The word retreading is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 14
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (64 words)
angered, angrier, arenite, darting, deraign, derange, dernier, detrain, dragnet, drainer, earring, enraged, gnarred, grained, grainer, grander, granite, granted, grantee, granter, greaten, greater, grenade, grinder, inerter, ingrate, integer, negated, nerdier, randier, rangier, readier, reading, reagent, rearing, regrade, regrant, regrate, regrind, reigned, reigner, reinter, retired, retrade, retrain, retread, retried, tangier, tardier, tarried, tarring, tearier, tearing, terrain, terrane, tireder, tradein, trading, trained, trainee, trainer, treader, treeing, triaene