  We examine the radius evolution of close-in giant planets with a planet
evolution model that couples the orbital-tidal and thermal evolution. For 45
transiting systems, we compute a large grid of cooling/contraction paths
forward in time, starting from a large phase space of initial semi-major axes
and eccentricities. Given observational constraints at the current time for a
given planet (semi-major axis, eccentricity, and system age) we find possible
evolutionary paths that match these constraints, and compare the calculated
radii to observations. We find that tidal evolution has two effects. First,
planets start their evolution at larger semi-major axis, allowing them to
contract more efficiently at earlier times. Second, tidal heating can
significantly inflate the radius when the orbit is being circularized, but this
effect on the radius is short-lived thereafter. Often circularization of the
orbit is proceeded by a long period while the semi-major axis slowly decreases.
Some systems with previously unexplained large radii that we can reproduce with
our coupled model are HAT-P-7, HAT-P-9, WASP-10, and XO-4. This increases the
number of planets for which we can match the radius from 24 (of 45) to as many
as 35 for our standard case, but for some of these systems we are required to
be viewing them at a special time around the era of current radius inflation.
This is a concern for the viability of tidal inflation as a general mechanism
to explain most inflated radii. Also, large initial eccentricities would have
to be common. We also investigate the evolution of models that have a floor on
the eccentricity, as may be due to a perturber. In this scenario we match the
extremely large radius of WASP-12b. (Abridged)
