Author Topic: c10 front brakes  (Read 1082 times)

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Online Owen

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Re: c10 front brakes
« Reply #60 on: October 16, 2020, 05:57:56 pm »
Glad you got it sorted.
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11

Offline isleofmanpaul

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Re: c10 front brakes
« Reply #61 on: October 16, 2020, 07:53:47 pm »
Hi, got the shoes on my Comet front brake relined, used "Friction Services (Bristol) Ltd . Got them back in just under a week , 4 shoes , paid £46.74 incl VAT ,well pleased .
 It's nice to be able to recommend someone , just saying . :)

Online Owen

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Re: c10 front brakes
« Reply #62 on: October 16, 2020, 08:11:39 pm »
I've got mine from  Martyn Bratbury and had no problems.
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11

Offline ThomasC11

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Re: c10 front brakes
« Reply #63 on: October 22, 2020, 12:30:30 pm »
Now that I have got the right brake shoes for my C11, I can give away the pair I have installed so far. Probably they are shoes of a Bantam. But I am not sure.

Also I can give away a speedometer cable. It is new and 125cm long.

Everything is free of charge and I also pay the shipping costs because I always get great help here. So if you can use it, please send me a PM.

Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai

Online BSAc11g

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Re: c10 front brakes
« Reply #64 on: October 26, 2020, 12:41:36 pm »
Hi Thomas,
In the diagram below, if the wheel is rotating in the direction of the arrow the leading shoe is the one on the left. As the drum rotates against it the friction between the drum and the shoe pulls the shoe out harder against the drum. This is called the self servo effect of the leading shoe. When Trevor refers to the outer edge of the cam I assume he means the lower edge in this diagram (that is, the edge closest to the outside of the drum).

Hi Trevor,
I think you've got the effect of the cam the wrong way around. When the brake is applied both edges of the cam move the same distance and at the same speed, but they effect each shoe differently because the outer cam edge is further from the pivot point of the shoes than the inner edge. The cam is like a small gear wheel acting on two larger gears (the shoes) with the centre of the large gear wheels being the pivot point of the shoes. The shoe being pushed by the outer edge of the cam is effectively a larger gear than the other shoe because the contact point is further from the centre. As larger gears rotate slower than smaller ones, the shoe being pushed by the outer edge of the cam will move slower than the other one. Also, as a larger gear has more torque applied to it the shoe pushed by the outer edge of the cam will have more force applied to it even though it is moving slower. So the question is, what's more important, the force applied to the shoe or how fast it's pushed out?
Jim

Jim,
In your diagram the cam should rotate in a clockwise direction so the leading shoe makes a rapid contact with the drum & the trailing shoe which has no self servo effect gets the greater force applied to it .
I hope that is what I wrote .
If you are utilizing the rotation of the drum then you don't need all that much force to be applied.
Just enough to prevent the shoe skipping off the drum.
Bike Beesa
Trevor

Offline ThomasC11

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Re: c10 front brakes
« Reply #65 on: October 26, 2020, 05:48:29 pm »
The brake shoes are given.
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai

Offline c11jim

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Re: c10 front brakes
« Reply #66 on: October 28, 2020, 09:50:17 am »
Quote
Jim,
In your diagram the cam should rotate in a clockwise direction so the leading shoe makes a rapid contact with the drum & the trailing shoe which has no self servo effect gets the greater force applied to it .
I hope that is what I wrote .
If you are utilizing the rotation of the drum then you don't need all that much force to be applied.
Just enough to prevent the shoe skipping off the drum.

Trevor,
I accept that the leading shoe needs to move out as fast as possible and the trailing shoe with more force, but to achieve that the cam would have to turn anti clockwise as I explained in my earlier post.
Jim

Online Lilyloodles

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Re: c10 front brakes
« Reply #67 on: October 28, 2020, 12:11:01 pm »
I've got mine from  Martyn Bratbury and had no problems.
Owen

Sorry to say that the issue I had with my brake shoes recently being way to thick were from Mr Bratbury
tony