Bicycle Mechanics - Question re busted spokes / wheel rebuild

Question: I've broken a couple of spokes on my rear wheel and wonder if I should keep replacing, or if its time to rebuild the wheel.

I'm getting back into riding after many years off. Bought a used Specialized Allez with the intention of riding myself back into shape, then (if?) indulging in a little bike lust and buying something hotter. The wheels are ok, but not great. Richie hubs, Mavic medium profile rims (I dunno which models). fifteen guage spokes. After a 100 miles or so I broke a spoke on the cassette side. Replaced it, no biggie. 150 miles later I broke a second spoke, also on the drive side. Replaced that too. But now I'm wondering if this is an indication that either the spokes are too weak for my somewhat portly (195lb) frame, or if they were not tensioned properly, or if they are just old, or if 15 guage spokes suck. Wheel is good and true, and spokes all seem to be tensioned properly...judging by sound and feel not w/tensionometer.

Question is, is this likely to keep happening, in which case I should rebuild the wheel, or does this sometimes happen? I've broken spokes before, but usually on my mountain bikes when I've obviously stressed it with jumps and the like. My riding on this bike has been pretty vanilla, no jumping curbs or hitting potholes etc

Also: if I rebuild, should I used the same 15 guage, or should I go up to 14 gauge?

Thanks.

PS: I'm fat, but I'm not THAT fat.

How many spokes are on those wheels? You shouldn't keep breaking spokes on wheels, it might be a crappy wheel build or you're just too heavy for it.

32 on the rear. Its not a particularly light or delicate rear wheel, although I do wonder about the 15 guage spokes.

15 gauge spokes are not typically used on the drive side of a rear wheel. Given your stature, these are a little light. However, it could be that they are under tensioned. Spokes without enough tension will tend to move around enough to snap off the elbow near the hub. This might be what you are seeing. Without a spoke tensionmeter, its hard to tell you to tighten them up or not. If you know how to true a wheel, you could go and put about 1/2 a turn on each spoke, true the wheel, and then see what happens. Unfortunately, you probably already have other spokes that are ready to go. Consider having the wheel relaced at the LBS using 14/15/14 gauge spokes (name brand like DT, Wheelsmith, Sapim).

My Fuji had A-Class Alex rims and hubs. After about 2000 miles I began to break driveside spokes on the rear. After 4, I had my local bike guru and friend rebuild the rear by hand. Since then, they have stayed very true and I haven't broken any more spokes. He used good quality spokes and has 100s of wheels in his experience. I think it cost 50 or 60 dollars.

Thanks for the responses. The bike and wheels are several years old, but are in pristine condition so I don't think they have many miles on them. All the same, I don't know their history. The spokes are breaking at the elbow near the hub -- but isn't that where they always break, if they're going to break? Maybe the entire wheel is under-tensioned as you suggest. I'll give them all a half turn, but don't want to collapse the thing. I'm OK at truing wheels, but really I'm only guessing as to the proper tension. Have replaced spokes etc, but never built a wheel.

I'll ride on it some more, but I'm thinking I should have the wheel rebuilt.

Many thanks.

I'm not a fan of straight 15 gauge spokes. Most hubs are drilled for 14 gauge spokes so the smaller diameter 15 gauge can wiggle around in the hub flange holes too much. My favorite spokes to work with are 14/15/14 gauge. If you want to save a few bucks, use straight 14 gauge.

If you are going through the trouble of relaceing the wheel, make sure that your rim is in excellent condition and is a brand and model that has a good reputation.

The spokes are breaking at the elbow near the hub -- but isn't that where they always break, if they're going to break?

True, but they usually break on the non-drive side, at least on a road bike, if insufficient tension is the problem. Since yours are breaking on the drive side I agree with the others and suggest that you replace all of the spokes on the rear wheel with 14-15-14 spokes. Straight 14 gauge spokes may be good enough but the double butted spokes should be better because the skinny middle part of the spoke has more elasticity and helps protect the "J" bend from impact shock (plus they look kool and chicks dig'm).

Al