The Sussex captain made his highest score of the season as his team, chasing 357, were dismissed for 293. Sussex have now gone seven Championship games without a win, while Leicestershire enjoyed their first victory in six matches.
Wells' fourth Championship century of the season contained 22 fours and two sixes, and came from 222 deliveries. He was ninth out, and the match ended with the next ball when the off-spinner Adrian Pierson had Nicky Phillips caught at mid-wicket to finish with 4 for 96. He was well supported by Gordon Parsons, whose pace bowling took 3 for 58 in 23 overs.
Surrey moved off the bottom of the table with their first Championship win for more than two months. A career-best return of 4 for 43 by Richard Nowell took them to a welcome 171-run victory over Nottinghamshire at Guildford.
Nottinghamshire never really got going when they resumed on 37 for 2, needing an unlikely 407 more to win.
A freak wicket started their decline shortly after midday. Tim Robinson drove a delivery from the 19-year-old Nowell straight to silly point, where the ball hit Nadeem Shahid's heel and looped to Graham Thorpe at short extra cover.
Robinson had made 52 and was looking well set. But once he and the acting captain, Paul Johnson, were out, Nottinghamshire subsided to 272 all out.
Somerset won their fifth Championship match in six games thanks to Mushtaq Ahmed. The leg-spinner finished with match figures of 8 for 216, and then struck a quick-fire 62 as Essex were beaten by seven wickets at Southend.
Mushtaq was promoted in the batting order after Somerset slipped to 54 for 3 in pursuit of a target of 138. His 42-ball innings was an exhibition of attacking strokes, with the off-spinner Peter Such being hit for three sixes.
Essex failed to collect a single point from the match for the first time in their history in a match uninterrupted by rain.Reuse content