1951 A7 Star Twin front brake

[Rex]

The little pressed tin 7"  front brake on my bike isn't really up to 21st century road conditions, and even though I try to ride according to the constraints of this brake it can still be a little scary at times.
The drum has been skimmed and the linings fitted to suit, the linings are new softer material and the cable is heavy duty, so not much more to be done there.
I've seen on the C10,11 and 12 forum (the C12 uses the same miniscule front brake, good old BSA cost savings again) that it's possible to adapt an Indian Enfield TLS front brake to fit, and wonder if anyone here has given it a go?
For about 40 quid delivered it's worth a punt I reckon.

adm edit: title edited > descriptive titles in the tech boards.

[BSA_54A10]

Traffic in Oz is nowhere near as heavy as the UK but I do thousands of miles a year on the M20 with even less effective brakes than any A series
The front brakes only ever get used to hold the bike stationary at traffic lights
The rears have been replaced a few times as I use them to stand the bike up after cornering
These bikes use mainly engine braking which is quite effective
Tap it back 2 gears and your eyeballs will just about pop out.
It is a common problem younger riders have when they get onto an old bike because they are used to disc brakes that do all the stopping and the engine often stays in top gear till they pull the clutch in .
In fact even on the SR500 I got pulled over by a cop because my brake light was not functioning
I pulled the brake lever in and it illuminated , same for the foot brake .
He then wanted too slap a defect sticker on it because he was ardent that I some how was bypassing the brake light .
I challenged himas to why he thought this andhe replied "I have followed your from Kings Cross through to Chatswood, right throught the city & did not see the brake ite come on once"
I replied "That is because I ride British bikes mostly that use engine breaking so I rarely need to use the brake "
I then jumped back on the bike tossed a U turn stopeed a dozen times without touching the brake .
SO I then got an earbashing about not supplying information to vehicles behind that I was slowing down & he wrote me up for Neg Riding
I took that to court & won hands down .
As luck would have it the magistrate rode a Trident & Interstate 

[Minto]

Rex, I wonder if you would mind popping up a couple of pictures of your current front brake along with a shot of the forks. I think I might have the same front "brake" as you, and after a couple of close calls with miopic drivers at junctions recently, I'm keen to find out about this possible Enfield enhancement.

[jhg1958]

Rex

I bought an extended leaver for my front brake on my A10. Whilst the front brake is hardly TLS performance I am impressed at its stopping power.

Cheaper and easier than a full change.

John

[Rex]

Rex, I wonder if you would mind popping up a couple of pictures of your current front brake along with a shot of the forks. I think I might have the same front "brake" as you, and after a couple of close calls with miopic drivers at junctions recently, I'm keen to find out about this possible Enfield enhancement.

OK, will do.
Regarding fitting a longer brake arm, "nothing is for nothing" as they say in the world of Physics, and although  a longer lever may give an easier but longer pull, it won't fix the brake's basic shortcomings, namely the drum is too small both in width and diameter and the backplate is little more than pressed tin with no inherent rigidity.
TLS won't instantly make it into a brake for doing stoppies, but it should improve it to a degree.

[muskrat]

G'day Rex.
Having the Ariel wheels on my Cafe the brakes were just ok. I did as John and extended the lever 1". The extra leverage made a big difference but at the expense of more hand lever travel.
Cheers

[RDfella]

The standard 7" front brake on my B31 wouldn't stop a wheelbarrow. Raced it like that for years (brakes only slow you down) but eventually swapped it for an 8" single sided. Much better but, still looking for improvement, fitted a longer arm. Well, after getting into a hairy tank-slapper when I locked the front coming into a corner, soon returned to standard length arm. Does make a difference! 

[Black Sheep]

A 1951 Star Twin should have an 8" front brake (in my opinion BSA's best) and my one will squeal the tyre with a good enough pull on the brake lever - as when a stag jumps out in front of you. At least I think it's the tyre that squeals... The pic should show you the correct brake.
You clearly have the standard A7 front brake. And yes, they are pretty rubbish.

[Rex]

A Google image search shows more Star Twins with the smaller front brake than the later better one, so either some bikes have been sensibly upgraded over the intervening 70 years, or BSA did what BSA always did, and used up existing stocks first.

[Rex]

Turns out that Enfield TLS front brake fits on the nearside, while the original BSA brake is mounted on the off-side, so unless a Twin Trailing shoe brake would be an improvement (unlikely!) this idea is dead in the water.

[Brian]

Rex when you are googling images of Star Twins and looking at the front brakes make sure you are looking at the correct years. The 49' and 50' Star Twins had the 7" front brake, the 1951 and onwards had the 8". The 49' and 50' Star Twins are "longstroke" A7's, the 1951 was a complete re design with the "shortstroke" engine.

[Rex]

Brian, rather than Google images I just look at my bike's front wheel, and it's a 7" brake.
Given that it's rather unlikely someone in the bike's past would swap out the 8" brake for a diminutive 7" inch unit, it's pretty certain that BSA used up old stock 7" brakes before starting fitting the later 8" types.
As previously said, there's plenty of images on the Net of '51's with the smaller front brake.
It's all rhetorical anyway; what I would like is a more effective front brake, and originality isn't a big concern of mine.

[Triton Thrasher]

Turns out that Enfield TLS front brake fits on the nearside, while the original BSA brake is mounted on the off-side, so unless a Twin Trailing shoe brake would be an improvement (unlikely!) this idea is dead in the water.

Can’t it be fitted on the nearside on a BSA, even if it means making a torque anchor or swapping the BSA fork legs/sliders over, left to right?

[Rex]

Fair point.

[chaterlea25]

Hi All
I have the 7inch brake fitted to a 21inch rim on my Ariel HT5
I know this bike is lighter than an A7 but when the drum is carefully skimmed and machined to size linings fitted it will easily squeal the front tyre 

John