Originally posted by Hebiki
there are rumors (someone please confirm) that if you run your bearings without the seals, it'll be more free BUT maintenance is required more often.
If you are using the blue sealed Tamiya bearings then -yes - removing the seal will improve efficiency slightly..but...it will be very easy for dirt to enter the bearing, so not only will the bearings require more frequent cleaning - but as soon as any dirt gets in the bearing becomes inefficient and your advantage is lost.
What you can do is remove the seal from one side of each bearing - the side that is not exposed to dirt - this will free the car up a bit plus the ouside seal is still there to protect the bearing from debris.
Or you could use standard metal shieded bearings which are a little more free running because the shield doesnt rub on the inside of the bearing....but again, be prepared for more maintenance.