Gears: setting up my front mech
Discussion
Can someone give me a complete idiot's guide to setting up a front mech (Shimano Deore circa 2004 if that makes a difference!)
My bike came back from the shop a while back having had a few new bits in the drivetrain and it never shifted properly. Basically the back appears to be okay, but the chain is fouling part of the front mech virtually all the time. It clears statically, so it's difficult to tell which bit it's actually hitting under tension. Originally I thought it was hitting the bottom of the mech, so - possibly rather stupidly - I slackened off the cable somewhat and physically moved the mech down a few milimeters on the frame tube. That's only made things worse, so I think I need to try setting it up from scratch.
So... can someone talk me through it? (Slowly and clearly as if you're talking to an imbecille, because, frankly, you are...
)
My bike came back from the shop a while back having had a few new bits in the drivetrain and it never shifted properly. Basically the back appears to be okay, but the chain is fouling part of the front mech virtually all the time. It clears statically, so it's difficult to tell which bit it's actually hitting under tension. Originally I thought it was hitting the bottom of the mech, so - possibly rather stupidly - I slackened off the cable somewhat and physically moved the mech down a few milimeters on the frame tube. That's only made things worse, so I think I need to try setting it up from scratch.
So... can someone talk me through it? (Slowly and clearly as if you're talking to an imbecille, because, frankly, you are...
)it is pretty straight forward....BUT if the bike shop messed it up then get them to sort it out
A simple step by step for you
Front Deraileur
The front derailleur is the simplest to setup and adjust. There are two setup steps here
Setup Once these setups have been done they should never have to adjusted again unless something breaks or is replaced. Even changing cables will not require these setups to be done again
1: Position on seat tube The front derailleur is fixed to the seat tube and should be parallel with the chain rings. The outer bottom edge of the chain guide should be 1-3 mm above the teeth of the largest chain ring when it shifts over the chain ring.
2: Cable tension With the derailleur all the way down above the small chain ring and the shifter all the way in i.e cable longest, connect the cable, pull tight and tighten screw.
3: Hi and low settings The hi and low settings position the end limits of the derailleur.
With the chain on the small chain ring in the front and large ring at the back the chain should just not touch the inside inner derailleur guide. Adjust the L setting screw to achieve this
Now shift the chain to the big ring on the front and small ring on the back. The chain should just not touch the inside outer derailleur guide. Adjust the H setting screw to achieve this.
Adjusting With the derailleur on the middle ring front and back adjust the cable tensioner at the shifter so that the chain is in the middle of the derailleur.
A simple step by step for you
Front Deraileur
The front derailleur is the simplest to setup and adjust. There are two setup steps here
Setup Once these setups have been done they should never have to adjusted again unless something breaks or is replaced. Even changing cables will not require these setups to be done again
1: Position on seat tube The front derailleur is fixed to the seat tube and should be parallel with the chain rings. The outer bottom edge of the chain guide should be 1-3 mm above the teeth of the largest chain ring when it shifts over the chain ring.
2: Cable tension With the derailleur all the way down above the small chain ring and the shifter all the way in i.e cable longest, connect the cable, pull tight and tighten screw.
3: Hi and low settings The hi and low settings position the end limits of the derailleur.
With the chain on the small chain ring in the front and large ring at the back the chain should just not touch the inside inner derailleur guide. Adjust the L setting screw to achieve this
Now shift the chain to the big ring on the front and small ring on the back. The chain should just not touch the inside outer derailleur guide. Adjust the H setting screw to achieve this.
Adjusting With the derailleur on the middle ring front and back adjust the cable tensioner at the shifter so that the chain is in the middle of the derailleur.
Edited by y2blade on Tuesday 14th September 13:18
http://www.parktool.com/repair/readhowto.asp?id=75
^^ this is bad, it will foul the front mech, your chain, rear cassette and mech will wear very quickly. Keep the chain as straight as possible, this means using the larger rear sprockets on the inner front chainrings and the smaller rear sprockets on the outer front chainring.
Chris71 said:
Basically the back appears to be okay, but the chain is fouling part of the front mech virtually all the time.
Learn not to cross chain^^ this is bad, it will foul the front mech, your chain, rear cassette and mech will wear very quickly. Keep the chain as straight as possible, this means using the larger rear sprockets on the inner front chainrings and the smaller rear sprockets on the outer front chainring.
itsnotarace said:
http://www.parktool.com/repair/readhowto.asp?id=75
^^ this is bad, it will foul the front mech, your chain, rear cassette and mech will wear very quickly. Keep the chain as straight as possible, this means using the larger rear sprockets on the inner front chainrings and the smaller rear sprockets on the outer front chainring.
I thought everyone knew this^^^ it is common mechanical sense....Chris71 said:
Basically the back appears to be okay, but the chain is fouling part of the front mech virtually all the time.
Learn not to cross chain^^ this is bad, it will foul the front mech, your chain, rear cassette and mech will wear very quickly. Keep the chain as straight as possible, this means using the larger rear sprockets on the inner front chainrings and the smaller rear sprockets on the outer front chainring.
....maybe not then, so good point
y2blade said:
itsnotarace said:
http://www.parktool.com/repair/readhowto.asp?id=75
^^ this is bad, it will foul the front mech, your chain, rear cassette and mech will wear very quickly. Keep the chain as straight as possible, this means using the larger rear sprockets on the inner front chainrings and the smaller rear sprockets on the outer front chainring.
I thought everyone knew this^^^ it is common mechanical sense....Chris71 said:
Basically the back appears to be okay, but the chain is fouling part of the front mech virtually all the time.
Learn not to cross chain^^ this is bad, it will foul the front mech, your chain, rear cassette and mech will wear very quickly. Keep the chain as straight as possible, this means using the larger rear sprockets on the inner front chainrings and the smaller rear sprockets on the outer front chainring.
....maybe not then, so good point
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