Ouch !

I've got a small but annoying problem with my gears.

When I shift from a large cog to a smaller cog at the rear, it will not move unless I move two gears at a time. Whilst if I shift back up the gears it moves okay one gear at a time.

I've tried adjusting it and I know it must be something slight but I cannot quite get it right.

Can anyone help ?

Thanks Ouch !

Maybe I should point out that I'm talking about my Kona Blast Mtb.

faith

Ouch;

Is the cable to your rear derailleur lubricated and in good working order? Mtb’s are known to pick up foreign material, water and other “crude” that greatly shortens the life of the rear derailleur cable, especially the short run at the derailleur end. Many have “grub” or “Nightcrawler” protectors to guard entry for this critical segment. If the cable doesn’t move freely I believe it can cause sluggish shifting. In which direction may depend on your derailleur spring design, is it conventional (homes to small sprocket) or Rapid Rise (homes to large sprocket)?

When did this problem begin? Has it just occurred recently? If so please check the angle of the derailleur hanger, it's exposed and vulnerable to damage from impact (dropping bike on right side). The derailleur jockey wheels should line up parallel to the sprockets, if they don’t it can cause all kinds of silliness in shifting at the rear.

See https://www.parktool.com/repair_help/DAG.shtml for illustrations of a bent derailleur hanger.

As for Adjustment of the derailluers, two excellent links are:

https://www.parktool.com/repair_help/FAQrindx.shtml

https://www.sheldonbrown.com/derailer-adjustment.html

Please review these links to see if they are of merit to your issue. Thanks!

knobbymojo

Does it only do this in certain gears or all gears? My bike did this when shifting down from 6th to 7th, it was caused by cable stretch from new cables, if this sounds like what you are experiencing, adust the derailleur either with the barrel adjuster on the back of the derailleur, or by loosening the cable clamp nut and taking up the slack that way.

Alan Perkins

Bunches of questions here
1. Does it happen in different front chain rings?
2. Does it happen in different gears on the rear cassette?
3. What type of shape is the cassette in?
4. What type/brand of shifters?
5. How new/old are the cables?
6. How new/old is the chain? Have you checked it for stretch?
7. Is the chain dirty or clean?
8. How clean/dirty are the cables and housings? (as Faith asked) Does the cable slide in the housing easily?
9. Have you tried the barrel adjuster on the rear derailleur? Can you see the rear derailleur physically move when you adjust it?

Basically clean and lube everything in your drivetrain. That will take care of many issues.
Make sure your shifters are adjusted correctly or take your ride the your local bike shop.
Replace (or have replaced via the LBS, again) each part in the drivetrain. Typically start with chain/cassette. That will solve 90%.

pat5319

Does your "pully cage" line up parallel with your cassette?

If not, somethings bent in your derailleur or your derailleur hanger.

Ride Straight
Pat

Ouch !

Hi guys and thanks for the replies. it has been the roadbike for the last couple of days so I haven't managed to have a look at the Mtb since you've posted but rest assured I will.

Alan it does happen in different front gears though it has to be said that the bike spends 95% of it's time on the large gear at the front.

The problem at the rear is across all the range and as the bike is roughly 15 months old most things are in pretty good shape.

A thought has just occured to me.(not something that happens often)

As I spend most of my time in the large gear at the front and that includes whilst climbing could that be putting stress on the chain and hence stretching it, because if that's the case maybe I be better off going to the Lbs and letting them sort it out.

Once again thanks for the replies.

faith

Ouch;

I’m certain your LBS will be successful in remediation of your shifting problem. Please be aware that the term “Chain Stretch” is diagnostic of it’s condition and does not imply that the metal itself has elongated. The elongation is caused by wear between the moving surfaces (where the pin (rivet) contacts the sideplate and inner plate and the roller (bushing)). This is why it’s so very important to clean and lubricate the chain frequently! It is prudent to replace the chain when wear has lengthen 12 links (12 inches) greater than 1/16 of an inch, certainly by 1/8 of an inch. Be certain to make the measurement while the chain is under tension otherwise you will not observe it's actual working length.

Please let the forum members know what the LBS does to correct the condition, so they can share it with other similar queries in the future, thanks.