Brake mount issue.
 

I have a bicycle here that needs front brakes.

The issue is that the original boss/post mount v brake system utilized an pin system to adjust tension that cannot exist with the current setup. The pin tension adjustment system is made up of a two parts- the pin which is the spring in the caliper and anchor hole located on the boss or fork. Usually one or three vertically lined holes which can be used. With the three holed system it is usually with age the spring pin is moved to increased tension. The problem is there are no holes on the boss or fork to mount v brakes with springs.

I haven't access to new bosses - thus Im looking for a brake system that mounts by bosses/posts yet doesn't use the pin tension adjustment system.

Any suggestions?

A number of older DiaCompe and SunTour brakes use a cam behind one arm to adjust tension. The cam is adjusted with a large cone wrench and locked in place when the mounting bolt is tightened.

But, and I'm not sure if any have these stop cams on both sides. I have a few of these brakes and will take a look later on.

The U-brakes used on freestyle bikes and some older mountain bikes work in the way you describe, but the bosses are located above the rim not below it. Some of the older Paul's cantilever brakes adjusted in the same way as U-brakes though, with a spring block which was held in place by the brake bolt, but they fitted conventionally-located bosses. It sounds like you may need something like that.

Working Blind .. send pictures, &/or more Data*,
or go out to bike shop for workers that can see what you have.

U brakes , only other U brakes fit. pivot-post is above the Rim
cantilever/V brakes are on bosses below the rim.

*measure boss location as a radius to the axle..

state that number, and the radius of the rim.

wheel size-type.

The bosses are for cati/vbrakes being below the rim. The bicycles in a mtb with a 26 inch wheel.

Measured from the axle mount on the fork, the distance to the bosses is ~25.5cm or 10 inches.. I'm a bit unsure as to where you mean by, "radius to the axle"

Are there any new v brakes that can be ordered?

Lots of them, state your price point. cheap or ?

cheaper the better - but something that functions - nothing box shop esq

I just checked, and I have some DiaCompe 987 and 986 brakes with spring adjusting cams on BOTH sides. These will work fine on bosses without spring holes. I can give you a good deal on either (typically the 986 us used in front, and the 987 (low profile) in the rear.

If you're interested send me an email either through BF or via the contact link at the Chain-L site.