The hosts were dominant from the off, Jayden Benham claiming an overthrown five-metre line-out before the ball was spun left for Isaac Tokura to burst through for the opening try.
James Gilman provided the extras, and Pett-Ridge added the second soon after.
The full-back – who grabbed a treble upon his return from concussion protocols for Berkshire Under 20s three weeks ago and a double on loan at Maidenhead 2nd XV on Saturday – chased down his kick before sensationally catching a charge-down to dive under the posts.
Gilman made it 14-0, and Louis Pereira was next to benefit from another kick as he hoovered up the ball for another converted try.
It was one-way traffic at Old Bath Road and Reading University fresher Ethan Bassett showed his quality with a brilliant 50-metre finish on the left, a strong hand-off precipitating a pacy finish.
More strong carries led to hooker Harry Bicknell finishing out wide, and Gilman maintained his perfect record from the tee for 35-0.
Brilliant Pett-Ridge bags treble
A moment of magic from Pett-Ridge then saw him flick a clearance kick into his own hands before beating four defenders from 40 metres for a sixth converted try.
Bassett’s fellow Uni wing Llyr Jones was next to scythe through, Pett-Ridge completing his treble from the restart following more superb Rams’ back play.
Gilman was now eight from eight and the lead 56-0, second row Paddy Jackson scoring an individual pearler before the break.
Tokura was a real handful throughout and again punched a big hole in the Chinnor defence, a superb cover tackle not enough to deny the centre off-loading to fellow Reading Uni man Jacob Kyte.
Matt Cox was now at fly-half and knocked over the conversion, but Chinnor continued to battle bravely and got on the scoresheet with a close-range try.
Ireland dots down before Chinnor consolation
With both sides ringing the changes the middle stages of the second period proved scrappy, Rams extending their lead late on as Ollie Ireland barged over.
Yet it was a gutsy Chinnor outfit who had the final word with the last play of the game, a second try added to as the second-half spoils were shared.
Rams Under 23s have two more festive fixtures at Championship sides Richmond on Saturday, January 3 (3pm) and Cambridge (Wednesday 7, 7.30pm).
Meanwhile Rams first XV close out their 2025 matches at Dings Crusaders on Saturday (3pm).
The club’s Christmas party then takes place at OBR from 7.30pm. To book tickets for just £5 including food, click here
