Hidden Wire Brake Cutouts - Brompton

[jerrysimon]

Been meaning to post this upgrade to my Brompton for a while. Firstly thanks to Dave for sending me a set of these nifty little devices. I have since ordered a few more sets from China.

Firstly I hate these cheap nasty generic cutout brakes but they were the only things that fitted with my thumb throttle. As I use cruise control I prefer to have at least one cutout brake.

These are what I really wanted to fit to my Brompton. New this year from Brompton they replace the older brake levers which have large casings that interfere with the small thumb throttle I use.

Here is one fitted though I later realised on the wrong side.

Jerry

 

[jerrysimon]

Next to install the little hwbc unit. This seemed the best position to me. You need to trim back/shorten the brake cable outer the same length as the hwbc unit about 2 inches or so. Its obvious which way round the unit goes when you fit it.

Another close up shot

There is a little red led underneath that lights when the cutout is initiated.

My guess is there is a little magnet inside that moves up and down to follow the brake wire as it moves inside it. This is why I think it can only be installed one way up. Next it needs to be connected up. There are three wires. The normal two wire brake cutouts plus a third +5v power wire required for the circuit inside the unit. For me its simple as I just pick up the associated pins in my umbilical plug that connects the bike to the controller in the bag. I pick up the +5v from the throttle lead. That is the red wire shown which also has the +5V throttle wire underneath it in the same pin. In terms of the other two wires you will know if you have them the wrong way round, as the led will light when the brake is disengaged if incorrect.

Overall it seems to work really well, is so much neater and allows you to use your own brake levers. I have used it for over a month with no problems. As I said I only use one, though fitting two would be belt and braces. I have a kill switch on my Brompton bag so am happy with just one.

Jerry

 

[jerrysimon]

Because it has worked so well I have also fitted one to my Dahon Uno/Duo conversion. Here it is shown fitted in the more traditional place at the end of the brake cable before it enters the brake assembly.

I still need to do a write up on this conversion. As you can see I have modified the Brompton luggage block to fit on the Dahon head tube mounting lug. This enables me to use the same bag and electrics on both the Brompton and the Dahon

Jerry

 

[shemozzle999]

Hi Jerry,

Is there any way to modify the end stop with a switch on new 2013 model like you did previously?

 

[patpatbut]

Hi Jerry,

thanks for the update. Can you show me the photo how to fit the rear brake sensor?

Pat

 

[jerrysimon]

Hi Jerry,

thanks for the update. Can you show me the photo how to fit the rear brake sensor?

Pat

I only fitted front ones

Jerry

 

[jerrysimon]

Hi Jerry,

Is there any way to modify the end stop with a switch on new 2013 model like you did previously?

I did look but there does not look like there is sufficient room inside the brake housing.

Jerry

 

[patpatbut]

I only fitted front ones

Jerry

Do you know it would be difficult to fit the rear one? Considering it is a long cable housing...

Pat

 

[shemozzle999]

I did look but there does not look like there is sufficient room inside the brake housing.

Jerry

Thanks Jerry, if you get a spare moment could you please measure the thread diameter of the end stop adjusting screw and depth to the brake lever in the off position from the outside of the casing .

 

[jerrysimon]

Do you know it would be difficult to fit the rear one? Considering it is a long cable housing...

Pat

You would need to cut the wire/outer and insert the unit into it. There is not enough room to put it in where the cable goes into the bottom of the caliper brake.

Jerry

 

[jerrysimon]

Thanks Jerry, if you get a spare moment could you please measure the thread diameter of the end stop adjusting screw and depth to the brake lever in the off position from the outside of the casing .

I will try though its hard now it is fitted. I did take one of the switches out of the stock cutout brakes and offer it up to the new lever to see if it would fit. There is no way it would fit like it did on the original Brompton brake levers.

Jerry

 

[Deleted member 4366]

Do you know it would be difficult to fit the rear one? Considering it is a long cable housing...

Pat

You can install the sensor anywhere in the cable that's convenient. It doesn't have to go at the end. just cut the cable outer and thread it on. That's it.

 

[shemozzle999]

I will try though its hard now it is fitted. I did take one of the switches out of the stock cutout brakes and offer it up to the new lever to see if it would fit. There is no way it would fit like it did on the original Brompton brake levers.

Jerry

Hi Jerry,

I was thinking along the possible lines of fitting one of these from the outside but it depends on its physical compatibility:

Micro miniature Push Button Switches | Rapid Online

 

[Deleted member 4366]

You need push-to-break. I think those are push-to-make.

 

[jerrysimon]

Interesting that might work, though as Dave said would need to be push to break. It should be easy to drill the hole out a little if need be.

Jerry

 

[shemozzle999]

You need push-to-break. I think those are push-to-make.

Not a problem d8veh if you use the brake high wire. If you solder a diode across the switch in reverse bias it will be shorted by the switch but come into cct operation when the brake lever is operated.

 

[jerrysimon]

Not a problem d8veh if you use the brake high wire. If you solder a diode across the switch in reverse bias it will be shorted by the switch but come into cct operation when the brake lever is operated.

Way over my head, but cool

Jerry

 

[shemozzle999]

Interesting that might work, though as Dave said would need to be push to break. It should be easy to drill the hole out a little if need be.

Jerry

Hi Jerry,

There are several suppliers, this one has a M5 thread and i have seen some with 1/4" 4/40 but it would be nice to try to match up directly with the Brompton lever hence my original request.

 

[jerrysimon]

I will check it in a bit.

Took the grub screw out. It's M5

PS This may work "normally closed" and thus open when the brake lever is not being pulled and pushing the switch, though not sure about thread size.

http://www.ebay.co.uk/itm/SPST-Mini-Momentary-Pushbutton-Switch-Closed-/120857708817?_trksid=p2054897.l4275

Jerry

 

[shemozzle999]

I will check it in a bit.

Took the grub screw out. It's M5

PS This may work "normally closed" and thus open when the brake lever is not being pulled and pushing the switch, though not sure about thread size.

SPST Mini Momentary Pushbutton Switch Closed | eBay

Jerry

Hi Jerry,

Thanks for the dimensional and the source information.

Can you estimate the length of the grub screw contained in the body of the lever?