While Tom will be riding for the Louth-based Honda Racing team, Tim has left the Morello Racing team and will make his debut for Hawk Suzuki in the two races at Oulton Park.
Tom secured his first podium finish for Honda Racing at Cadwell three weeks ago which elevated him up a place in the rider standings to fifth.
With two races at Oulton, he will be looking for a couple of top results to retain his top five spot and, perhaps, edge closer to the top four.
Alex Olsen holds fourth place, but has now left the championship to join Smiths Racing in the British Superbike Championship so Tom could snatch fourth place with two good results.
Tim announced he was leaving his team and is anticipating two good results with the Hawk Suzuki.
He said: “I’m excited to get back on a Suzuki and I must thank the team for this opportunity at such short notice.
“Although they will help me with set-up, I will be running the bike myself and will have my own mechanics.
“I’m looking forward to Oulton Park this weekend and hoping for a couple of good top-10 finishes.”
Friday – free practice 11.40am and 3.55pm; Saturday – qualifying 10.35am, race one (12 laps) 2.40pm; Sunday – race two (14 laps) 2.55pm.