Please help diagnose and solve this problem!

seanosborn

New Member
Hi CycleChat members,

I'm new here, I'm looking for some help to an issue my new bike has cropped up with. I got a Triban rc500 from Decathlon a couple of weeks ago, I've used it for about 150km since. The other day I the chain started making this clunking noise, it feels like the chain is slipping and unbalances the bike, particularly on inclines, and tends to be on lower gear sets. I've watched a variety of videos diagnosing all kinds of different solutions, I was hoping by posting on here I may be able to get some sound advice.

Thanks for your help,
Sean.
 

Sharky

Guru
Location
Kent
I'm sure Decathlon give a free 6 week service, so take it back. Probably just needs to be re-adjusted.
 

Cycleops

Legendary Member
Location
Accra, Ghana
Hello and we to the forum.
As it'd only done a low mileage I suspect the derailleur cable might have stretched. You should be due a first service at Decathlon so unless you want to tackle it yourself I should take it back.
 
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Ian H

I am an ancient randonneur, & I stop often for tea
Location
East Devon
Give it a good clean first, especially round the gears/chain. Then re-lubricate and see how it performs. Check the gear adjustment if you feel competent to do that. Then as above.
 

gaijintendo

Veteran
Location
Scotchland
Congratulations on the bike, looks like a sound choice.

Like the wiser and more attractive responders above said, what you are experiencing seems to be Chain Slip/Skip/Jump. We can't have you scooting about with that.

Get Decathlon to take a look if you can, but I'm afraid you have a gear adjustment in your future. The reason they offer a service, is things do stretch very slightly, like @Cycleops mentions.

Gear adjustment is one of those things it is really easy to adjust - it just requires a screwdriver or possibly a micro-adjust twist (those little ribbed things beside the shifter or along the cable). But it's also really easy to make things worse, so YouTube whatever you think the most trustworthy bike mechanic is.

If you are doing it yourself, note which gear/gears and try and see if it is at the chainring/crank end or the back/cassette side of things.

Welcome to the forum.
 

tom73

Veteran
Location
Yorkshire
Take it back they should be happy to sort it for you it's due a free post purchase check.
 
Location
Loch side.
Hello and we to the forum.
As it'd only done a low mileage I suspect the derailleur cable might have stretched. You should be due a first service at Decathlon so unless you want to tackle it yourself I should take it back.
Cables don't stretch.
The definition of "stretch" here is vague, but I assume you mean that it has permanently elongated. That doesn't happen.
 

CXRAndy

Guru
Location
Lincs
Cables don't stretch.
The definition of "stretch" here is vague, but I assume you mean that it has permanently elongated. That doesn't happen.
I understand what you mean, but its general term for the bedding in period of cable systems. Something must move for indexing or poor shifting to occur, because it invariably does with new bikes or newly fitted cables
 

JuhaL

Veteran
Location
Finland
Before gear adjustments it's good to check rear derailleurs hanger alignment too. In a delivery it can be easily twist especially if it's carelessly packed. Good to check hangers screws too are they loose. Anyway good tips above too.
 

derrick

The Glue that binds us together.
Cables don't stretch.
The definition of "stretch" here is vague, but I assume you mean that it has permanently elongated. That doesn't happen.

Cable stretch” is actually a broader term used to describe the action of the WHOLE cabling system settling into place. Your brake and shift cables pass through your brake and shift housing-the other key components in the WHOLE cabling system. When housing is cut and capped with ferules, it may not be fully seated into those ferrules, or fully seated into the frame stops, derailleur, brakes, shifters etc. As you shift and brake, a huge portion of the initial settling that occurs is actually the housing fully seating itself into place. Once settled, you can be left with a considerable amount of slack, causing the symptoms above.
 
OP
S

seanosborn

New Member
Hi everyone,

Thanks for the amount of responses, I'll cart it over to the shop later and get them to show me how to fix it myself in the future :notworthy:
 

Vantage

Carbon fibre... LMAO!!!
We do need a better term for the common 'cable stretch' as it's a load of cockwomble.

If as suspected by the forumites previously it is indexing, the op only need to turn the nut labelled B anti-clockwise a turn or two.
Give it a shot @seanosborn
It's one of those need to know things as a cyclist coz no doubt, your gears will go out of sync again before long.

Der-parts-2-768x1024.jpg
 
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