85/15 in millimeters
On a card whose left and right borders add up to 6 mm, 85/15 centering means a 5.1 mm border on one side and 0.9 mm on the other, a difference of 4.2 mm. That's easy to see at arm's length.
Questions
Can a 85/15 card get a PSA 10?
Not with a 85/15 front. PSA's Gem Mint 10 needs about 55/45 or better on the front. On the back, 85/15 is also past the 75/25 back limit.
Is 85/15 good centering?
85/15 is well off-center. On the front it limits the card to middle or low grades, and on the back it's past the 75/25 a PSA 10 allows.
See every ratio on the centering chart, or read the full centering requirements.