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I've decided I want a disc brake, at least on the front, which seems a good enough reason to go bike shopping, but am I overlooking the possibility of fitting a cable pull disc brake to my current bike?

I've been using a ten year old road bike as a commuter. It has carbon front forks with road caliper/rim brakes and integrated Shimano road brake/gear levers.

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    It's probably unwise to put a disk brake on a carbon fork that's not designed for disks. You'd have to clamp the brake caliper to the tine, and it would put undue stress on the carbon. Even with a steel fork it's a bit iffy. Feb 23, 2013 at 13:22
  • Surly manufactures a steel disc-ready road fork that I highly recommend (though it is a touring fork so it has high trail.)
    – WTHarper
    Feb 23, 2013 at 13:55
  • @DanielRHicks How can you mount a disk break to a fork with no mounts available?
    – trailmax
    Feb 24, 2013 at 2:43
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    I am interested in why you feel you need discs. On the road, there is rarely a time I can think of that cheap cable discs have an advantage over high quality V brakes (Tandems, insanely long (like 1000ft) descents). Would upgrading the caliper brakes to high end V's would be a better choice?
    – mattnz
    Feb 24, 2013 at 3:40
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    @trailmax - With difficulty. People have done it (especially in olden days when disk brakes were only available as a DIY project). Either you devise a clamp (there may be some on the market) or you weld tabs to the fork. Feb 24, 2013 at 3:45

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No. You'll need a replacement fork.

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To install disk brake, you need brake mount tabs on your fork/frame. Like this: Disk brake mount on a fork

Original Image

And hub with mounts for brake rotor: Shimano Rear Hub with brake rotor mounts

I've seen a few attempts to create an adaptor for fork/frame to install disk brakev tabs. But none were good enough for real life.

So your best route is to replace your fork and front wheel/hub. But sometimes it is easier to get a whole new bike.

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I have disc brakes on two of my bikes (one road, one mountain), and swear by them in the winter. As others have suggested, you will need to buy a new fork at the very least. You should consider whether it's worth replacing a carbon fork, though, since it will add quite a bit of weight and you may find that this offsets the improvements of the brake itself. A lightweight cyclocross fork with disc tabs will not be cheap, and the beefier steel or aluminum ones are neither light nor free. If you can describe some more of your current specs, I might be able to suggest some options.

But to play devil's advocate, I would strongly encourage you to read a few articles to familiarize yourself with some of the issues that can arise when using disc brakes on a road bike. Firstly, this critique by the proprietor of Rodriguez bicycles. Take note of the photo at the bottom of a crumpled road fork which wasn't up to spec for the installed calipers. Secondly, a concrete example of what can go wrong if you use the wrong type of discs on a road bike and push them too far. Also beware that to use discs on the front, you will likely need a dished wheel (unequal spoke length on the two sides). This increases the complexity of a wheel build, making it more expensive and typically more prone to going out of true.

That being said, I strongly recommend discs for commuting. Discs are quieter and require far less maintenance overall, because I'm not sanding my rims down every time I ride on gritty roads in the winter. As long as you aren't riding up and down mountains and sustaining 35 mph downhill for long periods, you should be fine. Go with mechanical calipers -- hydraulic ones aren't worth the cost, or complexity for a commuter. You'll get all the benefits without the downsides. I suspect it's even cost-competitive, because disc pads and rotors last so much longer than rubber pads (not to mention the wheel wear issue).

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    Even though I'm no great fan of disks, "Tyler's" story is an example of foolishness -- you should never ride your brakes on a long downhill. Not in a car, not on a bike. Feb 24, 2013 at 14:02
  • Very true. And it also sounds like he was testing out a set of ultralight rotors which, not surprisingly, overheated. I think that one has to stop the ridiculous quest of shaving fractions of a gram when it comes to something as critical as brakes. The fact that it's possible to boil off hydraulic fluid is terrifying, though, and screams poor design. I'm happy with my cables. Feb 24, 2013 at 17:17

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