trance 27.5

No matter what I do, this V brake doesn't get centered... what am I doing wrong ?

Thanks

SoSmellyAir

It depends on what you have tried so far. Is one of the arms stuck (even with no adjustment screw installed)?

trailangel

True the wheel first!

sweeks

At 3:05 it looks like Calvin has the thin concave and convex washers in the reverse of the correct position.

Andrew R Stewart 

The very first aspect I see is the rear wheel sitting off center. It might just be a photo angle thing but if the wheel is that far off it will make centering the pads (to the rim) a bit more challenging. I would look into this to see if the wheel's centering can be improved.

Not knowing what you have tried yet, with pad centering, has us at a disadvantage, or means we'll be repeating your previous efforts needlessly. Pivot post friction, pad mounting spacer thicknesses, return spring strengths and their adjusting screw position and even cable casing arrangement will all contribute. Andy

cxwrench

Trying to center the cheapest v-brake on the planet.

soyabean

Sometimes the washers are incorrectly ordered or perhaps missing.

This is common with a lot of new big box store bikes. Customers that buy new don't know any better.

Your LBS has the correct parts to solve this.

LBS can also true rim if required.

cyccommute 

Not “true”. Dish is what is needed (maybe). Make sure the wheel is centered in the dropouts first but it may need to be properly dished.

ClydeClydeson

You need to centre the wheel in the dropouts. This is a very common mistake that leads to much frustration when adjusting brakes.

trailangel

Oh my! I stand corrected.

Andrew R Stewart 

As to the wheel's needing dishing- I will not be surprised if it dished well. That the rim is centered WRT the axle ends (lock nuts likely on this grade of bike). Instead, I wonder if the frame is off as in one seat stay is longer than the other. Andy

hokiefyd 

All other suggestions are good. It appears the left arm's spring adjustment screw is threaded further in than the right arm's screw. Assuming the arms move freely on the posts, this is a pretty strong clue as to why they don't appear centered on the frame. Either tighten the right side screw or loosen the left side screw, or both. I definitely agree with others regarding the wheel centering and camera angle. If the tire and rim really are biased to the left, you'll need to fix that before the brake arms can be centered on both the frame and the rim.

trance 27.5

Thanks all, definitely the wheel is not centered, but I wouldn't touch the dishing. This is a walmart bike that I have changed the sprocket, chain and derailleur, and cable which is now better. The brake is the last thing I will try to mend on this bike and I will do it this weekend. Reason for buying this bike is, my daughter is short (4'11"), and it's very difficult to find anything that fits her. She doesn't like mtn bike type bikes. And she will be using the bike to university in a few months.

cyccommute 

Dishing really isn’t that hard. You could even do it in the frame. All you need to do is to tighten the spokes on the driveside of the wheel. Tighten each drive side spoke 1/4 turn to begin with. You may reduce the amount you turn the spoke each time as the wheel comes into dish but, again, I doubt it would be much of a problem.

You may need to loosen the spokes on the nondrive side but, given that this bike is a HelMart bike, I doubt that the spoke tension is proper anyway.

Use a zip tie feeler on the chainstays as a guide. You can check the dish by turning the wheel around in the frame without disturbing whatever you are using as a gauge.

I fully understand the small bike problem. I’ve dealt with it for more than 40 years. My wife is 5’ tall.

urbanknight

Are the brake pads touching the rim at the same time? If so, they are as centered as they need to be given the circumstances. If not, the best way I learned to adjust those cheap V-brakes is to manually bend the spring (thick, straight wire that should be behind each of those brake arms... does yours have them?) to pull more or less as needed.