Shimano Deore adjustment

Ferdinand

I bought a mountain bike new last fall, equipped with Shimano Deore front and rear derailleurs. The rear derailleur is now making a bit of noise during pedaling in some gears and responds slowly and a bit unpredictably when changing gears. I assume that it simply needs to be readjusted. This is the first bike that I've owned that wasn't a single speed - all previous bikes were for BMX racing and this is my first MTB. What typically needs to be done to a rear derailleur that's relatively new in order to get it back to the type of performance that it delivered when new? Thanks in advance.

billybob1992002

if you look on the back of the derailuer there is a knob where the cable comes in that turns half turns that should adjust it. here is a trick to know which way to turn it if it has problems going tword the wheel turn it tword the wheel if is has problems going away from the wheel turn it the opposite way. this should get your shifting back to normal

moparchris

"...there is a knob..." - barrel adjuster

"...that turns half turns..." - if you mean that by the clicks they usually turn 1/4 turns actually

if you unwind the barrel adjuster it will increase cable tension, wind it in it will decrease cable tension which in affect changes where the dealleur indexes due to the shifters stops. the cable most likely would have stretched from new and will probably need increased cable tension but just ride it, it might not shift up or down propperly and you'll need to adjust the tension for it to index right. if you cant figure it out take it to your local shop. you wouldnt believe the number of people we get that start adjusting cables and screws and not knowing what they do screw them up them come to us bitching and moaning that it wont work or that their deralleur has gone through the spokes or something stupid like that.

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GT Ruckus SS
2006 Giant Trance 1
Giant TCR Euro

Solanog

Take a look at the cables to see if they are moving freely, my bike has them routed on the downtube so the front wheel helps them get dirty by spattering them with mud or anything on the road.
What happened to me once I was going through some dirty roads the cables almost stuck, shifting was very difficult to the point I thought I needed new shifters because they were hard to actuate. Then on the same route but now asphalt it was raining and while riding the shifting went back to normal, the front wheel help wash the cables. They get specially dirty on the bottom bracket where there is something like a slider or guide for them.

peet9471

I usually take a small piece of wood or something and slide it under the exposed cables. If the problem goes away, take some of the slack out with the barrell cable adjuster.

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Trek 7000 ZX
Trek 760