Best brakes?

My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

--
Dieter Britz

On 12/2/2019 6:52 AM, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

Never use disks on a bicycle. Disks are magnetic media used in
computers. Your son will certainly be disappointed with the performance
when used on a bicycle, especially if he used floppy disks.

On the other hand, disc brakes are preferable to rim brakes or drum
brakes for stopping or slowing a bicycle or a car.

On Monday, December 2, 2019 at 6:52:43 AM UTC-8, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

What kind of discs? After installation, you need to set the pads with some repeated, firm braking. This takes a few minutes, and instructions are on the internet. There is a break-in period with disc pads, and I assume the pads were not contaminated with oil during installation -- which drastically reduces braking efficiency.

Well adjusted discs (cable or hydraulic) with good pads have very positive braking. None of my rim brakes (all Ultegra or better) provides the same rear braking force as my Shimano hydraulic disc brake. Front braking force is similar in dry weather, and hydraulic brakes are, IMO, much better in wet weather.

-- Jay Beattie.

On Monday, December 2, 2019 at 6:52:43 AM UTC-8, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

--
Dieter Britz

Check the pull on the levers. Disks should offer if anything too much braking. If he is not getting that a spongy feeling on the levers would indicate that either they have not been properly filled and bled or that there is a leak from over-tightening the "olive" which is the hydraulic line seal.

To check for these things first pull the lever and see if it compresses more than half way and feels spongy rather than a positive "stop" as the brake pad engages the disk. Also it you pull it and the pull increases with time you may have a leak and these are almost always visible if you look for them.

On 12/2/2019 9:52 AM, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

Disc brakes should give more braking force for a given force applied to
the brake lever (which is not necessarily an advantage, especially on
the road in dry weather). But your son's experience is an indication
that discs can be more difficult to set up and diagnose than caliper
brakes.

It might be easier to give advice if you tell the specific model of the
brakes, and give a little more detailed description of the problem.

--
- Frank Krygowski

On 02/12/2019 15:52, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

They should be roughly equivalent, but without more detail as to
make/model and how they were fitted, further advice is likely to be less
than useless (yesyes, sue me)

On Monday, December 2, 2019 at 10:58:47 AM UTC-8, Frank Krygowski wrote:
On 12/2/2019 9:52 AM, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

Disc brakes should give more braking force for a given force applied to
the brake lever (which is not necessarily an advantage, especially on
the road in dry weather). But your son's experience is an indication
that discs can be more difficult to set up and diagnose than caliper
brakes.

It might be easier to give advice if you tell the specific model of the
brakes, and give a little more detailed description of the problem.

--
- Frank Krygowski

You pretty obviously ride in fairly flat country. While I am not overly fond of disk brakes because it is so easy to over-apply them, they are very much stronger than normal rim brakes on carbon rims. I have to apply the rim brakes with almost my entire strength to get the bike to slow to a stop at the stop signs at the bottom of many steep descents around here. That is - with my entire strength I cannot lock the wheels whereas with the disks I have to be careful not to lock the brakes. I interpret that as being better braking.

If they're cable discs, there may be a mismatch in cable pull between levers and calipers. There's a roughly 2:1 discrepancy in cable travel between "MTB" and "road" versions.

If they're hydraulic brakes, there may be air in the hose or hydraulic fluid on the pads.

On 12/2/2019 2:32 PM, Tom Kunich wrote:
On Monday, December 2, 2019 at 10:58:47 AM UTC-8, Frank Krygowski wrote:
On 12/2/2019 9:52 AM, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

Disc brakes should give more braking force for a given force applied to
the brake lever (which is not necessarily an advantage, especially on
the road in dry weather). But your son's experience is an indication
that discs can be more difficult to set up and diagnose than caliper
brakes.

It might be easier to give advice if you tell the specific model of the
brakes, and give a little more detailed description of the problem.

--
- Frank Krygowski

You pretty obviously ride in fairly flat country. While I am not overly fond of disk brakes because it is so easy to over-apply them, they are very much stronger than normal rim brakes on carbon rims. I have to apply the rim brakes with almost my entire strength to get the bike to slow to a stop at the stop signs at the bottom of many steep descents around here. That is - with my entire strength I cannot lock the wheels whereas with the disks I have to be careful not to lock the brakes. I interpret that as being better braking.

Not surprisingly, I don't use carbon rims.

The centerpull brakes on my first two "ten speed" bikes were long-ish
reach and relatively weak. Still, I used the second set (Diacompe) on
that bike for several fully loaded tours, including Devon England plus
Scotland (around Loch Ness, etc.) in 1976. The hills we encountered in
Devon were very steep and still memorable. That bike also crossed
Pennsylvania fully loaded, and the Appalachians are much steeper than
the Rockies. No brake problems other than having to squeeze hard on
occasion.

But those brakes had a flexible feel I didn't like. Eventually I
replaced them with cantilevers, while that was still my only road bike.
Since then, most of my bikes have cantis or V-brakes. That includes our
tandem. And while they're not common, I know and ride several hills
steeper than 10%, and probably some steeper than 15%. With modern brake
shoes those brakes are fine.

The Diacompes are now on the 3 speed I built for puttering around the
village. That bike probably never goes over 25 mph, and the brakes are
fine for that duty.

Horses for courses.

--
- Frank Krygowski

On Mon, 2 Dec 2019 07:03:02 -0800, sms
wrote:

On 12/2/2019 6:52 AM, Dieter Britz wrote:
My son has put together a very fancy bike and (of course)
put in disk brakes. But he is disappointed by them. We are
not sure why they don't brake very well. I feel that good
caliper brakes are the best.

Is that true? Or should disk brakes be equally good?

Never use disks on a bicycle. Disks are magnetic media used in
computers. Your son will certainly be disappointed with the performance
when used on a bicycle, especially if he used floppy disks.

On the other hand, disc brakes are preferable to rim brakes or drum
brakes for stopping or slowing a bicycle or a car.


disk (n.)

1660s, "round, approximately flat surface," from Latin discus "quoit,
discus, disk," from Greek diskos "disk, quoit, platter," related to
dikein "to throw" (see discus).

disc (n.)

Latinate spelling preferred in British English for most uses of disk
(q.v.). American English tends to use it in the musical recording
sense (1888); originally of phonograph records, recently of compact
discs.
--
cheers,

John B.