Two brakes, one lever
 

So, I have a friend with a special need. She only is able to pull a lever with her right hand, the other hand she can steer with, but not pull (it is a "deformity" from birth). She has an old ladies cruiser and is wondering if I can set up both brakes on one lever.

I have a few ideas how to go about doing this, but I thought I would throw out the project here and see if others have some notions of the best way to do this. Coaster brake would be a last resort (her preference).

Thanks.
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http://cgi.ebay.com/New-Dual-Pull-MT...QQcmdZViewItem

Do a search for dual pull brake lever on google and you will find other options.

http://www.bikeparts.com/productinfo...220-50471.html

The BMX market also has a tonne of cable-splitters as well. The main problems I've had with setting up bikes like this is the danger of using even cable-pulls on both brakes. It's fine for the initial pull, but as you need more and more braking-force, such as in a panic stop, the modulation must increase pressure on the front and decrease pressure on the rear brake. The rear-tyre ends up locking up at only 50% of maximum deceleration and you end up losing control. So if theoretically, total tyre-grip allows you to stop from 20mph in 30-ft, without modulation control, you end up taking 60ft because the rear-tyre grip dictates the maximum deceleration possible. You end up leaving A LOT of braking-force from the as potential unused.

I've also had issue with people crashing as well. Unless you're going perfectly in a straight line and upright, grabbing both brakes evenly while leaned over causes the rear tyre to wash out and you end up coming out of the corner backwards. :(

Since 100% of the braking-force comes from the front-tyre under maximum-braking anyway, I suggest your friend practice braking with the front-brake only and learning to modulate and increase its force more and more.

That's an interesting lever. Is there a difference in leverages between the two cables?

you probably have told her; but she needs the coaster brake too; just for the sake of safety. Thinking about it; I don't know that I could set her up with only one way of physically using the brakes. I am guessing; but she probably counts on her "good" hand for dexterity. If she's scratching her nose; adjusting her glasses; flipping off a hipster...and suddenly she needs brakes; she's SOL.....just a thought.....

Do not know, never used one. Just trying to help find a solution. It would be a $20 gamble on his part, but it seems with the dual barrel adjusters, that it would not be too hard to find a decent balance for front/rear braking forces.

It's impossible to find the right balance. If the rear brake engages at all under moderate braking, it will always lock up the rear wheel under maximum braking. That's not an acceptable situation.
A bike with only a front brake will stop almost as fast as a bike with 2 brakes. The best solution for one-handed baking is a front brake plus a coaster brake. The second best is 2 separate levers on the same side of the bars. Use the rear brake for back-up and on long downhills, and use the front for most stopping.

em

Come on! She's lived that way her whole life. She knows what she's capable of doing one handed.

Come on! She's lived that way her whole life. She knows what she's capable of doing one handed.

Danno hit the nail on the head a few posts back. There's a serious need to be able to control the braking effort at each end of the bike to cover off all the scenarios. It's not all just about being able to use the greater effort on the front during an emergency though. Special cases where the need to use the rear more strongly or in isolation do happen. Like during wet riding or in slippery conditions due to ice or dirt or sand on the street or even spilled diesel fuel (can you say "slipperier than juicy snot"?). In such special cases it's nice to be able to use ONLY the rear or at least mostly the rear and no or very little front.

So I'd have to say that the best combo is a coaster on the rear and use the one good hand to control the front brake. And with coaster brake versions of multispeed hubs available there's no reason why she needs to be stuck with a basic beach cruiser either. A nice SS MTB or SS track frame could be set up with a coaster brake internal gear hub and V or disc front. In fact the disc front and internal brake rear would be an amazing sloppy winter weather bike.

Eddy has an interesting idea as well. Assuming she has the hand size for this to work.....

Two overlapping levers so that when applied they both engage. The fingers laying across both levers at the same time. The front under the first knuckle of the fingers and the rear lever down more towards the tips. By altering the finger pressure she can pull harder on the front while easing off the rear down by the finger tips. The rest of the time she can work it so there's more or less even pressure on both.

If she has a really small hand I don't know if this is really practical though.

Two girls one cup?

I think the lever shown in post 2 works only on the right side... which is what she needs anyway. Make sure the lever you choose works with the types of brakes she has (canti vs v-brakes). If she uses drop bars, there is only one model of levers that I'm aware of, the Dia Compe 287-T, which is made for 2 rim brakes on the right and one (drum) brake on the left. It might be out of production, I don't know.

That being said, both the lever and the cable splitter have their advantages and drawbacks.


Lever

– More expensive and very limited model selection. You'd have to make sure, amongst other things, that it doesn't interfere with her shifters, and if she has a small or not too powerful good hand, it might be a problem.
– Safer because there are two cables all the way.


Cable Splitter

– Cheaper: She probably has the levers. The splitters/adjusters aren't cheap.
– More choices for levers
– Less safe, as you have only one cable leaving the brake lever. If the cable breaks between the lever and the splitter, there is no other brake left, except Flintstone style.


Issues
Braking will work and be safe, but she will have to be aware of a few specific issues:

– As Sheldon Brown explained more than once, braking on a hard dry surface with the front brake only is as good as anything. But when riding on wet or oily pavement, the rear brake becomes more important, and it should almost be the sole brake on ice. With that in mind, I would recommend setting the brakes aggressively or conservatively depending on where/when she rides:
- 2/3 front for fast riding on asphalt in dry weather
- 1/2 - 1/2 if she rides a lot on gravel dust bike paths or if she is more of a casual-speed cyclist

– You need barrel adjusters on each cable and they need to be adjusted frequently. As the front pads wear faster than the rear ones, the front barrel has to be "extended" to keep adequate brake pressure in front.

– Even though brake cables rarely break (my experience anyways), they should be inspected frequently (say once or twice a year depending on mileage). It's even more imporant in her case as if the lever breaks or if the cable breaks (with a splitter), she's out of luck.

So? People gripe and preach about folks going to only 1 brake on the fixie scene??? Most of those fixie folks are only mentally challenged...they usually have two good hands. Because a person is challenged in a certain way all their life, does not change what makes sense and is prudent.

imo...she needs an additional way of braking........

an additional coaster brake solves this issue................we're talking about safety............This person (with only one option for braking) is asking for an injury......

how about mounting a regular lever in the standard position to control the front brake, and mounting an aero-brake (like for tt bars) at the end of the bar, with the lever pointing inwards for the rear (this way the cable runs along the bars, towards the stem).

Braking is accomplished by using the first two fingers for the front, the last two for the rear (or all of it on the front for a panic stop). Modulation on both brakes can be controlled individually and at the same time.

These are all very helpful. I am leaning toward installing a coaster brake (although I know little about them since my last BMX in 8th grade). This requires a special hub, right? Her bike is an internal 3 speed. I think this is problematic, no?

Also, I imagine she will very much be a fairweather, MUP type of rider. I am tentative putting someone on a bike with only a front brake, but for a slow, dry ride maybe this works.

there are 3 speeds hubs out there with a build in coaster brake so if you switch out the hub or wheel . I too have a friend who doesn't have use of a arm/hand and I use a dual brake lever for her and to this day she has no problems with it or her braking. I do adjust it for her on a monthly bases.

this same idea has come up in a conversation i had before with regards to freakbike building, and i wondered if you could modify/use out of the box a grip shifter as a brake lever. i realize the grip doesn't have a sprint in it, to put it back into "starting" position, but the brake springs should take care of that...

I'd be concerned about compromising my steering control while trying to turn and twist the grip for braking at the same time....especially if my other hand might not be too reliable.

Coaster brake is a good option. That's probably the best bet if you can install it.

Failing that, the only reason she absoluetely needs 2 brakes is redundancy for emergency situations, no? Because as mentioned, front-only braking is usually the best option for people with 2 fully functional hands anyway.

For emergency stopping, I might go with a modified lever or paddle that you could operate from your foot, maybe mounted on the chainstay. Might not have great modulation, but since it's the rear brake all you'd do is skid a bit (instead of doing an endo), and that's preferable to not having brakes.

Another option would be to mount 2 levers on the same bar. Depending on what type of bar, you could have one brake under and out of the way of the other lever, or at a different position (if it was a trekking or cruiser type bar). The first would be preferable if you could find two appropriate levers, as all she'd have to do is move her fingers a bit.

Good luck whichever way you go.

THAT just gave me an idea! A balance-bar is used to connect two brake master-cylinders on race cars and the pedal pushes somewhere on that bar in between the two. Split 50/50 in the middle and you get 50/50 front/rear distribution. Slide the contact point somewhere closer to the other end and you get more braking from one end, like 75/25 f/r. So you can connect the two levers in a way that splits the lever-squeeze force unevenly to operate the front-brake more.

However, that still doesn't solve the issue of a dynamic-split based upon deceleration rate. At moderate decelerations, you'd want a 50/50 split. At maximum-braking, you'll want 100/0 split. And under adverse grip conditions, you'd want something like 25/75. Damn hard to devise a mechanical method that works as good as a human brain.

OK, this may receive varied responses, but I'll throw the question out as I am unsure how I would answer the question (and several have already alluded to it):

Would you set up a friend (adult, late twenties) who is going to ride only in dry weather, at a slow pace on MUP or low traffic neighborhoods with only a front brake?

I'm dense...........MUP?

If that friend has no physical limitations.... I don't see a problem. Only in the event of a total failure in the brake or getting caught on a wet patch (rain, sprinkler, etc.) and needing to hit the brakes; would another brake be needed.

If that person had effective use of only 1 hand.....no.