problems with gears help please.

[jags]

lads help me out here ,when i tryed my sherpa fully loaded for the first time yesterday the gears skipped all over the place,im useing shimano m770 ex front and rear derailers is it possible that the rear derailer is to sensitive for heavy loads,there no  fine tuneing on this mech as in no barrell adjusters,would i be better to change the rear mech for deore lx would this be better and solve my skipping problem
my full groopset is m770 xt tiagra  9 speed shifters and yes i did get the bottom bracket faced thanks lads hope you can advise.

[julk]

Some thoughts.
Skipping between gears - could be bent, worn or misaligned rear gear changer/hanger, possibly too short an arm rear changer with a mega range block, worn out indexed gear changers...or probably as you surmise a lack of cable adjusters for fine tuning.
Chain jumping whilst remaining in the same gear - could be worn chain, block, chainrings, or low chain tension from too long chain, too little chain wrap round block...
I hope this helps.

[john28july]

lads help me out here ,when i tryed my sherpa fully loaded for the first time yesterday the gears skipped all over the place,im useing shimano m770 ex front and rear derailers is it possible that the rear derailer is to sensitive for heavy loads,there no  fine tuneing on this mech as in no barrell adjusters,would i be better to change the rear mech for deore lx would this be better and solve my skipping problem
my full groopset is m770 xt tiagra  9 speed shifters and yes i did get the bottom bracket faced thanks lads hope you can advise.

Never seen a rear gear without an adjustment screw/
John
PS Yes you need it adjusted!

[stutho]

Any chance your panniers are interfering with the derailer cable?   

[stutho]

Ps you definatly nead some form of cable adjustment.  maybe something like this would suit?

[jags]

thanks lads well all the gear is new 2008 ,sorry but i should have said there's  adjuster on the downtube stop,but no barrell adjuster on rear mech .i realined the mech today took her out for ten miles perfect no skipping but no load on ,i checked the hanger it looks fine  everything else  seems perfect im going to load it up tomarrow see how i get on ,i'll report back.am i mad thinking this rear derailer is not capable of changing under load .

[Dave Whittle Thorn Workshop]

New XT doesnt have an adjuster, as suggested fit an in line one, though with everything set up correctly should work fine, I have no complaints with all my 2008 XT kit fitted to me MTB.

[stutho]

New XT doesnt have an adjuster

Yep call me a cynic but I think this is yet another case of the marketing people having too much control over the engineering design team.  "Yes sir, this new model is lighter than the old model." 

[jags]

well i took it out for a test ride after adjusting the rear mech on the bike stand ,also i cut two inches of the cable housing and zip tied it under the rear rack so as the pannier could not touch it in any way .i cycled 20 hard miles up and down every hill i could think of to put it under as much pressure as i was able, it also lashed rain  for entire spin .well the gears were super smooth no skipping of any kind im hopeing i have it nailed .the xt groopset looks and preforms great when adjusted properly ,but  if they put the barrell adjuster on the mech it would be so mush easer to fine tune it,

[stutho]

A bit OT but one of the best bang for buck upgrade I ever made to made to a derailer bike was to fit a Avid Rollamajig.  I am not sure if they are still made but if they are then they are well worth the ~£5.  It help in the setup of the gears,  it reduces the cable length and increases the 'slickness' of a gear change.  Overall an excellent bit of kit.

[jags]

stutho i ordered the in cable adjusters from sjs  there supposed to be excellent for adjusting the rear mech (fine tuning) soon find out .