Wogster

There is a simple rule with wheels, lets start with a 150lb rider, and a 36 spoke wheel, as long as all the spokes are reasonably tight, it will last pretty much forever. However as you reduce the number of spokes, and/or increase the rider weight, spoke tension needs to increase. Depending on the rim, with some rims, for a given rider weight and spoke count, tension needs to be so high, that the spokes will pull the nipples through the rim.

Typically for heavier riders it's recommended to use strong rims, with lots of spokes, 36 is common, although 40 and 48 are possible. At 240-250 lbs you should be able to get away with properly built 32 spoke wheels, although the weight difference between a 32 spoke wheel and a 36 spoke wheel given the same hub and rim (with drilled differently of course) is probably around 30-50g. To look at this realistically, your bike likely weighs between 10,000 and 17,000g and the rider is 108,000 - 112,000g.

One point though, bicycles do not have enen weight distribution, the majority of the weight is over the rear wheel, so it needs to carry most of the load. So you can keep the current front wheel and just get a rear wheel built, or get a matching set made, with fewer spokes on the front.

Another consideration is tires, try and find out the widest tire you can fit on the bike, and make sure your new rim will handle that width, if you want to be able to go longer distances, wider tires at lower pressures can make riding more comfortable, then being stuck with a really narrow tire, at super high pressures.