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Posted: 7/2/2003 1:02:55 PM EDT
I acquired a new bike a few years ago and have recently started riding again. The problem is my bike doesn't like to shift right. Going between 2nd and 3rd primary gears is a pain. I can get it to shift from 2nd to 3rd but it will only go the other way if i'm peddling reeaaally slowly. And sometimes it likes to jump off the sprocket when it's in 3rd. Plus the secondaries aren't reliable either.Say I'm going from 3rd to 4th. I have to shift up to 5th and then back down to 4th. I've adjusted the derailer every way i can. By the way it has Shimano components. This is driving me crazy I just wanna ride.
Link Posted: 7/2/2003 1:33:26 PM EDT
They can be very difficult to adjust right! I have a mountain bike that I have adjusted the shifters on and got it working good...but it took a little coaxing to get it going! Do you have a manual...ie. Service/repair book? They make a real good one called "The Bicycle Bible" or something like that. Hope this helps some! BigDozer66
Link Posted: 7/2/2003 1:48:21 PM EDT
Let me see if I can help you with this. Its an easy process that is difficult to explain over the keyboard. Before you start this make sure the chain is clean and lubricated and that the inner cable is travelling freely in the housing. The key to proper shifting is proper cable tension and travel. On the rear deraileur where the cable goes is the tension adjustment. Put the shifter in the position where the cable has the most slack. This would be the shifter position for the smallest gear in the rear cluster. Now shift "down" one gear. i.e. bring the shifter one click off of the smallest gear. Note the position of the chain on the rear cluster. It will be in one of several positions. 1) Still on the smallest gear 2) On proper (second from bottom) gear 3) On the third from bottom gear To move the chain from to the proper position you will adjust the slack in the derailuer cable. Turn the tension adjustment so that the top of the adjuster is moving in the direction that you want the chain to move. i.e. if the chain is not moving up to the larger gears, turn the adjuster counterclockwise. When you are on the right gear, you will need to make some tension adjustments to get it to run clean. This will give you a good base tune to make fine adjustements from Hope this helps. You can call if you have more questions. -Z
Link Posted: 7/2/2003 5:39:29 PM EDT
Thanks for the replies. Crimson, I'll give it a try tomorrow before work.
Link Posted: 7/2/2003 5:50:29 PM EDT
[url]http://www.parktool.com/repair_help/index.shtml[/url] This should help you out a lot as well.
Link Posted: 7/2/2003 8:11:28 PM EDT
[Last Edit: 7/2/2003 8:29:54 PM EDT by wjshark]
There are a few other factors you must check. The bike must be in an upright position, spray every thing that moves with WD40 or similar product(don't get any on rims or brake pads). Check that the rear der. cage with the two little wheels (pulleys) is as close to perpendicular to the ground as possible. If not (often bent in from bike falling or getting knocked) grab whole cage and attempt to gently straighten. If body or mount area of der appears bent best to replace. Then check that with no tension on cable that when looking down from above the pulleys are directly below smallest gear. If not, there are two small limit screws that limit travel of der at both ends of its swing. Adjust so that when on smallest and largest gear, pulleys are directly below respective(smallest or largest) gear cog. Then on smallest cog slowly back pedal and watch for chain jump between pulleys. This will indicate frozen or twisted chain links that will cause gear cog jumping when pedaling under pressure. If der cage snaps forward or chain doesn't move very smoothly when back pedaling replace chain. Chains also have a fairly limited life span(usually only one or two years of average use) during which index shifting will work properly. Now you may attempt to adjust cable tension, loosen cable clamping screw, turn tension adjust barrel screw (that cable goes thru) all the way in then back out one or two turns. Grab cable with pliers and put tension on cable, move shift mech back and worth, if there is any stiffness replace cable and housing, if not, with shifter in position for smallest cog tension cable moderately with pliers then tighten cable clamping screw. Check shift and use adjust screw to get proper movement and no chatter(as described by CT). To adjust front der the only two important positions are all the way down and all the way up-use limit screws to adjust so chain does not rub cage(which must be parallel to front chain rings) when chain is in its most extreme crossed positions but still allows for shifting up or down without missing chain rings. After limits are set adjust tension on cable by placing der in position closest to frame, loosen cable clamping screw and pull cable moderately tight then retighten screw. Recheck shifting to all gears and make any minor adj needed. Or just take the thing to a bike shop and get it done right.
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