Lakeside notched a third successive home win as the Hammers saw off Leicester 57-35 at Purfleet.
Andreas Jonsson top-scored for the home side with 13 points as they moved up to sixth in the table, with Jason Doyle replicating that total for the Lions.
In the Premier League, Edinburgh moved ahead of Somerset on points difference at the top with an emphatic 64-28 win over Plymouth in a match delayed by the late arrival of several visiting riders due to traffic issues.
The home side had three riders unbeaten - reserve Erik Riss with paid-18, Craig Cook with paid-15, and guest Nick Morris with paid-12.
