Genesis Core 10 - 2010 Model, Problem with gears

jamesrt2004

Hi there,

Had this bike for around 6/7 months now (cant remember if i picked it up in June or July) and done between 1000~1200 miles through it.

I try take care of it as much as I can but since I actually purchased it it's had a problem with skipping gears (generally 3 skips to 5, and 7 always goes to 8) when shifting down.... shifting up goes 8 - 8 - 6 - 5(rattling)- 4/5 skips - 3 - 2 - 1...

Now im guessing it's either adjusted badly or the cables probably a bit off also.. now it is 'fairly' new and has done it since i've had the bike so i assume it was just set up wrong?

I want to take it to my LBS... but I don't have to much confidence lets say, in them and their 'work'.

Also replaced the chain today (hg50 to a sram 890) changed the length etc to match the old but noticed that now on the 8th gear it seems to skip when riding, though i don't know if it's shifting too far or short atm as it was dark out.

Anything you guys recommend ? I'm not afraid to get my hands dirty and learn as I do want to upgrade the bike just to learn about it really so ideally would do myself, but if it requires a decent setup then i'll just take it to a different bike shop

Thanks,
James

(sorry it's long winded just trying to provide as much info as poss)

Bike spec can be seen here - http://www.evanscycles.com/products/genesis/core-10-2010-mountain-bike-ec021329#features and feel free to suggest any upgrades, I do fancy suspension, brakes stem and handlebar atm to change a lot of the sturdiness and safeness on the bike

nicklouse

Cable tension needs regular checking and adjustment.

Running with poor set up could have worn parts out faster than normal.

The cassette sounds like it is worn out now.

Have a read of Parktools.

jamesrt2004

nicklouse wrote:

Cable tension needs regular checking and adjustment.

Running with poor set up could have worn parts out faster than normal.

The cassette sounds like it is worn out now.

Have a read of Parktools.

Cassette looks ok though, compared to what i've been looking at online today, yes slightly worn but as i don't tend to use many gears (generally on the middle or lowest up front and on gear 8 at the back and just power through hills as much as poss) I think i've managed to avoid any damage. Though with the chain now skiping on the 8th gear it could just need a slight adjustment right?

but you think cable tension is the most likely cause?


6] Problem: Rear derailleur doesn't change gear when selected or changes two gears at a time, or indexing is imprecise

Possible cause: Rear gear cable tension needs adjusting

6 rear gear cable tension needs adjusting: 6 rear gear cable tension needs adjusting

Select top gear, turn the pedals forward and select the next gear. If the chain doesn't move smoothly to the next sprocket, turn the adjuster anti-clockwise half a turn at a time until it does. Select the next largest sprocket and check that the chain will move cleanly to it. If not, turn the cable adjuster anti-clockwise a further quarter of a turn at a time until the change is clean.

Check that the upward shifts (to smaller sprockets) are still okay. If not, back off (turning clockwise) the cable adjuster until the shifts are correct. For 10-speed, select the second smallest sprocket. Press the STI lever just enough to take up the slack and turn the cranks.

If the chain shifts to the third smallest sprocket, turn the adjuster clockwise until the chain returns to the second sprocket. If no noise is heard at all, turn the adjuster anti-clockwise until the chain hits the third sprocket and makes a noise. Return the lever to second gear position; if the chain continues to rub on the third sprocket turn the adjuster clockwise until the noise stops. Check the rear derailleur now works correctly across the full range of the cassette.

Guessing I need to do this?

supersonic

Cable tension/dirty cables mostl likely, but could be a worn sprocket or two too.

Replace cables.

cooldad

Also if I read your post correctly, you are using the granny chainwheel with the smallest cog out back.
This will cross up the chain and cause premature wear.
See viewtopic.php?f=40043&t=12647117

You have loads of gears, might as well use them.