Do yourself a favor and do a search on the forum for "bike rack." (See the Search field at the top of the page.)
You'll learn more than you want to know, and will understand the can of worms you have just opened. This subject creates almost as much debate as the diesel vs gas or Ford vs Chevy vs Ram debates.
The basic answer is: probably not a good idea to just bolt a bike rack onto your 4" bumper.
I've had beefed up 2" receivers welded to the frame and bumper on my two TT's.
You can also hang your spare under the TT with BAL hide-a-spare. See here:
Installing BAL Hide-A-Spare on a Mini Lite
1988 Coleman Sequoia - popup (1987-2007)
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10