• Welcome to the website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Hon. Editor and Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this website.

    If you have previously registered to use this forum, you should log in now. CLICK HERE.

    If you have never registered to use this website before, please CLICK HERE.

FT: Frame (Twin) New 7" Brake Shoes

davidd

Well Known and Active Website User
VOC Member
Vincent,

I could only understand a very small portion of what was in the book. I think I have conveyed it correctly, but it would be nice if someone else understood the subject. It does contain much that is understandable.

The drum brakes analysis starts with what they call the "basic circle", which is used as a standard to do the more specific geometry for shoe factors and lining pressures. The pressure calculations are here and I stop before the next section, which is the shoe factor calculations:

Capture 082.PNG

Capture 084.PNG

Capture 086.PNG

Capture 088.PNG

Capture 090.PNG

Even without a full understanding of the material, it becomes apparent that the geometry of a brake is not to be taken lightly!

David
 

MartynG

Well Known and Active Website User
VOC Member
Vincent,

I could only understand a very small portion of what was in the book. I think I have conveyed it correctly, but it would be nice if someone else understood the subject. It does contain much that is understandable.

The drum brakes analysis starts with what they call the "basic circle", which is used as a standard to do the more specific geometry for shoe factors and lining pressures. The pressure calculations are here and I stop before the next section, which is the shoe factor calculations:

View attachment 33654

View attachment 33655

View attachment 33656

View attachment 33657

View attachment 33658

Even without a full understanding of the material, it becomes apparent that the geometry of a brake is not to be taken lightly!

David
Cripes - my head is in a tailspin!
 

vibrac

Well Known and Active Website User
VOC Member
Well there is a lot of math there but not a lot of conclusions one thing I can agree with is if you extend the linings over the 'valley' on a Vincent shoe then the center of the lining wears appreciably more than the ends
One thing I will try is a softer lining on the trailing shoe that 'good brake feeling' time after new linings that soon goes away needs extending
 

Matty

Well Known and Active Website User
VOC Member
There was a time when replacement brake shoes for the post war bikes were difficult to source. I have been involved with the development of replacement shoes and a photograph is shown of the items. They are made of LM25 heat treated and several changes (hopefully improvements) have been made to the originals. They are stiffer than the originals by incorporating stiffening webs. They do not have the small tongues sticking out to take the springs. Instead they have robust through holes. In addition they do not have the dips at the end of the brake linings which allows a longer lining to be use if wished. They will be supplied in pairs only, complete with the spring and metal end plates (H48) fitted. The price, per pair is £80 and you can organise the fitting of your preferred linings if you wish. Alternatively, they can be supplied with linings suitable for touring use or alternatively for racing use if you wish. The price for touring linings fitted is about £12 per shoe.
View attachment 32928
 

Matty

Well Known and Active Website User
VOC Member
Hi Timetraveller
The brake shoes could well be of interest to me, but where can I buy them please - presumably on line.
Matty
 

timetraveller

Well Known and Active Website User
VOC Member
Not on line. You have to buy them through me but at the moment I am still waiting for the lined shoes to be returned. Some thing are going very slowly at the moment and I don't know where the hold up is.
 

Matty

Well Known and Active Website User
VOC Member
I sent my old brake shoes to Saftec on Friday and they said when I rang them, that they arrived Monday 4 May and will be shipped this week with Green woven linings which I hope to try for grip when I have fitted them.
Will have to sneak out to get some medication and milk at a service station 2 miles away - but this will hardly be far enough for them to bed in and for me to make a proper assessment.,
 

vibrac

Well Known and Active Website User
VOC Member
You have a job to beat Saftec turn around knowledge and expertise they can certainly turn a clutch plate covered in holes for cork insertions into a full face dual sided non slip item in 3 days door to door
 

nkt267

Well Known and Active Website User
VOC Member
You have a job to beat Saftec turn around knowledge and expertise they can certainly turn a clutch plate covered in holes for cork insertions into a full face dual sided non slip item in 3 days door to door
Any sign of sinkage into the holes..i have found this on one set of plates on my brother in laws bike..No idea who did them. Had mine done in a random woven material by an old timer near Norwich and they are fine.
 

vibrac

Well Known and Active Website User
VOC Member
No all flat this is on a 1935 KSS works a treat and you know what velo clutches can be like. Before this one slipped on kicking over now it's like a newby! and yes I long ago made my 1/4" rod with a flat on so I do know how to adjust them:)
 

oexing

Well Known and Active Website User
VOC Member
A real silly idea to add chain links into the springs there. All you get is a heavy action on the bar levers as the short spring gets overly hard with stretch. Just get longer springs, soft enough to just return shoes to the stops, no need for extra stress for your hands. Plus I´d go for stainless steel springs that will not break in use - which seems to be a drama on Vincents in places ???
In the photo a Laverda drum brake , its levers got a pin (not shown) that goes into bores in the shoe, so no steel caps required. A little high temp grease in there and you´re done.

Vic
P1080082.JPG
 

timetraveller

Well Known and Active Website User
VOC Member
OK Gentlemen, the lined brake shoes have finally arrived. They look to be a very nice job and the linings are both bonded and rivetted. I will contact the two people who made definite orders, Vincent Speet and Peter Holmes and if any of the other people who made enquiries but did not place definite order wish to go ahead then now is a good time. The total price worked out as expected, £80 for a pair of shoes and £24 for the linings fitted. The sets come with new springs and new, H48 steel shoes fitted.
1589365720573.png
 

oexing

Well Known and Active Website User
VOC Member
The shoes look great but I see some scope for improvements: The springs look very hard being very short with small diameter of windings. And this at NO use that I could see. I´d move the holes a bit - 1/4" away from shoe ends and go for bigger diameter springs with windings at max. length so hooks can slip into holes - just. It is simply useless to have extra strong springs , a pain to assemble and extra strain on our old hands when applying brakes. Also get stainless springs, no breakages as these are a bit softer material but no problem with this in this application. Overly strong springs are often found in brakes but I just cannot think why this is done , not my thinking for sure. All pull for springs reduces power for hitting brakes by hand strain.

Vic
 

vin998

Well Known and Active Website User
VOC Member
VOC Forum Moderator
Vic
If you move the springs away from the shoe ends this moves the springs closer to the speedo drive gear which may be a problem. I know in the original setup the springs are extremely close.
 

oexing

Well Known and Active Website User
VOC Member
Yes, accepted, I don´t use these brakes and cannot tell. But this is a point to keep in mind for possible minor improvement. Also one could move spring holes a bit out direction linings for longer springs and more windings so in effect this makes for less strain on hands. Brake shoes can be narrower at their ends for moving holes out. Most bending action is in center of shoes, not at ends so doable.

Vic
 

peter holmes

Well Known and Active Website User
VOC Member
It would seem a little premature to condemn the shoes as badly designed, I think I will reserve my judgement until after I have fitted and tried them, as far as difficulty in installing them goes, doesn't the time honoured fashion of fitting them over the cam first and then stretching the spring using the shoes to engage them over the pivots make it a reasonably easy task, if your fingers have succumbed to arthritis get someone else to do this for you. I personally cannot wait to try them.
 

oexing

Well Known and Active Website User
VOC Member
I did not say the shoes were badly designed but cannot see any benefit of short hard springs when lighter types would do. One could have same spring but a thinner wire at same costs or less. Plus one could fit another at the lower hole positions undrilled in photo - as is typically done elswhere. All springs extra light for easy action when fitting and more so on the road. No reason given up to now why hard springs may be desirable as you got another set with twin drums on a Vincent . . . .

Vic
 

timetraveller

Well Known and Active Website User
VOC Member
Just to say that following Vic's comments I have used my bare hands on a pair of shoes with the spring fitted as shown in the photo and I can open them up about 6 mm (1/4") with my poor, weak 81 year old scientists hands, just by pulling, not levering, at the cam end. The body builders amongst you would move them more easily. :cool:
 

Latest Forum Threads

Can't Find What You Need?

Buyer Beware: Fake or Real?


Top