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Front derailleur downshifting issue

Old 05-15-19, 09:20 AM
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Front derailleur downshifting issue

Hello I am fairly new to bike maintenance and I have replaced my rear cassette, chain, and front crank set. Everything works well except shifting down on the front derailleur. I followed a park tools video on how to adjust the limit screws for high and low and after doing so it shifts up perfectly but down it can't quite make it from the largest gear to the middle one. I have to shift to the smallest then up one to get to the center gear. It appears if I need to adjust the high screw just a bit more but the screw is bottomed out. I am running all stock components on a dual sport 2. It worked fine before swapping on the new parts and also the parts I put on are the same that comes stock on the bike. Do I need to adjust the pinch cable length? Thanks
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Old 05-15-19, 09:46 AM
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Did you put the same model crank on? Or change to something else? If you have inline adjusters, then those can help you determine if changing the cable pinch point will solve the issue.

Shimano's tech docs are here.......... https://si.shimano.com/#/

Look for the DM's for your model. The SI's are pretty useless with a few exceptions.
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Old 05-15-19, 10:01 AM
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Originally Posted by GupBuck
... it shifts up perfectly but down it can't quite make it from the largest gear to the middle one. I have to shift to the smallest then up one to get to the center gear.
Limit screws do not control shifting to the middle chainring. Limit screws keep the chain from overshifting (chain falling off) the large and small chainrings. Your problem is incorrect cable tension adjustment. You need only as much tension required to shift to the middle ring from small, and then large ring from middle. Also make sure the height and rotation of the front derailleur are correct, and that you have the cable attached to the front derailleur correctly; some of the "newer" Shimano derailleurs are very particular about cable attachment. Good luck.
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Old 05-15-19, 10:19 AM
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Changing the limit screws (particularly the high screw) will not help your issue. From my experience, this sort of shifting problem is caused by a misrouted shifter cable. Make sure you route the derailleur cable *exactly* as Shimano intended.
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Old 05-15-19, 10:56 AM
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Originally Posted by Eggman84
Limit screws do not control shifting to the middle chainring. Limit screws keep the chain from overshifting (chain falling off) the large and small chainrings. Your problem is incorrect cable tension adjustment. You need only as much tension required to shift to the middle ring from small, and then large ring from middle. Also make sure the height and rotation of the front derailleur are correct, and that you have the cable attached to the front derailleur correctly; some of the "newer" Shimano derailleurs are very particular about cable attachment. Good luck.
Alright I didn't adjust anything on the cables except the barrel adjusters on the handle bars. My old chain was also almost half a link longer due to stretching so the tension could be off I suppose.

Originally Posted by Iride01
Did you put the same model crank on? Or change to something else? If you have inline adjusters, then those can help you determine if changing the cable pinch point will solve the issue.

Shimano's tech docs are here..........

Look for the DM's for your model. The SI's are pretty useless with a few exceptions.
Yeah It's the same thing. Different color but just a newer years model

Originally Posted by Aubergine
Changing the limit screws (particularly the high screw) will not help your issue. From my experience, this sort of shifting problem is caused by a misrouted shifter cable. Make sure you route the derailleur cable *exactly* as Shimano intended.
I haven't moved or changed any of the cables since I have gotten the bike. I have adjusted the rear derailleur tension as it was loose and not shifting to the smallest gear. But the barrel tensioner on the handle bars doesn't really spin so could the cable have stretched or slightly come loose where it attaches to the front derailleur?
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Old 05-18-19, 02:55 PM
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I tightened the cable and everything is shifting great now. Thanks for the info
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Old 05-18-19, 05:21 PM
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Originally Posted by GupBuck
Hello I am fairly new to bike maintenance and I have replaced my rear cassette, chain, and front crank set. Everything works well except shifting down on the front derailleur. I followed a park tools video on how to adjust the limit screws for high and low and after doing so it shifts up perfectly but down it can't quite make it from the largest gear to the middle one. I have to shift to the smallest then up one to get to the center gear. It appears if I need to adjust the high screw just a bit more but the screw is bottomed out. I am running all stock components on a dual sport 2. It worked fine before swapping on the new parts and also the parts I put on are the same that comes stock on the bike. Do I need to adjust the pinch cable length? Thanks
Does the crank have the correct length BB?
I'm assuming you tossed a new crank on to an old BB and don't know why things are "wonky".
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