Bicycle Mechanics - V-Brakes binding because of the cold

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Telly
01-31-12, 01:40 AM
Hello everyone,

Temperatures here have fallen below freezing, and with the added wind chill have reached -3 to -6 degrees Celsius (21-26F). This morning while commuting to work, the brakes on my bike started to bind and wouldn't release thereby scraping the rim. Is there any solution such as a better quality lubricant which I can use? Please keep in mind that the brakes are in excellent condition and perform great in all other conditions.


Bill Kapaun
01-31-12, 02:16 AM
Did they actually freeze, or just get "gummy"?

IF gummy, silicon type spray lubes work.
IF actually frozen, WD-40 displaces water.

Telly
01-31-12, 02:19 AM
The brakes wouldn't retract all the way back (only today in the above conditions), thereby touching the rims slightly. After I reached work and left the bike in the heated garage for half an hour, they were working fine.

I'll try and find some spray lubricant and add a couple of drops to the axles (won't be able to take them apart though).


Bill Kapaun
01-31-12, 03:06 AM
What do the axles have to do with it?
You use grease on axle bearings.

Do you have an internal gear bike???

Telly
01-31-12, 03:13 AM
Sorry, meant the axle rod of the v-brakes!

reptilezs
01-31-12, 05:45 AM
frozen cables

FBinNY
01-31-12, 07:48 AM
Odds are that the problem is in the cables, not the pivots. It's unlikely that both pivots would bind evenly so a pivot problem would cause only one arm to bind and the brake to open off center.

Odds are that the cold thickened the grease or other lube in the cables causing the problem. Run a few drops of a temperature stable thin oil, like Mobil 1 into the cable, and work it along the length by working the brakes. You don't have to take the cables apart to do this, simply use the [not so] quick disengage feature to free up some slack and apply the oil at either or both ends of the housing.

BTW- Wind chill doesn't apply to bikes. It applies to expoxed skin, and to a lesser extent to items warmer than ambient temperature.

HillRider
01-31-12, 08:50 AM
Wind chill doesn't apply to bikes. It applies to expoxed skin, and to a lesser extent to items warmer than ambient temperature.
It's amazing how many people misunderstand the concept of windchill. I remember a chemical salesman asking if he should recommend insulating a storage tank in Northern Florida that contained a liquid that froze at 8°F. I said no, it never gets that cold there and he replied, "but, the windchill can be lower than that."

fietsbob
01-31-12, 09:32 AM
Pretty common to bend the straight return spring,
thereby increase the force spreading the arms apart.

might overcome the 'stiction' ..

AEO
01-31-12, 09:42 AM
Odds are that the problem is in the cables, not the pivots. It's unlikely that both pivots would bind evenly so a pivot problem would cause only one arm to bind and the brake to open off center.

Odds are that the cold thickened the grease or other lube in the cables causing the problem. Run a few drops of a temperature stable thin oil, like Mobil 1 into the cable, and work it along the length by working the brakes. You don't have to take the cables apart to do this, simply use the [not so] quick disengage feature to free up some slack and apply the oil at either or both ends of the housing.

BTW- Wind chill doesn't apply to bikes. It applies to expoxed skin, and to a lesser extent to items warmer than ambient temperature.

sometimes, the pivot posts can rust, causing the diameter to change ever so slightly. However, that sort of stuff doesn't crop up when it gets cold.

FBinNY
01-31-12, 09:42 AM
Pretty common to bend the straight return spring,
thereby increase the force spreading the arms apart.

might overcome the 'stiction' ..

This should be an absolute last resort, and isn't indicated for a brake that's fine other than the winter blahs. Given that all is good except when it turns too cold, either live with it, or treat it as a lube issue, not a mechanical one.

fietsbob
01-31-12, 09:52 AM
Yea remove grease, use light viscosity oil, then re grease in the spring..
or do a frequent re app of oil.

FBinNY
01-31-12, 09:54 AM
sometimes, the pivot posts can rust, causing the diameter to change ever so slightly. However, that sort of stuff doesn't crop up when it gets cold.

Absolutely true, but I think because the OP didn't report one sticky arm, or off center opening. The odds of both arms getting stickier (for whatever reason) by the same amount at the same time are too high for my taste, so I went with the cable theory.

BTW- living in New York I have lots of experience with greased cables getting sticky as the temp drops, which I never grease gear cables.

HillRider
01-31-12, 09:58 AM
BTW- living in New York I have lots of experience with greased cables getting sticky as the temp drops, which I never grease gear cables.
I never grease cables either but both Shimano and Campy partially fill their cable housings with grease and that may contribute to the problem.

FBinNY
01-31-12, 10:07 AM
I never grease cables either but both Shimano and Campy partially fill their cable housings with grease and that may contribute to the problem.

yes they do. I always push out the grease with a brake cable, but most don't. When I was a Campy service center, I could predict the problems by the calendar. Every August, ergo levers would jam because of sweat corroding the thumb lever pivot, every November the Rd wouldn't trim because the grease got too stiff. It added to the credibility when I could describe the problem and fix for the cloent before he got 10 words out. G spring failure wasn't seasonal it was geographic with Connecticut and Pennsylvania the states with shortest spring life.

dsbrantjr
01-31-12, 10:52 AM
From my post last night on a similar subject:
Modern, lined cables usually do not require lubrication. Here's what Sheldon Brown said:
Cable Lubrication
In the old days, before the development of plastic-lined housing, it was necessary to coat the inner cable with light grease or heavy oil.

Modern plastic-lined cables have made the use of grease inappropriate, because the viscosity of the grease makes for sluggish cable movement. This is a more critical concern with modern brake and gear systems that use weaker return springs, and with indexed shifting in general.

Many manufacturers now recommend against using any lubrication on cables. It certainly should be avoided in the case of sealed systems such as Gore-Tex ®. Bicycles used in wet conditions, however, will often benefit by the application of a bit of oil, more as a rust-preventive than as a lubricant. The area of particular concern is the short loop of housing which carries the rear derailer cable around from the chainstay to the derailer.

Read more here:
http://sheldonbrown.com/cables.html

Telly
01-31-12, 11:00 AM
Just got in and found all your emails, thanks to everyone for the help!

Since I was on the road most of the day, I didn't have time to do much other than put a few drops of oil on the pivot posts and work the (released) brake arms a bit which seemed to do the job. Since the weather had been humid and I did catch some rain during the past week, maybe there was some water egress in the pivot posts causing some binding and today's low temperature might have been coincidental. So far the brakes are working fine, and I will take the time to disassemble, clean and grease them during the weekend.

As for the cables, they're the stock original cables which came with the bike, so I can't tell you if they'e greased or not.


Edit: Can you recommend a specific type of grease?

FBinNY
01-31-12, 11:00 AM
Many manufacturers now recommend against using any lubrication on cables.

With all due respect to Mr. Brown, and I mean that sincerely, there's a bit of a contradiction here in that both Shimano and Campagnolo pack grease into their housings. Campy for one used to be very specific about which end to cut from, and which way to thread the wire so the grease which filled one end would be spread by the inner wire as it was threaded.

In all fairness, Campy and Shimano together make up "most", probably Shimano alone is "most"

AEO
01-31-12, 11:11 AM
With all due respect to Mr. Brown, and I mean that sincerely, there's a bit of a contradiction here in that both Shimano and Campagnolo pack grease into their housings. Campy for one used to be very specific about which end to cut from, and which way to thread the wire so the grease which filled one end would be spread by the inner wire as it was threaded.

In all fairness, Campy and Shimano together make up "most", probably Shimano alone is "most"

I was surprised to find out that the new 2011 cableset from campy didn't pack any white lithium grease in the housing. At least, not in the gear housings. Not too sure about the brakes.

vredstein
01-31-12, 11:18 AM
sometimes, the pivot posts can rust, causing the diameter to change ever so slightly. However, that sort of stuff doesn't crop up when it gets cold.
People who know the pivot posts should be greased would be shocked to find out how many are not greased from the factory. I never used to check this working at shops ten years ago, but now with new production protocols in China, I have to remove all brake arms when building bikes and check. At least half have posts as dry as a popcorn fart.
You'd also be surprised to find out how many posts are machined too thick incorrectly or have too thick a coat of paint on them causing binding even with grease.

gyozadude
02-01-12, 02:27 PM
One last thing to do for cold/wet/icy weather is to check the brake lever pivot bolt tightness. High quality units come with slim tolerances and little play. But if water gets in there and starts to freeze, the lever can get stuck because of its own precision. Solution is to loosen slightly the pivot bolt to give the lever a tiny bit more play and use oil lube to displace water. If the nut doesn't have a friction shim that prevents the bolt from vibrating and unscrewing, remove the pivot bolt completely, lube the contact portion with the brake lever pivot bushing, but put some anti-seize loctite or something on the threads to help prevent the nut from coming loose. It may not always prevent lossening like a properly spec'd nut with a plastic shim, but should help make the repair last longer. Check it once in a while, especially if the levers get more play over time.

bicyclridr4life
02-01-12, 08:26 PM
I had the same problem. I removed 1/2 of the rubber cable mud guard (or what ever the proper term for it is) between the brake arms and have not had a problem with them since.