If the tire is new then it sounds like the caster is out of adjustment. Someone may have adjusted it lower due to tire where and then a new drive/steer tire was put on.
Your local Raymond dealer can help you with a manual or tips on adjustments. If you go to www raymondcorp com, remove the spaces and add periods then in the upper right side of the website you will see "Find A Raymond Sales and Service Center"
Also I know there are a few service guys on here that are familar with the Raymond line that should help you out as well.