There are 44 Trophies that can be collected.

Bronze

Ride Your Way
Host a multiplayer race.

Online Dominator
Win 21 races online.

Hometown Champion
Win on your home circuit in Career Mode. Not unlockable by Co-riders.

DIY
Customize every aspect of your bike and rider. Not applicable to Co-riders.

Dinner with Friends
Win a race against a full grid of human riders.

Collected
Obtain a full complement of sponsors. Not unlockable by Co-riders.

Running the Economy
Spend a total of 10 minutes slipstreaming in Challenge Mode.

Spick and Span
Win with no penalties, all clean sections, no crashes, no collisions. Not unlockable by Co-riders.

Voltaire
Successfully perform every type of dynamic objective. Not unlockable by Co-riders.

Big Business
Hire a full complement of staff in Career Mode. Not unlockable by Co-riders.

Methodical
Get every type of time bonus within the same lap on Challenge Mode.

Show Off
Do a wheelie lasting at least 500 feet on a motorbike. Not unlockable by Co-riders.

Time Hoarder
Finish a race with more time than you started with without using any continues in Challenge Mode.

Dedicated
Use your own Career Mode motorbike and rider in a multiplayer race.

125cc World Champion
Win a 125cc class season. Not unlockable by Co-riders.

A Class
Obtain an 'A' rating in all sessions of a race weekend in Career Mode. Not unlockable by Co-riders.

Victory
Your first win. Not unlockable by Co-riders.

Ding
Obtain a reputation level of 1 in Career Mode. Not unlockable by Co-riders.

New Kid On the Block
Obtain a reputation level of 5 in Career Mode. Not unlockable by Co-riders.

Self Sufficient
Obtain a reputation level of 10 in Career Mode. Not unlockable by Co-riders.

Admired
Obtain a reputation level of 15 in Career Mode. Not unlockable by Co-riders.

Professional
Obtain a reputation level of 20 in Career Mode. Not unlockable by Co-riders.

Consistency
Earn first place 10 times in any mode. Not unlockable in Splitscreen Mode or by Co-riders.

Addicted
Earn first place 20 times in any mode. Not unlockable in Splitscreen Mode or by Co-riders.

Stabilisers Are Off
Ride over 100 miles. Not unlockable by Co-riders.

Oil Change
Ride over 200 miles. Not unlockable by Co-riders.

Bedded In
Ride over 400 miles. Not unlockable by Co-riders.

Piggy Bank Full
Amount 50,000 in savings in Career Mode. Not unlockable by Co-riders.

Fixed Overheads
Spend over 100,000 on staff wages in one pay day. Not unlockable by Co-riders.

Savvy
Spend over 100,000 on upgrades. Not unlockable by Co-riders.

Leader of the Pack
Qualify for pole position. Not unlockable by Co-riders.

Silver

Star
Obtain a reputation of 25 in Career Mode. Not unlockable by Co-riders.

Untouchable
Earn first place 30 times in any mode. Not unlockable in Splitscreen Mode or by Co-riders.

1st Service
Ride over 1000 miles. Not unlockable by Co-riders.

125cc Elite
Win 125cc class season on Insane difficulty. Not unlockable by Co-riders.

Moto2 Elite
Win a Moto2 class season on Insane difficulty. Not unlockable by Co-riders.

The G.O.A.T.
Win a MotoGP class season on Insane difficulty. Not unlockable by Co-riders.

Been Practicing
Win any race on Insane difficulty. Not unlockable in Splitscreen Mode or by Co-riders.

Hoarder
Amount 100,000 in savings in Career mode. Not unlockable by Co-riders.

Staff Liability
Spend over 200,000 on staff wages in one pay day. Not unlockable by Co-riders.

Gold

Superstar
Obtain a reputation level of 30 in Career Mode. Not unlockable by Co-riders.

Hardcore
Complete a full Challenge Mode season without using a continue.

World Champion
Win a MotoGP class season. Not unlockable by Co-riders.

Platinum

The Ultimate Prize
Complete all other Trophies.

http://www.ps3trophies.com/forums/showthread.php?t=55180