Gear changing question

jeannot18 · October 2009

John.T wrote:

If you paid to have the shifter fitted and it does not shift then take it back and get them to make it work. Almost certainly an adjustment issue but as they have fitted a new shifter and cables they should have left it working correctly.

Hi John, I paid to have the right hand shifter replaced acting on the cogs at the back but not for the left one. The LBS asked me if I wanted to replace the shifter on the left but said no, first to limit cost and secondly they told me that it worked ok. I have never tried it before as I always stayed on the small chain ring. On Sunday, I went out for a ride with a mate, and he told to change the chain ring, but it did not work. The derailleur is moving ok, and seems to push the chain against the large chain ring but it does not change over. I am pretty sure that it is a matter of adjustment. I need to find a video or a descriptif on how to do it before contacting the LBS again. Now that the rear cogs work I am enjoying my rides even more. Almost managed to stay with my mate during the ride except on the steep hills (he is an experienced rider), but what a difference with before the fix.
JC

John.T · October 2009

http://www.parktool.com/repair/readhowto.asp?id=75
Try this.
Bookmark these for future reference.
http://www.parktool.com/repair/
http://www.sheldonbrown.com/
Between them they answer most questions you may have.

jeannot18 · October 2009

Thanks John, will check tomorrow morning (can't view videos at work)

JC

jeannot18 · October 2009

Went for a ride this morning and I managed to change chain ring which is great. As I was approaching an hilly bit i started to change gear, going from the small cog to the larger one. When I reached the largest one the chain just blocked and almost made me come off the bike, just had to the time to unclip and stop the bike. What could be wrong? The other cogs work ok. Is this not a normal setup on the bike ==> Large chain ring + largest cog? In advance thanks for the help as usual.

JC

le_grimpeur · October 2009

Hey JC,

Sounds like the chain was 'crossed' and thus a jam was caused by too much tension as the chain was more diagonal than straight - and possible causing the sprockets to jam. The chain should be as straight as possible, thus Large at the front and small at the back (outer at front and outer at back) and conversely, small at the front (inner) and large at the back (Inner). As you go up or down the chain should be as straight as possible, so as you go higher at the back, once you've reached just over your half way point, change up at the front, then continue to go higher at the rear

jeannot18 · October 2009

le_grimpeur wrote:

Hey JC,

Sounds like the chain was 'crossed' and thus a jam was caused by too much tension as the chain was more diagonal than straight - and possible causing the sprockets to jam. The chain should be as straight as possible, thus Large at the front and small at the back (outer at front and outer at back) and conversely, small at the front (inner) and large at the back (Inner). As you go up or down the chain should be as straight as possible, so as you go higher at the back, once you've reached just over your half way point, change up at the front, then continue to go higher at the rear

Thanks for the tip Le Grimpeur, to tell the truth i nearly crapped my shorts.... Still I managed to enjoy the ride

John.T · October 2009

jeannot18 wrote:

Went for a ride this morning and I managed to change chain ring which is great. As I was approaching an hilly bit i started to change gear, going from the small cog to the larger one. When I reached the largest one the chain just blocked and almost made me come off the bike, just had to the time to unclip and stop the bike. What could be wrong? The other cogs work ok. Is this not a normal setup on the bike ==> Large chain ring + largest cog? In advance thanks for the help as usual.
JC

It is not recomended to use the big/big and small/small gear combinations due to the chain line extremes that LG mentioned but they should still work OK. With the bike on a stand if possible try to change into the big/big gear with care. If should go in easily. If it jams then it may be that your chain is too short. If the mech is pulled hard forward this is probably your trouble.

jeannot18 · October 2009

Thanks John
JC

Gear changing question

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