Make a FWH brake better ?

[Vincent.vanGinneke]

Hi all,

Ariel folk say it's a BSA design, BSA folk say it's a Ariel design.
Yes it's a heavy hub and indeed needs some TLC to coax some retarding from it.
I think part of the problem is that the 'pillars' where the shoes attach on are too high/long.
Possibly this makes it flex just enough to influence the braking .
Norton had something like this for the drum front brake called a stiffening kit.
As my wanted ad in the Cheval for a 2LS brakeplate got zilt-nada-njet result, this :
I like to make a stiffening plate from 6mm Dural with a round 'notch' that fits in the opening at the adjuster side.
On the actuator side it is held by the castellated nut.
There is some 4mm height difference to overcome between the two points.

So..Anyone out there done something like this on a FWH front brake and want to share some info ?
Or has this been done already ?
Thanks.

[nevhunter]

Just Put very soft Material on the trailing shoe so they wear more evenly. Nev

[SEDoan]

Hi Vincent, I'd be interested if that helps.

I've been kinda spoiled by the "sliding cam" servo-brakes at the front of my '47 Red Hunter - it really works when set up well. My pre-war Guzzi on the other hand was horrible until I read the article (pictured) and made some changes.

I removed some of the trailing edge of both shoes - especially from the trailing shoe. I also ground out the eye at the leading edge of the trailing shoe so that it could rise to make contact with the drum. It seems sloppy but this movement mimics movement of the sliding cam brake or other servo type brake. (Back in the day we also called them "self-energizing brakes")

When I got the '39 running it had terrible brakes even though the linings were new and I thought I'd set them up correctly. After messing with it a bit I finally shimmed the leading edge (not at the cam) of the trailing shoe for both the front and rear (fixed cam) brakes and the difference is wonderful. (the leading shoes were not shimmed). I was concerned that the asymmetric shimming would cause a problem with the rear brake but it has been fine.

Hope this is the kind of info you are looking for. Let us know how it works!

[Vincent.vanGinneke]

Thanks Nev, that was definitly one of the things to do !
Thanks SEDoan
I think the 'problem' is the cast aluminium, just like the rear brake plates on SQ4 Mk 1&2, they warp.
I also want to change the spot where the brake plate sits against the bearing- fork abutment,
thats also alloy, it all gives room for play.
The older brake plates are steel with steel spacers against the bearings, no room for play.

[allan.walker]

Norton had something like this for the drum front brake called a stiffening kit.

The stiffening kit is still available from Norton specialists, but I think that it should be mentioned that it was designed to be used with a twin leading shoe brake plate.
I have never seen anyone produce a stiffening kit for a single leading shoe brake. Does that mean it won't help? I have no idea, but I am interested in your suggestion.

I have a twin leading shoe conversion on one of my bikes, which I believe was made by a Club member. I bought it from a seller on Ebay and when first fitted it was pretty useless, mainly because the shoes were not contacting the drum evenly over the whole surface area. The lining material was rather strange, resembling moulded very hard rubber. I sanded the high spots of the linings after a short test ride, where I used the brake hard. I repeated this several times until there was even contact all round.

The brake was then reasonably good, certainly better than the standard sls, but there was very little lining left! I had new linings fitted (I think that they are made from something called 'green gripper.' The chap at the brake place said that he fits a lot of it for the classic racing lads.) I was suspicious of this woven material when I first saw it, but having used the brake enough to bed it in properly, it now works pretty well. The self-servo effect is noticeable, too.

[Roger Gwynn]

The best improvement is to remove 1/3 of the trailing lining or as Nev suggests use a softer lining on the trailing show, which will have the same effect. As the trailing shoe does less work that the leading shoe it wears more slowly so the leading shoe is less effective because it is always waiting for the trailing shoe to catch up. The 2 methods mentioned are devised to equal out the wear rates. Use soft linings, they will wear faster but stop better. I think those plates are very stiff and not likely to bend unless the torque arm is bent or is a BSA and not lined up with the plate. Release the t/arm from one end at a time to see if it sits in the correct place, also place finger across the gap between plate and hub, then apply brake, any movement will be felt.

[Vincent.vanGinneke]

Thanks !

[Paul Slootheer]

Be cautious and don’t be to over enthusiastic in your aim for better braking power. I’ve read horror stories about ‘exploding’ FWH front brake plates probl. due to a combination of aluminium fatique and increase in torque.

[Vincent.vanGinneke]

Hi Paul , that happend with -if my memory serves me right- with a FWH brakeplate with hydraulics fitted from a Mini.

[will_curry]

There is an article in Cheval on page 16 of the March 2016 edition which goes into
some detail about the failures.