Run 215/75-14 tires. They fit, and will get you a 7% rpm reduction. And you will need new tires sooner or later, so your gear swap will be "free"

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)