The BSA A7-A10 Forum

Technical => Frame => Topic started by: BSA Biker on 05.12. 2017 21:23

Title: Front Brake Upgrade
Post by: BSA Biker on 05.12. 2017 21:23
Over the last few years it has become apparent that the standard 8" front brake on my 1960 A7SS is not up to modern standards. Has anyone changed to the later A50/65 twin leading shoe model as used in the later 1960's, is it a straight swop or is it necessary to "adjust" things. The biggest concern is finding a set up (plate, shoes and cable etc) at a sensible price. Any information gratefully received.
Title: Re: Front Brake Upgrade
Post by: JulianS on 05.12. 2017 22:32
Not straight forward. The lug on the A7 A10 fork leg is shorter than the A65 twin leading shoe type. The TLS brake plate does not properly engage unless some work is done.

This has been dealt with before on this forum if you use search facility you will find it.
Title: Re: Front Brake Upgrade
Post by: KiwiGF on 06.12. 2017 00:25
Over the last few years it has become apparent that the standard 8" front brake on my 1960 A7SS is not up to modern standards. Has anyone changed to the later A50/65 twin leading shoe model as used in the later 1960's, is it a straight swop or is it necessary to "adjust" things. The biggest concern is finding a set up (plate, shoes and cable etc) at a sensible price. Any information gratefully received.

Have you tried all the various mods to handlebar levers, drum lever angle and position, sanding shoes/drums etc? I’m about to try to improve an a65 brake, which by all accounts SHOULD have been an upgrade to the std 7” inch.....but was no better. Very disappointing. See pic.

I guess I’m saying fitting a better brake is not a 100% cure for poor braking, every brake needs setting up to work at its best, which is not always easy. I’m not sure how good the late 8” brake is on the a7, or if it’s possible to get them to work well.

I’m working on improving my a65 brake today, I’ll let you know how I get on.
Title: Re: Front Brake Upgrade
Post by: KiwiGF on 06.12. 2017 02:17
Here are some pics, the leading show was only contacting on less than 25% of its surface, it’s now contacting on 100% of the sand paper, but that is slightly smaller diameter than the drum....hopefully if it needs to wear in that will happen fairly quickly.

I tried 280 grit first (being thinner, so affecting the drum diameter less) but the paper tore. 140 grit worked fine, it clogged quickly so I had to clean it once before the shoes became evenly sanded. I guess I turned the wheel about 40 times with only light pressure on the brake.

I used car decal “refit tape” to glue the sand paper to the drum. When finished getting the rubbery glue off that was left on the drum took a while, using brake clean fluid and elbow grease. I used a bit of left over sanD paper to make sure it was all off.

I’ll road test the brake later on today, but I’m already happier the shoes will contact the drum better :-)
Title: Re: Front Brake Upgrade
Post by: worntorn on 06.12. 2017 02:30
Stick on abrasive disc work well for this. They can be cut into strips @the correct width for the drum. Thickness is minimal this way.
The stick on discs don't seem to leave adhesive behind.
They can also be put on the other way around to true the drum. The drum side takes a little longer and more effort than the shoe side, but it's still not a big job.

Re the A65 2 leader- I fitted one of these to my A10. Initially I just used the A65 brake plate in the A10 wheel and drum. That did not work well as the A65 brakes are a little too wide for the A10 drum.  I have since fitted the entire A65 wheel to the A10 and it is a very good brake.
Lug alterations , either on the fork or on the brake plate are necessary as Julian posted.

Glen
Title: Re: Front Brake Upgrade
Post by: olev on 06.12. 2017 02:45
I noticed in Berger's intro post he had modified his brake so the arm was pointing forward.
My old velo venom also had the arm facing forward.
Keith seems to like his setup and from memory there was nothing wrong with the velo's braking.
Any ideas if this makes a difference?
cheers
Title: Re: Front Brake Upgrade
Post by: KiwiGF on 06.12. 2017 04:09
I noticed in Berger's intro post he had modified his brake so the arm was pointing forward.
My old velo venom also had the arm facing forward.
Keith seems to like his setup and from memory there was nothing wrong with the velo's braking.
Any ideas if this makes a difference?
cheers

I will try this mod to brake arm position next, after sanding the shoes I’ve found the brake is better by maybe 30% but still not a good brake. It feels like it’s still bedding in and improving though. I feel I’m hi jacking the OP thread so I’ll report on this other mod elsewhere.....I recall seeing it mentioned elsewhere, the improvement (I think) was something to do with improving the leverage on the leading shoe, as that does most of the braking work.
Title: Re: Front Brake Upgrade
Post by: JulianS on 06.12. 2017 09:35
Worntorn makes a good point re the A65 hub. It has a 1 5/8 inch brake surface (A10 1 1/8) and has a verticle spoke flange which greatly increases its strength. See first photo.

The lug on the A65 TLS fork is longer. The second photo shows A65 Lightning 1968 leg top and A10 leg bottom.

To get the necessary safe engagement in the brake plate either the fork lug needs lengthening or the brake plate slot needs building up.

When properly done the brake is great.
Title: Re: Front Brake Upgrade
Post by: mikeb on 06.12. 2017 09:45
kiwi - extending the thread hijack, are you talking about rotating the arm so it faces forward? and also rotating the brake plate accordingly some degrees with a longer anchor strap and so the cable holder becomes the anchor point. its covered well in other threads the theory being the SLS brake cam then pushes out the leading shoe a little further than the trailing shoe so the leading one bites first (the standard setup has the trailing shoe being pushed further which has less bite/brake). think about the rotation of the cam and the shoe sitting on the inner edge gets pushed more than the one sitting on the other edge (if you draw it it makes sense - triangles and stuff). Some BSA racers in the 50s did this apparently. you may need a longer cable.
ANYway if that's what you mean i did it to my b33 and it helped a bit - not massive difference - but now a better brake than the a10. probably worth the trouble. wish i had a proper TLS setup
Title: Re: Front Brake Upgrade
Post by: duTch on 06.12. 2017 10:13

 Just to hijack a bit further-  *smile*   I think what K-GF and mike are saying is the same logic behind the Rigid models rear brake- I tried to do it on my Plunger A10, but was a dismal failure due to messing with the plunger unit/axle travel....but probably works fine on a Rigid
Title: Re: Front Brake Upgrade
Post by: chaterlea25 on 06.12. 2017 13:02
Hi Kiwi and All,
In the fist photo of the brake, the arm is at a very inefficient angle to the cable *problem*, are the linings worn?
The arm and cable angle should be less than 90 degrees,
This makes a massive difference to the braking effort
The brake arm can be reversed on the cam to get finer angular adjustment as the "splines are not cut square to the arm
You may find that the steel "shoes" between the cam and shoe are missing ? or that semi worn shoes need packing out ??
I have cut 1.5mm thick steel strips and folded them around the cam end of the shoes, in the absence of the original parts

Once set up properly the 8 inch single sided BSA brake is regarded as the best performing BSA front brake
without resorting to modifications

John

Title: Re: Front Brake Upgrade
Post by: KiwiGF on 06.12. 2017 19:51
kiwi - extending the thread hijack, are you talking about rotating the arm so it faces forward? and also rotating the brake plate accordingly some degrees with a longer anchor strap and so the cable holder becomes the anchor point. its covered well in other threads the theory being the SLS brake cam then pushes out the leading shoe a little further than the trailing shoe so the leading one bites first (the standard setup has the trailing shoe being pushed further which has less bite/brake). think about the rotation of the cam and the shoe sitting on the inner edge gets pushed more than the one sitting on the other edge (if you draw it it makes sense - triangles and stuff). Some BSA racers in the 50s did this apparently. you may need a longer cable.
ANYway if that's what you mean i did it to my b33 and it helped a bit - not massive difference - but now a better brake than the a10. probably worth the trouble. wish i had a proper TLS setup

Hi Mike, yep that was what I’m thinking of trying, using the cable holder as the anchor point. I did a search under “frame” and did not find a thread on doing this, it’s probably there but I don’t know the correct search phrase  *dunno*

I’ve a slight concern as to whether the cable anchor strap should be used for the torque arm, as on the a65 brake it looks like the torque arm bolt may be reinforced, it does stand proud of the plate, on a domed area. I’ll have a close look inside it to see.

It also occurred to me that it may be possible to make the shoes floating type if the shoes pivot bolt is no longer used as a cable holder.

Any chance of a pic of what you’ve done ?

Title: Re: Front Brake Upgrade
Post by: JulianS on 06.12. 2017 20:46
Link takes you to some photos of the A7 Daytona racers with reversed brake arm.


https://www.flickr.com/photos/michel_67/galleries/72157622269890351/?rb=1

However I must agree with chaterlea25 about the lever angle - the brake will not work at its best until this is rectified.

Note the lever to cable angle on the Daytona photos.
Title: Re: Front Brake Upgrade
Post by: berger on 06.12. 2017 22:11
I like that Daytona bit, the goldstar racer who advised me on mine must have seen that done. anyway if you look at the pic on mine on the introduction you will notice you don't need a longer anchor on the brake plate but a shorter one, I re drilled mine and left the original hole just in case of putting it back, the holes in the brake plate were put in before I got the bike in the seventies and it had an  air scoop on it with the small holes now hidden behind the brake arm and those big holes that used to sit at about 9 oclock. ps ive run it for 8 odd years like this and hard braked with no trouble. we pushed our bikes side by side and snatched the brake on ,mine didn't stop dead and his did. when I did the modification without fettling the drum or shoes mine stopped dead also.
Title: Re: Front Brake Upgrade
Post by: berger on 06.12. 2017 22:16
sorry should have said , pictures stories and introductions section to enlarge the pic of my brake drum.
Title: Re: Front Brake Upgrade
Post by: Sluggo on 06.12. 2017 22:58
I have a bunch of the TLS wheels and brakes and they work great when properly sorted, but the problem is their appearance for stock bikes,  But if you can get past that

(I do easily, I even have Choppers,,shsshh dont tell anyone *whistle*, you date a sheep just once and you forever are known as that Sheep shagger)

But I have an old WASSELL catalog from the mid 1960s and theres some ads in there (Very comprehensive catalog its about 2 inches thick and nice quality pages) for TLS brake conversions.  I can scan some tonight and post up in a separate brake posting, And I have an old original Eddie Dow Duetto accy catalog,, all kinds of accy but he was known for his TLS brakes he called Duetto's..

I also have a complete collection of the old Domiracer catalogs and they are a trove of useful data, Ill take a peek in there too.

I collect old catalogs, sales literature, magazine articles and factory tech materials (A little bit OCD & Hoarder) but I used to reprint and sell this stuff back in the day.  There is a shortage of it and most people are unaware of most of it so, I felt it was useful.  So did others, especially a Aussie who bought a lot of my stuff and included it on his CDs he sells, and then has the temerity of asking people not to pirate or copy his material (Talk about Sheep Shaggers & Buggery).

I was meaning to contact admin and ask about server size and hosting, I dont want to bury his data cache in tons of material but happy to share some of it,
Im coming out with a updated version of some of my old chopper guides (Sportster chopper guide, How to chop a Harley 74, Triumph chopper guide, Triumph Mechanics guide, AEE chopper guide, Jammer chopper guide, and some others.  With all these young millennials and skinny jean hipsters getting into old bikes they are pretty excited about old stuff that was made before they were a gleam in their daddys eye.)