Rear derailleur caught in spokes

Danjamin1

Happened to me on the cycle home from work today about halfway in, the thing got mangled. I managed to stay upwards at least! I'm looking at a new derailleur, hanger and possibly chain because of it. Anyone have any experience of this? Thinking its a job for the LBS but part of me would love to give it a go myself.

07Lapierre

If u need a new chain, you might need a new cassette too.

You will need:
Chain breaker
Chain whip
Cassette removal tool ( if you need a new cassette)
New gear cable
Cable cutters
5mm Allen key
Screwdriver ( to adjust the new derailleur adjustment screws)

It's an easy job if you know what your doing...if it's your first time..it can be very frustrating!

As a one off job, it's more economical to go to your LBS. but if you intend doing all you own bike maintenance, then buy the tools and parts and do it yourself.

P.s. Wheelworx run bike maintenance class's and search YouTube.. Lots of tuition videos

Wishbone Ash

Danjamin1 wrote: »

Happened to me on the cycle home from work today about halfway in, the thing got mangled...

That's what the great unloved pie plate is there to prevent but most of use remove them!

Did you damage the RD lately in a minor fall? It may have been slightly bent causing it to throw the chain over the large sprocket.

RobertFoster

Good to hear you stayed upright. I've no experience of a rear derailleur ending up in the spokes :eek: but I have replaced a worn one. It's not a difficult job, so if you have the tools it'd be worth giving it a go yourself.

https://www.youtube.com/watch?v=CPLiW-0zLa4

07Lapierre

30% off too!

All the tools you need and more..

http://www.chainreactioncycles.com/ie/en/x-tools-bike-tool-kit-18-piece/rp-prod40997

cython

Wishbone Ash wrote: »

That's what the great unloved pie plate is there to prevent but most of use remove them!

Did you damage the RD lately in a minor fall? It may have been slightly bent causing it to throw the chain over the large sprocket.

To be fair, from the picture it doesn't look as though the chain went over the large sprocket, but the cage on the derailleur went into the wheels instead. A pie plate will not stop that or really help at all if the hanger or mech is bent and the cage "leans" into the spokes, which it seems like happened here. Most likely there was a knock to the mech as you suggest alright, but the means of damage seems a bit different.

Wishbone Ash

RobertFoster wrote: »

...I've no experience of a rear derailleur ending up in the spokes :eek:...

Happened me on the steep part of the village side of Howth just after the church. Not nice!

Wishbone Ash

cython wrote: »

To be fair, from the picture it doesn't look as though the chain went over the large sprocket, but the cage on the derailleur went into the wheels instead...

Doh! - yes, brain low energy mode!

Danjamin1

07Lapierre wrote: »

It's an easy job if you know what your doing...if it's your first time..it can be very frustrating!

As a one off job, it's more economical to go to your LBS. but if you intend doing all you own bike maintenance, then buy the tools and parts and do it yourself.

P.s. Wheelworx run bike maintenance class's and search YouTube.. Lots of tuition videos

Think I'll leave it as a job for the LBS in that case, as it's the first time playing with the derailleur I'll get the job done properly.

Wishbone Ash wrote: »

Did you damage the RD lately in a minor fall? It may have been slightly bent causing it to throw the chain over the large sprocket.

I took a spill off the bike about 10 months ago but when I got it checked out after that there was no problems, I specifically asked them to check the derailleur as the bike skidded out on that side too.

cython wrote: »

To be fair, from the picture it doesn't look as though the chain went over the large sprocket, but the cage on the derailleur went into the wheels instead. A pie plate will not stop that or really help at all if the hanger or mech is bent and the cage "leans" into the spokes, which it seems like happened here. Most likely there was a knock to the mech as you suggest alright, but the means of damage seems a bit different.

Exactly, the cage got caught in the spokes, you can see where it ripped away. The hanger is completely mangled, not sure if it bent beforehand but I have a feeling it must have done to cause this damage.

I'll get on to the LBS this morning with pictures so they know what the damage is and see if I can get it in to them this afternoon for repair. Yesterday was my first day back on the work commute after a couple months off so I want to get up & running again ASAP!

hesker

Probably best left to LBS. I would check the alignment by eye afterwards just to satisfy myself. You could also attach a bit of tape to the RD to check how much clearance you have.

Luckily I haven't experienced this yet but I'm worried enough that I set the inner stop so that I can't use the largest cog. Seems drastic but when I run on that cog I can hear the RD pinging against the spokes when I climb and the wheel flexes a bit. Not good. It's a 10 speed setup with wheels straight and true, RD straight also. I wonder if it's a feature of modern setups with tight clearances.

dastardly00

This happened to me last year. Rear derailleur got caught in the spokes and it sheared off. Quite a mess. I was just starting a descent and luckily I kept control and skidded to a stop.

I needed a new rear derailleur (obviously), cassette, chain, and the rear wheel needed to be trued.

It happened a few days before a sportive so I got my lbs to fix it, reluctantly. If I hadn't of needed it to be fixed asap, I would have done it myself.

I attributed the cause to two things: (i) the bike fell from a bike stand when I was cleaning it a few weeks beforehand (the wheels were off, so the first point of contact with the ground was the rear derailleur); and (ii) the road surface I was cycling on when I got the mecahnical was absolutely atrocious, lot of potholes and gravel for about 20 km.

Wishbone Ash

dastardly00 wrote: »

..... the bike fell from a bike stand when I was cleaning it a few weeks beforehand (the wheels were off, so the first point of contact with the ground was the rear derailleur)....

That's exactly what happened in my situation. I didn't notice the damage for a few days as I had no reason to use the lowest gear. Then I went to Howth....

07Lapierre

hesker wrote: »

I set the inner stop so that I can't use the largest cog. Seems drastic but when I run on that cog I can hear the RD pinging against the spokes when I climb and the wheel flexes a bit. Not good. It's a 10 speed setup with wheels straight and true, RD straight also. I wonder if it's a feature of modern setups with tight clearances.

No its not a feature of modern setups..Something definitely not right there..You should be able to use the large sprocket without the RD touching the spokes.

Some possible causes:

The RD cage could be bent

The RD adjustment screw for the large sprocket just needs 1/4 clockwise turn, to move the RD away from the spokes and into the correct alignment with the large sprocket.

The Rear cassette may be too close to the spokes..missing spacer? (Unlikely, as the cassette would rattle, as the lock ring would not be able to tighten in far enough)

The Rear wheel is flexing under load...may need to be rebuilt or even a new wheel.

hesker

07Lapierre wrote: »

No its not a feature of modern setups..Something definitely not right there..You should be able to use the large sprocket without the RD touching the spokes.

Some possible causes:

The RD cage could be bent

The RD adjustment screw for the large sprocket just needs 1/4 anti-clockwise turn, to move the RD away from the spokes and into the correct alignment with the large sprocket.

The Rear cassette may be too close to the spokes..missing spacer? (Unlikely, as the cassette would rattle, as the lock ring would not be able to tighten in far enough)

The Rear wheel is flexing under load...may need to be rebuilt or even a new wheel.

RD Cage is not bent to me eyes. When I sight it from the back it hangs down at correct angle. I did give it a bit of a nudge over but maybe I need to use a bit more persuasion. Anyway shifting has been crisp and precise through all the gears. It works fine on the largest cog except when climbing.

Some wheel flex is going to occur esp when climbing out of the saddle. Maybe some extra tension could be added to the spokes but they don't feel any more loose then other wheels I have and they have stayed true for the last 3 years.

I tried adding a spacer but the lockring would not engage at the other end.

Only other thing I can think of is redishing the wheel but it seems a bit drastic.

07Lapierre

hesker wrote: »

RD Cage is not bent to me eyes. When I sight it from the back it hangs down at correct angle. I did give it a bit of a nudge over but maybe I need to use a bit more persuasion. Anyway shifting has been crisp and precise through all the gears. It works fine on the largest cog except when climbing.

Some wheel flex is going to occur esp when climbing out of the saddle. Maybe some extra tension could be added to the spokes but they don't feel any more loose then other wheels I have and they have stayed true for the last 3 years.

I tried adding a spacer but the lockring would not engage at the other end.

Only other thing I can think of is redishing the wheel but it seems a bit drastic.

If that's the case, then the RD should not touch the spokes under any circumstances. I had a similar problem...I turned the "L" screw on the RD 1/4 turn CLOCKWISE to move the RD cage away from the spokes...I've had no issues since.

hesker

07Lapierre wrote: »

If that's the case, then the RD should not touch the spokes under any circumstances. I had a similar problem...I turned the "L" screw on the RD 1/4 turn CLOCKWISE to move the RD cage away from the spokes...I've had no issues since.

That's what you would think isn't it. Only it's definitely not an L screw adjustment. If I adjust the L screw enough to stop pinging then the chain is not centered on the cog and rattling & shifting problems arise, meaning it won't climb reliably into the last cog.

I might switch the RD out for another to see if it makes a difference.

07Lapierre

hesker wrote: »

I might switch the RD out for another to see if it makes a difference.

Good idea...if the RD is worn it wont operated as precisely as a new one.

One way to check the RD is to hold the RD body in one hand and then hold the jockey wheel cage and see if there is any sideways movement. the cage should only move up and down...it should not "Rock" from side to side.

hesker

Wear is not an issue. It's been like this since I bought the bike brand new. I did switch the included Miche cassette for a Veloce so that's something else I can check. As well as smaller shims as spacer.

Bent derailleur hanger is also a possibility although that's never suffered any impact.

crosstownk

hesker wrote: »

Bent derailleur hanger is also a possibility although that's never suffered any impact.

The hanger could have been damaged/leaned on in storage or by some other means while not in your presence. It does sound like a possible reason. RD interference with the spokes is not normal - something is wrong somewhere. It's just a matter of identification which could be painstaking given you've checked all the obvious stuff.

youtheman

Had this happen to me once. Mangled the RD, broke a spoke which punctured the wheel. Had to walk all the way down the Conor Pass, couldn't even free-wheel. To top it all there was no phone coverage so I couldn't even call for help.

Lessons Learnt : It you are in the lowest gear and you hear a light metallic 'ting-ting' sound then STOP immediately, this is your RD clipping off the spokes. It's the most expensive sound you can hear coming from your bike, and you're only seconds away from disaster.

Danjamin1

Dropped it in to the LBS this afternoon, should have it back by Friday. Cost not confirmed yet, I'm looking at a new derailleur, hanger bracket, chain and possibly the cassette, they're recommending a new cassette with the new chain anyway but they said they'll check it first, I may get some more life out of it.

triggermortis

I've had this happen to me twice on two different bikes. The first one I was coming to a stop at lights and changed gear, and everything got mangled. I still don't know the reason, but it cost me a new RD, hanger, chain, cassette and cables. Did it all myself (first timer) then had to take it to LBS as I didn't know the difference between brake and gear cable outers....
Second time was due to spokes pulling through a rim and the wheel buckling while I was climbing. That bike hasn't been fixed yet but needs a RD and chain (and a new wheel).
I'm hoping it doesn't happen to my new bike as it will be expensive to replace an Ultrhra Di2 RD!