51mm
Actually There are definitely trucks 7.65. Get those they are the closest.
yes you can
8.000
All skateboard bearings will fit ANY sized skateboard wheel because the bearing hole is designed to be the same in all wheels.
7.75 by 31
You should get a 7.75x3.15
You should always have the same size trucks
around 51mm-55mm, personally i would go for the 53's because that is in the middle
The smallest skateboard size is about 7 inches in width by about 24 inches in length. The skateboard is legal size for contests and events.
Yes, most bearings are the industrial standard of 8mm unless you have special longboard trucks, most notably Bear 1052's or 1045's or Bear Smokeys, these trucks run 10mm but are not very common. If you can take wheels off with the same wrench on both trucks, then they have the same size bearings.
7.75
If you street skate then you should get a 7.75 but if you are more of a vert person you should at least get a 8.