Hydraulic brakes with one functioning hand

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Harry Sp
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Hydraulic brakes with one functioning hand

Postby Harry Sp » 25 Jan 2019, 9:41am

Hi

I was wondering whether anyone has any experience of adapting hydraulic disk brakes so the back and front brakes can both be controlled by only my right hand (I have a brachial plexus injury and not able to use my left hand).

Really appreciate any ideas. I have di2 so don't need to use my left hand for gear change but the mechanics at my local bike shop are struggling to find a solution for braking (beyond switching back brake to right hand).

Thanks so much, Harry :D :D :D

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[XAP]Bob
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Re: Hydraulic brakes with one functioning hand

Postby [XAP]Bob » 25 Jan 2019, 10:01am

There are various cable splitters, not sure whether a simple hydraulic split would quite do what you want...

The issue you'll face is that you need to move twice the amount of hydraulic fluid, or run with half the clearance. At least pressure is transmitted well though, so you should be able to get decent performance.


What's your current bar layout (are you on flats, drops, tiller, superman...)



Lots of ideas: http://www.mtb-amputee.com/bikemodifications.htm
Last edited by [XAP]Bob on 25 Jan 2019, 10:07am, edited 1 time in total.
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thirdcrank
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Re: Hydraulic brakes with one functioning hand

Postby thirdcrank » 25 Jan 2019, 10:05am

You need two separate braking systems so one lever operating both brakes without any other system won't do.

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Mick F
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Re: Hydraulic brakes with one functioning hand

Postby Mick F » 25 Jan 2019, 10:08am

Welcome to the forum! :D

We had a discussion regarding single handed braking recently. Have a read as some of it is relevant.
viewtopic.php?f=5&t=116920
Mick F. Cornwall

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[XAP]Bob
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Re: Hydraulic brakes with one functioning hand

Postby [XAP]Bob » 25 Jan 2019, 10:12am

thirdcrank wrote:You need two separate braking systems so one lever operating both brakes without any other system won't do.


Whilst that is what the law requires "Two independent braking systems" I'd suggest that leaving an 'idle' brake lever on the other side would suffice - hook up a cheap lever to a cheap rim brake that is never used because you only have one hand.

Laws that require you to have two hands should be laughed out of court in any case.

Many of the flat bar examples I posted a link to do use a pair of levers on the same side though.
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pwa
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Re: Hydraulic brakes with one functioning hand

Postby pwa » 25 Jan 2019, 10:19am

Not hydraulic, but I did find it possible to use two flat bar Mtb type levers with one hand at the same time on a tandem. It isn't the most ergonomic arrangement and you don't get quite the same level of fine control, but it kind of works.

Brucey
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Re: Hydraulic brakes with one functioning hand

Postby Brucey » 25 Jan 2019, 12:54pm

unless I missed it you don't say if you are using flat bars or drops.

With flat bars there are choices, eg there are tektro hydraulic brake systems that are fitted to tadpole configuration trikes; these work two brakes from one MC. Not sure if the system uses special calipers or special MC tbh but at least it can be done.

With dropped bar systems I think there are fewer choices.

A traditional solution for one-handed riders is to use a backpedal (coaster) brake, but this may not be easy on your machine. It is an approach that works well for a utility machine because a lot of IGHs (up to nexus 8s) are available with a coaster brake included.

The other thing to note is that two brakes might be a sensible thing and a legal requirement but in terms of stopping quickly you need a front brake and that will end up doing most of the work in a really hard stop anyway. Thus it is usually Ok if the rear brake isn't used in normal braking.

If you have partial use of your left hand (eg you have a left thumb with some strength to it) or would be happy to use one brake as a drag brake with your right hand, you can set up a mechanical brake to work from a friction/ratchet action thumbshifter (eg a sun race LH thumbshifter). Normally the cable is stretchy enough to give some modulation but you can add a V-brake modulator ( which contains a spring) into the cable run and give it better modulation that way if you like; it does mean more lever travel is required though. [Motorcycle racers often use a thumb lever-actuated rear brake operated by the left hand, with the lever set under the LH grip.]

BTW if you fit a LH thumbshifter to the RH side of a flat handlebar, it will sit under (and beyond) the grip, and you could potentially grip the bar with fingers 3 and 4, operate the main brake lever with fingers 1 and 2, and the rear brake with your thumb. Using a revised shifter mount (eg a Kelly's take off) you could potentially mount a shift lever to control a rear brake on the RHS of a dropped bar setup. Not sure how the ergonomics would work out though.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

peetee
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Re: Hydraulic brakes with one functioning hand

Postby peetee » 25 Jan 2019, 4:01pm

I have just today worked on a flat bar bike with both brake levers and a trigger shifter and twist grip on one side. It worked just fine.
The brakes were cable and the levers less bulky but having tried this I think the right sort of hydraulic levers would be manageable for average size hands.
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TrevA
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Re: Hydraulic brakes with one functioning hand

Postby TrevA » 25 Jan 2019, 5:56pm

I have a friend who only has one arm. He runs both brake levers on the same side of the handlebar, one lever is inverted, so that he can use both brakes with one hand. He can only use both brakes from the drops though.

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andrew_s
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Re: Hydraulic brakes with one functioning hand

Postby andrew_s » 25 Jan 2019, 7:11pm

Two levers that can be operated with one hand is the way to go; best if it's middle & index fingers for the front brake, and ring & little for the rear brake.

Any attempt to operate front and rear brakes with one lever is bound to give problems, short of sensor-controlled front/rear dynamic balancing.
Unlike a car or motorcycle, the weight distribution on a bicycle is such that the rear wheel can be completely un-weighted under heavy braking. As that point is approached, rear braking will give a rear wheel skid, either leading to loss of control, or forcing you to ease off on the brake lever.

brynpoeth
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Re: Hydraulic brakes with one functioning hand

Postby brynpoeth » 25 Jan 2019, 7:21pm

Riding fixed or using a back-pedal brake could be worth trying
I have hand-operated brakes too but they are hardly ever used :wink:
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9494arnold
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Re: Hydraulic brakes with one functioning hand

Postby 9494arnold » 25 Jan 2019, 9:21pm

I have seen ratchet or index gear lever (flat bar or bar end on drops) linked to a standard (non hydraulic) brake might be useful to
1/ Comply with the law
2/ As a 'Drag ' Brake ( Sometimes on Tandems ), you pull the ratchet and it stays on till you pull /push it off .
Allows you to think about steering on a long descent rather than fighting with the brakes .
Did my CTC Cycle Instructor Training with a guy with one arm, he had a combination of twist grip and lever gear levers , a dual cable pull single lever ( Google or look on e Bay for Tandem dual lever) going to 2 cable disc brakes and a 'drag' Brake going to a rim brake (if memory serves) all on one side of the bars.
No knowledge of how to achieve this with hydraulics . Perhaps a linkage between single lever and 2 reservoirs ? Theoretically that is. Drum brakes ? There are lots of permutations. Good luck :)

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Tigerbiten
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Re: Hydraulic brakes with one functioning hand

Postby Tigerbiten » 25 Jan 2019, 10:19pm

I use a Tektro Auriga Twin (HD-T525) setup on my recumbent trike.
This is a single lever into twin caliper setup.
They work well on a tadpole trike because you have twin front wheels to brake.
If you adapt them to use on a bike then you'll need to replace at least one brake pipe.
Also I'm not sure if they are OEM or not.
So it is possible.

One of the main reasons I ride a recumbent trike and not a bike is the brake balancing issue front/back under varying conditions.
It's not simple with only one hand.
My second braking system is a BB7 drag brake on the back wheel worked off a fiction lever.

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

NickJP
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Re: Hydraulic brakes with one functioning hand

Postby NickJP » 26 Jan 2019, 4:14am

Harry Sp wrote:I was wondering whether anyone has any experience of adapting hydraulic disk brakes so the back and front brakes can both be controlled by only my right hand (I have a brachial plexus injury and not able to use my left hand).

Really appreciate any ideas. I have di2 so don't need to use my left hand for gear change but the mechanics at my local bike shop are struggling to find a solution for braking (beyond switching back brake to right hand).

Why would you want to switch the rear brake to your functioning hand? If you currently have the front brake controlled by your right hand, use just the front brake - it will stop you far more rapidly than the rear, and on dry roads, with good brakes, you can brake just as quickly with front brake alone as with both brakes - maximum braking deceleration is achieved when the rear wheel is almost unloaded, at which time the rear brake is contributing almost nothing to the stop.

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Tigerbiten
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Re: Hydraulic brakes with one functioning hand

Postby Tigerbiten » 26 Jan 2019, 6:55am

NickJP wrote:
Harry Sp wrote:I was wondering whether anyone has any experience of adapting hydraulic disk brakes so the back and front brakes can both be controlled by only my right hand (I have a brachial plexus injury and not able to use my left hand).

Really appreciate any ideas. I have di2 so don't need to use my left hand for gear change but the mechanics at my local bike shop are struggling to find a solution for braking (beyond switching back brake to right hand).

Why would you want to switch the rear brake to your functioning hand? If you currently have the front brake controlled by your right hand, use just the front brake - it will stop you far more rapidly than the rear, and on dry roads, with good brakes, you can brake just as quickly with front brake alone as with both brakes - maximum braking deceleration is achieved when the rear wheel is almost unloaded, at which time the rear brake is contributing almost nothing to the stop.

I agree that in the dry most of your braking is from the front brake.
But ......
In the wet the use of the front brake becomes a lot more iffy.
If the back wheel skids under braking in the wet then you should/may be able to recover it.
If the front wheel skids under braking then you'll probably hit the deck.
So in the wet the back brake becomes more useful.
It's that shift in the balance front/back that cannot be overcome easily with one lever to two brakes.

Unless you're on a trike.
Then you must be doing something very silly if you fall off when you skid a wheel.

The other question is how safely you can let go of the handlebars with your good hand.
That's one of the reasons my back brake is setup as a drag brake.
I can set it to slow me down and then stick my hand out to indicate a turn, mostly useful for downhill turns.

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