It is important that the spindle of the dynamo is aligned with the wheel axle, otherwise energy will be lost driving the dynamo (imagine what would happen in the extreme case of having the dynamo rotated ninety degrees; the dynamo wouldn't turn, but rather it would act as a brake). This does require a lot of fiddling around with the bracket (which as you can see, has three bolts), but it is worth the effort. A piece of string stretched taught works well for this task.
