Product review (3 stars): DIY alternative
I thought long and hard whether to buy this $70 tool and decided against it. I could not get myself to buy something I'd likely use just once! So I made my own, as follows:
1) Two L-shaped carpentry brackets
2) 3 small 1 inch bolts and nuts
3) a piece of coat-hanger wire
Total cost: approx $7. Time to make: 20 mins.
The first picture shows the tool in the closed position. The elastic is just there to simulate the spring you will need to expand. The second picture shows the tool in the open position. Note how the coat-hanger wire allows the tool to remain locked in the open position. This is very useful as you can then remove/re-install the hub's circular wires using BOTH hands. The third picture shows the nuts that grab into the circular extremities of the spring. The external spring is easy to remove, The internal one is a bit more hidden, but if you position the tool correctly expanding the spring is just as easy.
So for those DIY folks, make your own tool!