My husband has a 1990 or 91 Technium 400 that has broken 4 spokes on the rear wheel in the past year, despite being re-tensioned and trued (by our LBS) a couple times. It's a Rigida 27" rim with a cheap Nakano hub. The bike is not high end, but it rides smoothly, fits perfectly, looks sharp, and was recently completely overhauled. So he wants to keep the bike, but lose the spoke problems. What would you say is the most economical fix?