I recently built a new bike using a compact 2x10 drivetrain(48/34 front, 12-27 rear). I could have gotten away with a 1x10, but I occasionally need to use the 34t ring when carrying heavy loads. Given that, I spend a good deal of time in the big ring, and mostly ride using the 5 largest rear cogs.

Things are pretty much dialed in, but if I backpedal for more than a full revolution of the crank, the chain skips off the largest 2 cogs of the cassette and eventually jams up. When sighting down the chain, I can see that the chainline is way out in the big/big combo.

It appears to me that I can address this issue several different ways:

1) Use a shorter bottom bracket spindle. I can probably get away with moving the crank about 4mm inboard without any ill effects.

2) Go with a smaller big ring in the front. Putting a 46t ring on would probably allow me to spend more time in the middle of the cassette, and I'd be less likely to need a big-big combo.

3) Learn to live with it, spend less time cross-chaining.

Thoughts?