Dual caliper brake?

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rg12   10 kW

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Dual caliper brake?

Post by rg12 » Mar 02 2018 5:14am

Hey Guys,

I didn't see any normal dual caliper sets.
There is the Tektro which looks super tiny and cheap calipers and there is the insane gator brake that costs about 1 million dollars.

I have a dual disc hub, two discs, one hydraulic lever and two calipers (in theory).
I have two issues to solve, one is that I don't have a mirrored caliper so I guess I will flip it and the question is if I can change the angle of the hose to point up after flipping the caliper?

second issue is how to get a Y adapter to split the lever hose into two hoses.

oh and a third issue I guess is if one lever will be able to provide enough pressure for two calipers.
Mongoose EC-D 2007 (18" motocross wheels), 21s 10Ah LiPo, Greentime 72V 110A Controller (soldered shunt), 9kg Hub Motor

2WheelsMovesTheSoul   100 W

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Joined: Oct 17 2017 12:59pm

Re: Dual caliper brake?

Post by 2WheelsMovesTheSoul » Mar 02 2018 1:15pm

Interested to see some suggestions on this issue. I too was recently looking for a decent and thrifty solution.

In my case, I resolved this issue last night after a week's worth of lunches spent in the company tool room on the lathe and mill.

I have to post some more pics later. I think I only have one on my phone right now.

Setup:
DNM-USD8 forks with the dual rotor option
x3 ZEE (Shimano) M-640, 4-pot Calipers
x3 Hope 203mm, 2pc Floating rotors
L&R OEM style Motorcycle Hydro master cylinders (each have 14mm piston)

I have to post some more pics later. I think I only have one on my phone right now but I just fabbed some adapters to go from the Banjo fitting (M10x1.25) threads on the moto master cylinders to the M8x0.75 threaded hose connections with the little brass olive and insert. I made both of them the same but only drilled and tapped 2 hose connections on the one as I may end up doubling up on the rear brakes at some point in the future. Also made two M10 spacers as well so I can clock the adapters to the right angle so the hoses are free and clear.
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markz   100 GW

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Location: Alberta Canada

Re: Dual caliper brake?

Post by markz » Mar 03 2018 2:47pm

dual pull brake levers are available, I bought one on ebay for $20 and I scored one from used bicycle store for $5. What Im doing with mine sooner or later, is using a V-brake and disc brake.

2WheelsMovesTheSoul   100 W

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Re: Dual caliper brake?

Post by 2WheelsMovesTheSoul » Mar 05 2018 11:34am

I'll snap some pics of the front calipers tonight and post up tomorrow.

The left side was a breeze, bolt on and bleed. The right side was a PITA. I had to fab a custom mounting bracket for the caliper since the mounting points on the caliper body are slightly off center vs the actual center of the caliper. So yes, you do have to flip it around the other way. No, I haven't had any issues with leaks even though it's technically upside down-ish.

These 14mm piston Master Cylinders (MC's) produce plenty of pressure for the dual 4 pot calipers.

It's definitely overkill for the single rear caliper but I knew that to start with. I was more concerned with:
1. Having mirrored/matching MC's & levers.
2. Having a MC with built in mirror mounts.
3. Having a MC with brake switches.
4. Having a large reservoir.
5. Oversized piston for application.
6. Only having to order one size replacement piston/seal/spring kit.
dual pull brake levers are available, I bought one on ebay for $20 and I scored one from used bicycle store for $5. What I'm doing with mine sooner or later, is using a V-brake and disc brake.
Pretty sure this guy is talking about cable operated dual pull for that cheap. Not hydro. Unless you want those TRP/Juin Tech cable actuated hydro calipers. Might be an option if fabbing parts is not.
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2WheelsMovesTheSoul   100 W

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Joined: Oct 17 2017 12:59pm

Re: Dual caliper brake?

Post by 2WheelsMovesTheSoul » Mar 06 2018 12:28pm

Here's a snap of the right side caliper and mounting bracket. Despite these forks being shipped with "dual brake brackets", a lot of work was needed to get this on and working.
KIMG0237.JPG


Apparently I chose one of the more difficult calipers out there to match up with the DNM dual brake forks. The caliper sits off center and at an angle compared to say a basic bitch AVID BB5. The circular BB5 pad sits pretty much right middle.
avid_bb5.jpg
avid_bb5.jpg (16.37 KiB) Viewed 672 times
The ZEE's 1&2 pot are are in the exact same place, however, the 3&4th pot changes the angle of the pad in relation to the rotor.
zee-m640.jpg
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This meant the mounting points were way off and a custom bracket was needed to get the pistons & pads to line up with the rotor. This was as close to mirrored as I could get with these ZEE calipers.
KIMG0236.JPG
KIMG0238.JPG
My thoughts are if you want a dual setup... stick with cable brakes and save yourself some time, headaches and money. Hope http://www.hopetech.com/product/v-twin-brake/ has a "V-twin" dual master, half hydro half cable, not to my liking though. I also came across a cable adapter from Tartybikes (UK)https://www.tartybikes.co.uk/rim_brake_ ... 11623.html in my searches but it's also for Hope hydro hoses which unfortunately are 1 mm smaller in diameter than the Shimano hoses that the ZEE uses.

Chances are a single will stop you fine. I haven't seen one of these "Electric Enduro" bikes with a real dual hydro setup so I dove right in to see why people seem to avoid it.

Once I get this rolling and complete the shakedown I'll make a few passes on the mill, take some meat off the bone to lighten it up, then powder coat the bracket. I may even remake the whole thing without the need for spacers once I get the angle of a wear pattern I like.

markz   100 GW

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Joined: Jan 09 2014 11:38pm
Location: Alberta Canada

Re: Dual caliper brake?

Post by markz » Apr 17 2018 4:35pm

This is a good setup, might do the same with the rear brakes.
dual brakes.jpg
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dual brakes1.jpg (196.06 KiB) Viewed 382 times

nomorefours   1 mW

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Re: Dual caliper brake?

Post by nomorefours » Jul 03 2018 11:44am

Hey great post - thanks for the pics and info!

I have been looking (and looking, and looking) for a way to improve braking power on my bike, and you may have found the solution!

Here is a pic of my bike, for reference:

Image

Just in case the pic does not post, here is the link:

https://www.dropbox.com/s/tsdohnueb7ig4 ... 0.jpg?dl=0

The bike weighs over 100 lbs, and I weigh around 250 lbs. Top speed (although I don't spend a lot of time there) is about 65 mph.

Right now I have a single 203mm disk with 8 piston Gatorbrake on the front, and it is not enough. It works, but takes a MUCH harder pull on the lever than I would like, even at lower speeds.

I have the same forks you do, DMN USD-8, except mine have IS caliper mounts instead of PM on both sides.

Do you know if this can be changed? Can I purchase the PM ends and swap them out for the IS ends? At least that might provide more options...

If so (I will check directly with DNM), I have some questions for you...

1. Now that you have it all put together, how is the braking power. compared to a single disk?

2. What is your bike / rider weight, and speed of your bike?

3. Do you have any interest or willingness at all, to fabricate another RH caliper mount, and hydraulic splitter? If so, what would you charge?

4. Can you please provide a link to the hydraulic master cylinders you purchased to put this all together?

5. I believe you said at one point, you wouldn't bother doing it again...so my question for you, is what brake system would YOU choose if you were me? Theoretically, my existing Gatorbrake should be about the same (more or less) power as any other 203mm single disk system out there...I don't mind spending $$ to fix this problem, BUT, I am very reluctant to spend hundreds of $$ on a completely new system I haven't tried, only to find it is more or less the same as what I already have.

ANY thoughts or suggestions you can provide, would be MUCH appreciated!

Thanks,

Doug Green

2WheelsMovesTheSoul   100 W

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Re: Dual caliper brake?

Post by 2WheelsMovesTheSoul » Jul 03 2018 2:16pm

Do you know if this can be changed? Can I purchase the PM ends and swap them out for the IS ends? At least that might provide more options... I'm not sure about this. You may want to get a hold of DNM to find out, in most cases I would assume it is possible and likely the lower fork parts are interchangeable

If so (I will check directly with DNM), I have some questions for you...

1. Now that you have it all put together, how is the braking power. compared to a single disk? Honestly, it doesn't feel much more powerful when grabbing a handful, but there IS ZERO brake fade and I've run the battery flat making back to back high speed passes. With the duals, the MC lever does compress more than the single but has plenty of feel and feedback. The MC for the single rear provides far more pressure than needed so its either off or on. Lever feels hard and doesn't move much but will lock the rear at full speed without a problem. If I use the variable regen or motor braking, the actual full speed to stop distance and time is chopped in half. I feel this is far more effective than adding the second front brake.

2. What is your bike / rider weight, and speed of your bike? Chinese EEB frame, QS205-50H-v3 3T, Kelly KLS-7230S, overall bike weight 152 lbs, I'm another 200lbs, GPS verified 61 mph fresssh off the charger.

3. Do you have any interest or willingness at all, to fabricate another RH caliper mount, and hydraulic splitter? If so, what would you charge? The caliper mount was really easy, the splitter was the PITA. Main issue was not having the right tooling. You can buy the right sized tap for a "through hole" use which means the end is tapered. This splitter needs a straight ended thread cutter to work properly. I had to MacGyver the shit outta them to accept and function with the brass olives that seal the hose ends. I really need something like this https://www.ebay.com/itm/SCIENTIFIC-CUT ... SwLYBaEbKj to do the work properly.

Long story short, yeah I can do both. First, let me call my buddy who's a 5 axis mill operator and see what a run of 5 sets will cost. Maybe I can off a few extras to ES member from these threads. If I make them, I'll be charging you straight up for the cost of end mill, plus parts and labor. Otherwise I really wouldn't do it, I don't want you to end up with an equally MacGyver'd set. Give me some time on this part.... Perfecto is always busy, let me see what he says first. If it's a no go with him, I'll work out something mutually beneficial.

4. Can you please provide a link to the hydraulic master cylinders you purchased to put this all together? https://www.amazon.com/gp/product/B071P ... UTF8&psc=1

5. I believe you said at one point, you wouldn't bother doing it again...so my question for you, is what brake system would YOU choose if you were me? Hard to say... The only reason I said that is directly related to the 3 failed prototypes, 10 hours of wasted lunchtime's on the company mill, 2 weeks of waiting for parts, 2 different pairs of absolute shit master cylinders from eBay and a whole lot of frustration. Now that have some reliable master cylinders, know the exact parts I need, have a working version to copy and improve on and now If I get the right tooling... I wouldn't hesitate to fab this same system.

BTW if anybody else want to hop on this, let me know. I'm trying to gauge interest to see if making a few extra sets would be worth it. I could offer all 3 pieces or just 2. Price reflects quantity so the more the merrier. I see lots DNMs around here.... but nobody else rockin duals!

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