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Is it considered cross gearing to be in the middle front ring and big rear cog? I could see where chain rub could be a problem but the chain is dropping to the small ring when I do this.
I don't use this combination for long periods but occasionally need it to get up a steep hill where I don't have time to shift to the small ring first..
Is this a problem for anyone else?
Jerry
 

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the catalan connection
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I´m afraid it IS

I don´t have it now here, but once I had a shimano drawing showing forbidden ring/cog combinations in their drivetrains.(well, if not forbidden, was something like "avoid them") I´m sure that one you ask was one of them. I would say even the next smaller sproket and the middle ring are forbidden too.
I just don´t look at which cog I am when riding. Just at the front ring and how parallel is the chain to the top tube.
 

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Vaginatarian
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HAUC2002 said:
Is it considered cross gearing to be in the middle front ring and big rear cog? I could see where chain rub could be a problem but the chain is dropping to the small ring when I do this.
I don't use this combination for long periods but occasionally need it to get up a steep hill where I don't have time to shift to the small ring first..
Is this a problem for anyone else?
Jerry
while its not ideal, it shouldnt be a problem, my bikes will use all the gear combos. but you put alot of stress on the deraillier and chain when you cross gear. worst is big to small & small to big . each shift would be that much less strain. That said, the front middle should be fine through all combos. I would say either the front deraillier is out of whack, or you could have a bent middle chainring tooth, or your chain could be too short
check the middle ring first, if its ok, try unscrewing the front deraillier adjuster 1/4 turn(at the lever) if it gets better but not perfect try another 1/4 turn untill its perfect. if neither one of those work check your chain length and make sure your rear wheel is all the way in the drop outs
 

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I wouldn't sweat it. Ned Overend even recommends occasionally going big big in a pinch. He says it isn't worth it in a race situation to shift down to the middle because of the risk of missing a shift if he's only going to need the big cog on the back for a few seconds. Of course, he is sponsored so what does he care about the premature wear he is causing.

Still, most everyone I know runs all the cogs on the back from the middle with no problem..

Drew
 

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ravingbikefiend
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I am a bit of a minimalist so only run one bike with more than 7 speeds in the rear and am pretty partial to riding SS and like my old SA internal gear hubs.

With geared bikes the issue of deflection arises when you run the chain at it's extreme limits... ie big ring and big cog or small ring and smallest cog. These gears exist in other combinations and will run with a straighter chain line which is easier on the drivetrain over the long haul and maximizes power.

You should be able to run any of the rear gears off the middle chainring without issues but you should limit the gearing you use when you are running the granny or big ring to reduce deflection.

For off road I don't find that a big ring is even needed so generally remove it and replace it with a light bash guard. This simplifies the drive and also adds ground clearance.
 
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