There are a few measurements that you need to be aware of regarding boat trailers. To get the measurement it's easiest if you remove your tires and wheels. It's also helpful to have a friend hold one side of the tape measure but not absolutely necessary. To obtain the hub face measurement, first hook your tape measure to outside art of hub, that is the part of the hub that is facing the wheel. Measure across the axle to the exact same spot on the opposite side. Be careful not to measure to the inside of the hub, only the outside. This is the primary measurement that is needed. The rest of the measurements below are alternative measurements that can be used to arrive at this measurement.
This measurement is critical. If the springs are misplaced due to bad measurement, you can end up bending the axles. This one is difficult to do alone. Have a friend hold the tape measure end right in the middle of one of the springs while you extend to the center of the opposite spring. If you don't have a friend, then you can cheat by hooking the tape measure on the outside of one spring and then extending it the inside of the opposite spring.
If your axle is broken outside of the spring, there is still hope. You can still get the hub face measurement provided:
If that is the case, take the spring measurement as above.
Then, on the good side, measure from the spring center to the outside hub face. Multiply that measurement times two and add it to the spring center measurement to obtain your hub face length.
If you don't happen to have the hub on the good side of the broken axle but the good side is otherwise unharmed, you can still get the measurement.
Again, we assume that the axle is not broken between the springs. Get the spring center measurement as above. Now, on the good side, measure from the center of the spring to the tip of the spindle and multiply that by two and add to the spring center measurement. For 2000 and 3500 pound trailers, subtract 5 inches from that total to arrive at the hub face measurement.
To do this one, you have to pull the wheels off of both sides. Now hook your tape measure on the outside of one spindle and extend to the same point on the opposite side. Once you have that measurement, subtract 5" for 2000 and 3500 pound trailers and you'll get your hub face measurement.
If any of this is at all confusing, give us a call at Champion Trailers at 800-229-6690 and we'll be happy to answer your questions or step you through it.