I've had my Giant Escape 2 for just under a year. I do a 10 mile daily commute (total) in the hilly/crappy-road Atlanta area. I weigh 205 and carry 10-20 lbs of stuff in panniers on a rear rack. So as I understand it, that's a situation that puts a bit of extra wear/fatigue on the mediocre stock wheels of this bike. Still, I was a bit disappointed when I broke two spokes within a couple weeks (both right at the spoke nipple). From a bit of web searching, and from going back to the LBS where I bought it, it sounds like I need to either rebuild the wheel or replace. What do y'all think? The LBS says it'd be about $75 to rebuild with new spokes. That's not terrible. Then again, I've grown very frustrated with this particular LBS and am looking around at other shops. I emailed another place, and they suggested upgrading to a higher quality wheel for $185--but I don't know the details yet of what they're thinking. Anyway, I'm just trying to cover my bases and ask around for different perspectives. Trying to find the right balance between a solution that will meet my needs (ie, not break spokes or axles!) without spending a disproportionate amount of money (the bike itself was only $500 new). For reference, the Giant Escape 2 has 700c wheels, rim brakes. I have a very new Continental TourRide tire on it that I'd like to keep using, and I'd rather not replace the Schrader-valve tube if I don't have to. Thanks!
The number one reason for spoke failure is uneven spoke tension, and this is a common problem with machine-built wheels, even when using decent components. However, those failures almost always occur at the other end of the spoke, where the spoke turns 90 degrees to meet the hub flange, so your failure point is a bit of a puzzle. At the price point of your bike, you will have had machine-built wheels, and they are a common site of cost-cutting by the manufacturers.
Given your total load, there isn't a reason to go with a very heavy duty rim, nor to 40 or 48 spokes. A properly selected rim built properly with 36 spokes should last you a long time without problems or necessary adjustments. I just looked at Universal Cycles, who, among other things, has a custom wheel building shop that I have used. Their specs are no more than 0.5 mm of vertical and lateral movement and no more than 5% tension variance between spookes. Assuming that you re-used your existing hub and built a wheel with 36 stainless Wheelsmith spokes on a Mavic rim ( I arbitrarily chose the Open Elite Rim, but I don't know your tire size), the cost would be $120.30 plus shipping. That wheel ought to last you for at least a few years without any problems, and not likely even any spoke adjustments. In the event of a problem, you probably have a custom shop nearer to you, and the cost for hand building doesn't vary that much between builders, so you may want to check one out. I was in Ohio when I ordered my first hand built wheel, and was concerned about the distance (Oregon) when I ordered the wheel, but I haven't had a problem with any of the wheels, so the distance hasn't been an issue.
Some years ago when I was having wheel problems a cycling friend told me about hand built wheels, which I of course dismissed as elitist poppycock. But I was not having any success with anything else, including my LBS at the time, so I gave it a try for my commuter's rear wheel. The cost was reasonable, it didn't take long, and I now have over 13,000 miles on that wheel. I check the spoke tension and truing every so often, and I have not had to adjust it or have it adjusted. I have replaced the cassette twice, the derailleur once, and the brake rotor once, but nothing with the spokes or rim. It made a believer out of me, and since then it has been only hand built wheels for me. I may sound like a shill for wheel builders, but I place a high premium on reliability, particularly for my commuter, and I wouldn't have believed it if I hadn't seen it. I had the same concerns regarding the cost (my hybrid commuter out of the box was about $850, with a mixed bag of wheel components but lousy machine builds), but from a reliability standpoint it was probably the best money I have ever spent on bicycling.
You're not peloton-svelte, so I'd recommend a 36 spoke rear wheel/rim that otherwise duplicates all the measurements of the stock rim.
More spokes is a stronger-better wheel. 40 and 48 spoke is also possible, but they're a bit more rare.
A $500 USD bike is better than a BSO, but it will still have average wheels at best. An upgrade to the rear wheel is a good idea, if you like the bike and it fits you well. Shop around, you might find a pair for fair price, being not a lot more than a single.
The other option is to buy a rim/spokes/hub separately and have a good LBS build it for you.
Yup, you are on the right track, but it sounds like the shops you're dealing with may be looking at the "heaviest duty" solution, and from your description, you may be able to get away with a lighter duty one. To start with, breaking a couple spokes isn't so bad. Those may very well be the only 2 spokes you ever have to replace on that bike, and if not, it may do you well to have a couple spares and carry a spoke wrench and learn how to true your wheel.
Outside of that, it kinda depends on the wheel you already have and what you want. For my money, the two quickest and cheapest ways to get a stronger wheel are to get one with(or upgrade to) stainless spokes, and if you're already there, start looking at double wall rims or wheels. I would think you should be able to find a decent set of wheels that would hold you for about $80-110 depending on your market and whether you want to shop online(which I usually don't recommend for this, since a shop will do a quick true-up on wheels they are selling).
One more piece of advice, as Batman mentioned in the comments, make sure you're inflating your tires to the recommended inflation. It really does help minimize damage.
Wheels are where low end bikes really cheap it. Most people don't put many miles on a bike.
You are getting into a mid range bike but wheels are still lower end. At $100 you get a decent wheel but at $200 US I think you get the best miles / dollar. Lower end wheels are not built to take miles.
I suggest you take tube as deciding factor off the table.