Misc: Everything Else Brakes, Linings, Drums and Shoes

greg brillus

Well Known and Active Forum User
VOC Member
Matty I have to ask if you know what material your front brake drums are made of........The early ones are steel and no modern normal linings will work, only the very course woven linings work with these drums. From your description this sounds like your problem........A change to cast iron either plane or ribbed drums will make all the difference. Cheers.......... Greg.
 

davidd

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VOC Member
will it work better if the torque arms hang down like a "D"?? when it was done I had double the movement on the brake pedal so cut and shortened the brake arms by an inch?
I think that it will have the opportunity to work better with the levers hanging down. I am not certain why the lever would move further. A friend of mine walked into the shop when I had all the Vincent brake plates on the bench. He asked what I was doing and I mentioned the problem stated above. He told me that he had changed the lever on his Suzuki rear drum from down to up and in the last race he realized that his rear brake did not work as well as it did before. After I explained what he had done, he moved it to the original down position and it regained its former performance.

If you notice that your brakes tend to work better in reverse, then switching the arm would be logical.

I still wonder if it is really the material of the drums or if ribbed Shadow ones are the answer.
If your drums are cast iron I suspect you will find them about the same as Shadow drums. I tend to agree with Trevor that the major problem with Vincent brakes stems from the soft shoes. The shoes are not up to the task. Having changed the shoes I went with high friction linings and the combination seems to work well.

However different the performance is from the cam and the trailing shoe, the real culprit is the "equal work condition" problem that has been discussed before. It is almost impossible to get shoes to wear equally. What happens is that the leading shoe is pushed into the drum aggressively and wears very quickly. You are now stuck with the slow wearing (and performing) trailing shoe hitting the drum first until it wears enough to allow the leading shoe to hit the drum aggressively again. Matty has described how this happens. By eliminating or minimizing the trailing shoe you will get better performance. The reasoning is that the trailing shoe is preventing the leading shoe for doing a good job. A soft, high wearing lining on the trailing shoe would be an advantage. This is what Bill Hancock used to advise.

Apologies to Corey for the divergence.

David
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
I think that it will have the opportunity to work better with the levers hanging down.""" I am not certain why the lever would move further."""

David.
With normal set up with the cross shaft, cranks & rods to brake arms, if brake pedal pulls the cable 1/4" then rear arms move 1/4". With model "P" system where a continuous cable goes from brake pedal to LHS arm round the back of the wheel to RHS arm to an anchor point. Now 1/4" movement of cable will move LHS 1/4" but as the cable sheaved around the back of the wheel it has to be moved another 1/4" for the RHS arm to move the same as the LHS. Does that make sense? any way it is better but will look into hanging the arms down as sons "D"Rap ear brake has always worked better than the "B"&"C" rear brakes.
 
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Albervin

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VOC Member
A bit off tangent so sorry. Douglas was experimenting with expanding brake shoes and disc brakes in the 1920s. They had a combination of cable and rod for the front brakes operating on spun or pressed steel drums. Using the rod reduced sponge but braking was still woeful so they tried different linings and bang. If only they had used steel discs and fibre callipers instead of the reverse they would have nailed it.
 

Matty

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VOC Member
Thanks Greg - going back a few steps it could well be that my drums are steel - I will have to try with a file to try to find the texture of the metal. I have always felt there was some sort of incompatibility between the lining material and the drums.
I will have a look on the spares site for prices which will no doubt be high for plain or ribbed ones .
But does any one have some plain ones I could buy that they have taken off to replace with ribbed ones to make a Shadow wheel please.
Matty
 

Matty

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VOC Member
Yes the cost of new brake drums is very high, but where can I get some of the course woven linings to try as a cheaper option please
Matty
 

davidd

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VOC Member
I know that McMaster does not sell to the UK, but I think these linings are Green Gripper Woven (GGW) made by Scanpac. They have a high coefficient of friction at .52 cold. This is much higher than AM4 at .44. However, when hot the friction goes down to .43, still very good when compared to AM4 as AM4 drops when hot also. I think the static friction is very high at .56. This is good at stoplights on hills.

The cold friction performance is very good because the lining contains aluminum oxide, which is the material in your grinding wheels. Some complain about the higher wear, but I don't think I would be one of them. Several Vincent owners have used these linings for years and like them. I know that Carleton Palmer just put these linings on his Godet front brake. This is not a racing lining, just street.

I would see if your local brakeman can install Green Gripper. It cost me $35/shoe.

David
 

Hugo Myatt

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VOC Member
Yes the cost of new brake drums is very high, but where can I get some of the course woven linings to try as a cheaper option please
Matty
Villiers Services do relining of brake shoes for all bikes. They claim to suit linings to the particular model. The ones they supply for Vincents are woven. Whether they are coarse or not I would not know.
 
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