gear shifting - avoiding cross chaining for newbie.

[goldTopDeluxe]

So - I got 2 rings at the front, 1 big, one small. and then 9 different positions available at the back.

I know that i'm not supposed to use big and big, and small/small.. but what combinations can I get away with that dont stress the gears/cross chain? I've seen guides like the image below which depict 3 chain rings at the front, but nothing for a bike with 2 chain rings?

Can i get away with using the big chain ring all the way up to the second from largest cog etc - or not go past the 3rd largest etc? hope the question makes sense.

.. yes.. i'm an absolute newbie /img/vbsmilies/smilies/rolleyes.gif

 

[oldbobcat]

Don't over-think this. Your schematic shows a triple but your narrative says double. With a 9-speed double don't do small-small or big-big. And don't worry if you cross over. If the bike's tuned properly, all you'll have is a mildly unpleasant experience emanating from your drivetrain. The cross-chaining police will not arrest you without a warrant.

9-speed doubles are about the most foolproof setup you can use. The rings are ramped and pinned, the cassettes are ramped, and the chains are pretty darned flexible and durable.

 

[An old Guy]

Cross chaining is a made up issue.

You have 18 combinations of chainrings/gears. You can use them all.

Properly adjusted components will let you shift into any combination and will keep you there.

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There are two reasons to not "cross chain":

1) You can not shift from the big/big to the big/bigger

2) You can not shift from the small/small to the small/smaller.

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One reason to "cross chain":

In a race on a climb to the finish shifting from the big/big toward the big/small is the best way to sprint. (None of this shifting the front from the small to the big when the sprint starts.)

 

[oldbobcat]

Originally Posted by An old Guy .

1) You can not shift from the big/big to the big/bigger

2) You can not shift from the small/small to the small/smaller.

I like this.

Cross chaining really is a personal issue. Many people on this forum will take issue with this. For example, I do use big-big on my 10-speed double setup, but avoid small-small religiously for reason #2 and because the chain rubs lightly on the inside of the big ring. On another forum that will remain unnamed this last statement caused pages of hate mail and condescending insults.

Triples can be more of a hassle because of the tiny inner chainring and the span caused by that third ring, but far more damage has been done to drivetrains by dirt, lack of lubrication, and general lack of maintenance than by cross-chaining.

 

[davereo]

On my 9 speed double I use big/big. I never use small/small. I only shift to the small up front on long steep grades and tend to ride the center cogs while doing so.

 

[An old Guy]

Originally Posted by davereo .

On my 9 speed double I use big/big. I never use small/small. I only shift to the small up front on long steep grades and tend to ride the center cogs while doing so.

That is exactly what people do. They come up with a way to shift that is easy for them. Few of us have enough power that chainline angle or cross chaining matters.

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I use a 50/20 for most of my riding. I have a cassette, 16-30, that puts the 20 in the center of the cassette. My chain line seems reasonable.

If I used a 12-21 cassette like many of the racers here use, I would be in the same 20 (or so) and be cross chained as they are as they pass me. But few of them are strong enough that it matters.

 

[danfoz]

Originally Posted by oldbobcat .

far more damage has been done to drivetrains by dirt, lack of lubrication, and general lack of maintenance than by cross-chaining.

+1

 

[alienator]

Cross-chaining can increase wear a bit on chains, cogs, and chainrings and make some noise, but that's about all you'll surffer while doing it. Given the very little time (as a fraction of the total time they ride) that most anyone spend extremely cross chained, it's even less of a worry.