Brompton brake failure
 

So I left the house on my way to work in New York City this morning. Temp is 22F or -5C. I go for a few blocks and noticed that my front brake is not working. Is this a common thing on Bromptons? Mine is a 2013 S6L-X purchased this summer. I rode in the rain last Thursday, so I'm thinking there might be some moisture trapped by the calipers or cable housing. I've been riding in sub freezing temps for years on my roadbike and usually it's been problem free. What other "surprises" should I be aware of since this is the 1st time I'm riding a Brompton thru the winter.

http://farm8.staticflickr.com/7396/1...9b02e6f3_c.jpg
TEMP, 22F or -5C by 1nterceptor, on Flickr

oh snap! are you at the white castle on metropolitan ave? :P

if you want assistance with the brake problem, you'll need to describe in detail what the issue is.

My recommendation before assuming it is the brake cable, is to remove the cable from the caliper and check to be sure the caliper is still operation effectively by squeezing it with your fingers. If it is not, lubricate it until it is. In my experience, it is the caliper itself that is seizing more often than the cable.

Don't know if there's anything particular to Bromptons, but I've had cables freeze up before under the right conditions where a bit of water entered and then the bike was left out in freezing temperatures. Freezing rain forming an ice layer on the cogs and chain can be a problem. Also learned the hard way not to just stop and park the bike after riding through wet snow and/or slush with fenders. The wheels froze up solid and I had to carry the bike to a place where I could take it inside to thaw out. A good shaking before parking would have cleared enough snow out of the fenders to avoid the problem.

For the most part I like the design of the 2013 break levers but the cable end isn't shielded, and so water will more likely get funnelled down into the cable than with other designs.

The U formed by the Housing & cable path Has been a problem with Step thru frames
with the side pull brake on the seat stay, pulling from Below.
I saw them in repairs , the brake seized, because the water had settled in the housing and rusted the cable ..

At sub 0C, water may be freezing in the space.. you got the cable boot in place?

adding a V Brake boot to my Mk2 Brommy was simple to do, the new ones have an equivalent ,

though it could be forming a better seal .. and greasing the cable may help ,

they adopted a coated cable, but the coating wears through ..
I changed brake levers, and used the die drawn cable the shop had when I put it back together ..

My guess is ice formation in the brake cable housing. That rarely happens now since I grease all of my cables, even when the housings have a teflon liner. The grease seems to reduce the occurrence of water penetration into the housing and even if it does get in and freezes it doesn't stick as easily to a greased cable.

So after work; I was able to disassemble the brake cable to do some investigation.
Squeezed the calipers by hand and they seem to be fine; lubed the pivot points anyway.
As soon as I turned the cable housing upside down; droplets of water started to come
out. The boot has a rip halfway across and it was letting water in. I pulled out the bottom
cable housing and lubed it. Tomorrow I'll pick up a new boot or tape the one I have if no
one has them in stock.

http://farm4.staticflickr.com/3763/1...618affa6_c.jpg
Front brake 2013 Brompton by 1nterceptor, on Flickr

regular V brake Boots are fine. Its what I used to fix up my Mk2 Brommy..

man, you are brave to be riding in those temps! I've been out (all bundled up) the last two days but it's been in the mid-60's on the west coast.

ps. That's a dramatic photo.