I'm looking to replace my 2008 comfort cruiser with a fitness style hybrid. My budget allows for maxing out at $500 (on the new fitness hybrid bike itself). I ride rails-to-trails with the kids, charity rides, and would like to commute to work on occasion (15 miles round trip).
Ultimately the decision comes down to bike feel, but with the limited budget, am I better to put my money into upgraded components or disc brakes?
Typically, you don't need disc brakes on a bike which lives on the road or other nice surfaces. The primary advantage on the road is that you don't have to deal with wheel true-ness as much, and that they look cool. For wet weather riding, they can stop you a bit quicker, but with properly adjusted V-brakes, you can stop pretty damn quickly once you learn to feather the brakes. Discs also cost significantly more than rim brakes, and lower quality disc brakes (which you'll get in the ~500 dollar price range) will perform about as well as decent rim brakes. Your rims will last longer with a disc brake, but this is rarely to never an issue with a hybrid rider who doesn't put very high mileage.
The disadvantages of disc brakes are many -- for example, the front fork will be heavier since it needs to be more robust to handle the forces of disc brakes, and they weigh more than most rim brakes (weight weenie-ing isn't a big deal on a 500 dollar bike). Also, you'll have to take a lot of money (probably 20% of the budget) for the disc brakes, versus well less than half of that for rim brakes.
I think this article from John Allen makes a good summary with a nice point-by-point list of advantages and disadvantages. Generally, for most people, the rim brakes in this price range are the better choice and enjoy the better components all around (these days, you'll probably get 1 level up in the drive train and a carbon fork, which is nice). And your dollar will go a lot farther on a used bike than a new bike (another post recently described a used Trek 7.5 FX for ~450 dollars, which would be a fantastic non-disc option for a hybrid).
If you do want to get discs in the future, you do need a disc compatible frame and fork (excluding solutions like BrakeTherapy), as well as hubs on the wheels, so if you think you'll want them in the future, you probably should just buy the disc brake version (or buy the non-disc version, sell it and then buy a disc bike).
Side note: Hybrids generally have two distinguishing options between models from a given manufacturer: with/without suspension and with/without disc brakes. Generally, you should choose no suspension (unless your doctor tells you otherwise (i.e. you have severe back problems)) and fit decently large tires, and without disc brakes since for most riders they wont see an advantage unless the disc brakes are high quality and their riding conditions require it. Usually, cheaper hybrids run mountain bike groups on a flat bar setup, while more expensive ones run road bike groups on a flat bar setup. You also get carbon forks after you spend a bit of money, which is nice.
$500 is close call as the money in the disc is money they did not use elsewhere. I think you should evaluate the bikes you like at $500 and use disc as one factor. At $500 I would look for upgraded components.
At $800 you start to get a lot more disc.
Yes you will get disc on $500 bikes and you will get full suspension but that does not mean it was the best use of money.
Consider used if you know bicycles. I have picked up $1200 retail bikes used in great shape for $400. Some of the best deals are not disc as you get people that traded up to disc.
Also look for year end sales.
Good answer from Batman but I do like disc brakes on a road bike. At $500 disc brakes is probably not the best use of money but at $800 I would look for disc. I really like disc. Nice touch and good stopping power even in the rain. At $1000 like the SIRRUS ELITE DISC but that is clearly past your budget. Cyclocross are great fitness bikes and have disc. There you do find a lot of used as many racers will upgrade every two years. There you can get a $2000 retail bike for $800 but you take a risk of crash (bent) bike. Again past your $500. At $500 you are not going to get much past a good basic bike. But it is still a big step up from a department store bike.
I mean it depends on your current component spec, but I would tend to say disc brakes.
Good brakes will do wonders for your confidence riding, and will allow you to ride a broader range of trails, in terms of both trail style and technical difficulty.
That said, you can get set up with a set of Avid BB7s for a pretty reasonable price, and leave yourself some money to spend on other components as well. BB7s are a really good, affordable alternative to hydraulic brakes. And they're super easy to maintain.
(Note: I don't work for Avid, and I run Shimano hydraulics on my bike. I just think that BB7s are absolutely the best mechanical brake out there, and the best for beginner bikers based on cost, function, and maintainability).
I asked a similar question (similar, because people recommended a hybrid): What bike+equipment for a long daily urban commute?
The bike that I bought cost $700 after a discount for being last year's model, so it afforded/included disc brakes (and I like it very much).
The best thing about disc brakes is that they work:
For example, this comment:
Disc brakes stop when it's wet - I'm in Vancouver! Hydraulics have a lot more braking force - I can lock the wheel with a finger, with regular pads I had to squeeze hard and hope on the steep sections.
They're also useful, apparently, off-road in mud: if your rims get muddy.
If that's not the type, time, place, and speed of riding that you're doing, perhaps disc brakes are less important?
Now, I'm riding in the country-side instead of in traffic: so I don't need to do 'emergency stops'. Brakes are important, but perhaps more enjoyable are nice gears, and (especially) good tires.
