Snapped chain and rear derailleur - suitable replacement?

markwarner13

I own a claud butler urban 100, purchased second hand a few months ago. It's had a fair few mods and its been on a fair few miles since it was new you can see from the condition, buts its been serving me very well in getting me back into road cycling.

Anyway - last week the chain snapped whilst attempting a steep hill, i got it fixed but was advised that chains only snap due to age and wear generally and it could be a sign that other stuff will start to give up soon.

Well the cycle shop was right cos whilst on a 20 mile cycle today my rear derailleur decided to snap after some crazy lock up with my gears for no apparent reason.

So my question is ... What should I be replacing now these two have shown their age? The cycle shop mentioned i'd need a complete 'chainset' kit - what does this consist of and am I ok to attempt replacing all these bits myself or better just putting it in to a repair shop to ensure all set up correct from the start?
Also - vital question - how much is it all gunna cost for parts that anyone might be able to recommend.

Thanks in advance. Any advice is much appreciated

JayKosta

It is likely that the rear gear cluster is so worn that the new chain doesn't mesh properly with it. Similar trouble is possible with the teeth on the front chainrings.

I'd start by comparing the shape and size of the teeth on the rear cluster and chainrings with those of new parts. Buying a bunch of new parts can become expensive...

Jay Kosta
Endwell NY USA

k-dog

They're right - parts of a drivetrain wear together so you need to replace them together - especially if they were old.

You have a new chain, you'll need a new cassette and now a derailleur. The problem was probably caused by the new chain and old cassette.

What groupset do you have at the moment. Derailleurs aren't especially expensive. Cassettes are £15-30 depending which one it is.

Easy enough to do - and worth learning because you can keep your gears running perfectly that way.

rolf_f

Seems premature to me to assume a knackered drive train. The derailleur snapping is probably unrelated though it might imply the bike has been poorly maintained and chains can break whether heavily worn or not.

Obviously a new mech and chain are needed. Fit those and see how it works. If the new chain slips, replace the cassette. If that doesn't solve the problem the chain rings might be toast - only then do you need to consider a new chainset (or chainrings but these tend to be barely cheaper than complete chainsets).

As above - try to fit the parts yourself.

markwarner13

Apologies for mis-communication - I didn't actually replace the chain, the chain was simply repaired with a 'powerlink' for those precise reasons advised above - that all parts wear together so a new chain was not advised.

So with me still having my old chain how best to proceed? Still go ahead with replacing the chain and then a new derailleur and casette? or stick with my old chain and see how it copes?

The groupset at the moment I believe is just an entry level Tourney TZ50 set, it was serving it's purpose fine but if now is the opportunity for a slight upgrade I would consider it, money being tight though and not using it for massively long journeys so no top notch stuff required.

Thanks

Yossie

I'm not sure what a CB Urban 100 is offhand but (with apols if I'm wrong) I don't think its going to be worth spending shedloads on parts - I'd go for a KMC chain from CRC for a tenner or so and 105 (again, assuming its Shimano compatible) rear mech and cassette in the deals (CRC, TREDZ, Merlin, etc).

105 is cheap and bomb proof.

You won't be able to match a new chain with old cassette (well, you can run them but it will skip and jump and be jack) but the front rings, unless totally shot, should be fine.

Remember new rear inner and outer cable.

monkimark

Tourney mech suggests the current set up is 6 or 7 speed so a 105 mech probably isn't going to be compatible.

Yossie

Nah - it'll work fine if you get a 9 speed and just have the 2 spare unused clicks set up at the bottom cog of the cassette.

I'm running 10 speed mech with 9 speed cassette on the winter commuter with no issues, so an additional spare click shouldn't be a problem.

Otherwise Amazon have loads of 7 speed stuff kicking around for pence.

rolf_f

Yossie wrote:

You won't be able to match a new chain with old cassette (well, you can run them but it will skip and jump and be jack) but the front rings, unless totally shot, should be fine.

OP has not, as far as I can see, given us any good reason to assume the cassette is knackered. An unloved bikes visual appearance is no real clue to the number of miles its done. For all we know the bike shop simply wants to sell the OP a cassette, chain and chainset rather than check whether just the chain or just the chain and cassette need replacing.

I'd get a new chain and see if both old and new chains worked with the existing cassette. If they do, then both chains can be used to reduce wear on the cassette. If they don't you know the cassette needs replacing and you already have a new chain to use on it.

Yossie

Agree - I assumed that it would be shot due to the chain snapping but I could be wrong. Generally I'm not though, so lets go with my assumption shall we?

rolf_f

Yossie wrote:

Agree - I assumed that it would be shot due to the chain snapping but I could be wrong. Generally I'm not though, so lets go with my assumption shall we?

Can you please define generally? If 'generally' means you are right more than 95% of the time then I'm prepared to go with you. Less than that and I think the error margin is sufficiently high for a reconsideration. I wouldn't go with my opinion as I am only right 64% of the time.

Yossie

I'm Italian - generally means more if the sun and gelati are shining, less if some tosser in a bar or petrol station wants to give me sweets instead of change when completing a purchase.

I'd say that I have a 96.547% hit rate of success though. And that's being modest like we Italians generally are.

markwarner13

Ok, sorry for delay in replying and bringing this whole issue back up again but I've been out of cycling action for a couple of weeks anyway so I haven't looked properly into the repair...
I have now checked the set up and it is as follows:
Tourney TX Rear Derailleur (broken)
Shimano super low 14-34T 7 speed cassette (MF TZ31)

Just to clarify, haven't replaced chain, it has been repaired.

I appreciate now, from further research, this is a fairly low spec system, but it was working fine and satisfactorily - I don't need a super high end set-up at the mo as I'm just a casual cyclist. However, I'd like something that will serve me well and give me a couple of years service... so my question is...

Can I simply replace the rear derailleur for a quick return to the road, and if so should I just go for a Tourney or something slightly higher such as Alivio < seems to be the highest spec possible for a 7/8 speed cassette and still only £20 which I don't mind as an initial outlay.

Or - is this false economy and should I look at trying to invest in a better all round set-up - seems rear cassette's are more commonly found in sets of 9/10 for road cycling - but this would need new gear shifters etc as well...

As always, appreciate all advice given :-)

JayKosta

I would do a detailed close inspection of all the links on the existing chain that broke.
Thoroughly clean the exterior of the chain so you can really see the outside of the links.
Look at both sides of the chain to see if there are any cracks on the outside plates at the pins. Also verify that none of the pins protrude excessively on either side - if any do that could have caused the deraileur breakage.
What WAS the weakest link has already broken, now you are waiting for #2.

If you are willing to take the risk of another broken chain, then buy an inexpensive rear deraileur and be hopeful. But a replacement deraileur might suffer the same fate as the old one due to a bad chain.

To really FIX the problem would entail the parts and expense that was discussed earlier.

I would be looking for an inexpensive replacement bike....

Jay Kosta
Endwell NY USA

spankwilder

markwarner13 wrote:

I own a claud butler urban 100, purchased second hand a few months ago. It's had a fair few mods and its been on a fair few miles since it was new you can see from the condition, buts its been serving me very well in getting me back into road cycling.

Anyway - last week the chain snapped whilst attempting a steep hill, i got it fixed but was advised that chains only snap due to age and wear generally and it could be a sign that other stuff will start to give up soon.

Well the cycle shop was right cos whilst on a 20 mile cycle today my rear derailleur decided to snap after some crazy lock up with my gears for no apparent reason.

So my question is ... What should I be replacing now these two have shown their age? The cycle shop mentioned i'd need a complete 'chainset' kit - what does this consist of and am I ok to attempt replacing all these bits myself or better just putting it in to a repair shop to ensure all set up correct from the start?
Also - vital question - how much is it all gunna cost for parts that anyone might be able to recommend.

Thanks in advance. Any advice is much appreciated

I would guess..... Your drivetrain is completely worn out. It's not common for a new chain to snap so going to guess yours is old. The power link fitted will likely not fit well on a worn cassette and may have helped the rear mech part company. So:

7SPD Freewheel: £15-25
Chain: £20-25
Derailleur: £25-30
Gear inner £2.50

Chain set/chain rings would need inspecting

These are all basic service parts, you will need a tool to change the freewheel. If your not familiar with setting it all up - I would take it to the shop for a quote, if you set it up wrong you might find your buying some of the bits again along with a rear wheel. Also if your not familiar with the history of the bike probably get them to give it a full check over hubs, BB etc. Sometimes (funds permitting) a new bike is the better way to go.

desweller

The only chains I've had fail like that have been new ones. And 7/8 speed stuff is normally super robust - lasts a lot longer than 10-speed.

What gear were you in when the derailleur was destroyed? There's no chance your chain was just too short and you went into the big/big combination of gears is there?

markwarner13

DesWeller wrote:

The only chains I've had fail like that have been new ones. And 7/8 speed stuff is normally super robust - lasts a lot longer than 10-speed.

What gear were you in when the derailleur was destroyed? There's no chance your chain was just too short and you went into the big/big combination of gears is there?

Funny you have mentioned that because it was that exact situation - biggest front ring with biggest rear ring - the bike shop told me to avoid selecting this gear after they had repaired my chain, I flicked the gear lever once too much and it went up 2 gears rather than 1 and then that's when it ceased up. I wonder if the bike shop just removed a chain link which has made the chain smaller? Because it never used to be a problem going into this gear before the chain snapped.

Either way I think it's right what people are saying - the whole lot seems like it needs replacing. Thing is I'm really happy with the frame, seat, handelbars etc... basically all other parts on the bike, so I guess I have a decision to make on going for a new bike or trying to restore this bike.

I have the option of taking up the 'bike to work' scheme through my employment so I could affordably go for a slightly better specced £4-500 bike. Thinking this could be the way to go for an immediate return to the road, then keep my old bike as a project to repair as and when funds permit and build it back up to a decent spec.

rolf_f

markwarner13 wrote:

Either way I think it's right what people are saying - the whole lot seems like it needs replacing. Thing is I'm really happy with the frame, seat, handelbars etc... basically all other parts on the bike, so I guess I have a decision to make on going for a new bike or trying to restore this bike.

I have the option of taking up the 'bike to work' scheme through my employment so I could affordably go for a slightly better specced £4-500 bike. Thinking this could be the way to go for an immediate return to the road, then keep my old bike as a project to repair as and when funds permit and build it back up to a decent spec.

If you want a new bike, get a new bike. However, economically that makes no sense. It looks like you need £20 for a rear mech and maybe a tenner for a new chain (if your current one is too short).

Pictures would help folk advise but there's a good chance your bike doesn't need anymore spending on it than the above. That's about one months payment on the C2W. Then in the meantime maybe you can save up a bit so you can afford something a bit nicer than a £500 bike (not that there is anything wrong with those - just after a few months riding your current bike your ideas of what you want from a new bike might change a bit).

desweller

Does sound like your chain was too short. Check that your right chainstay is not bent. The Tourney stuff is cheap but having used it myself over many thousands of miles I can confirm that it's not especially weak.

IMO you should try replacing the chain and derailleur first. Maybe budget for a new freewheel. Chainrings normally last for yonks (10s of thousands of miles); if you are worried they need replacing take a (focussed) photo of the teeth and post it on here. I am prepared to bet that they're OK.

bockers

IMHO if a chain has snapped due to age and wear then I would not hessitate to replace the rear casette too. Not doing so could be dangerous and it is hardly likely to break the bank. I would advise the OP to just get a new chain casette and deraillier plus cables. Should be no more than £50 if you get some bits from ebay. Then if you enjoy riding that bike consider the B2W scheme for a newer one if you think you will be doing the miles and keep the claud butler as a winter weather bike.