Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
E-bike hydros use mineral oil... We are talking about Shimano, Magura, TRP, Tektro.
Mechanical brakes vs Hydraulic brakes
- Thread starter Jmggc
- Start date
linklemming
Well-Known Member
While they would 'technically' be safer, I have had no need for them on any of my DIY bikes (TSDZ2, Torque sensing GMAC, 2 BBSHD). The only scenario I see it being of use is a stuck throttle like I was agreeing with. I dont see lag being a requirement for brake cutoff,. Yes, my DIY ebikes have lag cutting power buts its not anything a light touch of brake (without cutoffs) cant arrest.
I played with stopping with a stuck throttle (100%) today and could easily do it. I could even manage to turn off the eggrider (which was very hard due to throttle, brakes and eggrider button being on the same hand). Less experienced riders probably couldnt do this.
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J.R.
Well-Known Member
- Region
- USA
- City
- Piedmont Highlands
Sram-Avid uses DOT 5.1. There can be performance advantages. I have Avid on a bike that uses 5.1 and mineral oil on another. I've been fine with both for years. No problems whatsoever with either. I've ridden in temperatures of 14°F to 104°F.... not on the same day
Why did SRAM choose DOT 5.1 over mineral oil?
We specifically choose DOT fluid for its performance characteristics: Heat/moisture management: DOT fluid manages heat better. While pure mineral oil and pure DOT fluid both have boiling points a...
support.sram.com
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m@Robertson
Well-Known Member
- Region
- USA
See previous post. In addition to SRAM and Avid brakes using DOT 5.1, you can add Hope. I'm sure there are more.
This is a pretty good read on brakes and brake fluid. Hope makes a detailed case for using DOT fluid.
J.R.
Well-Known Member
- Region
- USA
- City
- Piedmont Highlands
There's nothing mysterious about DOT 3, 4 and 5.1, they are just synthetic hydraulic fluid. All high performance vehicles, automobiles and motorcycles equipped with ABS use glycol based brake fluid. My motorcycle, non ABS, uses DOT 5, which is paint safe silicone based fluid. As most vehicles use glycol fluid, it really isn't an issue.
m@Robertson
Well-Known Member
- Region
- USA
I don't miss DOT fluid one bit. I know it has a higher boiling point, but mineral oil is just soooo much easier to deal with. Especially over a long term on wheels where a lot of red-hot bleeds are involved; the calipers, mounts and hoses start getting pretty nasty. Thats auto racing and not bikes, to be fair. But given an alternative with ebikes, I have embraced it and have seen no negative consequences.
Interesting points on using the brakes like that on trails.
I don't use a gear sensor, either, although I DID try to use a manual cutoff switch like you mention above and my results were exactly as you thought they might be. Not natural to do and so I never used it.
I have had bikes whose PAS engaged at oddball times and found that cutoffs ensured no shenanigans. I keep the brakes engaged so no surprise motor engagement. Especially when creeping forward at a light beside traffic. If I don't guess just right about how little I should rotate the pedals I can kick the motor on when I don't want to. For me keeping PAS from firing off in such circumstances is most of the benefit of cutoffs. as my riding tends to be all on streets so intersections are a big part of what I have to navigate.
Gionnirocket
Well-Known Member
- Region
- USA
- City
- Y. O.
Good reason to program PAS 0 as just that... No PAS, neutral, nada, nothing but walk mode.
tomjasz
Well-Known Member
- Region
- USA
- City
- Minnesnowta
If you look back I distributed the first iteration to fellow endless_sphere posters in 2014 and tested before they were marketed and cloned by Chinese kit sellers I'd suggest that IGH builds might benefit. But IME learning how to use the brake cut out while changing gears works well. IMO a GS is just another gadget to go bad.
m@Robertson
Well-Known Member
- Region
- USA
Long ago I tinkered with setting PAS 0 as a very VERY mild assist under the thinking that even on a crowded pedestrian path where I am only going 3-5 mph I still wouldn't mind a touch of juice. But I've long since stopped doing that and kept it at zero. Not for this reason though. For a time at least that was regarded as necessary so other bad things wouldn't happen. The places where I have had slightly wonky PAS are KT controllers with hub motors.
Yeah I'm aware you were a pioneer on that one. I have one gear sensor on my second HD build and I never put another one on. I just learned how to do without one on my original and the technique is so second-nature to me, I do it no matter what and almost never suffer consequences. I don't use the brakes, though. I do the stutter-step. Stop. Click. Start. Maybe get the shift completed by the extremely short delay left in the HD's power cut. Especially with SRAM drivetrains that shift on something like a 1/5 cog turn.
AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Those "false starts" can happen at the worst possible moments for darn sure. One of the worst is when climbing on to your bike! That can get your heart going pretty quickly, and it's only a matter of luck regarding the following events. I learned that right away with my first torque sensing bike. Twice. After that it was like the dog only burns it's nose once kinda lesson, but I'm so trusting it took me twice! Thankfully, an easy remedy to pretty much guarantee that won't happen. You can turn to PAS 0 on most bikes of course, but I think from an instinctive move standpoint (kinda like a kill switch on an ATV/Snowmobile/Motorcycle) is to get in the habit of having a handful of brake if you don't want the bike to get a mind of it's own. Clearly, any push on the torque sensing pedal can create a "go" signal for the motor. On a geared hub bike with a KT controller, you have the ability to control the sensitivity of the PAS sensor (as well as the BBSxx) motors). I generally ride with the PAS sensor set at max sensitivity. Love the control it gives me at low speed in tight sections of trail. Downside is, if just 1 magnet happens to go past the sensor, that motor gets a "go" signal - unless you have your handful of brake.
My Ultra is programmed for a very small amount of power on PAS 0 as well.... FWIW, -Al
My Ultra is programmed for a very small amount of power on PAS 0 as well.... FWIW, -Al
linklemming
Well-Known Member
Good point and a great reason to use brake cutouts.
I do ride streets although I try to limit it and havnt seen any such issues yet
I have had no such issues with my GMAC/CA3/Torque sensor and/or BBSHD (with mostly stock EM3EV and Luna settings, only keep current and speed limits changed). The GMAC setup was nice in that I had it setup to only assist once I had input a set amount of power (i.e. 10 w) so it never did this. THe BBSHD hasnt done it yet either.
If I did decide to go to cutouts, it would likely be on only the front
AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Different strokes. I would go rear (rh lever) as I tip the bike toward me to get on and off, and that lever will be in my hand. As mentioned, my hand WILL be on that brake at those times....
linklemming
Well-Known Member
The thing is I typically use the rear more than the front to slightly make small speed adjustments/settle the bike so having a brake cutout there would annoy me all the time(and it did
) . I grab both brakes when mounting/dismounting or basically anytime Im straddling the bike but not pedaling, a habit I learned was essential on my CCX which sometimes did lurch with small pedal inputs(one time at an intersection, it wheelied out in front of me).I view it the same way as a bad shift on my BBSHD. If it happens, its my own damn fault for not doing something correctly. I do have the shift sensor cutouts but have never installed them, I would only use them as a backup.
I use 'little dabs' on the brakes all the time while still pedaling, its something you do in a pack of bikes and definately something you do when your drafting someone with only a few inches between your tires.
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Sierratim
Well-Known Member
- Region
- USA
- City
- Nevada City, CA & Paradise Valley, AZ
An interesting discussion of disc brake options from a bike bike trekker's view point;
Mechanical disc brakes: (My)an overview & what I'm riding right now
I'm currently looking into mechanical disc brakes, have created an overview and tell you why I now ride hybrid brakes.
www.biketour-global.de
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