I recently stumbled on a link to a tire substitution chart, but didn't bookmark it. It was unique in that you entered your current tire size at the top, then it showed a whole page full of tire sizes, showing the differences in specs for each from the current tire. In particular two columns: 50 mph (current) = XX mph (sub), and 1000 miles (current) = xxx miles (sub).
Nope. You enter current tie size at top, then it shows a whole page of dozens or tires, and how they all compare in, chart format, to your current tire. And it sorts them, with best diameter match at top,
Discount Tire Direct will give you plus zero tire sizes when you search tires by car model, if you want a thinner or wider than stock tire. Then use their, or another, tire size calculator to find the exact percent difference. It will be small. Mostly under 1%.
That ejelta.com link doesn't match anything for 165/70-13 (Civic VX) size. ;-(
Wow, those were the tires I bought the YARDIS with! It turned out soon that these were the culprits behind the odometer's error, because they were of smaller diameter than the default 155/80-13. I replaced them soon, I needed winter tires anyway...
Looking up the mentioned calculators I even learned that 165/75 would have been a good replacement with negligibly different diameter. I don't know why the previous owner chose 165/70. Probably she just didn't care.