disc brakes for bicycle

I have a bike similar to this http://cgi.ebay.com/21-Speed-Mounta...ameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting it has shimano rim brakes, i know that shimano makes disc brakes, ny question would i be able to put disc brakes on this bike? I really am considering riding my bike alot more to work this summer once the hours change ofer to the summer shify schedule, and i only live about 3 miles from work. The gas prices are killing me, now i dont want to project but right now the prices are what they were last year in august, i cant imagine what will they will be this year by august. The guy at the gas station said $4 for reg by july. any way i was also looking at one of these http://electricrider.com/crystalyte/images/phoenix_stream.mov video of an electrified bike, i found another site where they can be had for less than $250, but no where as fast, just an idea. what do you think about my brakes

That bike doesn't appear to have the tabs required to mount disc brakes, but I've gotta add that I've only found discs to be clearly superior to "real" v-brakes in two situations -- mud or ice on the rims. With water/rain the v-brakes still excel, and if you think about it, your rim is an even bigger disc brake already.

I'm not trying to dissuade you from putting disc brakes on. They're great in the muck, but what are you running now for brakes? If they're not Shimano XT (link to Shimano's picture) or XTR v-brakes then they don't have the parallel-push to them and they're going to be just as finicky as regular cantilever brakes to get set just right. The v-brakes are amazing and they're also suuuuuuper easy to set up. They're easy to swap for regular cantilever brakes (or the long-lever canti brakes that call themselves "v-style brakes" but don't come close).

I'd recommend getting a set of XT v-brakes and levers, replace the crummy cables with some fully-sealed ones and you should be saving money all around. And you won't need to replace your hubs either, which you'd need to do also to install discs.

Just a thought. I totally understand wanting real discs, though.

edit: Oh yeah -- disc brakes also don't pop your innner tubes like a rim-brake will if you're braking for a long time down a really long hill. Riding a rim brake can heat up your rim so much your tube pops. Then the fun really starts! This takes a hugely long hill, though. Not what you find in a city -- even SF isn't that bad. I don't know where you're heading to work, city or mountains.

I'll bite!

Disc brakes on bicycles require disc brake mounts on the frame and fork to bolt the calipers on the bicycle. The hubs on the wheels require flanges to bolt the discs to complete the conversion.

The bicycle in the picture can be converted to disc brakes for the front by changing the fork and front hub to disc specific parts and using a cable operated setup that is compatible with linear pull brakes (also called V-brakes) Avid makes excellent brakes for that purpose.

There is a catch (as always) The COST of making the conversion is more than that bicycle is worth. It is better to purchase a bicycle that is setup for disc brakes instead of trying to convert a bicycle to use them.

I'll be adding disc brakes to the front of my recumbent this fall. Already purchased a fork that has the mounts (MEKS Carbon AC $300) and a Phil Wood disk hub with a wheel built around it will run another $200+ and throw in the around $80 for the Avid disk and caliper the costs climb quickly.

I have no use for disc brakes in the back since I rarely use the rear brakes and most of my stopping power is provided by the front brakes. My Cane Creek Direct Curve 3 linear pull brakes with Kool-Stop "salmon" pads work very well so disc brakes on the back would be a waste. Just crossed 10,000 miles on my recumbent so the cost will be worth it to me.

+1 to what BentHeadTX said. [and I just discovered what "BentHead" means]

The places you really get the full benefit of disks on a standard configuration bike is while mountain biking in muddy/gritty or icy conditions. On the road, I don't think you'll see that much benefit.

change pads only

disc brakes are superior ANY time.
While there is always the same brake action, no matter if dry/wet/cold/snow. Any rim brake works very differently at these conditions (except for dry, of course), consistency is this called I think. Also the power You have to put into the lever for the same brake power is much less - very good on long descents.
BUT
the cost factor has already been mentionned (and the downside that they generally need more care for to work proberly).

imho there is no use to get a complete set. If a bike has no discs from the beginning, the only change that makes sense is to swap the front brake only (I drive my bike this way), or to get a new bike if one wants them front & rear.
But not possible here, You would have to change the fork.

The only way to go, that I see here, is to get better V-brake pads. Best I have tested are Ritchey brake pads "blue". They improve braking very much to the much harder and longer lasting Shimanos.
Get these, mount them, clean the rims and go.

I guess the disc option is out of the question now, I think i paid $169 for mine, its the 26" model, i do want to make it more comfortable to ride, the seat is horrible, i could put some road tires on it, since 99% of the riding will be on pavement. Can you reccomend me some good tires, mabey a better rear shock?

By the way thanks for taking the time to post the replies

+1 for the "real" V-Brakes...

My riding buddy tried out my recently upgrades brakes and said they were almost as good as his discs on his Bianchi BOSS.
They are a huge upgrade over stock cantilevers and well worth the small investment

2000xlt said:

Can you reccomend me some good tires, mabey a better rear shock?

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I think your intentions are more clear now, and I'm gonna go with suggesting you get a better mountain bike to start with. Putting money into/onto a frame of this quality level just won't pay you back by any measure. Plus, if you are considering a better shock that implies you don't like the way it soaks up the bumpies.

Get thee to a local independent bike shop or two, not a department store, not a Costco or big package store, and ask to ride anything/everything in your price range. You'll be absolutely amazed what's available and how much better it is than the Next.

Have them professionally fit you with the best helmet you can afford and you'll be one very happy biker! OH -- the LIGHTS, but you might already have those.

PS: You can probably give us your dream bike specs (price/suspension/terrain/whatever) and CPF, which is absolutely LOADED with avid/rabid bicyclists, will offer up no shortage of suggestions. Maybe there should just be an annual CPF bike buying guide, as this question seems to have been coming up for years now. It's always fun to tinker with answers, though.

(edit)
The questions are always slightly different, but...
examples:

nirad's thread
geepondy's thread
AlexGT's thread

Bike tires? Schwalbe Marathon 26x1.50 work great, can handle grass, light trails ect. as they are basically touring tires. They have kevlar belts under the tread to stop flats and the sidewalls are reflective so you can be seen from the sides. I use them on my sons and wife's bikes and they have not had a flat yet although they try by running over glass all the time. They cost around $25 each but are great tires for commuting, glass, mild trails or riding around the world.

I am partial to coil spring rear shocks since they don't break and require little maintenance. My rear shock is a basic one with an upgraded 750 lb. spring. You can try the cheap route by getting a stiffer spring to see if that works for you (?? $10-20 ??) For road use I prefer a stiffer rear shock.

It has been years since I rode a bike that uses an *** hatchet...errr... "regular" seat but I found the most comfortable one was a Brooks Champion leather saddle with rear springs. Not sure if the spring thing will be for you but if you keep the shock stiff and let the seat absorb the little bumps it might be a combination that will work for you. Cost? Bwahahahaha!

Lights for your bike? I use a Fenix L1D CE as a helmet light in turbo mode and it works very well. A simple tap on the rear switch will kick the strobe mode on which can be seen from a looooooong distance in the rain.

CPF'er bikes can cost less than the lighting systems on them.

binky said:

Have them professionally fit you with the best helmet you can afford and you'll be one very happy biker! OH -- the LIGHTS, but you might already have those.

PS: You can probably give us your dream bike specs (price/suspension/terrain/whatever) and CPF, which is absolutely LOADED with avid/rabid bicyclists, will offer up no shortage of suggestions. Maybe there should just be an annual CPF bike buying guide, as this question seems to have been coming up for years now. It's always fun to tinker with answers, though.

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I agree good "V-brakes" can be as good or better than disc brakes. You guys gotta try Hydralic Disc brakes. A touch on a the lever and you'll slow amazingly quick if you treat them like traditional brakes there's a good chance you'll get bucked off the bike. They are great for when you're hopping from rocks down hill on a trail.

One thing you gotta consider is this if this is a commuter bike there's a good chance it'll get stolen once you get all the good gear on it. I know because I got mine stolen, it had 2 locks but when you're indoors for 8 hours and someone scoped you out they know they have time to bust all the locks.

Guys, I posted a bit ago on recommendations for a $600 mountain bike. I read good things about the Specialized Rockhopper. Do you think it's worth spending more on the Rockhopper Disc (MSRP $660) with disc brakes versus the plain Rockhopper (MSRP $520)? Never experienced a bike with disc brakes.

geepondy said:

Guys, I posted a bit ago on recommendations for a $600 mountain bike. I read good things about the Specialized Rockhopper. Do you think it's worth spending more on the Rockhopper Disc (MSRP $660) with disc brakes versus the plain Rockhopper (MSRP $520)? Never experienced a bike with disc brakes.

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You said in your thread you want to ride trails. Your location shows Mass. I'm over here on the South Shore and Wompatuck is a total mess. Discs are the only way to go when you're riding through muck. For commuting or even XC racing in good weather I'd go with V-brakes, but the discs can't be beat for the bad weather.

The discs I have used are hydraulic from lever to pistons. The Rockhopper is given cable-actuated discs. I know the Avids get great reviews, but I haven't read up on the Shimano cable-actuated ones. I even tried to look up the 4xx series brakes that Specialized uses on the Rockhopper Disc, but at the Shimano web site I couldn't find them. They should be at the 'Alivio' level but I didn't see them.

There must be some local bike shops to you. If you want to PM me I'll check that (haven't PM'd since 2004!) and get back to you asap.

Thanks Peter. I live close to NH border and there's a bike shop I go to in Hampton, NH called Gus's that is pretty popular. Also several down near where I work (Peabody). I didn't realize that amongst disc brakes, there so many differences. Hydraulic sounds better unless it is more trouble prone.

+3 or +4 on the 'real V brake' comment. I have XT Vs and levers on my KHS with KoolStops in the front. I'm a pretty heavy guy but if I'm going even slightly downhill and I get hard on the brakes while I'm out of the saddle, the bike starts to shift the weight forward almost to the point that it feels like I might be thrown forward off the bike.

I've talked with a few very smart people that honestly feel that front disks give more stopping power than the best V brakes. My understanding is two reasons mentioned... the obvious one of if you are in serious mud or ice, the benefits are obvious... and the heating of the rim issue... esp on the rear.

Tires make a HUGE difference though. I buy and sell bikes as a side business. I recently got two road bikes that have identical brakes and I replaced both front pads with the same Kool Stop pads. One has 700x23 Continental Ultra 4000s and the other has some ultra high performance race tire that is 700x20. My buddy that is much more knowledgable about the hardcore racing scene than I do assures me that this tire is a good one, but it almost feels like the brakes don't work compared to the other bike. Again, same brakes and same brake pads... all installed and adjusted by the same guy. The difference is the tires.

On the 'new bike or upgrade an old bike' issue... all I can say is if you like older steel bikes, there are some amazing deals out there on used bikes... If you know what to look for and are willing to wait until you find what you really want. I have less than $600 in my main road bike, my main mountain bike and my 'commuter' mountain bike. The commuter was perhaps the best deal. A rigid KHS. Weighs 27 lbs which seems like a lot, but it is a VERY comfortable and forgiving frame. I replaced the levers and shifters with XT and LX respectively and put on some smooth but thick Geax Evolution tires. All new cables and grips and saddle. I currently have a set of Race Face cranks installed, but those are WAY over the top for the nature of the bike. Discounting the cranks, I have about $120 in it and I doubt I'd sell it for $400.

Since you're only about 3 miles from work, which is actually easy walking distance, my opinion is the bike you have is probably just fine. You probably won't be on it long enough to notice its shortcomings. You can always get a better bike if/when you start riding a lot more than the 6 mile round trip from work. I live in NYC, which means a lot of stopping. I've ridden over 56,000 miles just fine without disk brakes. In fact, I rarely use my brakes at all, but instead just gauge things so I don't need to. For example, if I see a red light two blocks down, I'll stop pedaling then coast down as I approach it. By the time I get to the light it'll just be changing to green while I'm approaching it at 10 or 12 mph, and then I'll accelerate back up to my usual 23 or so mph. I always watch in advance for potential obstacles so as to go around them if the need arises rather than hitting my brakes. Granted, I still need the brakes "just in case", but this "just in case" scenario doesn't really pop up very often. And my rim brakes serve me just fine when it does. I've known lots of riders in NYC who even take their brakes off completely (i.e. the famous cyclists who go through intersections yelling "no brakes, no brakes"). The reason is the as rims get wobbly from constantly hitting potholes rim brakes tend to rub all the time, so these cyclists just take the pads off. Disk brakes definitely have an advantage here, although once my rims get so wobbly that my brakes rub I'll either true them or replace them.

All I'm trying to say is don't fall into the trap a lot of people make when they start riding more, spend a small fortune on equipment, realize it's not for them, then sell it at a fraction of what they paid. I've been riding the same bike for the last 15 or so years. It serves me well even though it has rim brakes, downtube shifters, no shift indexing, no shock absorbers, basically none of the bells and whistles newer bikes have. My only two reasons for buying a new one would be if the frame cracks beyond repair, or if I can buy something significantly faster. The latter is only possible if I buy a recumbent, or especially a faired recumbent. I may even do it one day when finances are better, but for now I'm perfectly happy to ride 10 or 15 miles at a time on the bike I have.

Another thing is if you plan to do most of your riding on pavement look into road bikes. They're a good 5 mph or more faster for a given pedaling effort than mountain bikes. Sometimes that can make all the difference as to whether someone continues riding after they start. Often a lack of forward progress consummate with the exertion put in causes many riders to just give up. A good road bike will definitely help here, especially with a disk rear wheel. A faired recumbent is of course better, but the price tags for those are well into the four figures. Oh, and look into airless tires. I'm planning to get a set as soon as my present tires wear out. Nothing more disheartening than to be all psyched up for a ride, and find your tires flat from a slow leak, or to have a great ride interrupted by getting a flat. Of course, 95% of the time the flat is on the rear tire which is 10 times harder to get off than the front. Whatever their shortcomings, airless tires will prevent those scenarios.

jtr1962 said:

Another thing is if you plan to do most of your riding on pavement look into road bikes. They're a good 5 mph or more faster for a given pedaling effort than mountain bikes. Sometimes that can make all the difference as to whether someone continues riding after they start. Often a lack of forward progress consummate with the exertion put in causes many riders to just give up. A good road bike will definitely help here, especially with a disk rear wheel. A faired recumbent is of course better, but the price tags for those are well into the four figures. Oh, and look into airless tires. I'm planning to get a set as soon as my present tires wear out. Nothing more disheartening than to be all psyched up for a ride, and find your tires flat from a slow leak, or to have a great ride interrupted by getting a flat. Of course, 95% of the time the flat is on the rear tire which is 10 times harder to get off than the front. Whatever their shortcomings, airless tires will prevent those scenarios.

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Stay away from those "airless" tires, they will destroy your rims! When an air filled tire hits a pothole, it transfers the force around the rim, airless tires transfer the hit directly to the rim at that point. This is fine if you ride a BMX bike a few miles a week but a road bike wheel will crack quickly. A recumbent riding buddy of mine destroyed his rather stout 20" rear wheel in a few hundred miles with those airless tires. They are also very heavy, give a jarring ride and are hell to put on.

If you want a close to flatproof as you can get, use the correct tires. Schwalbe makes a tire called the Marathon Plus that has the usual (for Schwalbe anyway) kevlar belt but adds a thick blue rubber belt to prevent thumb tacks from puncturing the tube. I have one (20x1.75) tire on the rear of my wife's recumbent after using for over 2,000 miles on the front of my recumbent. The Marathon Plus is heavy and not a fast tire but no flats. My wife has never met glass or nails that she never liked. After flatting Kenda Kwests a few times, I switched her to Schwalbe Marathons and no more flats. The Marathons held for three years and now I put the Plus on the rear.

All my bikes (4 of them) run Marathons be it the Cross (MTB), Racer/Slick (mine) Marathon/Plus (wife) or regular Marathons (son) No flats...none...ever. I've replaced my spare tubes in the bag on my bike due to age (4 years), not because I needed them. I am taunting the flat gods...

geepondy said:

Guys, I posted a bit ago on recommendations for a $600 mountain bike. I read good things about the Specialized Rockhopper. Do you think it's worth spending more on the Rockhopper Disc (MSRP $660) with disc brakes versus the plain Rockhopper (MSRP $520)? Never experienced a bike with disc brakes.

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Well, might as well save up for something other than Specialized, like say a Karpiel. Then again, time and your money may vary accordingly.

Enjoy!

I got my front brake, an Avid mechanical, in 2001. Works perfect. And do not plan the change this setup.
Might even get these (Avid BB 7 now, imho better than #5) instead of any hydro on a new bike, if this is possible.

What I have seen during the last years, I can live with a brake that does not offer the same performance, than one of the very few, expensive, good Hydos maintained perfectly & regularly!
For me the bonuses of the mechanical easily cover this bit of less power.
(the bonuses/cons of hydro/mechanical brakes in general are a constant debate in bike forums and its no use to go into much detail here)

PS: I agree there is no use to push any money into this bike. Just to change the parts, with have to be changed, to raise it to a munimum rider-safe level and possibly very much better are too much.