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Rear derailleur snapped in half or just bad weld?

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Rear derailleur snapped in half or just bad weld?

Old 04-10-10, 04:31 PM
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Rear derailleur snapped in half or just bad weld?

I've had this brand new REI Navaro Forza hybrid bike for less than 4 months. Today the metal completely split and crushed the plastic around my back freewheel. I was on flat, even ground with no rocks but was in a low gear with a strong headwind. I can't tell if this is the frame that split or the rear dérailleur?? Is this common? Did I do something wrong? Should REI replace it? Is it easily fixable? Do you like your chocolate chip cookies with or without nuts?

I have a three-day planned in August, and would hate to have this happen in the mountains. Any advice to help avoid this happening again would be greatly appreciated.
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Old 04-10-10, 04:37 PM
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I've seen this happen to a new bike when a stiff link in the chain refused to go through the derailleur.
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Old 04-10-10, 04:51 PM
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The derailleur is what broke, but it's possible that there is damage to the derailleur hanger and/or the rear wheel. I would take it to REI to have it checked out. Usually they're good about warranty issues. If just the derailleur is messed up, then it's a pretty cheap fix.

As for the cause, it could be that the derailleur spontaneously broke, or the derailleur was maladjusted and the chain got thrown into the spokes, or a stiff link as Al1943 suggested, or lots of other things. Were you shifting when it broke? Is it possible that a stick got sucked into the drivetrain? When was the last tune-up?
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Old 04-10-10, 05:00 PM
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Originally Posted by Al1943 View Post
I've seen this happen to a new bike when a stiff link in the chain refused to go through the derailleur.
That would make sense. I had been complaining that the gears were not catching well, and were sometimes slipping for no reason. No one I knew had insight on that, so I figured it was ok. Do you think that was a warning sign?
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Old 04-10-10, 05:04 PM
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Originally Posted by stedalus View Post
The derailleur is what broke, but it's possible that there is damage to the derailleur hanger and/or the rear wheel. I would take it to REI to have it checked out. Usually they're good about warranty issues. If just the derailleur is messed up, then it's a pretty cheap fix.

As for the cause, it could be that the derailleur spontaneously broke, or the derailleur was maladjusted and the chain got thrown into the spokes, or a stiff link as Al1943 suggested, or lots of other things. Were you shifting when it broke? Is it possible that a stick got sucked into the drivetrain? When was the last tune-up?
I was on flat, clean roadway. I wan't shifting, but had shifted to a very low gear minutes before due to a strong beach headwind.

Thanks so much for your input. I'm very curious as to how this happened so as not to let it happen so soon again. There was no quick fix, and had to have someone drive out to pick me up. I'd really hate to have this happen really far from home.
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Old 04-10-10, 05:21 PM
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Originally Posted by steffie224 View Post
I was on flat, clean roadway. I wan't shifting, but had shifted to a very low gear minutes before due to a strong beach headwind.

Thanks so much for your input. I'm very curious as to how this happened so as not to let it happen so soon again. There was no quick fix, and had to have someone drive out to pick me up. I'd really hate to have this happen really far from home.
5:1 it was a mis-adjused low gear limit screw. This allowed the RD to move too far inboard and snag a spoke or put the chain over the top of the cassette causing similar results. Limit screws don't move by themselves, but if, for example the bike fell over bending the derailleur hanger inward slightly, that would be change the setting. It could go unnoticed for days, weeks or months because it would only become a problem when you shifted to the innermost sprocket.

It might also be the "B" screw setting which controls the angle of the RD to the frame. If the RD rides too high he jockey wheel could interact with a cassette sprocket, causing the RD to be kicked back with enough force to break it or the hanger. Again a problem that often doesn't show up except in the lower gears.

REI will do the repair, but if you're concerned about a re occurrence during your trip this August, you can prevent it by having he bike checked before starting, and doing a quick daily 1 minute check of brakes, RD, tires, wheel alignment, headset, and other basic adjustments. (the check takes less than a minute unless problems are discovered and need fixing) BTW- if you're doing a long out of town tour, buy and carry a spare derailleur hanger (if it's replaceable). These are easily replaced on the road, but there are so many different ones that you might not be able to buy the right one on the road.
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Old 04-10-10, 05:23 PM
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Originally Posted by FBinNY View Post
5:1 it was a mis-adjused low gear limit screw. This allowed the RD to move too far inboard and snag a spoke or put the chain over he top of the cassette causing similar results. Limit screws don't move by themselves, but if, for example the bike fell over bending the derailleur hanger inward slightly, that would be change the setting. It could go unnoticed for days, weeks or months because it would only become a problem when you shifted to the innermost sprocket.

It might also be the "B" screw .........
Excellent. Thanks!
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Old 04-10-10, 05:34 PM
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If you can find a macro lens I'd be intetested in seeing a closeup of the break. From this distance it looks like a dark oxidized region surrounded by a bright shiny region -- classic signs of fatigue failure. That's an unusual thing to happen to a derailleur especially with low miles, though, so maybe you got a derailleur that had a flaw in the casting.

The chain might have done some damage to the spokes when it went behind the sprockets. You might have spokes breaking in the future if you keep riding that wheel, and if there's visible damage to the spokes I'd want the wheel replaced under warranty.

It's more common to have a derailleur taken out by a rock or a stick that gets thrown up in the chain. If that worries you make sure your toolkit contains a chain tool, so that you can shorten the chain to bypass the derailleur and ride as a single speed.
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Old 04-10-10, 05:52 PM
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Old 04-10-10, 06:04 PM
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Originally Posted by steffie224 View Post
? Should REI replace it? Is it easily fixable? Do you like your chocolate chip cookies with or without nuts?

I have a three-day planned in August, and would hate to have this happen in the mountains. Any advice to help avoid this happening again would be greatly appreciated.

This is a rare incident, assuming the derailleur was adjusted properly. Although a mis-adjusted limit screw is a possibility (REI should've set it up properly to begin with), I vote for a defect in the manufacture, like a poor casting - statistically speaking, it will happen.

Regardless, if it's due to maladjusted limit screw or poor casting, REI should replace under their warranty. I am not sure what warranty they offer, but 4 months seems to be within most limits. I'd also have REI check the spokes and wheel for trueness, replace the cable, make sure the derailleur hanger or frame are not bent, check the chain and cassette for damage.
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Old 04-10-10, 06:07 PM
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Originally Posted by steffie224 View Post
Ah, OK. The dark spot I was seeing was just the shape of it from a funny angle.
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Old 04-10-10, 08:23 PM
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Wow. You guys are good. I cannot thank you all enough for your input. I appreciate the knowledge as I go into REI on Monday to present my little mishap to them. I'll let you know how it goes and what they say. At least I will have some extra input when it comes to making sure they cover all their repair bases.

It's incredible that this has happened so soon. I've already become addicted and I dont know how I will survive if the repairs make me miss the next bike club ride.
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Old 04-10-10, 08:45 PM
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I hope you don't miss any club rides. One strategy for avoiding missed rides is to always have a functional Backup Bike.
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Old 04-11-10, 07:11 AM
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5:1 it was a mis-adjused low gear limit screw.

+1
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Old 04-11-10, 08:40 AM
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Originally Posted by FBinNY View Post
BTW- if you're doing a long out of town tour, buy and carry a spare derailleur hanger (if it's replaceable). These are easily replaced on the road, but there are so many different ones that you might not be able to buy the right one on the road.
I fail to see what good a spare hanger would do in this case, as it is the derailleur that is broken. however on long rides out in the sticks a chain tool and maybe a cheap tensioner (or spare) derailleur and the knowledge to install them may be useful.

also there is no weld in this area it is a cast part.
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Old 04-11-10, 08:41 AM
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One great advantage of buying new from REI is their guarantee. They stand behind product they sell, with a lifetime guarantee. Low limit set screw was probably off, but with a 4 month old bike, that still falls into their lap. And they stand behind their stuff regardless.

I never buy new, but if I did, I would probably buy from REI (with the aid of a member 20% discount and 10% dividend). I always buy used, as the deals are compelling IMHO.
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Old 04-11-10, 08:56 AM
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Originally Posted by Bianchigirll View Post
I fail to see what good a spare hanger would do in this case, as it is the derailleur that is broken.
My thinking about carrying a hanger was based on the calculus that hangers are very small and light, and most important non-standardized, so there's a serious risk of non-availability on the road. OTOH, derailleurs are readily available, so not worth carrying. You can't carry everything, so you have to assign priorities.

As a long time tourist, who began riding when you couldn't get pizza or race bike parts outside of major cities in the USA, I've developed a formula for what spares to carry. Someplace between nothing but a credit card and the kitchen sink, my approach balances the weight penalty of carrying too much, against the risk against of unavailability when needed on the road. In short I try to cover the most possible problems with the fewest tools and spares.

BTW- Time and distance from home are a key part of the calculation, I do long weekend rides with nothing but trust in my machine, but carry tools and some spares on longer multi-day tours.
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Old 04-11-10, 09:39 AM
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Originally Posted by JanMM View Post
I hope you don't miss any club rides. One strategy for avoiding missed rides is to always have a functional Backup Bike.
I actually do have a Novara Aspen as a back up, but it is in desperate need of a tune up. I suppose something like this happening is enough incentive to have that become priority. I took for granted that a new bike would be reliable for a while.

Originally Posted by wrk101 View Post

I never buy new, but if I did, I would probably buy from REI (with the aid of a member 20% discount and 10% dividend). I always buy used, as the deals are compelling IMHO.
That's kind-of how I purchased this bike. Seasonal employee benefits were too good to pass up on. 40% off this bike, and an employee friend fitted me at the store.

Originally Posted by FBinNY View Post
My thinking about carrying a hanger was based on the calculus that hangers are very small and light, and most important non-standardized, so there's a serious risk of non-availability on the road. OTOH, derailleurs are readily available, so not worth carrying. You can't carry everything, so you have to assign priorities.

As a long time tourist, who began riding when you couldn't get pizza or race bike parts outside of major cities in the USA, I've developed a formula for what spares to carry. Someplace between nothing but a credit card and the kitchen sink, my approach balances the weight penalty of carrying too much, against the risk against of unavailability when needed on the road. In short I try to cover the most possible problems with the fewest tools and spares.

BTW- Time and distance from home are a key part of the calculation, I do long weekend rides with nothing but trust in my machine, but carry tools and some spares on longer multi-day tours.
I would LOVE to see your list of essentials. Please?
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Old 04-11-10, 09:41 AM
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Originally Posted by Bianchigirll View Post

also there is no weld in this area it is a cast part.
This is what I wasn't sure about. Thank you.
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Old 04-11-10, 10:11 AM
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Originally Posted by steffie224 View Post

I would LOVE to see your list of essentials. Please?
I don't have any fixed list, and even if I did it might not apply to your situation. The key to my tool and spares list isn't in the particulars, but in the thought process.

The first step is to prevent problems by choosing equipment with reliability in mind. Since I'm not racing, I don't sweat the last few grams and, for instance pass on carbon seatposts and handlebars and opt for the proven reliability of aluminum.

However, I still ride tubulars as I have for 40 years, trading some reliability for comfort, though it isn't as bad a trade off as one might think. In the event of a serious glass cut, I have a complete tire vs. just a spare tube. On multi-day solo trips I carry 2 spares, but when riding with friends we each carry only one, figuring we can cover for each other if needed.

The next step is to consider scenarios, what can happen, how likely, how serious, and what can I do while on the road. I balance that against the weight consideration. For instance, I carry only those absolutely critical tools that aren't available everywhere, such as a cassette lockring tool, but figure I can always beg or borrow the wrench to turn it with.

Also the rules are different if I'm in an area where total self-suffiency is necessary, such as Northern Maine where I may not see another human for days, vs central Pensylvania, where I can always hitchhike to the next town.

In your case, I'd carry a hanger on a multi-day trip because I wouldn't want to wait around for the correct one to be overnighted to me, but for a weekend road trip, I'd leave it home. Either way I'd be sure my derailleur was 100% before leaving.

One other things friends and we did when we did long tours, was arrange logistical backup support in advance (this was before Fedex) with someone back home, who could locate emergency spares, and get them to us, by mail or Greyhound bus. I've Greyhounded entire replacement bikes to friends who's bikes were totaled in a crash.

So as I said, it isn't a matter of a list, but of considered planning.
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