New to the site. Just purchased Giant roam 3 yesterday. Love so far. I got this knowing it didnt have disc brakes, but could upgrade to them. I purchased it on sale for $385 giving me flexibility to do so. I just so happened to get a amazon gift card for xmas and i dont shop on amazon. I want to use this card to upgrade the rear brakes to hydraulic disc. The same brake is on amazon for less than $100 that are used in the roam 1. Has any body does this transformation, and could I do it myself? Would the cables fit b/c it is not bike specific on amazon. Is it a fairly easy thing to do? Should I buy and have LBS install. Thanks for your help.

First,pics or a link would have really helped. Is this your bike?
Roam 3 (2015) | Giant Bicycles | United States

From the hi-res pic,it looks like you have a rear disc mount on the chainstay,but I can't be sure if there's one on the fork. If you're only going to install one disc brake,you'd do best putting it on the front since that's where the majority of your stopping power will be. The only plus I can see to putting a hydro disc on the rear is you'll have one less brake that requires adjustment;it won't improve your stopping ability at all. Additionally,I can't tell if your bike has disc hubs or not. Look at the left side of the hub(opposite the cassette),do you see 6 threaded holes going around it? If not,you'll need to either replace the wheel,or have it rebuilt with a disc hub.

Unless you have disc hubs and the caliper mount on your fork,I wouldn't consider this bike to be a good candidate for adding discs. For the amount of money involved,you prolly would've done better getting the next model up which has discs and better parts.

You'd also need a new shifter since the hydraulic brake lever isn't integrated.

I'd not do it, front or rear. Your rim brakes will work just fine, enjoy your new bike!

I've been riding a 2012 Roam 0 with Avid hydraulic discs for the last month. I don't notice a difference in stopping power over rim brakes. Of course, I ride early in the morning on the street and seldom do any hard braking. After researching how to bleed the brakes, which is more complicated than automotive brakes, I won't get discs next time. My LBS charges $50 per wheel to bleed them. The DIY kit is around $50. I don't think changing to discs would be worth it.

Cost prohibitive to change, IMHO. brakes, levers, wheels, etc..... Better to buy them when new, or stick with Vbrakes.

Unless you ride in the rain often, I wouldn't bother with disc brakes, and as others have noted, especially as an upgrade, it is not cost effective because of the number of additional changes needed.

I would suggest a tire upgrade to the best tire for whatever conditions you ride. I ride a lot of crushed stone and gravel, and some pavement, and I notice that my current favorite tire is available on Amazon, the Clement X'Plor USH. It is 35mm, and I am riding the 60 tpi version, but my next tire change on that bike will be to try the 120 tpi version, since they should be even better. They roll well on pavement, but provide a great ride and traction on crushed stone and gravel. I ride almost exclusively in dry conditions, so I can't say how they perform in the wet... But, even if not these tires, there is probably a high quality tire available that would fit your needs and be a definite improvement.

Along with the tires, there are two components that are relatively crappy on almost any new bike because many riders have their own favorites, and they are very personal choices... Therefore, you may want to consider a better saddle (unless the one you have works great for you), a nicer set of pedals, and possibly (depending on your spending limit) get shoes and go clipless.

Almost anything else, unless required for your riding style (lights, rack etc) is probably not gong to be cost effective.

Whatever you decide to upgrade, enjoy the ride!

Discs aren't hard to bleed at all. Play with the linked brake system on a Honda motorcycle sometime if you want to have real fun. Also,discs don't have more stopping power than V's,they just work better in bad weather,don't wear rims,and require less futzing. Hydros require zero adjustments,just pad replacement and bleeding every few years. Cable rim brakes require adjustments for pad wear,cable stretch,and the cables themselves need periodic maintenance and replacement.

I know it's hardly the sophisticated technical answer but hydraulic brakes just feel good. I don't know if the weight matters and I doubt the wet performance would matter to me either but I checked out some bikes with hydro's while I was shopping around and the levers were just so smooth and effortless to use. Too bad Hydraulic V-Brakes arn't more popular, something like the Magura HS33.

That's a valid point,hydro have better feel than cables because hydraulic fluid doesn't compress. Cable systems have a touch of stretch in them,as well as a bit of drag.

Not a fan of hydro rims. Rim pads are much thicker than disc pads because the pads are intended to wear instead of the braking surface(the rim),so they need to have more material. This means that as they wear down,more of the piston is exposed,which allows them to get dirtier,and the seals can get damaged. So you have to regularly clean the calipers to get proper life out of your seals. Discs don't have as much of an issue in this regard.