SRAM hydraulic brakes

On 01/09/15 18:44, sms wrote:
On 8/31/2015 6:08 PM, jbeattie wrote:
On Monday, August 31, 2015 at 5:26:30 PM UTC-7, John B. wrote:

snip

I think road discs have a clear advantage over caliper brakes and
particularly cantilever brakes in wet weather -- particularly if
you are using STI road levers. Apart from stopping better in wet
weather, they do not destroy rims. I could never get my STI levers
to work well with cantilevers (and I do know how to set up
cantilevers). I've never owned a bike with v-brakes, so no comment
there.

Discs are becoming more common because newer wheels can't dissipate
as much heat as discs. For flatland riding this isn't an issue, but
for long, steep, downhill runs it's an issue.

I have a rear wheel with a drum brake for my tandem, but it only is
installed for touring when the bicycle is fully loaded.


How hot does that get on a long descent?

On Monday, 31 August 2015 11:38:33 UTC+10, Peter Smith wrote:
I purchased a Salsa mtb a few years ago, built an extra set of wheels for commuting, and ended up using it almost purely as a commuting bike. So the brakes do not get used a whole lot.

Over time, the brakes have gotten more and more draggy - they don't completely release when I am not braking. Brake pads wear out despite hardly doing any stopping.

Variously parties have said:
1) you must clean the pistons by extending them with shoes removed, cleaning, forcing back, repeat... (it helped some, not much)
2) you must refill the brake lines (done for the front, didn't help, fluid was slightly more amber colored than the new)*, and
3) it is an inevitable outcome of using post-Avid brakes, and now the only solution is to buy either NOS Avid or switch to Shimano. (from my LBS)

Do any experts have deeper knowledge?

Thanks.

Peter
*My 1st time bleeding brakes, maybe I did something wrong? I did my best to follow SRAM's instructions.

A few things:

No-one has mentioned checking to see if the tab/post mounts are square to the plane of the bike/ parallel to the plane of the bike. Would be worth putting the (special, expensive) tools on the mounts to see (friendly bike shop job).

Quite often, this is not done correctly at the factory, and as the brakes get older, it shows up their deficiencies.

I agree with some of the above, but not the Luddites (you know who you are ), who say get rid of them.

You probably need a total brake service (full stripdown/rebuild of master cylinder and caliper, new seals, etc., all new fluid): I hope no-one has bled them with the wrong fluid . . . sounds a bit like seal swell to me (symptom of^).

Buuuut, nowadays, some OEM brakes new are cheaper than getting this done, or even the parts required to do it yourself. Look around, you might find some low-end (but still impressively good) Shimano or SRAM/Avid brakes for less than $100/end, INCLUDING new rotors, pads,mounting hardware, etc.

Or, if you want to go all Ludditey, +1 for BB7 cable discs. They really are very good.

My $5.27 worth.

On Wednesday, 2 September 2015 02:37:33 UTC+10, Tosspot wrote:
On 31/08/15 16:31, jbeattie wrote:
On Sunday, August 30, 2015 at 11:16:11 PM UTC-7, James wrote:
On 31/08/15 12:41, Peter Howard wrote:
On 31/08/2015 11:38 AM, wrote:
I purchased a Salsa mtb a few years ago, built an extra set of
wheels for commuting, and ended up using it almost purely as a
commuting bike. So the brakes do not get used a whole lot.

Over time, the brakes have gotten more and more draggy - they
don't completely release when I am not braking. Brake pads wear
out despite hardly doing any stopping.

Variously parties have said: 1) you must clean the pistons by
extending them with shoes removed, cleaning, forcing back,
repeat... (it helped some, not much) 2) you must refill the
brake lines (done for the front, didn't help, fluid was
slightly more amber colored than the new)*, and 3) it is an
inevitable outcome of using post-Avid brakes, and now the only
solution is to buy either NOS Avid or switch to Shimano. (from
my LBS)

Do any experts have deeper knowledge?

Thanks.

Peter *My 1st time bleeding brakes, maybe I did something
wrong? I did my best to follow SRAM's instructions.

In my view hydraulic brakes on bicycles are not worth the
trouble, especially if you are using your mtb almost exclusively
as a commuter.

I mate who commutes daily in Brisbane on a bike with disk brakes,
says get the cable actuated hydraulic disc brakes. This eliminates
regular adjustment of the otherwise fixed brake pad, and easily
allows for road style brake levers, possibly including an
additional inline brake lever if you want.

Having experienced the regular tweaking of ordinary cable actuated
disc brakes on my MTB, I'd say it's not a bad suggestion for a ride
everyday in the city commuter bike.

My daily driver has BB7s -- and they're great. I've been commuting
on that bike for maybe 8 years. All disc pads wear faster than rim
brakes, but in my wet climate, rim brakes eat rims. I use road levers
and have no interest in buying the exotic and expensive Dura Ace or
SRAM road hydraulic discs. I don't want to have to deal with fluids
on a commuter. I also don't want to have to beat on a hydraulic disc
pad to open it up after accidentally hitting the brake lever while
doing a flat change. Cable discs are better than rim brakes in wet
weather and may not be as good as hydraulic discs, but I'm not doing
DH on my commuter, and cables are just a lot more simple.

I'm surprised. My commuter has Shimano oil in the brakes, so I'm
thinking of never changing it, the pads last longer than my old V-brake
pads i.e. longer than 2 years, provide better wet/snow/ice braking
performance, and I don't have to adjust them or change the cables every
couple of years.

For me, hydraulic disc (but *not* DOT5) every time.

Ooooh, if you want them to last, you'd better . . .

Fluid (even mineral oil) breaks down and gets contaminated over time, and starts to clag up. A friendly squirt through with fresh stuff occasionally (each 6 mths for regular use; yearly otherwise) will freshen them up, protect the quad seals and give you that 'just serviced' feel . . .

On Sunday, August 30, 2015 at 8:11:36 PM UTC-7, Frank Krygowski wrote:
On 8/30/2015 10:41 PM, Peter Howard wrote:

7. This is all my opinion only, based on experience with mechanical
Shimano, Gusset, Tektro and no-name Chinese disk brakes. Avid BB7 is the
winner as far as I'm concerned. Others may have a different opinion.

Of course others have a different opinion! This is Usenet!

My opinion is to use cantilever brakes. All is visible, troubles are few
and diagnostics are easy.

But YMMV. As someone recently said, this is Usenet. ;-)
--
- Frank Krygowski

In my experience Frank is correct.

Disks will invariably drag a bit since you have to have a LOT of power to operate their smaller diameter braking surface. This means you have to have a lot of leverage which means much less movement of the brake shoes since the amount of motion of the bar lever is fixed.

Rim brakes have far more leverage on the larger diameter braking surface and hence require less leverage at the brake allowing more clearance.

On Monday, August 31, 2015 at 12:43:47 PM UTC-7, Frank Krygowski wrote:
On Monday, August 31, 2015 at 6:00:40 AM UTC-4, Peter Howard wrote:
On 31/08/2015 1:11 PM, Frank Krygowski wrote:

My opinion is to use cantilever brakes. All is visible, troubles are few
and diagnostics are easy.

But YMMV. As someone recently said, this is Usenet. ;-)

Always, the trick on Usenet and indeed the whole Internet is to assess
whether an opinion is backed up by knowledge and experience.

My opinion is that the newer V-brake possess most of the advantages of
canti's except massive pad clearance plus having some advantages of
their own.

Agreed. I generally consider V-brakes to be a subspecies of cantilever brakes.

There are two problems with V-bakes - if you use them on a bike with wide tires they may not open wide enough to allow the tire to fit in-between the brake shoes and the tire. Since they have a lot more leverage their clearance has to be a lot less than with V-brakes.

On Friday, September 4, 2015 at 9:01:46 AM UTC-7, wrote:
On Sunday, August 30, 2015 at 8:11:36 PM UTC-7, Frank Krygowski wrote:
On 8/30/2015 10:41 PM, Peter Howard wrote:

7. This is all my opinion only, based on experience with mechanical
Shimano, Gusset, Tektro and no-name Chinese disk brakes. Avid BB7 is the
winner as far as I'm concerned. Others may have a different opinion.

Of course others have a different opinion! This is Usenet!

My opinion is to use cantilever brakes. All is visible, troubles are few
and diagnostics are easy.

But YMMV. As someone recently said, this is Usenet. ;-)
--
- Frank Krygowski

In my experience Frank is correct.

Disks will invariably drag a bit since you have to have a LOT of power to operate their smaller diameter braking surface. This means you have to have a lot of leverage which means much less movement of the brake shoes since the amount of motion of the bar lever is fixed.

Rim brakes have far more leverage on the larger diameter braking surface and hence require less leverage at the brake allowing more clearance.

Hmmm. My BB7s cheap-o mechanical discs don't drag -- not when they're adjusted. They have a lighter pull than my cantilevers and stop way better in wet weather. The BB7s also work well with STI levers, they are convenient, don't interfere with fenders, take little effort to adjust -- and even the initial installation (assuming you don't buy them mounted on a bike) takes less time than setting up cantilevers. The only downside is pad wear and pad cost -- but in my wet climate, that's a reasonable trade-off.

-- Jay Beattie.

On Fri, 4 Sep 2015 09:09:17 -0700 (PDT), wrote:

On Monday, August 31, 2015 at 12:43:47 PM UTC-7, Frank Krygowski wrote:
On Monday, August 31, 2015 at 6:00:40 AM UTC-4, Peter Howard wrote:
On 31/08/2015 1:11 PM, Frank Krygowski wrote:

My opinion is to use cantilever brakes. All is visible, troubles are few
and diagnostics are easy.

But YMMV. As someone recently said, this is Usenet. ;-)

Always, the trick on Usenet and indeed the whole Internet is to assess
whether an opinion is backed up by knowledge and experience.

My opinion is that the newer V-brake possess most of the advantages of
canti's except massive pad clearance plus having some advantages of
their own.

Agreed. I generally consider V-brakes to be a subspecies of cantilever brakes.

There are two problems with V-bakes - if you use them on a bike with wide tires they may not open wide enough to allow the tire to fit in-between the brake shoes and the tire. Since they have a lot more leverage their clearance has to be a lot less than with V-brakes.

What are "wide tires"? I've used vee brakes on 2.5" tires with no
problems with tire clearance. After all they do have a "quick
release".

As for brake clearance, that is more a factor of brake lever, i.e.,
handle, design than any mythical clearance. As I have previously
written I have used vee-brakes with just about all styles of brake
levers available with no problems.


--
cheers,

John B.

Thanks again.

I got the front working well, but from what I am seeing and also reading elsewhere, it looked as if the back is suffering from terminal balkiness. Other groups seemed to agree that Shimano hydraulics don't have this problem. Relatively small amounts of drag are very annoying on bicycles, not to mention the accelerated pad wear.

On 9/4/2015 6:42 PM, John B. wrote:
On Fri, 4 Sep 2015 09:09:17 -0700 (PDT), wrote:

On Monday, August 31, 2015 at 12:43:47 PM UTC-7, Frank Krygowski wrote:
On Monday, August 31, 2015 at 6:00:40 AM UTC-4, Peter Howard wrote:
On 31/08/2015 1:11 PM, Frank Krygowski wrote:

My opinion is to use cantilever brakes. All is visible, troubles are few
and diagnostics are easy.

But YMMV. As someone recently said, this is Usenet. ;-)

Always, the trick on Usenet and indeed the whole Internet is to assess
whether an opinion is backed up by knowledge and experience.

My opinion is that the newer V-brake possess most of the advantages of
canti's except massive pad clearance plus having some advantages of
their own.

Agreed. I generally consider V-brakes to be a subspecies of cantilever brakes.

There are two problems with V-bakes - if you use them on a bike with wide tires they may not open wide enough to allow the tire to fit in-between the brake shoes and the tire. Since they have a lot more leverage their clearance has to be a lot less than with V-brakes.

What are "wide tires"? I've used vee brakes on 2.5" tires with no
problems with tire clearance. After all they do have a "quick
release".

As for brake clearance, that is more a factor of brake lever, i.e.,
handle, design than any mythical clearance. As I have previously
written I have used vee-brakes with just about all styles of brake
levers available with no problems.


--
cheers,

John B.


Tom is right in that depending on the bike clearances and
the tire, linear "V" brakes can be a problem. A deflated
tire drops right out but with pressure there just isn't room
as the brakes can't open as wide as most cantilevers.

(Some cantilever setups with long pads also use up all the
room between fork blades or stays with the same frustrating
result)
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Sat, 05 Sep 2015 07:41:04 -0500, AMuzi wrote:

On 9/4/2015 6:42 PM, John B. wrote:
On Fri, 4 Sep 2015 09:09:17 -0700 (PDT), wrote:

On Monday, August 31, 2015 at 12:43:47 PM UTC-7, Frank Krygowski wrote:
On Monday, August 31, 2015 at 6:00:40 AM UTC-4, Peter Howard wrote:
On 31/08/2015 1:11 PM, Frank Krygowski wrote:

My opinion is to use cantilever brakes. All is visible, troubles are few
and diagnostics are easy.

But YMMV. As someone recently said, this is Usenet. ;-)

Always, the trick on Usenet and indeed the whole Internet is to assess
whether an opinion is backed up by knowledge and experience.

My opinion is that the newer V-brake possess most of the advantages of
canti's except massive pad clearance plus having some advantages of
their own.

Agreed. I generally consider V-brakes to be a subspecies of cantilever brakes.

There are two problems with V-bakes - if you use them on a bike with wide tires they may not open wide enough to allow the tire to fit in-between the brake shoes and the tire. Since they have a lot more leverage their clearance has to be a lot less than with V-brakes.

What are "wide tires"? I've used vee brakes on 2.5" tires with no
problems with tire clearance. After all they do have a "quick
release".

As for brake clearance, that is more a factor of brake lever, i.e.,
handle, design than any mythical clearance. As I have previously
written I have used vee-brakes with just about all styles of brake
levers available with no problems.


--
cheers,

John B.


Tom is right in that depending on the bike clearances and
the tire, linear "V" brakes can be a problem. A deflated
tire drops right out but with pressure there just isn't room
as the brakes can't open as wide as most cantilevers.

(Some cantilever setups with long pads also use up all the
room between fork blades or stays with the same frustrating
result)

True, however...

All the Vee brakes I have come across have a quick release gizmo to
essentially disconnect the brake cable from one arm and let them flop
wide open.

Your second point is also true, in certain circumstances. I find that
the "long" pads are usually particularly bothersome in the front brake
and often substitute a "short" pad for the longer "original" pad on
the front brake while the "long" pad normally is fusible in the rear
brake.
--
cheers,

John B.