beach_cycle

Hello, the front linear-pull, v-brake on my trike stopped working properly; it worked for 1,500 miles, but now half the time when I pull the brake lever, it does not squeeze the pads on the rim. I purchased a new v-brake, and going to install it today. I watched a video, and it appears to be a straight forward task. However, the original brake only lasting 1,500 miles is short compared to my other v-brakes; i.e. my spare trike has one that stops better, and has been in service 5,000 miles. Is that because of quality, or something else?

Wilfred Laurier

What happens when you pull the brake lever and the pads to not contact the rim? Does the intermittent braking change from non-functional to functional or vice-versa with no other changes, or do you stop and fix something to get it to work?

A more common scenario is when there is excess friction in the cable or on the brake pivot and the brakes go in, but do not fully retract.

AnkleWork

Welcome to the Psychic Bike Mechanic Network. As soon as one of our psychic bike mechanics can be contacted they will divine the nature and source of your problem and then post the solution here. Unfortunately, they can only be contacted by earthly means (email, text, phone, etc) which is not reliable like psychic communication. Please stand by.

(In order to make best use of your wait time, maybe disassemble what you have, clean and inspect it carefully and post detailed pictures. Psychic clue: a new brake is probably not indicated.)

Wilfred Laurier

@AnkleWork is correct, if maybe a bit snotty. We need a better description of the problem or some photos to offer more helpful advice.

zacster

You purchased a new brake without trying to figure out what was wrong with the old one? Bike mechanics is not rocket science. Usually things can be easily fixed, and there is almost always a video for that too.

dsbrantjr

As mentioned, we need more to go on. Being a simple lever there is not a lot to go wrong. I am especially puzzled by your statement that the brake only works half the time. What does it do the other half? What if anything do you do that makes it change?Lack of braking doesn't usually come and go. Ont thing you did not mention, does the curved "noodle" through which the inner wire passes stay in its correct position?

HillRider

He is usually both; snotty and correct. . In this case the snark may be justified.

You don't replace a part until you understand why it stopped working. No brake should ever fail to the replacement point is 1500 miles unless it is badly and obviously damaged. I expect the issue is in the cables or lack of pivot point lubrication.

AnkleWork

And childish name-calling is OK, right?

HillRider

Hmmm, I didn't think I was calling you names, I thought I was being complimentary.

beach_cycle

When I squeeze the brake lever, half the time the pads make full contact with the rim and stopping is instant; the other half the time the lever pulls all the way to the grip, but the brake pads either minimum contact the rim, or not at all. It seems as if the brake arms are failing. But the video I watched mentioned an adjustment screw on the brake arms I was not aware of. Maybe an adjustment will correct that issue. I'll try that first...


Thanks for the advice... I'm on it.







Indeed... I assembled that trike in July, and only rode 500 miles during the summer. Now that school is in session, I've commuted 1,000 miles the last couple months, and have less time for bike repair. But it is a necessity, so I make time for maintenance (lube, air pressure, etc.) and today instead of homework, brake repair. I'll document what I do with photos, and post any problems or solutions.




Yes, in school and don't have much spare time for bike mechanics right now. Over the last month, the braking would become soft, but prefer hard braking on the front. So I tightened the cable a couple times. Last Sunday, it worked great for 5 miles, and then didn't work about half the time. I rode 32 miles to and from school a couple times this week, Long Beach City College, and had to be cautious with cars pulling in the bike lane and sudden intersection light changes. 90% of my stopping power is in my front brake, so I usually use the rear brake when stopping can be slow, but for quick stops, I rely on the front brake. I'm off today, so I'll attempt to get it working right.








The other half the time, I pull the lever all the way to the hand grip, but the brake pads make insufficient contact with the rim. What I did before that started happening was tighten the brake cable. I then loosened the cable, but still experienced intermittent brake pad to rim contact. The arms do not fully engage half the time, but the noodle stays in position.

dsbrantjr

Make certain that the brake inner wire is not frayed; look at the whole run, including inside the brake lever where the cylindrical piece seats in the lever. Perhaps it is frayed and/or not seated properly in the lever and is sometimes catching in different positions. Another possibility is that your adjuster is not holding its adjustment and is working itself loose as you use the brake. There is often a locknut on the adjuster(s); are you using it?

dabac

Brakes are fairly simple things. Pull lever, lever pulls cable, cable pulls brake arm. Pad moves towards rim.
It really isn’t something that can change back & forth from time to time.

The only thing I can think of that would fit your description is if you have the cable casing moving about. Sometimes fetching up against the edge of - say the barrel adjuster - and then providing good braking. Sometimes settling inside the barrel adjuster and then causing the lever to bottom out before providing good braking.

Miele Man

Could be any number of things as others here have mentioned.

Could be a hook on either or both ends of the cable housing.
Could be that the ferrules at the end of the cable housing are deforming.
Could be that the cable is frayed inside the cable housing.
Could be that the cable is corroded inside the cable housing.
Could be that the inside of the housing is corroded or kinked.
Could be that the inside of the V-brake link noodle is deteriorated.
Could be that the brake pads are worn a fair bit.
Could be that the levers are contaminated with gunk.
Could be that the caliper pivots are contaminated inside.

Do the brake arms move freely if the cable is unhooked from the brake calipers?

So many things that could be wrong.

I'd loosen the cable anchor bolt and let the cable come back almost to the end of the cable then snug up the bolt. that way you can test for freedom of cable movement by pulling lightly on the cable and also check for tightness of the brake lever by holding the cable and squeezng the brake lever. If the cable moves freely then the problem is either in the brake calper pivots or in the brake noodle.

Cheers

beach_cycle

Special thanks to the bicycle mechanics community for the helpful tips regarding bike maintenance and repair. Now that I'm older and live on a fixed income, my bike is my only transportation, but with your help, I've been able to assemble, maintain and repair my last couple bikes. For that I am grateful, and pass on the knowledge whenever possible.

Today's project was a success. The pads are wearing faster than on my last bike, I think. I've been getting residue on my front rim and lower spokes, and believe it is coming from the brake pads. I noticed the pads were both high and low: left side about on the tire, and right side almost off the rim. That was possibly why it was only contacting the rim half the time; on a borderline that would go on the rim half the time, and on the spokes the other half causing excessive wear. I last adjusted the pads just before the school commuting season, but they shifted positions undetected. I'll have to watch the pads closer, and hopefully get back to normal wear.

The noodle was probably damaged during assembly. It was assembled in China, then disassembled for the boat ride to Port of LA. When I received the box, the brake was attached, but too loose for actual braking. I loosened the lock nut to tighten the cable, but it was too short for that; instead, the brake arm flung the noodle across the garage with such force as to cause damage. Spring action of the unexpected kind. I bought a new cable, but had to buy a ten pack. I installed it in a couple days, when I received it, but the noodle may have been damaged. Today, I replaced the noodle because the piece that attaches to the boot was no longer connected; it was the only part I used from the new v-brake, so now I have a spare. It was an expensive lesson... I also replaced the cable yesterday; it was not frayed, but one of the strands broke, and could become problematic. It was necessary and I had spares. I coated it with lithium grease, so it moves through the housing with ease, and crimped the end to prevent fraying.

The front wheel is out of alignment; it was delivered that way. I tried adjusting the hub, but damaged it. So last summer, I had to learn about thru axles, cups, cones and bearings. Installed a new through axle, and packed the bearings. Another example of how bike forums has helped my education and experience. But I also learned the wheel is true, but out of alignment; therefore, adjusting the brake was a challenge. Today I learned about a screw for alignment of the arms. Now they start to contact the rim at a 33% squeeze; rather than 75%. Braking is now superior; should be excellent for Sunday rides on the beach path where children often unexpectedly run onto the path chasing a ball. The quicker braking will be nice, but starting from a dead stop in seventh gear, 111 gear inches, not so much.

I installed the 60t crankset prior to commuting. Another lesson learned from bike forums. With seven cogs on the back (28t - 14t) the bike is much faster. Still slow compared to high performance road bikes, but fast compared to similar adult trikes. Even that makes braking important. Rarely, but a couple weeks ago, I experienced an unexpected speed wobble and to stop before being thrown into traffic, I had to put my feet down. It was only about 15 MPH; a car following me too close while going over a bridge with narrow sides made me wonder, 'is it going to pass and run me over', so the excessive body movement watching the car caused the speed wobble. Nevertheless, putting my feet down jammed my prosthetic hip, so I was in pain a couple of days. If I had better brakes, maybe I could have stopped quickly without putting my feet down at 15 MPH, or twice that at times.


Thanks for all the tips.

SalsaShark

Your front wheel hub appears to have a nutted axle, and it should be fairly simple to re-center the wheel in the fork. This would allow you to properly adjust your brake caliper, and likely improve your braking performance.

Miele Man

On that front wheel. Do you have the same amount/thickness of cones and washers on each side of the hub?

Is there a bicycle co-op or a good bicycle shop near you?

A good bicycle shop, if visited in the off hours (when they're not busy), might have a quick look at your tricycle and tell you what's wrong with that front wheel. A bicycle co-op often has knowledgeable people there who are more than willing to help others.

A possibility for the off-center wheel is that the rim itself is not centered over the hub. You can check that very easily simply by taking the wheel off the bike and putting it back on the opposite way. If you do that and the wheel is closer to the other side than it is now then you know it's the rim that's off center.

One other thing. It's a long shot but is the front fork bent sideways a bit? To check that take the wheel off the trike and set the fork blades on a LEVEL surface. Then take a string with a weight on one end of it and tie the string to the hole in the center of the fork at the top. Allow the weight to dangle between t he fork blades. Check that t he distance between each fork blade and the string are equal. If they're not then the fork is bent sideways or not assembled properly.

Cheers

Wilfred Laurier

With the wheel that far off centre it is possible that one of the brake pads is diving under, or otherwise not properly contacting, the rim when braking.

You must ensure the wheel axle is fully seated in the dropouts and the nuts are securely tightened before you set up the brakes. You would be amazed how often this step is overlooked, even by experienced and pro bike mechs. The results of this mistake are often weirdly functioning brakes and lots of time wasted trying to figure out why this one bike doesn't snap together like the previous 10000 bikes.