Fixing spokes/chain/cassette

[I like Skol]

...... There is also a possibility that the bike may receive an unnoticed knock to the rear derailleur which results in the same unfortunate outcome. I suspect this may be what has happened to the OP as he has said his indexing was out earlier in the ride before the event that damaged the spokes, I am really surprised that nobody has suggested checking the gear hanger before putting it all back together! .......

My lbs replaced the wheel & gave it a brief gear service, but when I took the bike out, the chain was chattering & hopping all over the place. I took it straight back to the lbs who reindexed, but advised the mech was bent, but not enough to replace it. It means I will get some 'occasional' skipping. This 'occasional' skipping was constant on the second cog of the rear cassette. Should I replace the mech now?

I don't like to say 'I told you so' but......

It may not be the mech, could just as easily be the hanger although the bike shop should have checked this before passing diagnosis on the mech (although this raises the question of if they should, as you have actually asked them just to replace the wheel?). Ask the shop if they checked the hanger was straight.

 

[livpoksoc]

I don't like to say 'I told you so' but......

It may not be the mech, could just as easily be the hanger although the bike shop should have checked this before passing diagnosis on the mech (although this raises the question of if they should, as you have actually asked them just to replace the wheel?). Ask the shop if they checked the hanger was straight.

Well I am beginning to wonder. They assessed the bike & they recommended the change of wheel vs a rebuild. I wasn't all that impressed & don't mind the told you so, I'm a newb to actually maintaining my bike, so happy to learn

 

[Crankarm]

Well I am beginning to wonder. They assessed the bike & they recommended the change of wheel vs a rebuild. I wasn't all that impressed & don't mind the told you so, I'm a newb to actually maintaining my bike, so happy to learn

A complete new wheel with a new rim and brand new spokes will be far stronger and more durable than a rebuilt wheel, especially your wheel if it were rebuilt, which you managed to forcibly break several spokes. There may be other spokes in your broken wheel that came close to breaking but didn't. If you had one innocuous broken spoke then I would say replace it but what you did to the wheel which btw looks an old wheel, has made it as good as scrap imho. Re-indexing if you paid to ahevt his done then the gears should change faultlessly. Asmentioned if they don't it could be either a knackered rear derailieur or bent hanger which might be bent if you pulled to hard on the shifter pulling the read deraillieur over the largest rear sprocket into the wheel. The bike looks well old. Do you have down tube shifters? I am so glad bikes have STI units or rapid fire indexed shifters these days as the old down tube shifters were a nightmare. Thankfully bike component technology has massively improved. A new hanger is less than £10 and a new deraillieur - Tiagra or 105 is £25 to £40 then you'll probably need new cables as well. An expensive mistake! Still you won't do it again, hopefully, that is if you set the limit screws properly.

 

[Crankarm]

However as the OP proves, they do have a use, when the gears have not been set up correctly, so it's a bit like saying a cycle helmet is of no use so long as you don't fall off your bike!. (Some would argue that helmets are of little use even then - but let's not go there!)
I think calling them dork discs is a bit
of cycling snobbery in the same way that the term suicide levers was used for dual lever brakes in the 80's.
Having said the above....I have always removed the discs on my cycles - but am confident that I can set up a rear derailleur so it won't go into the wheel. It's also fair to say that in my experience, I have always found that the plastic discs degrade and become brittle after a few years.

Because they were terrible that's why, absolute crap!

 

[livpoksoc]

A complete new wheel with a new rim and brand new spokes will be far stronger and more durable than a rebuilt wheel, especially your wheel if it were rebuilt, which you managed to forcibly break several spokes. There may be other spokes in your broken wheel that came close to breaking but didn't. If you had one innocuous broken spoke then I would say replace it but what you did to the wheel which btw looks an old wheel, has made it as good as scrap imho. Re-indexing if you paid to ahevt his done then the gears should change faultlessly. Asmentioned if they don't it could be either a knackered rear derailieur or bent hanger which might be bent if you pulled to hard on the shifter pulling the read deraillieur over the largest rear sprocket into the wheel. The bike looks well old. Do you have down tube shifters? I am so glad bikes have STI units or rapid fire indexed shifters these days as the old down tube shifters were a nightmare. Thankfully bike component technology has massively improved. A new hanger is less than £10 and a new deraillieur - Tiagra or 105 is £25 to £40 then you'll probably need new cables as well. An expensive mistake! Still you won't do it again, hopefully, that is if you set the limit screws properly.

An expensive mistake indeed - I attended a bike maintenance class where they said if you index the gears correctly once, they shouldn't need adjusting again unless you break/replace something. The thing was that the gears were jumpy on 4-5 that day, so the indexing was out anyway.

As for the post repair, I'm not overly impressed that they could let the bike leave the store without checking the rear indexing when I had paid them to do so. They fixed it when I took it back, but it's still not perfect. They said the mech was slightly bent, but that it didn't warrant replacing - which is what I'm unsure of.

The bike itself, four years old. The wheels are possibly as old as the bike, but can't be certain if they were replaced at any point in the last four years. Drivetrain is probably as old as the bike, but can't be sure. In the grand scheme of thinggs she probably hasn't done many miles. i coversda couple of thousand in the first two years, since then not much until the summer.

I am considering replacing it & keeping this one as backup, but it's a shame I likely won't be able to get a new one & be acquainted with it before next weekend (pru).

 

[livpoksoc]

Why go to the bother of taking them off? I know how to set up gears, but it's a little (almost) free insurance against a mishap. I certainly don't place any reliance on them, but adjustments don't always stay accurate, especially on a mechanism that is subject to vibration and dirt ingress.

I'm still not up to speed on the hatred I'm supposed to be feeling for a little plastic disk!


Steve

I would recommend replacing all 3 spokes before truing the wheel.
a) assess the tension of a pair of undamaged gearside spokes by squeezing them against each other*
b) replace the 3 broken spokes, tightening them until they are about the same tension as the test spokes at (a)
c) true up the wheel using the brake blocks as a pointer

* if you have a good musical ear, you can also assess spoke tension by the pitch of a plucked spoke.

If there are any other damaged spokes, like those shown in post 11, replace those between (b) & (c), tightening them up to the same tension as the test spokes too.

Trying to true a wheel with two missing spokes is going to mean making adjustments that wouldn't be necessary if the spokes were there. Undoing those adjustments after adding the missing spokes isn't going to be simple, so you are much more likely to end up with uneven spoke tensions. Provided none of the other spokes or the rim is damaged, you should in theory be able to return the wheel to its previous trueness just by bringing the replacement spokes up to the same tension the broken spokes had.

^^^^

''Trying to true a wheel with two missing spokes is going to mean making adjustments that wouldn't be necessary''

where do that statement come from.?

i advised to replace 1 damaged spoke [and to true the rim] 1 at a time - thus keeping the rim as close as possible to its original lateral position

I take them off because as they become brittle they often shake loose as the holding tags snap - and I am confident in my abilities to adjust a derailleur. I would certainly not recommend a novice cyclist to remove one. As for learning to hate them, you're simply not trying hard enough!

The pie dish/dork disc debate has rattled on for years and has IMO descended into a stand between vanity, fashion following and weight weenieism against common sense, prudence and independence!
It is quite wrong to say that properly set-up gears cannot send the chain over the top sprocket and into the spokes. The chain can easily be misdirected by a foreign body like a twig or carrier bag no matter how well maintained and adjusted the gears are. There is also a possibility that the bike may receive an unnoticed knock to the rear derailleur which results in the same unfortunate outcome. I suspect this may be what has happened to the OP as he has said his indexing was out earlier in the ride before the event that damaged the spokes, I am really surprised that nobody has suggested checking the gear hanger before putting it all back together! The dork disc will help prevent the serious damage that this can cause with minimal down side.

I have always left them on my bikes if fitted and did try to buy replacements for my 36 hole XT wheels I built for the MTB and commuter. I couldn't find good ones at the time due to the flange size and spoke count but would buy some without hesitation if they became available (I don't want the nasty ones that 'spin' onto the spokes, they have to have the proper claws that fit the hub flange ).

Just checking my bike shed and as suspected the dork disc is still in place on my best summer road bike, ironically probably the one that least needs it, but it is doing no harm so can stay where it is

Somebody did suggest that the derailleur may still catch the spokes even with a dork disc fitted but that is a different fault altogether and not what the OP experienced. The dork disc stops the chain sawing at the spokes if it over shifts. If the derailleur is touching spokes then it is either a bent mech, a bent hanger or a badly adjusted set-up (or all three?). A large pie dish might help?

Sorry long multi quote. What would the gen consensus be f I bought a new mech? Would that do the trick if I fitted it myself? Or is it a bigger job to replaced. I'm loathed to go back to my lbs after they didn't seem too interested in offering the full fix though I probably need it

 

[I like Skol]

Before you buy a mech try checking the gear hanger - Niggly niggly derailleur not quite right annoyance

If the hanger is bent then straighten or replace then see if the gears are any better before making a decision on the mech itself.

 

[Nigelnaturist]

I hate this term re-indexing as it's wrong, the indexing is controlled by the shifters and can not be changed, all you are doing is adjusting the RD so when you move the shifter it changes gear, set the stop limits first attach cable take up slack whilst the shifter is in the highest gear, the rest should change correctly unless some other mechanical problem worn pivots bent hanger ect. Test by going through the gears and make any minor adjustments.

 

[mrandmrspoves]

Because they were terrible that's why, absolute crap!

Some people thought they were crap - others found them quite useful. Bearing in mind most brakes back in the 80's were single caliper, often trying to squeeze 2 small brake blocks onto a chromed steel rim, the levers were not the biggest problem (especially in the wet) Cycling has always had its share of snobs - weight weenies, Strava segment chasers, Lycra lovers, cleat champions, dork disc disrespecters......and so on. Why else would people get so heated about someone else's bicycle?

 

[Crankarm]

Some people thought they were crap - others found them quite useful. Bearing in mind most brakes back in the 80's were single caliper, often trying to squeeze 2 small brake blocks onto a chromed steel rim, the levers were not the biggest problem (especially in the wet) Cycling has always had its share of snobs - weight weenies, Strava segment chasers, Lycra lovers, cleat champions, dork disc disrespecters......and so on. Why else would people get so heated about someone else's bicycle?

Well I guess living in Narfork suicide levers must have confused you know end. How ever if you actually had to go down a steep hill relying on them say for instance in the Peak District or the Chilterns then you said your prayers as quite often they didn't work they were that crap. And in the rain forget it they were double CRAP, lethal. Bicycles and cars are so much better these days as are cars ……….

 

[John the Canuck]

Well I guess living in Narfork suicide levers must have confused you know end. How ever if you actually had to go down a steep hill relying on them say for instance in the Peak District or the Chilterns then you said your prayers as quite often they didn't work they were that crap. And in the rain forget it they were double CRAP, lethal. Bicycles and cars are so much better these days as are cars ……….

no need to get your knickers in a twist

dual levers did/do serve a function - a mild braking pressure whilst pottering along on the '' tops'' - about 70% of my cycling fits this

 

[mrandmrspoves]

Well I guess living in Narfork suicide levers must have confused you know end. How ever if you actually had to go down a steep hill relying on them say for instance in the Peak District or the Chilterns then you said your prayers as quite often they didn't work they were that crap. And in the rain forget it they were double CRAP, lethal. Bicycles and cars are so much better these days as are cars ……….

Gas Hill, Ketts Hill and Thunder Lane in Narridge (spelt Norwich) were adequate tests of a bicycle's braking ability. I never went down any of them using the "suicide levers" - because I could see I was going down a steep hill where the main brake lever would be more effective. In traffic, unless I was going very slowly (when the dual levers would be effective enough) I always rode in a position where I could reach and apply the brakes effectively using the standard levers. In the wet, with chromed rims and naff Fibrax brake blocks, your best chance was dragging your shoes along the ground, sticking your foot through the spokes in the front wheel, or jumping off the back of the bike a split second before impact with the object you would have ideally liked to avoid colliding with! (I tried all 3 methods at some stage or other)

 

[rb58]

An expensive mistake indeed - I attended a bike maintenance class where they said if you index the gears correctly once, they shouldn't need adjusting again unless you break/replace something.

I'm not sure that's correct. The cables will stretch over time, so occasional tweaks on the barrel adjuster keep things sweet. For me anyway.