hydraulic disc brakes v cable disc brakes

Cycle-touring, Expeditions, Adventures, Major cycle routes NOT LeJoG (see other special board)
reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 10 Feb 2020, 4:05pm

Biospace wrote:I chose four significant benefits of each system, of course there are plenty more smaller benefits on each side. For me, feeding larger and lob-sided forces into something as finely engineered as a good bike, especially given these forces act in a way to pull the front wheel out of the fork, more than balances the benefits of brakes which keep a bike cleaner in wet weather and which wear down the braking surface of many thousands of miles.

Throughout this thread I've mentioned more than a few times a disc brake tandem(Cannondale Road Tandem),the extra weight(190kg all up)a tandem carries far outweighs any touring bike.We never ever had any problems with the front wheel pulling out of the fork or stopping the bike,whatever the conditions braking was consistently and predictably very good.Similarly so the three solos I own,which BTW all have the front dropouts facing forword so any braking forces push the wheel into not out of the dropouts.They're well engineered machines :wink:

From https://road.cc/content/feature/213876- ... ind-tunnel,
"We've measured a 16% increase in wheel drag between a disc-braked wheelset and a standard wheelset", Jean-Paul told us. "We performed a direct back to back test of the Zipp 303FC in standard version and disc brake version, for our own competitor comparison purposes. That 16% is a constant offset in the performance curve across the entire cross wind angle range."

Forgive me for mentioning the fact this is a mostly touring forum and mostly slanted in that direction,shaving seconds or minute or five off a ride isn't in most tourists remit.
The linked article is mostly about wannabie stava strugglers or racing,and the 16% saving is based on a consistent wind yaw,rides seldom if ever have such consistencies,roads tend to change course constantly.There's also touring luggage to consider which from a wind POV far outweighs any minor disadvantage a disc rotor or caliper may cause.
We could argue back and forth about this,but the thing is,as a(slow)tourist the reason I choose discs is because they have real value to me because they stop me consistently and predictably in all conditions with great moduation and enough power to lock up either wheel should I wish,my bikes are comfortable for all day riding whatever the conditions.
I don't chase times or look at averages or do strava segments,etc,they have no appeal to me.So whilst a slight loss of aero may be of value to you and I have arguement with you on that,predictable stopping has far more value to me and I suspect the OP and other tourists on this thread who,for very good reasons choose discs over rim brakes.
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djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 10 Feb 2020, 7:52pm

coming back to the hydro vs mech discussion, all of us riders have to judge our speed vs line of sight vs potential side intrusion risks vs road conditions vs traction etc etc in relation to how we know our bike will slow down at a given speed.

as someone who spent their life snow skiing, having motorcycles with a bit of track experience, car driving on snow etc, I have a pretty good sense of judging how fast can I go vs how much stopping power / time I am dealing with.

what I am very happy with is that even with mech discs, on a loaded touring bike I know have a lot more safe time on descents because I know the bike can get rid of a whole lot of speed much faster, safer and with a lot less finger pressure than my rim brake tourers.
The obvious advantage to this is that its more relaxing on descents, having that extra safety margin for dealing with unexpected road conditions like potholes or whatever like debris.

the diff between rim and discs is rather noticeable to me, and along with not wearing away rims if riding in wet, dirt and gritty conditions, certainly makes disc systems, even mech , to be a real plus.

but of course, we rode with rim systems forever and it worked too. You just always have to make proper judgement calls of speed and keeping speed in check for a given situation.

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Tigerbiten
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Re: hydraulic disc brakes v cable disc brakes

Postby Tigerbiten » 10 Feb 2020, 9:22pm

djb wrote:But of course, we rode with rim systems forever and it worked too. You just always have to make proper judgement calls of speed and keeping speed in check for a given situation.

Did they .......

If you think hydraulic brake fade is bad then you've never used chrome rims with "standard" brake blocks in the wet.
That combo was always very 50-50 on how fast you'd stop once it started to rain.
I went through more than one junction simply because I couldn't stop in the wet.
To get a more consistent stopping power in the wet you needed brake blocks with leather inserts.
It's only really with modern rims and blocks that you can have a consistent stopping power in all conditions.

Luck .......... :D

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 11 Feb 2020, 3:26am

Tigerbiten wrote:
djb wrote:But of course, we rode with rim systems forever and it worked too. You just always have to make proper judgement calls of speed and keeping speed in check for a given situation.

Did they .......

If you think hydraulic brake fade is bad then you've never used chrome rims with "standard" brake blocks in the wet.
That combo was always very 50-50 on how fast you'd stop once it started to rain.
I went through more than one junction simply because I couldn't stop in the wet.
To get a more consistent stopping power in the wet you needed brake blocks with leather inserts.
It's only really with modern rims and blocks that you can have a consistent stopping power in all conditions.

Luck .......... :D


I'm in my mid 50s so I did ride some terrible bikes that hardly stopped in the rain, but going back 30+ years my bikes were alright in the wet, not great but ok.
But certainly any sort of disc setup is great, I was simply saying how we managed to tour with rim brakes. I luckily didn't tour much in rain, and not in mountains with serious downhills.

Biospace
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Re: hydraulic disc brakes v cable disc brakes

Postby Biospace » 11 Feb 2020, 10:50am

djb wrote:I luckily didn't tour much in rain, and not in mountains with serious downhills.


Last Spring in typical Lake District heavy drizzle there was more than enough power in the cantilevered rim brakes to stop very quickly down a fast hill, more to the point with enough control to bring the rear wheel right to the point of locking. I was carrying about 12kg in a front bag and rear panniers. A builders truck and a bus had met at a narrow section and were inching past each other, while waiting a small group of cyclists arrived to a hail of "BRAKES!!" - both riders who fell off had modern bikes with disc brakes, of the other three, two didn't have discs. They weren't casual cyclists and the bikes looked to be well maintained.


Tigerbiten wrote:
If you think hydraulic brake fade is bad then you've never used chrome rims with "standard" brake blocks in the wet.
That combo was always very 50-50 on how fast you'd stop once it started to rain.
I went through more than one junction simply because I couldn't stop in the wet.
To get a more consistent stopping power in the wet you needed brake blocks with leather inserts.
It's only really with modern rims and blocks that you can have a consistent stopping power in all conditions.

Luck .......... :D


Haha! That feeling of acceleration as fingers pulled harder and harder with chromed steel rims on a wet day. If you're referring to vapour lock when you mention "hydraulic brake fade", it's worse than the wrong blocks on wet chrome - there's no braking whatsoever.

reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 11 Feb 2020, 11:10am

Biospace wrote:
Last Spring in typical Lake District heavy drizzle there was more than enough power in the cantilevered rim brakes to stop very quickly down a fast hill, more to the point with enough control to bring the rear wheel right to the point of locking. I was carrying about 12kg in a front bag and rear panniers. A builders truck and a bus had met at a narrow section and were inching past each other, while waiting a small group of cyclists arrived to a hail of "BRAKES!!" - both riders who fell off had modern bikes with disc brakes, of the other three, two didn't have discs. They weren't casual cyclists and the bikes looked to be well maintained. ............


Is this another 'good brakes bad' claim based on a single incident?
If so no one here or anywhere else FTM,can help it if some people can't handle the bike they're riding with the brakes they've chosen,most people however can.
The only time I've ever been concerned about my brakes ability has been with(properly set up and decent pads)cantis in the piddling down rain.
Since going over to discs over ten years ago I've never had that concern and I've never fell off due to good consisent braking ability of discs
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djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 11 Feb 2020, 12:34pm

I realize I had not expressed myself properly--while I toured with cantis for decades, and at times in mountains and other steep descents, it was rare that it was raining.

But of course there were times it rained, and like all of us, we just managed our speed for what braking ability our bikes could do and no dramas.
As the bus incident shows, the importance of looking as far ahead as possible, and monitoring ones speed for the line of sight and conditions and braking ability is the most important, leaving leeway for possible surprises.

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Tigerbiten
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Re: hydraulic disc brakes v cable disc brakes

Postby Tigerbiten » 11 Feb 2020, 12:43pm

Luckily I've never suffered from vapour lock on my hydraulics.
But I have had 3 failure modes on my bent trike.

I've heat glazed my pads on a steep hill.
I slowed down from plus 40 mph to roughly 20 mph, but that was it.
I was only able to fully stop at the bottom of the hill.

I've suffered from a main piston seal failure a couple of times.
On my bent trike the lever is positioned vertically with the seal facing up.
Dust/grit settled on it and in the wet formed a grinding paste.
Once the seal was damaged enough then all the oil leaked out for a total brake failure.
I now have a thin neoprene cover over the lever to keep the dust/grit out.

The failure mode in the cold was "interesting".
Water in slot between the piston and the calliper body froze.
I had enough mechanical advantage to break the seal and pull the brakes on.
But they only released once they had dragged enough to get warm up enough to melt the ice.

Luck ......... :D

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 12 Feb 2020, 3:50am

Tigerbiten wrote:But I have had 3 failure modes on my bent trike.

I've heat glazed my pads on a steep hill.
I slowed down from plus 40 mph to roughly 20 mph, but that was it.
I was only able to fully stop at the bottom of the hill.



these certainly sound like excessive heat buildup issues
dragging brakes for more time than necessary usually is the culprit.
Remember, using the front brake predominantly (70%f 30%r) and short, hard applications to bring speed down, then letting bike run and repeat, is the safest and most effective way to keep brake systems heat buildup to a manageable level.

another factor I've found is that there are lots of riders who arent comfortable really hammering the front brake, which is the most effective brake of the two.

this fellows comment in this thread was very good:

by reohn2 » 9 Feb 2020, 10:29am
Your braking technique on big descents pretty much matches my own,let the bike run,brake,let run again and never drag the brakes.If I'm forced to do anything approaching dragging the brakes I alternate front then rear and repeat.I call it 'pulse' braking and find it keeps the heat under control.

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Tigerbiten
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Re: hydraulic disc brakes v cable disc brakes

Postby Tigerbiten » 12 Feb 2020, 6:07am

djb wrote:
Tigerbiten wrote:But I have had 3 failure modes on my bent trike.

I've heat glazed my pads on a steep hill.
I slowed down from plus 40 mph to roughly 20 mph, but that was it.
I was only able to fully stop at the bottom of the hill.



these certainly sound like excessive heat buildup issues
dragging brakes for more time than necessary usually is the culprit.
Remember, using the front brake predominantly (70%f 30%r) and short, hard applications to bring speed down, then letting bike run and repeat, is the safest and most effective way to keep brake systems heat buildup to a manageable level.

I know but I got caught out by circumstances.
I caught up to a very slow car which I couldn't overtake on a steep hill.
I quickly and safely slowed down behind it but then got stuck.
My bent trike is road legal with two independent brakes but with only one hand my braking options are limited.
I couldn't let go of the front brakes to let them cool down due to the car in front.
Not being able to release my front brakes ment I couldn't use my back parking/drag brake.
If I got my back brake on then I could have let my front brakes cool down.
That how I normally keep my brakes cool on a long hill.
I then tried to stop on the hill to give me more room but by that time it was not possible due to brake fade.
So I was forced to just follow the car to the bottom of the hill before I could finally release my brakes and let them cool down.

Luck ......... :D

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 12 Feb 2020, 10:36am

Morning TB, very understandable set of circumstances. The times I've read of one armed riders, I've always wondered about the brake balance aspect. Seems to me I once read of one man on a two wheeled bike that had the one lever doing both brakes with a certain percentage setup like a cars, front/back. Must have been an interesting custom setup.

I know someone who rides an arm powered trike, in the UK no less.
Must be challenging being able to use only one brake lever at a time, but as you described, this was a particular set of circumstances.
Would a larger rotor/rotors be an option/ possible, or not worth it?

In any case, thanks for the explanation
Your bent must be a neat bit of kit. Recumbents over here are rather rare, I see them once in a blue moon on some bike paths, road riding in Montreal is pretty busy, so not great, especially with being low.
Cheers

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RickH
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Re: hydraulic disc brakes v cable disc brakes

Postby RickH » 16 Feb 2020, 2:03pm

Tigerbiten wrote:I know but I got caught out by circumstances.
I caught up to a very slow car which I couldn't overtake on a steep hill.
I quickly and safely slowed down behind it but then got stuck.
My bent trike is road legal with two independent brakes but with only one hand my braking options are limited.
I couldn't let go of the front brakes to let them cool down due to the car in front.
Not being able to release my front brakes ment I couldn't use my back parking/drag brake.
If I got my back brake on then I could have let my front brakes cool down.
That how I normally keep my brakes cool on a long hill.
I then tried to stop on the hill to give me more room but by that time it was not possible due to brake fade.
So I was forced to just follow the car to the bottom of the hill before I could finally release my brakes and let them cool down.

Luck ......... :D

Hope do a brake with 2 independent levers - the Tech 3 Duo - that might be worth considering to give 2 brakes from 1 hand position?

Image

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 16 Feb 2020, 2:45pm

RickH wrote:Hope do a brake with 2 independent levers - the Tech 3 Duo - that might be worth considering to give 2 brakes from 1 hand position?


that is a really neat solution. I wonder who this is marketed to and for what reason? (dropper post lever on other side perhaps?)
But it certainly looks like an interesting option for a one handed rider.
Pricey though, 200 pounds is about $350 cad.

unrelated question--do all of you have your bikes setup with front brake at right lever?
Here in N America its the opposite, but about 20 years ago I bought a bike off my Scottish brother in law, and got used to the UK setup immediately, ie front on right. I had many motorcycles and so its logical and instinctual to me to have front brake with right lever (still my "no time to think reaction") so Ive changed nearly all my bicycles to this setup now.

just curious, I assume its a standard thing over there.

reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 16 Feb 2020, 3:13pm

Yes the front right hand brake is standard in the UK(like motorcycles),there's a couple of theories as to why,but the one that's most logical to my mind is that turning right in the UK involves turning across on coming traffic,so the safest brake to use is the rear as the right hand is outstretched signaling.
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Tigerbiten
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Re: hydraulic disc brakes v cable disc brakes

Postby Tigerbiten » 16 Feb 2020, 3:53pm

RickH wrote:Hope do a brake with 2 independent levers - the Tech 3 Duo - that might be worth considering to give 2 brakes from 1 hand position ?

Nice idea for a bike when you have to balance the brakes front/back.
But probably not useful for me on a trike where I normally want to keep my front brakes roughly equal.
While it is possible to use independent front brakes to help you turn.
The only time I really need to use a single front brake is so small that it's probably not worth it.

Also with single lever on a gentle downhill slope I can pull on the front brakes, rest my thigh against the lever to keep the brakes on and my speed steady.
That frees up my hand to wave at traffic/indicate and/or use my back brake.
If the lever was split then that trick would be a lot more iffy due to the possibility of a single lever slipping and suddenly getting hit by brake steer.

Luck ............ :D