MTB Issues

[AL_s13]

Hi guys

I have a GT Avalanche 1.0 which i bought to get back into riding and to cut bodyfat. When i try and ride uphill, the chain skips like its changing gear on its own. I believe the term is Ghosting. Now i'm a big chap, 6"2 and 19st 6, so i believe what is happening is the frame is flexing when under load. Is there any way to solve this? The bike is very new and has had a service recently

:sxoc::sxoc:

[trackstar]

All the gears have little notches on them to help the chain move between ratios when you shift, if the mech isn't aligned right it can catch on them which usually makes it jump a tooth. Its just a LOT more obvious when you're going uphill cause you've got the extra tension on the chain.
Its pretty common on new bikes, the cables will stretch a little bit initially so it'll probably just need a minor tweak. Do you know if its happening on the front chainrings or the rear cassette?

[AL_s13]

I think its happening on the rear

[ferretca18]

frame flex should be pretty minimal, probably cable stretch or the rear mech has has a slight knock:) easy to fix, if youre happy doing it youreself, put a quater turn on the shifter end of the cable to put a little more tension on to see if that makes a difference:)

[Si]

What gear are you in? If you are 'cross-chaining' you'll be strainign the drivetrain no end - i.e. largest front sprocket, largest rear.
If you are doing this, drop down a ring at the front and rear to get the same gearing with less stress on the drivetrain.

However, as the bike is new, I'd suggest it was merely the rear mech being out of alignment due to the cable stretching (they do this from new)
I'd look at re-adjusting it. If you're not confident doing this yourself it may be worth finding someone local, as it's a bit of a black art sometimes. Basic rule of thumb is:
Shift to smallest sprocket
Slacken the cable right off on both shifter and mech (where available)
Using the stop adjustment screws on the mech (usually 2 small x-head), wind up the lower stop so the upper rear mech pulley is slightly to the outside of the smallest sprocket.
Undo the cable clamp bolt, and pull it through to take up the slack.
Take up the last bit of slack with the adjusters on mech and/or shifter.
Ride, see how you get on. Fine tune with the adjustment on the shifter

Other option is if you've wanged the rear mech, you could have bent the hanger - depends on the sort of riding you do really :)

HTH

:)
Using the adjustment screws on the mech, wind the mech

[ferretca18]

also depends if youre running SRAM or Shimano groupset's (the adjustment is very slightly different):thumbs: forgot about that!

[Si]

Yeah, I'm not up on this newfangled SRAM stuff - give me 90's XT and I'll do it in my sleep :D

[ferretca18]

im all fingers and thumbs with old shimano, sram is mega easy to set up tho, unless you have a bent mech hanger like me, then its an art from lol:wack: