I'm slowly getting into self-supported touring; slowly due to time commitments. I have an overnight ride in July, a 5 day ride next year, and a 650 mile ride in 2017. I currently ride a Diamondback hybrid with 700 x 28 tires. It's all I can afford for several more years. I would like to replace my rear tire (32 spokes) with one with 40 spokes before the 650 mile ride. I currently weigh 240 (working on it), so me plus gear would be a heavy load. So my question is; can you recommend a good place to buy such a wheel?