Runeazn

So my rear derailleur wont easily shift to the biggest sprocket a 34t sprocket. Shimano megarang btw.
What shoukd i do to make it shift more smoothly? Adjust b screw? Which way lower or higher?

Also my front derailleur doesnt want to shift from 3 to 2.
But doe do 3 to 1
And 1>2>3 does work fine

Infidel79

Sounds like the rear derailleur needs a little more cable tension. Regarding the front chainrings, I don't know what you mean by 1, 2, and 3, so if you don't mind, please re-state in terms of small, middle and large chainrings.

Runeazn

1 small 2 middle 3 big

1st gear 2nd gear 3rd gear

And tightning as in adjustin the SIS?

Infidel79

Tightening as in turning the barrel adjuster where the cable attaches to the rear derailleur. Try unscrewing (loosening) the barrel adjuster half a turn at a time (this pushes the outer cable housing away from the derailleur body, effectively making the path that the inner wire must travel longer, which for a given length of inner wire, pulls it tighter) until you can reliably shift into the 34t cog. Just make sure you can still shift up and down between the other gears on the cassette. If it used to shift fine, and you haven't bent or damaged any parts, then this adjustment should be all that is necessary for the rear derailleur.

Whiteknight

My wife and I have 4 Trek bikes. A pair of Navigators that date to 2004. A pair of Mulititracks. Three have Sram grip shifters and Sram rear derailleurs. One has a Shimano rear derailleur. All have Shimano front deraillers with the typical 3 chain ring sets. All have the Shimano megrange freewheels.

All give us delays in shifting down from the middle chain ring to the smallest chain ring if we are putting a lot of pressure on the pedals when climbing hills. 3 down to 2 is no problem. Going back up from 1 to 2 and then 3 is fast and quiet.

Going from the 28 tooth rear sprocket to the 34 teeth sprocket is slow and loud if there is a lot of pressure on the pedals.

After awhile you learn to anticipate the need to shift and do it before you are too slow and putting a lot of pressure on the pedals.

Runeazn

shifts same as the optimal setting said by shimano

optimal setting is set on third gear, tighten barrel till it fall, loosen barrel till it stays on and makes not "trying to switch sound" and check all of the gears if they make sound and if they do loosen the barrel..

this setting and almost totally loosened is the same..
still shifts funky..
deraillleur moves lower, tries to get the chain on the last gear but this happends all very slowly so the derailleur gets stuck a lil milisec. and then makes much noise and then switches..


also i dont really care about that gear,

What more important is,
that my front derailleur can switch from third gear to 2nd gear.
but can switch from 3rd gear to 1st gear
gearing up to 3 from 1 is normal.

Runeazn

okay took it for test ride eventough the problems arent fixed yet.

seems like when i am in my 7th gear it skips somewhere, and you will hear a sound. seems only to happen when i put a big force on it, stand cycling.
what could the problemaker be?