Convert your mechanical disc to hydraulic discs!!

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Lurkin   100 kW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Lurkin » Jan 15 2016 11:10pm

Kettle corn ready.

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Leebolectric   1 kW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Leebolectric » Jan 15 2016 11:24pm

LOLOLOL :roll:
P.S. Chalo: my HOPEs use DOT5.1....an industry standard for disk brake fluid ...in all forms of motor vehicles
there are standards...and cheap versions...you just didn't complete your research. ;)

(how can a bike shop exist without knowing how to bleed brakes effectively?)
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DanGT86   10 kW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by DanGT86 » Jan 16 2016 1:35am

caliper capt.JPG
caliper capt.JPG (27.03 KiB) Viewed 1026 times
So my extremely unscientific screen grab from the you tube video leads me to believe they are pretty narrow at the back. Looks like the thickness is about 1-1/2 times the width of the caliper mount. Btw, is there a brake caliper spacing thread around here? Would be nice to have a collection of that data if it doesn't already exist.

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tomjasz   10 GW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by tomjasz » Jan 16 2016 1:45am

Redacted
Last edited by tomjasz on Jan 16 2016 12:19pm, edited 1 time in total.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Chalo   100 GW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Chalo » Jan 16 2016 10:37am

Leebolectric wrote:LOLOLOL :roll:
P.S. Chalo: my HOPEs use DOT5.1....
So do the Avids I just bled. I was talking about lack of technical consensus.

Trust me when I say I've serviced more hydraulic brakes than you've serviced any brakes in your life. Outside of my long diversion into machining, I've been working in bike shops since 1992.

Some of these things work just like tiny motorcycle brakes, and they're cake to deal with. Some don't, and aren't. They don't all work the same because they're toys, not tools.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Leebolectric   1 kW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Leebolectric » Jan 16 2016 10:52am

Chalo wrote:OK then, find me a motor vehicle disc brake with a 1.8mm thick rotor. Or one that uses mineral oil as hydraulic fluid. Or one with no reservoir. Or one that has more voids than metal in its rotor surface.
The fact that there is no design consensus on bicycle disc brakes or hydraulic systems is prima facie evidence that these things are mostly half-baked gimmicks.
There are reasons to have discs: stub axle wheels, very fat tires, wheel size versatility. There are reasons to have hydraulics: long/indirect cable paths, multiple brakes on one lever.
But what most of y'all are doing with hydraulic discs amounts to wanking. I mean, enjoy yourself, by all means-- but don't try to justify your wankery as some kind of technical necessity.
Yup, and they probably have a master cylinder (resivoir, ya know, that cap on the lever with the rubber diaphragm) (i HATE avid brakes)
Huge amounts of research goes into them, because if they really failed so easily...they would be sued,recalled, etc.
Shimano...who swears by MineralOil...is no slouch on research and development....they are the biggest brand and their top end has a reputation to uphold.
If they sucked that bad...riders would bitch...a gimmick may fool you on the shelf or in the advertisement, but the trails tell no lies.
Those gaps in the rotor are for air flow, to cool these brakes at high speeds...v-brakes are rubber, and would MELT.

There are cars with cheap gimmics too...gimmics are everywhere....that's no reason to discount the quality products for the failings of the crappy ones.
Preaching from a lack of experience is much like wanking too, except we are forced to watch...enjoying a quality brake is a private pleasure. :lol:
2015 Intense Tracer275 with Tangent Ascent inside triangle https://endless-sphere.com/forums/viewt ... 28&t=75045
2010 Turner 5Spot with BaffangHD https://endless-sphere.com/forums/viewt ... 28&t=75569
2009 KHS Velvet 6" with BafangHD (see above thread^)
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macribs   1.21 GW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by macribs » Jan 16 2016 2:37pm

Chalo wrote:OK then, find me a motor vehicle disc brake with a 1.8mm thick rotor. Or one that uses mineral oil as hydraulic fluid. Or one with no reservoir. Or one that has more voids than metal in its rotor surface.

The fact that there is no design consensus on bicycle disc brakes or hydraulic systems is prima facie evidence that these things are mostly half-baked gimmicks.

There are reasons to have discs: stub axle wheels, very fat tires, wheel size versatility. There are reasons to have hydraulics: long/indirect cable paths, multiple brakes on one lever.

But what most of y'all are doing with hydraulic discs amounts to wanking. I mean, enjoy yourself, by all means-- but don't try to justify your wankery as some kind of technical necessity.
I am sorry Chalo, but you pull arguments from where the sun don''t shine. Of course no semi truck weighing in at 50 metric ton will use 1.8 mm thick rotor. And of course those rotors will not have much void, and certainly not like mth/dh rotors. Because those 50 ton semi trucks are weighing in at 50 ton. Even your big arse or mine and a heavy smoking ebike will not even make 0.5 metric ton. Those semi truck weigh like 100-150 times more - of course their brakes are a little different.

Some hydraulic brakes uses mineral oil - do some googling. Not all hydraulic bike/mtb/dh brakes are using oil. Many are using DOT brake fluid.

You might call it wanking, for me it sure looks like the mind of old grumpy dude, a little behind on his research and a lot of anger issues. Just let it go man. Some feel they need hydraulics disc brakes. And there are so many valid arguments for that. If you feel you don't - well good for you. But don't act like an arse because others choose different. People are neither wankers nor idiots for not having your mindset.

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nutnspecial   1.21 GW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by nutnspecial » Jan 16 2016 3:28pm

Well said, but maybe due to this being my first prolonged argument with him I think he's just playing around, right? He's plenty smart enough to be playing anyone of us that takes the challenge.

BobTheBuilder   100 mW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by BobTheBuilder » Jan 23 2016 12:31pm

I just ordered another set for my next build!!))
My 4th set

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Kodin   1 kW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Kodin » Jan 13 2017 1:39pm

OK guys... so first off - EVERYONE HAS THEIR OWN PREFERENCE

Regarding modulation - Chalo has a point, however that point is being interpreted differently by every person in this thread, including Chalo himself. What I gather he was trying to refer to regarding modulation and force magnification: pull the lever 10% toward handlebar - Let's say 10mm in - Get 50% braking force for a "standard" stop. This has a lot to do with lever vs. caliper force ratios rather than anything to do with one tech or another. Some of that can easily be modified by changing the ratio of master vs. slave cylinder volume. Since this changes the force multiplication, it will change how far you have to pull the master cylinder to achieve a given brake force. The only way to accurately measure that would be with a fish scale hooked on the lever, and a hubmotor with current sensor spinning a wheel. Basically a dyno setup. Here's the thing. Potentially, EVERY model will have a different ratio, and most brands do differ slightly in their cylinder volumes. Even between models. This becomes very apparent when you go between 2-pot and 4-pot callipers in the hydro category. Pads also play a MAJOR role in modulation, as they dictate how aggressive the braking force comes on and stays on. If you guys want to compare apples-to-apples, you need to test with various types of pads on various types of rotors. Chalo - I get you have had poor experiences in the past with hydro setups as well as cable-to-hydro units like the one listed in this thread. Please keep in mind there are many variables that no one is keeping consistent. That also goes for the rest of you. What works well for you may not for someone else, and vice-versa. In my opinion, (Having literally built hydraulic systems from billet; I realize that's not a great qualification, but I know a thing or two about design,) I can see two things potentially being problematic with these. 1: Heat build-up. There are no provisions for cooling if you heat up the calliper too far. 2: The feel vs. straight mechanical or full hydraulic brakes WILL be different. A lot of that will depend on what else you pair with these, regarding cable housing, adjustment pre-load, levers, etc... That all can be accommodated for, but you need to understand what the manufacturer was going for when they designed this product. Not likely that the manufacturer targeted a design that gives the best experience for everyone, as there are always trade-offs with any part of a design. You can make modulation better at the expense of maximum brake force, for a given lever design. You can make maximum brake force better, but you WILL sacrifice modulation, again, with the same lever design. There is only so much lever travel, and that's the window you have to work with. Typically manufacturers try to balance things, and sometimes they get it right for a given application, sometimes they don't. Just remember, the "perfect" brake setup for one person will NOT be the perfect brake setup for another. I've been able to stand a 30 lb pedal bike on it's front wheel with BB5's from 30 mph, and I've also used some of the higher-end hydros. The feel is different between both, and a lot has to do with adjustment and tuning.

Side note: The comment on page 2 regarding Hope brakes being able to stop a car? Any brakes will stop a car, it's just a matter of how quickly. Please keep in mind that brake rotor mounting bolts will likely fail at "normal" car braking forces. The rotor will warp, the bolts will break, the calliper will break off the mount, etc... That is, IF you are able to exert enough force to get there. Trust me, it won't be enough to slow a 4000 lb car by any appreciable rate. If you want to do a more direct comparison, look at motorcycle brakes. In fact, no one has mentioned motorcycle brakes as an alternative for heavy ebikes at all. Bigger, thicker rotors, FAR more options for handles, usually with switches built in for ebrake activation, adjustable levers, and in most cases, FAR cheaper than higher-end bike hydro systems. I got a 4-pot caliper, hose, and nice handle with contact switch for about $100. A Hope would cost at least twice that. The downside is if you want to use a motorcycle rotor, you have to make a custom hub adapter, and if you want to use a motorcycle caliper, you need to make a custom mount adapter. They are also heavier by a fair margin, but holy crap do they have more headroom in all ways. Also usually far easier to bleed as the tubes are much larger inner diameter so you aren't fighting capillary action.

Lastly: DOT 5.1 is a bike-only brake fluid. DOT5 is used in cars, 5.1 is used in bike brakes. All brake fluids can and do absorb water, and though the DOT-based fluids have a higher boiling point than mineral oil, they will all gel up with enough water absorption. Guess what happens when fluid gels? It gets under the piston seals, and pushes them out, eventually siezing the pistons in the bores. I recently rebuilt an Avid Code 4-piston-per-caliper brake set that was sitting on a shelf since 2008. The fluid had pretty much ALL been gelled to the point where the main reservoir looked like it was filled with silica gel with a single drop of fluid, and the pistons wouldn't pop until I had 140 PSI of air pressure pumped into the callipers, then required scrubbing with a soft scraper to get all the crud out of the seal grooves. Bleeding your brake fluid makes FAR more sense to do more often than less for this reason alone. That said, people tend to want less maintenance on cars just as much as on bikes, than they probably should be exercising. Preventative maintenance is much easier than post-failure repair. But I digress...

Oh, and one more thing - Most bike parts are made of aluminium or magnesium which are BAD options for cylinder bores when water absorption is a factor. Eventually you'll see corrosion in the bores. I saw it in the master cylinder for the Avid Code brakes. I'd love to see a full-stainless brake set for bikes. Yes I realize that is the most un-sexy-thing ever, mostly because of weight considerations, but it'd be completely bulletproof.

Comments and thoughts are welcome, but personal experience without actual test data to back it up may be dismissed. Don't say I didn't warn you. :)
Tank Bike - (Previously YAG - Yet Another Genesis) - LeafBike 1500W 5t, custom shaft, 9 speed cassette, Chinese "Tank" EEB clone frame, Sabvoton SSC048150

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Chalo   100 GW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Chalo » Jan 13 2017 7:53pm

I think DOT 5.1 is an enormously stupid name for a glycol based fluid. DOT 3 is glycol, DOT 4 is glycol with tighter specs, DOT 5.1 is glycol with even tighter specs. But DOT 5? Silicone. Totally different chemical with totally different compatibility issues.

Why would anybody name a brake fluid DOT 5-point-anything if it's not a variation of DOT 5? Why wouldn't a "super" DOT 4 be named DOT 4.1? Or DOT 6?

For what it's worth, this afternoon I did a brake job on a mechanical caliper that was every bit as difficult as a nasty hydro brake job.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Kodin   1 kW

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Re: Convert your mechanical disc to hydraulic discs!!

Post by Kodin » Jan 13 2017 8:30pm

I won't argue with you there. :P I think it was named DOT5.1 for marketing purposes. Fun part about DOT3 is many manufacturers now make DOT3 with DOT4 specs anyway, as it doesn't make much sense to have two separate fluid production lines.
Tank Bike - (Previously YAG - Yet Another Genesis) - LeafBike 1500W 5t, custom shaft, 9 speed cassette, Chinese "Tank" EEB clone frame, Sabvoton SSC048150

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