the motor going up that steep hill with full power.

Derailleurs change nicely when under load. IGHs don't.
IGHs change when stopped. Derailleurs don't

Take your pick. Neither is a problem if you have a high-torque hub-motor.

 

[Danidl]

I have two mid-drive BBSxx bikes, one with the Alfine 8 and the other with a 7 speed derailleur. Stopped in the middle of a hill? The IGH is simplicity itself, couple of clicks and you`re off, no faffing around trying to get the chain up onto the right cog, the same with an emergency stop. Chains and cogs will last longer as the IGH will always have the chain engaging on the cogs in a perfect straight line, not so with a wide cassette. As for weight, its negligible there`s only a few grams in it.
Only one downside that i can see is the present price, upwards of £1k for the latest Rohloff is too rich for me, the Alfine 8 all in at £220 inc. wheel is much more acceptable, i`ve had it two years now along with the BBS02, so far so good.
The IGH out on the road makes cycling much more enjoyable and relaxing over the clunk-click-graunch of a derailleur .................. all imo of course.

It's funny but years ago the only multigeared bikes available in Ireland were the strumley archer 3 speeds, and derailleur bikes were exotic. Probably the influence of Raileagh ..
I found it surprising to see nearly all the ladies touring bikes in France in the early 1970s had derailleurs. I would have seen them as the more modern design... The gears not the ladies, well on second thoughts!!
Rather than just a few grams, I think you will find a kilogram as the difference.

 

[flecc]

It's funny but years ago the only multigeared bikes available in Ireland were the strumley archer 3 speeds, and derailleur bikes were exotic. Probably the influence of Raileagh ..
I found it surprising to see nearly all the ladies touring bikes in France in the early 1970s had derailleurs. I would have seen them as the more modern design... The gears not the ladies, well on second thoughts!!
Rather than just a few grams, I think you will find a kilogram as the difference.

Derailleurs were a French invention (in 1905) and they were on the roads in France in numbers in the early 1950s. Although they also reached Britain then (I saw my first 5 speed derailleur in 1952) they didn't get popularity then outside of the full on sport enthusiasts. It was mountain biking from 1980 that made the derailleur the most popular choice, almost killing off hub gears.
.

 

[Danidl]

Derailleurs were a French invention (in 1905) and they were on the roads in France in numbers in the early 1950s. Although they also reached Britain then (I saw my first 5 speed derailleur in 1952) they didn't get popularity then outside of the full on sport enthusiasts. It was mountain biking from 1980 that made the derailleur the most popular choice, almost killing off hub gears.
.

If that's the case the internal hub gears are even older ... According to the SA historical website, they date from 1902!

 

[tommie]

It's funny but years ago the only multigeared bikes available in Ireland were the strumley archer 3 speeds, and derailleur bikes were exotic. Probably the influence of Raileagh ..
I found it surprising to see nearly all the ladies touring bikes in France in the early 1970s had derailleurs. I would have seen them as the more modern design... The gears not the ladies, well on second thoughts!!
Rather than just a few grams, I think you will find a kilogram as the difference.

Yes a few grams, you`re just not totaling everything that has to be changed,
in this instance a tad over 3 grams --> http://singletrackworld.com/forum/topic/stu-mcgroos-lets-put-this-alfine-weight-issue-to-bed-once-and-for-all-thread

first bike i had, a Raleigh had the 3 speed SA, i can still hear the tick-tick-tick of it yet.

A world of difference away from the modern Rolhoff, NuVinci CVH items now.

 

[Danidl]

That person has chosen to compare a 30 speed derailleur with their afine hub. Now I don't see it feasible to have 30 speeds without a triple chainset , so that means two extra chainwheels. A more valid comparison would be a single chainwheels, and say a 7 set cassette., Or in the case of a SA a 5 speed derailleur. A chainwheels might be 400 grams?

The weight elements are for comparison
The extra chain, the weight of the cassette the weight of the bottomhanger bracket are required in the derrailler.
In the hub gear, there is some saving on chain length, and of course no bottom hanger. .. but there is a lot more steel in the hub. Both types need a trigger so no difference there.
This isn't a diatribe against hub gears. They are fine, they are pretty reliable and very robust in crash situations. But in comparison to derailleur they are normally heavier, harder to repair, .. more expensive both to buy and repair, and consume more of the cyclists energy .

 

[Deleted member 4366]

Yes a few grams, you`re just not totaling everything that has to be changed,
in this instance a tad over 3 grams --> http://singletrackworld.com/forum/topic/stu-mcgroos-lets-put-this-alfine-weight-issue-to-bed-once-and-for-all-thread

That's about the worst bit of scientific analysis I've ever seen. Look at the size of his new chain-wheel compared with the old triple one. He also changed the crank to a lightweight Hollowtech type. Why didn't he just change the crank and chain-wheels and then boast that he had found a way to save 1.5kg instead of adding the IGH and getting a weight increase?