So i was riding my road down a straight blvd probably going about 25 (I was going quite fast) when my Derailure snapped in half


Is this common? I been riding for years and i have broke everything from tires (The usually), rims(Bad accident), broken pedals, My crank set even fell apart before. (3 bikes in 5 years )


Is this common?

It's not COMMON, but it happens. I've broken three or four, but I've been riding for 40 years.
Often the problem is poor maintenance or abuse. if you've gone through all the stuff you say you have, then I'd bet on a combination. Do you check your bike every few rides, lube the chain, make sure the derailleurs are adjusted, soft-pedal when you shift, pay attention to what things sound like and feel like? I've ridden my main bike, a five-year-old Atlantis, at least 12,000 miles with NO failures other than flat tires, and my oldest ride, a mid-'80s Trek, gets just easy maintenance and rolls on and on.

Not common but it happened to me about three weeks ago. I have since replaced it and the bike is riding like new. Perhaps it wasn't such a bad thing to happen?

i have had that happen about once a year. usually it is cause by something causing the chain to get stuck and pull the derailure up and over. sometime it can also be caused by the derailure being out of tune and getting caught in the spokes and pulled around.

I think it was utter abuse. This particular bike is only about 5 months old. i Actually readjusted it not to long ago. Thats why im surprised it happened. it was doing so well until it snapped in half LOL. $20 to get the sane one again. Sigh.. If bikes really only cost $100 dollars a year to maintain i already spent more then $50.. Patches / Brake pads / And now this

i think the last time i actually spent money on my bike was 2-3 years ago when i paid $15 to get my bottom bracket removed. usually i would just install a derailure that i remove from a bike that i stripped for parts. sometimes i have to modify the parts a tiny bit but the usually always work. all the parts on my bikes over the last few years have cost me nothing.

It happens a lot more now that all the little bike bits are made of aluminum and not steel.

People hit stuff, bend the rear der a bit, so they just figure "just bend it back", and that's a no-no with aluminum. When it is bent and then bent back straight, it will open up deep cracks in what was the "inside corner" of the bend.

If you crash and damage an aluminum part and need to ride to civilization, try to ride the bike with the part bent if possible. If you bend it back straight, you're instantly going to lose 30%-50% or more of its strength.




If you got the $$$ and the desire to make this event much-less-likely: get a new rear derailer, take it to a machine shop and ask them to duplicate the cages in stainless steel (-titanium would be even better, but would cost about 10X as much-).

I have put in a pot load of miles (road) and I have never had a derailler fail. I once saw a cyclist have his derailler fall off when it was hit by a suicidal squirrel (the squirrel ran off cursing so the cyclist lost the collision).

Not terribly common but impossible to determine the cause without seeing it.

Normally all parts are covered by a one year warranty that excludes abuse or damage caused by accidents.

That you replaced it with the same model for only $20 pretty much indicates that it was a basic model intended for light city use. From the sounds of things you`re pushing the limits and are well aware of it. Might be a good idea to give the complete bike a close visual inspection for cracks and loose bolts on a weekly basis.

broken parts = time for upgrade.

if you only had to pay $20 for the exact replacement and the 1st part didnt make it 6 months, I'd say you should (have) consider(ed) spending another few bucks and getting a better unit.

Just my $.02

But i had a bike with the same derailure (That got stolen) and it lasted 3 years and never failed.

I'm lucky - have never had an RD break spontaneously or by shifting into the spokes.

I wouldn't let my expectations get too 'lengthy' over a $20.00 derailler. bk

You now have a good excuse to go and buy a much better bike. Use the old one for parts. Or not, whatever. Just suck it up and go get a good bike.

Gotta check the little things, like deraileur pulley bolts, deraileur pivot pins, mounting bolt, cable adjuster, etc. In short, check everything all over the bike. Many times while riders are fretting over the exact sweet spot in their derailleur adjustments for perfect indexing they forget the little things that, when they fail, could be catastrofic.

...or the derailleur just 'gave up' due to fatigue, cheap materials, etc

I just bought this bike. I cant afford a new one yet.


Well i need a new DR. Must be 7 speed and it cant be terribly expensive. Any suggestions?

Heres a picture with MUCH more detail.

OK So looks like a Shimano Tourney rear derailleur, which has a steel lower cage and isn`t likely to get ripped in half like that just by a simple chain misalignment.

But I`ll repeat - if the bike is really only 5 months old - it should be a warranty issue. If you simply bought it used 5 months ago there is no possibility of knowing the history of that RD.

The other bad news is that unless you replace that chain thats been seriously twisted - you stand a good chance of looking at another new rear derailleur a lot sooner than you might like.

I think there's something wrong with your derraileur.

NO this isn't common.
OK, maybe with preteen kids throwing their bikes around, crashing them, leaving them in the drive where they get run over it's more common.

If it's truly 5 mo old - It is a warranty issue, AND they need to replace or realign the derailler hanger or it's going to happen again. I would insist on LBS fixing it under warranty as most likely it was an adjustment/set up problem. Even low end Shimano stuff generally "works" even with no to low maintenance. Most of my bikes are 20+ years old and get thousands of miles a year and all are original deraillers. Of course they are a bit higher up the food chain and get regular maintenance.

If you really have to buy it yourself, a Tourney can be had for about $12, and an upgrade to Altus for $20.
Without getting into pull ratio discussions the derailler doesn't care about speeds, the shifter takes care of that.

https://www.treefortbikes.com/product...d-8-Speed.html

https://www.amazon.com/Shimano-RD-TX7.../dp/B001606M9G

If you go for the warranty claim, I wouldn't mention this to the shop.

Well i got it readjusted at the shop..

And this is a shimano Altus

Wait! Hold it. I don't think the chain's supposed to go around there that way...

Don't worry it happens experience make you skill rider

Umm so i noticed. Where the derailure gets attached to the frame. Is that supposed to be bent?