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Need help and clarification(2 posts)

Need help and clarification3SPRINTER
Jun 2, 2002 6:41 AM
U all know the (1)b tension screw, (2)RD 'high' 'low' screw and (3)FD adjusment screw. I am kinda new to this...so i need help on WHEN i need to adjust these...and how......like the signs of me needing to calibrate it...like for egs...if chain keeps jumping between sprockets?....or a lot of noise during gear change?etc
The manual states how...but not when u need to adjust

I am using shimano...
Need clear explanation on this......THANX!!
re: Need help and clarificationC-40
Jun 2, 2002 10:32 AM
(1) The b screw moves the upper derailleur pulley closer or further from the biggest cog. The upper pulley should be relatively close to the big cog, but not touch it, when the derailleur is in the little chainring/big cog combo.

(2) The high and low screws keep the chain from over coming off the largest or smallest cog. If the screws are turned in too far, the rear derailleur won't shift onto the largest or smallest cog. Adjust until both shifts are made and the derailleur is centered below the cog.

(3) The TWO screws on the front derailleur adjust the upper and lower limits of the derailleur's travel. Just like the rear derailleur, if the screws are in too far, it won't shift up or down. If you back them out too much, the chain will travel too far and come off the small ring on the down shift or off the big ring on the up shift. Ideally, the screws should be set to keep the derailleur cage from rubbing the chain in either extreme position.

(4) If the chain jumps between cogs or is constantly noisy, none of these screws will help. The rear derailleur cable tension can be adjusted at the end of the cable as it enters the rear derailleur and/or at the cable stops located on the downtube or headtube. Turning either barrel adjuster out (to make it longer) increases the tendency to shift to larger cogs. Turning the adjusters in (to shorten) moves the chain down toward the smaller cogs. The idea is to set the tension so that both upshifts and downshifts are quick and there is no residual noise, indicating that the derailleur is centered with the cog that the chain is on.

(5) The barrel adjuster for the front derailleur cable is used to take up any slack in the cable, when shifted to the the little chainring. The adjuster should be turned out, to lengthen it, until there is no slack in the cable when the derailleur is shifted all the way down (on the little ring). Too much tension will override the lower stop screw on the derailleur, making it ineffective.