The 13-0 Buckeyes have two tough games ahead of them, but this has to be one of the most complete seasons pre-bowl game put together by a Big Ten team in decades.  Each of the 13 wins have been double-digit margins.

Considering only undefeated Big Ten teams pre-bowl game:

2012 OSU had a lot of escapes within a weak schedule.

2006 OSU included a defensive meltdown against TTUN with the 42-39 shoot-out and a 17-10 win at Illinois.

2002 was a season of escapes (and may always be my personal favorite because of that)

1997 TTUN was driven by defense and had 3 wins by 7 or fewer.  

1994 PSU rolled but had 3 wins by 7 or less.

1979 OSU had close wins at Minnesota, vs NW, and at TTUN

1975 OSU rolled everyone but top 10 PSU and top 10 Michigan (both of whom they beat by 7+).  Definitely a candidate...

1973 OSU and TTUN tied

1971 TTUN won their last two by 3 points each

1970 OSU had a tight 10-7 win at Purdue.

(1969 OSU if not for the worst game ever would likely be our best candidate.)

1968 OSU dominated everyone but did have 3 wins by 7 or less.

1966 MSU tied ND and only won at OSU by 3

1965 MSU dominated with double-digit wins all season but had a 14-10 win at highly ranked Purdue.  Another strong candidate...

1961 OSU tied TCU

1954 OSU had 3 wins by margins of 8 or fewer

1948 TTUN had two single digit wins but only 4 of 9 teams scored on them.  TTUN outscored opponents 394-53.  Another candidate...

1947 TTUN dominated all season aside from 2 wins by just 7

1944 OSU won every game by double digits until their 18-14 finale vs TTUN (OSU was not a National Championship team in 1944 because of Army's great season)

1943 Purdue ran the table but had 3 single-digit wins.  TTUN actually would have had a slate of double-digit wins had they not scheduled and lost to 1) ND

Beyond this we get to the era when the great conference champion teams outscored opponents by ridiculous combined scores of 300-16 or whatever, but typically had 1-3 very close games in a 6-0 or 3-0 fashion.