DubT

We headed out for our morning ride and started out on a regular route and found out the road was being paved which we are very thankful for. I thought that we might be able to ride up to where they were paving and walk the shoulder up to where we could continue our ride. The new asphalt went to far so we turned around, as we started to pedal off we heard some terrible noises from the rear wheel. The rear derailleur somehow got lodged in the wheel and bent the derailleur cage and the actual hanger bracket on the bike and destroyed several spokes. I caught a ride home with a trucker and picked up Chris and the bike and took them home. I replaced the derailleur with a new spare that I had and installed the spare wheel.

I am scratching my head as to exactly what happened, it appears that the bottom jockey pulley screw came out and caused all kinds of havoc when it did. That screw is missing and the inside cage was torn off.

Bottom line make sure that the bottom jockey pulley screw is tight and treated with thread locker.

The wheel is on its way to Topolino to be rebuilt, hopefully it will be back in time for the Midwest Tandem Rally.

WAyne

mwandaw

Ouch! Sorry to hear about your trouble.

Thanks for the reminder about the pulley screw.

TandemGeek

Yikes... Well, that s--ks.

What year/make/model of derailleur?

Which of the rear sprockets was the chain in when the derailleur and wheel intertwined?

How badly bent was the hanger on your frame?

merlinextraligh

I'd order a new derailleur hanger. They're relatively cheap, and over time the one you just bent and straightened is now more prone to fail. Also, if it wasn't bent too bad, you can keep it for a short term emergency backup.

DubT

1. Dura Ace RD7800 GS (Long Cage) new when we built the bike a tad over a year ago.

2. I do not know, I think the third largest, 21 tooth.

3. Around 15-20 degrees, after removing the rear derailleur I used a crescent wrench to straighten it, checked with a level and it looks straight. After installing the new (brand new derailleur just like it took off) derailleur and adjusting the cable the shifting seems to be OK. We are going to head out again in about an hour so I will know better after and actual ride. I may have to take it to the local shop and have them check the alignment.

DubT

It is a permanent part of the bike and made out of titanium. The only way to replace it is to send it back to Calfee.

DubT

I did just get off of the phone with Steve, the GM at Calfee and he said that bending the titanium hanger bracket back into position was no problem. They have had to do it several times and the titanium they use is not hurt by the straightening process.

CaptainHaddock

Oh my god, that must have been both the worst sound ever, along with the most sinking of feelings! Good luck on your follow up ride!

diabloridr

Let me offer an alternative failure analysis for your consideration:

1) Spoke breaks and gets sucked into drivetrain where chain enters lower jockey wheel, jamming drivetrain.

2) Momentum of wheel pulls derailleur backward, bending hanger until force is sufficient to fail the cage screws, popping the inner cage off and liberating the spoke.

This exact sequence happened to me on my single once. Only difference was I ripped the derailleur hanger completely off the bike.

TandemGeek

I'm baffled...

Unless the jockey wheel / cage was taken apart at some point, I'd be surprised to see one come loose. The screws are typically installed with thread locker and take a good bit of effort to break loose. But, stranger things have happened.

As for a spoke breaking and getting wrapped around the derailleur, I don't believe the Topolino spoke network fails in such a way that a spoke can start flopping around like normal spokes. That said, when they break they tend to break at the threaded part of the "terminator". So, someone would have to look at the failure mode of the spokes to see if one showed signs of fatigue failure vs. a sheering type of a failure mode resulting from the derailleur going into the spokes.

Good to hear that y'all won't be sidelined by the incident.

DubT

The spokes were destroyed by the derailleur. I do not know what caused the failure but the spokes were sheared and several had marks on them from the derailleur. Something caused the derailleur to move into the spokes, the inside cage was torn off, the outer cage was badly bent and the jockey wheel screw was gone. We were in a construction zone and there were chunks of asphalt lying around, maybe something got into the drive line and caused the problem.

I am confident that a spoke did not break the failure mode indicated that something, the derailleur caused the damage to the spokes.

DubT

We did get a ride in this evening 17.6 uneventful miles. We had to wait until around 6:30 to get out because of the heat. This morning was perfect, cool and cloudy.

It is obvious that the Topolino provides a smoother ride. We both could feel the harshness of the Bontrager compared to the Topolino. It would be nice to have a Topolino back up wheel.

TandemGeek

So am I.

I should have quoted diabloridr's comments about spoke breakage. Topolino's spoke design somewhat precludes a broken spoke from flopping around to where it could get wrapped up in the gearing without some other force acting on the spoke.

Homeyba

Just a note from personal experience, I'd check that alignment really closely. I had a similar thing happen to me a number of years ago and while the bike seemed to work fine riding around town after I straightened my hanger it turned out to not be quite right. Much to our chagrin, when the speeds got up above 45mph the bike start a nasty head shake. It turned out that while it "looked" to be in the right angle it wasn't and the rear wheel was out of alignment just enough to cause that wobble at higher speeds. Just be careful as you start ramping up the speed so you don't have a surprise.

Carbonfiberboy 

New one on me. I've seen RD pulleys come out on other people's bikes and it's just been a hassle finding the parts in the ditch. Yeah, thread locker. I never let a bike shop (any bike shop) mess with my FD or RD or cassette unless I take it apart when I get the bike home and put it back together to spec. I get a wheel back and I go over it with my own tensiometer. I've had stuff come apart when wrenches I really personally trusted worked on my bike. Now I don't trust anyone. A person can get killed that way.

We just had a guy die on RAMROD from wheel shimmy. Which may have nothing to do with a wrench, but still. I was on a ride a month ago when a single's rear wheel locked up because the cassette came off. Luckily he was going slow and just got a flat spot on his tire.

waynesulak

That is an interesting failure mode which I suppose is caused by the spoke continuing in one piece through the hub to another terminator. Trying to picturing this in my mind I imagine the loose spoke flops around then gets wrapped around the hub?

How many Topolino spokes have you seen broken?

TandemGeek

Topolino's don't use individual spokes, per se. Each wheel is a modular component made up of two fairly rigid spoke networks or "wheel halves" that sit on a common axle and are laced into a rim just like a regular wheel.



The spokes are co-bonded to their respective half of the front or rear hub assembly at a pre-defined and rigid angle and cross laced as they exit the hub body.



If a spoke breaks at the threaded "terminator" (I've seen photos of 3 or 4 of these and talked to the wheel owners, noting these were all essentially 1st Gen AX3.0 Tandem wheels) the spoke looses tension but otherwise remains in place pointed straight at the now empty spoke hole in the rim now that the nipple with the other end of the broken thread has most likely fallen into the rim.

More / better photos of Topolino's including a severely crash damaged wheel can be found HERE.

The bonded hub half with spokes looks a bit different on the AX3.0 tandem wheels, but works the same as the other model pictured above. This is a close-up photo of our rear wheel's hub (chewed-up by an Ultegra 10 speed cassette before I discovered the American Classic Shimano cassette clips) where you can clearly see how the spokes are wrapped around the hub and an integral part of each "wheel halve".

DubT

The spokes were cut. 2 of them completely cut all the way through, several others were a abraided by the derailleur. The derailleur getting into the spokes caused the wheel damage.

Homeyba

I broke a spoke on my first generation AX3.0's a few years back. I hit a rock in the road at something over 50mph. It bent the rim and broke a spoke. The spoke didn't flop around at all. It pretty much stayed in it's normal position and the wheel stayed true. The only reason I new anything was wrong (before I got off the bike) was when I hit the brakes they pulsed from the bent rim.

There is no way a broken spoke on a Topolino caused this. When I had this happen to me I was coasting down a hill after a short climb and hit a bump which caused the RD to bounce over into the spokes (my best guess at the time). Once the it caught in a spoke it was all over. It's kind of an odd thing to have happen but it does happen.

merlinextraligh

I was assuming it was a replaceable aluminum hanger. You should be ok with ti.


I don't like frames without replaceable derailleur hangers. Replaceable aluminum derailleur hangers are cheap, usually less than $30.

Also, they snap off before the frame is damaged. I don't really see the logic of using a nonreplaceable ti dropout on a CF frame. I assume Calfee has some reason for it.

witgen01

We also had the rear derailluer hanger failure. Ours was due to a rock that shot off the front wheel and ended up in the rear cassette between the chain and gear. It broke the hanger of and we lost the rear wheel off the bike. Good thing we where on a climb and at low speed.

diabloridr

My experience is the replacement is easier and no more expensive than replacing a dropout/hanger on a steel frame, since it is only a matter of disbonding the old dropout and bonding in the new dropout. No paint cost.

At least that's how it worked out after my mishap.

obrentharris 

Interesting this subject should come up now. I was just talking to a framebuilder about the cost of replacing a dropout in a steel bike. He charges $40 to $50 plus paint. A complete repaint can, of course, vary greatly from about $80 (more for a tandem) to several hundred depending on the complexity of the paint job.What was your cost to replace a dropout on a carbon bike?
Brent

IanS

A very similar thing happen to us a couple of weeks ago as well but possibly for different reasons. The end result was that the rear derailure flipped backround on itself and became wedged in between the hub flange and cassette. This took out about 10 spokes and bent the lip surrounding the hub internals which prevented the wheel from turning. This is on a stock c'dale tandem with the DT Swiss hubs on the 40 spoke Mavic rims. It also bent the derrailure. Fortunately we were able to bend the derrailure back and more importantly, remove the damaged section of the lip which had locked the wheel so it does now run again. Haven't had time to replace the dmaged spokes yet though.

Still not exactly sure how the derrailure managed to get stuck in this way which is why this thread is interesting to read. In our situation, the only real obvious issue was that the cassette was very warn and we were litterally on the last ride before we had planned to replace it. The issue happened as we tried to start up a reasonably steep hill and after a very unsettling loud crash from the rear of the bike which I assume was caused by the chain slipping on the warn cassette sprokets, our ride was over and the bike is still off the road.

I don't know if this is of any help in this your situation but I'd be interested to hear whether a warn cassette aloan is likely to have been responsible or whether we perhaps need to look at another possibility. I can't see why warn cassette sprokets and the chain slipping over them could have flipped the derrailure as I would have just thought it would have slip through it.

PMK

Not to post the obvious, but are you folks setting the limit screws on the rear der properly. Not that I say my way is correct or proper, but on a stand, pedals turning slowly, I move the rear der by hand without the shifter to set the 1st gear limit screw.

I have had older Shimano xt 1998 rear der sucked into the spokes, but on those times, the pivot pins / pivots were really worn and the cage was sloppy.

Hope I didn't jinx us but something seems wrong, almost like an overshift.

FWIW, if you run SRAM rear der, and maybe others, the limit screws are not threaded into metal, they are into a replaceable plastic insert. We have had these screws forcibly moved out of adjustment when a woman crashed into our rear cassette. Just an idea of maybe how you got the cage into the spokes. As for debris, I guess it's very possible, but we sure get a lot of crap go into our rear der on the Ventana in the woods. We are always aware and stop turning pedals immediately if the drivetrain becomes fowled. Almost instinctive with any sound.

Overall the entire failure seems odd, guess the obvious question, and maybe I overlooked it in these posts, did you have the pulley removed ever, and if so was it properly threadlocked by cleaning the oils and using an appropriate grade of Loctite?

Regardless, hope it is repaired quickly and gets you riding the wheel again soon.

PK