Brakes for F-frames

The brakes that come with most F-frames are very heavy chromed steel calipers with equally heavy (and none too comfortable) levers. Despite being flat bar levers, they take a “road” cable, with a barrel nipple on the end. The brake blocks were originally John Bull Rubber no.25 in metal shoes. After 60 years or so, the stopping power of this setup is very limited, and almost non-existent in the wet, due to the chromed steel wheel rims used.

Some models come with GB (Gerry Burgess) Sport Mk.III alloy calipers and matching levers, which weigh far less but are hardly more effective at stopping the bike.

If you must stick with the chromed steel rims (and they would need to be in exceptional condition – most well-used bikes have worn them down to rusty unplated steel on the braking surfaces), the best upgrade you can make is to fit Fibrax Raincheater blocks. These have been around since at least the 1970s and have a leather face to absorb water and give higher friction against wet chromed steel. They must never be used with alloy rims, as they will chew through them in no time.

For alloy rims, Kool-Stop salmon pads are the best. They have high friction, work very well in the wet and don’t embed grit or chips of alloy, which kill rims before their time.

Replacing the calipers is fraught with difficulty for two reasons:

• the brakes should pull from the right-hand side, looking at the caliper, because this is how the frame cable guides are arranged. Most modern brakes pull from the left, because they are designed for countries where the left lever operates the front brake, not the UK where the right lever operates the front brake.
• there is limited space between the rear brake mounting hole and the “cup” to which the suspension block is riveted.

Brakes with a right-hand pull tend to be vintage single pivots: GB, Alesa, Weinmann. These are worth upgrading to if you want to save weight.

Alhonga make dual-pivot brakes with right-hand pull but these will not fit into the space available. You will need to include a deep stand-off washer of about 12mm tall between the caliper and the rear forks. These are sold for BMX use and can be filed as necessary. I found it was necessary to chamfer the washer to get the caliper at the right angle, more or less parallel to the rear forks. Inserting a spacer has the added problem that it brings the RH rear brake block mounting nut very close to the chain, and a normal cylindrical washer tends to leave the caliper angled upwards, making things worse.

I used Tektro drop bar levers to pull the Alhonga calipers on my retromod speed, and they are not ideally matched; the levers pull rather too much cable, so the brakes are firm but not very powerful, much like they would be if using V-brake levers. Unfortunately you will not find much compatibility information available for obscure low-end components like these. The brakes are safe enough but not a patch on a properly matched set of Shimano dual-pivots and levers (which you can’t use, as the brakes are left-hand pull).

If you want good reliable braking above all else, an optimal solution (without frame modification) would be a rear coaster brake and a good front dual-pivot. A caliper with left-hand pull works well enough at the front as there is a good distance between the single cable guide and the brake, far enough for the cable housing not to be contorted into a tight radius. All coaster brakes have a reaction arm which must be clipped to the LH chainstay, but this is no problem. You can also get internally-geared hubs with coaster brakes, including the 2-speed models (vintage Sachs Duomatic or modern Sturmey-Archer S2C) that need no cables to the rear of the bike.