anjhaankit

Friends, Ankit from India here. I recently bought myself a multispeed rockrider 340 bike. This is my first multispeed bike. Unfortunately and unexpectedly, the rear derailleur broke on the very second day of my ride. I live on plains, and rode at a flat surface and was riding it very gently. Since the bike was assembled by myself, maybe there was an issue in rear wheel alignment. What I want to ask you guys is that--
1. Are multispeed bikes very prone to derailleur damage?
2. The derailleur is Shimano TZ30 which is the cheapest by shimano. I spent nearly 300 dollars worth of rupees here on this bike only to get the cheapest parts. Btw, is there any sturdy alternative to TZ30 by Shimano/ SRAM? These are only brands available in India.
3. Lastly, should I consider converting my bike into a singlespeed one? I really wanted to ride a geared bike but I will never opt for walking back a broken bicycle nearly 5 kms (guess that's what happened with me) or maybe seriously injure myself should there be an accident.
Thanks to you all for patiently going through the questions and looking forward for your valuable suggestions.
PS I'm sorry for any bad english.

350htrr

You need to get another derailleur, unless it's just the bolts that broke holding it on, a good one set up properly should last for years and years... Should not be a problem with the wheel alignment unless the wheel was wobbling too...

anjhaankit

There was no wobbling, I rode it just fine for two days. I think it was just bad luck. The derailleur itself was broke as it's parts were bent and twisted. . TZ30 is mostly made up of plastic and looks very weak. I thought it would be better if there were any better and stronger alternatives.

CliffordK

My Mongooose that I used as a basis for my cargo bike build came with a RD-TZ31 derailleur. That derailleur definitely did not go into the final build. So, I have a "new-pull" sitting here on the desk.

I presume the reason your derailleur broke was poor derailleur adjustment. The stops need to be adjusted so the derailleur can't be shifted into the spokes, or drop the chain between your cluster and the dropouts. And, you can not expect a boxed bike to be adjusted properly.

Unless you tipped the bike over on the derailleur, or hit a stick or something.

Unfortunately, the reason I chose not to use the TZ31 derailleur was that it had way too much flex. I could literally wiggle the derailleur body 1 cm or so, and I did not believe I could get a reliable adjustment.

Get a new, slightly higher quality derailleur, and you should be fine.

Oh, one other thing. Is this your bike?
Rockrider 340 - Mountain bike - Black/Blue/Fuschia - Leisure bikes

Does it come with a spoke protector (often dubbed "dork disk")?
For a well adjusted derailleur, they are completely unnecessary. For a poorly adjusted derailleur, they can be a life saver. The local bike shop where you get the derailleur should have the spoke protectors for a couple of bucks, and help you get it installed.

anjhaankit

A very small sized spoke protector is there. As I earlier said, I put no stress while riding. It was most probably adjustment issue.
Can I replace tz30 with any available derailleur? I thought the derailleur should be a "compatible" one.
This is how my bike looks like-

CliffordK

As I understand it, all of the new Shimano dérailleurs, (EXCEPT perhaps the 11s derailleurs) have the same cable pull and are "compatible".

You will have to make sure your derailleur is compatible with the freewheel. In particular the largest sprocket. What is that? 28T? Most derailleurs should be able to handle it, but it doesn't hurt to check.

Do you have a small bike shop that would be willing to help you get the new derailleur installed and adjusted properly?

anjhaankit

Installation- yes, but proper adjustment- I highly doubt their capability. They mostly deal with cheap single speed bikes and one I earlier visited tried different permutations and combinations before finally being able to fix up my bike. It seemed to me that he had no idea what he was doing, and thus it is better to asaume that I am on my own here with as little support as possible.
I should have considered this aspect before ordering this bike.
Regarding the sprocket aspect, the official shimano website gives no information. I will have to probably inquire at the store from where I ordered this bike. He is surprisingly adamant that I use the stock derailleur. He says that it is first time that someone has complained about a broken derailleur.

Btw, I am sincerely thankful that you dedicated so much time and effort to answer my queries.

2old

Everything that your pictures show is a bike with no derailleur hanger (make sure that you understand this before procuring another derailleur). This means that you must purchase a derailleur with its own hanger which is attached using the axle nut. This limits severely the ones that you can use. However, the good news is that derailleurs come with excellent directions. Just set the limit screws, then adjust the tension of the cable. After you get your new one someone here could guide you through the process (probably better in the Bike Mechanics section). Good luck.

CliffordK

That is exactly what my Mongoose looked like.
Just remove that Allen bolt holding the derailleur on, and it takes a standard 10mm derailleur mounting bolt.

I believe it even had the notch for the B-Screw.

anjhaankit

I thought every derailleur comes with it's own hanger. My bicycle has no fixed hanger. I am going to receive a replacement tz30 free of cost. It will include a hanger. I can probably use it in any upgraded derailleur that I order.
Also, the head part where the hanger articulates with derailleur in tz30 looks like cheap plastic. It should have been metal. A cheap chinese version that I saw at local store was iron based and very tough looking. The only reason I did not use it was because I was afraid that it would mess with shifting mechanism.

anjhaankit

Or maybe simply I would look for a better derailleur that comes with it's own hanger, and has a tough metal head.

CliffordK

The bar you're calling a "Hanger" is an extension of the derailleur body. I'm not sure why it is on there, perhaps to increase heel clearance.

I've marked up your photo from above.



Here is a photo of the dropout and derailleur hanger from my Mongoose Massif that had a nearly identical derailleur.



There are some derailleurs with an integral derailleur hanger, for example many of the old simplex derailleurs. That is not what you have.



That 10mm mounting bolt is usually integral with the higher end derailleurs.

Note the high and low limit screws. They must be set so that the chain does not fall off of either end of the freewheel.

Oh, note, your derailleur has a peg that goes into that notch, but not an actual B-Screw.

fietsbob

Since this is the electric assist bike section...

If the Hub motor was on the front wheel you could use a different hub with internal gears instead , but with a rear hub motor , do as Clifford says .

tds101 

I managed to leave the fact that the bike in question isn't motorized. Lol! Thanks for letting the worms escape the can!

fietsbob

Maybe the Moderators can Move thread from this section to where it should have been started

CbadRider

Moved from Electric Bikes to Mechanics.

anjhaankit

I'm sorry for posting in wrong section. That was really inadvertent.
Here is the derailleur that has been sent back to seller-

And here's the one he is sending me as a replacement- I think this one includes a hanger.
Here's a pic from the bike-

I'm still waiting for the replacement to come.

anjhaankit

I'm still not sure how I will be able to set this up once it comes. I read the post on sheldonbrown website Derailer Adjustment but it has so many technical terms that I was left wondering whether I got something out of such a long post. I shall have to visit the local store again I guess.

sanchitbhoir712

derailleur that comes with it's own hanger will make it better, i HAVE BEEN FACING THE SAME PROBLEM but its better now.

anjhaankit

Dear Sanchitbhoir712, do you have the same bike? And is it possible to use the direct mount in this case? I have a friend who says that I'll have to use exact same type of derailleur that came with bike.

vamsiviswa

anjhaankit i got the same problem with the same bike what happened is the my derailleur got into wheel and is broken. can you help me?

HillRider

This is just a guess but I expect the low limit screw was not adjusted properly and the derailleur moved inward far enough to hit the spokes. That is an all-too-common cause of rear derailleur damage.

cny-bikeman

Derailleurs don't just break, but no way for us to easily tell what happened. branch could have been flipped into the drive train, derailleur limit out of adjustment, etc. As you already had one mishap I would strongly suggest you get assistance in mounting the new derailleur.

rmfnla

Thank you for this; I was thinking I was having an episode.

At least he doesn't call it a "mech"...