brakes

[RDfella]

Hello fellas.
The A10 GF saga continues. Full restoration of engine, frame, gearbox and tinware was a nightmare at every stage. What wasn’t worn out was either bodged, missing or broken. Anyway, took it for its first test ride yesterday. Frame handles well  - one of the best of the dozens of bikes I’ve owned / ridden over many years. Gearbox is fine. Engine has an intermittent annoying chain-like rattle. Not the dynamo or primary chain. Will have to look into that.
But the brakes. What brakes? I wasn’t impressed with the standard sls full-width setup, so made a tls conversion. Wasn’t keen on the sponginess so opted to fit a Triumph tls backplate unit. I had skimmed the drum, and it is still round despite the usual struggle to force a modern mis-shapen rim into a reasonable circle. The linings are new and a good fit. The linkage is properly adjusted, yet the brake is next to useless - the rear brake has considerably more stopping power than the front.
My M21 has a single-sided BSA 8” drum with tls conversion. It will bottom the forks. My B31 with sls single-sided BSA 8” drum will lock the front wheel. But this Triumph / BSA set-up on my GF wouldn’t skid on gravel. I appreciate that the older and no longer obtainable woven asbestos linings had far superior stopping power compared with modern materials, but this is unsafe. Anyone had similar issues, or should I change the wheels for something better? Those wheels are absurdly heavy and I could find far superior items, but I was trying to keep the bike as original as possible.
I realise brakes have been covered elsewhere, but a quick trawl didn't really throw up anything other than the consensus that these full-width brakes are rubbish.

[muskrat]

G'day RDfella.
Those brakes should be a LOT better than the standard. Something definitely amiss. Been 40 years since I had one so can't really shed light but I'm sure a member will be along to do so. Good luck.
Cheers

[Black Sheep]

Our A10 has the same setup as yours and the brake is good. There must be summat up.

[duTch]

  ^^what the other guys said ^^....I had one on mine on first rebirth, and as far as I recall it worked ok.....

 ** The same TLS was also fitted to '68-'70 BSA twins (may have different stamp numbers), so you can at least pretend it's one of these 

[JulianS]

The BSA/Triumph full width TLS is usually a fine brake, it can feel spongy but the stopping power is still there.

Some modern grey anonymous linings leave much to be desired.

You can get woven asbestos free linings fitted by a number of suppliers including Villiers services;


https://villiersservices.co.uk/index.php?main_page=page&id=9&chapter=4

With a skimmed hub you need thicker linings or just the leading edges will contact the drum.

The original A10 full width hub with straight spokes does loose strength when skimmed. The BSA/Triumph hub with verticle spoke flange is much stronger and resists distortion.

[Joolstacho]

The 'racer's trick' is to set the brakeplate up on a lathe, shim the operating lever(s) a touch so the shoes are JUST opened a mm or 2, then machine the shoes so they will be dead circular WHEN THEY CONTACT the drum track. If you examine the shoes as is, you'll probably see that they are only contacting over limited areas. You might need to start with oversize linings.

[duTch]

 

.... ** The same TLS was also fitted to '68-'70 BSA twins (may have different stamp numbers), so you can at least pretend it's one of these  .

  For what it's worth, and I'm sure you're aware, I better note that the '68 TLS is slightly different to the later ones #37-3462 (like mine- Just checked), but don't know if the Try- hard ones are same #number

[chaterlea25]

Hi RD,
The rear cable operated brake has a poor reputation usually because it has been set up badly and because of the wrong length cables being fitted
Your bikes rear cable /arm angle do not look too bad though?
The pattern shoes available are crap
Originally the A10 rear linings were thicker than "normal", thin linings will make the lever angle wrong
The shoes need centering in the drum, loosening the pivot nut and re tightening with the brake applied

I used to get Supreme motorcycles to fit the softest non woven linings they had to original shoes
get them oversize and machine them to size
Sadly Supreme are no more, but I found a company nearer home that have the same material 
They use it to reline shoes for classic rally cars

The only thing I can think of about the TLS front is the quality of the linings??

John

[BSA_54A10]

Mechanical brakes have to dig into the drum to use the momentum of the drum rotating to force the shoes into the drum.
There is no way a human hand or foot can apply enough energy to stop a motorcycle.
Thus the shoes are radiused to a slightly digger diameter than the drum.
When the leading edge his the drum, the drum forces it to flex and press against the drum.

Think about the last time you were driving a car and the engine cut out so the power booster was not working.
Two feet on the brake and all your muscle power barely slows the car down.

Hydraulic brakes are ground to the same radius as the drum because they are being forced into the drum by 300 to 3000 psi

[duTch]

 

...
Think about the last time you were driving a car and the engine cut out so the power booster was not working.
Two feet on the brake and all your muscle power barely slows the car down....

 well...um..hasn't happened in a while, but you're now bringing in Power assisted(boosted) that's a bit of a different equation...?

[RDfella]

Thanks for those replies. fellas.
Consensus appears to be linings. As I said in my original post, I’m no fan of modern lining material and have never found any to match the effectiveness of woven metal-reinforced asbestos. Having said that, this brake is not just bad, it’s appalling. I’d expect a new installation to be poor (it’s only done 4 miles so far) and to improve over a couple of hundred miles, but this starting point is so low it’s never going to be acceptable / safe. It’s even worse than BSA’s lousy 7” single-sider. Maybe an agricultural supplier somewhere has some NOS asbestos linings of appropriate thickness that I can cut to suit. Any suggestions in that area appreciated.
In the meantime I’ll pull the front brake – again – and see if I can improve anything. One thing I find surprising is the way the cams are linked. If you use the outer cable on one and the inner on the other (as I did on my 8” tls conversion) you get twice the leverage compared with sharing the leverage as is the case by linking them.

[worntorn]

Took a bit of fiddling and now my Super Rocket has excellent brakes front and rear.
TLS front.
New cheapo eBay shoes on the rear will lock the wheel on pavement .
I used stick on Emory to true drums and shoes.
This got rid of all pulsation and greatly improved the brake effect.

Glen

[chaterlea25]

Hi RD,

It’s even worse than BSA’s lousy 7” single-sider.

I will have to disagree with that statement 

I have a 7in. BSA hub wheel fitted to my 500 Ariel HT5 that's in road trim
It used to have green Ferodo linings in it which gave an excellent brake
I had the shoes relined with woven material and turned the shoes to suit the drum diameter,
The result was very dangerous, it would lock up the front wheel event though the shoes were well chamfered
Long story short was the linings did not work at all in the rain and soon buckled between the rivits
Supreme replace the linings with the soft non woven material I mentioned and once these were machined to fit
the brake was and is brilliant,
Mostly the Ariel is ridden two up with a combined weight of probably 24 stone 

Works for me
John

[RDfella]

chaterlea - we'll have to agree to disagree. Know from your posts that you know a lot more than you let on, but my experience with 7" s/s has been not good. Started racing a B31 in the early sixties in hill climbs and sandracing. No matter what I did to its 7" it was at best poor - hence my fitting the 8" which works great. Will lock the wheel if you get too ambitious! My son now races it when he gets time. Similar experience with my M21. Agreed the added weight / speed of its vee twin engine puts extra demand on the brakes, but it was again vey poor and it now has a tls conversion on another 8" s/s. Personally I prefer iron drums, either alone (eg 7") or in alloy, as I've seen 8" cast iron ones crack.
On a PS, the B31 and my Weslake (and the Hagon japanese I had at one time) are on methanol. I always liked motors on dope - they seemed to respond better, or is that just my immagination?

[chaterlea25]

Hi RD,
Notabother 

I have an A65 single sided iron hub with a Taylor Dow TLS brake on  the front of my SR
(it has the slightly narrower shoes though ) It works well but needed a lot of setting up due to inaccurate machining first day
About 10 years ago I smashed my right wrist and it has never been a strong as it was before, so I need to have the brakes as good as possible
I found a B44 single sided hub in USA some years ago that will be fitted to the B33.9 under construction
(must investigate a TLS setup as £6-700 for a replica would hurt)
(B31 frame and hybrid big fin goldie engine, STD box and so on)

Know from your posts that you know a lot more than you let on

Dunno about that I have not made my own engine like you have

Although a future project is a set of castings (some part machined) to build one of these quasi japanese V twin replica engine ( I hope the project will be more subtle on the cycle parts side though)
http://lamb-engineering.com/spirit-of-endeavour

John