Disc Brakes?
 

Hello
I got a bike (700c, aluminium) a couple months ago; I have experienced
that the brakes the bike have are not the best and I am wondering if I
could install disc brakes.
Already checked on a bike shop and they showed me that the frame has
the necessary calipers to mount disc on the back, but they told me
that it is impossible to mount the disc on the fork.
I am not an expert, this is my first commuting bike and I would highly
appreciate if you could give me some advice on this? Is there any
adapter I could buy to install the disc on the fork? The people at the
shop told me they could modify the fork to mount the disc (welding
additional parts) and as far as I have read online I have found that
this is not a good choice.
What would be the best to do with this? Is there any solution to solve
this using adapters or any other solution that does not involve
welding additional parts?
Thanks in advance!!!!!
PS. Attached you will find some pictures of the fork and the frame.
http://bikeforums.net/attachment.php...hmentid=386786http://bikeforums.net/attachment.php...hmentid=386787http://bikeforums.net/attachment.php...hmentid=386788http://bikeforums.net/attachment.php...hmentid=386789http://bikeforums.net/attachment.php...hmentid=386790

Those are very cheap brake calipers that are probably flexing under braking. The easiest way to get significantly better braking is to replace them with more modern calipers. Tektro is one such brand that makes inexpensive but robust calipers, in a variety of lengths.

If you really want to go with discs, consider replacing the fork for one with disc tabs. Keep in mind that you'd need new wheels (or at least new disc-compatible hubs and new spokes laced to the existing rim).

Cheers and welcome to BF.

My first action would be to make sure the current brake setup is well adjusted, has good calipers, brake pads, new cables and housings. When working properly, caliper brakes are perfectly capable of sending you flying over handlebars if you don't pay attention. This is probably the most cost effective option you have. Add fenders and a rear rack, lights and a lock and you have a commuter bike.

If however you have set your mind on disc brakes: unless you're inclined to do the work yourself you'd probably be better off looking for a new disc brake equipped bike (possibly with fenders and rack). Instead of welding stuff you can also have the current fork replaced to a disc capable fork, but things can escalate from there rather quickly as mentioned (also new brake levers, and if your brake levers are integrated with your shifters, new shifters...) Your bike shop can tell you their total cost for that upgrade in your case, but my guess is, it's not worth it.

--J

Those brakes suck. Long reach dual pivot Road calipers are what you need. Possibly just one on front would be enough.
Is there a nut sticking out the back of the fork crown? If so you need a nutted setup, or you can drill out back of fork to fit recessed nut.

Measure distance from brake bolt to center of brake pad bolt to get your reach.

Agree those are sad. A set of Tektro dual pivots would make a massive difference for not a lot of money.

How much are you willing to spend?

Putting discs on the rear would involve getting a new hub if it is not the type that you can put a disc on. Money wise probably the best thing to do is just upgrade your caliper brakes.

Best: now you go shopping at a proper bike shop for a new bike with Disc brakes .. decent = $500 plus.
[upgrade parts & labor will reach that]


agreed .. Tektro dual pivot brake calipers , in adequate reach will improve the braking significantly..


YGWYPF .. whole bike is a collection of low end parts to hit the selling price you were willing to pay.

Thanks everyone for the answers!!!!
A friend of mine gave me the discs and the levers as a present....
I know this bike is a cheap one, and decided to buy it since it is my first one to go around.
As JiveTurkey said, they are flexing already.
Last week took a friends bike for a ride and it has discs equipped (Cannondale bad boy 9); I would love to have that bike, but right now I do not have the money to buy a bike like that; that is why I want to equip discs to mine.
Saw this adapter online, and would like to give it a try www.a2zcomponents.com ; does it work for my fork?
If not, can you recommend any of Tektro calipers?
Thanks again!!

Tektro 539 or 540.

You can absolutely get good braking performance without all the hassle and expense and kludgery of trying to convert that bike to disk brakes.

i agree with he suggestion to get a set of better calipers
and I would bet that just installing them on the front will be most of what you need
to be confident in your braking

you might try to simply replace the cable and housing with higher quality stuff
and get better brake pads
this will cost you about fifteen bucks per wheel
instead of the cost of new calipers
and certainly a lot less than the new wheels and fork needed to convert to disks

even if you get new brakes
disk or caliper
you should change the cables to something better than what came stock on the bike

That adapter is for frames/rear brakes, not for forks/front brakes.

The forces on a disc brake are far higher than rim brakes due to how close the disc is to the hub. Leverage ratios at work, ya know....

Runout and flex on disc brakes counts for a lot. It takes very little movement to run into disc brake performance loss at worse and lots of scuffing noise at best. So a clamp on disc mount isn't something I would trust. And that A2Z mount is a clamp on style. At best you will need to be either very lucky or tinker with it quite a lot to make it work well.

Which disc kit did your buddy give you? I ask because there are a lot of cable operated disc kits out there which do not work as well as a good rim caliper. So you might go to all this trouble and still not have a good stopping bike.

The information about that clamp on adapter on the A2Z site also says that you don't need special rim hub wheels. I'm calling BS on that. If the hubs do not have the mounting flange for the rotors then it means you're tying the rotor onto the spokes. And that's never a good option. Spokes are not meant to withstand bending loads. And a disc brake setup that binds to the spokes will generate high loads of this sort. It's a bad situation any way you look at it.

So to make the bike work with the disc kit you got you'd need new wheels and that fork adapter. And if the brakes you were given are one of the poor performing disc setups then you're looking at all this money and STILL having bad brakes.

However I can tell you from personal experience that if you buy the Tektro dual pivot long reach calipers and fit them with Koolstop salmon coloured pads that you will be VERY happy with how well your bike stops. This is ironclad. I've done it and this combination flat up works.

If you can find some Avid Speedial levers to go with all this you'll be even happier.

Mate all this up with some good quality cables and housing and you will grin with satisfaction every time you stop.

There is nothing at all wrong with rim brakes if you have the right stuff. But the ones you have are clearly not the right sort.

Even putting a set of Kool Stop Salmon compound Pads, 'continental' the simple bolt on ones ..

and getting the brakes adjusted, better cables and Housing , would help.

Everything BCRider said.

And with regards to welding a disc caliper mount onto that (I'm thinking) aluminum fork it seems like a great way to anneal the alloy in the zone (which would then see significant braking forces, adding insult to injury) and probably dis-align the fork in the process. A pretty bad idea, that one. -- edit: if we are in fact talking about brazing a new mount on, that would make more sense, but still nowhere as much sense as better calipers.

You donot want to put a disc brake adapter onto a frame that was not designed for the stresses generated by it... It coukd cause anything from poor handling to component/frame failure.

Never tried such an adapter, would probably not want to unless I had a really good reason.

You need to measure brake bolt to brake pad bolt distance before you pick a brake. Looks like a pretty long reach to me so I'd guess R539 would be the ticket. But you really need to measure to make sure, or take it to a shop so they can measure and check out the nutted/recessed situation and select the right brake for you.

Thanks again everyone for your advice!!!! It is much appreciated!
I just checked the measure and it is about 2-3/4" between the bolt and the brake pad; which set of calipers would be the best?
Also, if there is any budget friendly option, I would highly appreciate it too!!! http://bikeforums.net/attachment.php...hmentid=389241http://bikeforums.net/attachment.php...hmentid=389242

There are BMX adapter plates, for replacing a brake with a center bolt, with V brakes ..
But. given the direction the forces are applied , it would have to be mounted on the back side of the fork..

they are used on the back of BMX bikes , so forces push the adapter into the seat stays for back up..
when it flexes.

it is a possibility .. (NB still a rim brake )


Disc brakes buy a new fork .. add up 2 wheels a fork the discs and levers ..

then compare the sum of those parts buys, [& Labor to have it done right].
with just buying a disc equipped bike already set up and ready to ride..

Thanks! I have decided to go with calipers (Tektro or similar), i would like to know what are the needed specs to get them online.

Good luck I get a little payroll from the Bike Shop and wont do that for you. for free.

Google makes money off you looking ..

I understand....I am in Colombia (South America) and will be buying them online so a friend can take them next week that he is travelling back! Thanks anyway!

convert that reach dimension to the metric system and you will be able to understand the how big question better ..

when going to TEKTRO BRAKE SYSTEMS

Already checked; the distance is 70 mm from bolt to the pad; would this be ok? TEKTRO USA
Also, is there another brand? Shimano? or something else to compare?
Thanks