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[JP] 11-11-2019 10:11 AM

Confused about brake drums
 

Hi all,
need some help before my head melts.

I had a post about this some time ago where I was trying to figure out drums and hubs... but now I have a different one.

Starhubs - have the bearings in the hubs
Midstar - the hubs have bearings on it.

Correct?
If so, looking at my photo below, which I had up here at some point:

https://live.staticflickr.com/65535/...e85d0c1a_b.jpg


#1 and #2
Both drums for star hubs, backing plate for 63-66, along with the drums - juice setup

#3 has a 58-62 backing plate and also a 58-62 drum as it has the sunk in bit for the plate. and it's for a star hub - juice setup

and finally #4
All complete and its for 67-72, and bearings in drum is for mid star hub.

now, I got a complete mech rear brake setup... the bit (don't know the name) inside the drum is really tall. there's no bearings in it, so I assume it's for star hub right?
but why so tall in comparison with the other drums I have that are for star hubs?

https://live.staticflickr.com/65535/...4ccfc6ed_b.jpg

thanks!
JP

VonWegener 11-11-2019 12:46 PM

Re: Confused about brake drums
 

6 Attachment(s)
JP, the star hub was in production from 1936 to 1966. During that time Harley had three rear brake changes. The mechanical brake for rigid frame lasted until 1957.
In 1958 with the introduction of the swing arm frame they introduced the first hydraulic set. These drums are the same width as the mechanical drums but are different on the inside because of the different design of the hydraulic backing plate.
In 1963 as the bikes became heavier and more accessorized a wider rear brake was introduced. This wider brake design lasted until the end of drum brake rears in 1972.

Now with the wider width a new backing plate was needed. This one also lasted until 1972. All would be easy if they hadn't changed hubs for 1967. Therefore we have two kinds of wide drums. Since on a starhub the bearings are in the hub the first generation of wide drums has a similar design to the two drums before it. The '67 and later hub has the bearing inside and as such is easily detectable.
The mechanical backing plate is mechanical (duh) and has a star shaped embossing in the design. The first generation hydraulic backing plate has kind of an omega shape embossing and the 63-66 has a big ring around the outside and looks kind of like an early Ford backing plate.


There are two Axles for star hubs. A slightly shorter design (275mm) for the rigid frame and a slightly longer (285mm) one for the swing arm. All three share the same design of an axle or brake sleeve that rides on the axle and goes through the axle plate of the frame or swing arm.
That is followed by a backing plate to axle plate spacer and because of the different designs the spacers are different.
We have 4 designs of brake sleeves you can encounter. the mechanical one, the first hydraulic one for the narrow drum, the second hydraulic one for the wider drum and last the axle/brake sleeve for the 67-72 midstar hub hydraulic brake.


The backing plate to axle plate spacers are as follows.
No spacer on the mechanical brake.
A 29mm wide spacer for the 58-62 hydraulic brake.
A 13mm wide spacer for the 63-72


Hope this helps

[JP] 11-11-2019 02:05 PM

Re: Confused about brake drums
 

Thanks for the explanation Mike!
I need to print this off and take to the garage so I can read and point at what I have, looking at the screen is not working for me! haha

Once I gone through it, I'll update and correlate your description with photos of my stuff, so it may help someone else how comes along looking for this info.

VonWegener 11-11-2019 03:21 PM

Re: Confused about brake drums
 

Glad it helps you JP and linking the pics to the text will really help. I do not have pics of the drums as in the catalog pics they all look alike :)

[JP] 11-11-2019 04:12 PM

Re: Confused about brake drums
 

Yes.. I had a look on WW and all the photos are from the wrong side! haha

[JP] 11-12-2019 07:59 AM

Re: Confused about brake drums
 

Right, let's see if I'm getting this right and match photos to your explanation...

Quote:

Originally Posted by VonWegener (Post 2063428)
The mechanical brake for rigid frame lasted until 1957.
In 1958 with the introduction of the swing arm frame they introduced the first hydraulic set. These drums are the same width as the mechanical drums but are different on the inside because of the different design of the hydraulic backing plate.

here we have it, mechanical on the right, first hydraulic set on the left.
We can see both drums are the same - they both have the indentation that allows the backing plate to 'fall into the drum'

https://live.staticflickr.com/65535/...96b6e0f4_b.jpg

Inside we can see the drums difference between the mechanical and the early hydraulic - both are for star hubs.

https://live.staticflickr.com/65535/...a361d863_b.jpg

and on this one the different axle sleeves.

https://live.staticflickr.com/65535/...1128e483_b.jpg


Quote:

Originally Posted by VonWegener (Post 2063428)

In 1963 as the bikes became heavier and more accessorized a wider rear brake was introduced. This wider brake design lasted until the end of drum brake rears in 1972.

here's a comparison.
narrower at the top, wider at the bottom - we have lost that indentation that allowed the backing plate to 'fall' into the drum, therefore the need for the backing plate to be different and then gain a 'lip' that goes over the edge.

https://live.staticflickr.com/65535/...f4113bc8_b.jpg


Quote:

Originally Posted by VonWegener (Post 2063428)
All would be easy if they hadn't changed hubs for 1967. Therefore we have two kinds of wide drums. Since on a starhub the bearings are in the hub the first generation of wide drums has a similar design to the two drums before it. The '67 and later hub has the bearing inside and as such is easily detectable.

here we can see both types, on the outside they are the same, but inside the difference on the drums.
Star hub on the left - Midstar hub on the right

https://live.staticflickr.com/65535/...842eae44_b.jpg
https://live.staticflickr.com/65535/...3d25f97b_b.jpg

Quote:

Originally Posted by VonWegener (Post 2063428)
The mechanical backing plate is mechanical (duh) and has a star shaped embossing in the design. The first generation hydraulic backing plate has kind of an omega shape embossing and the 63-66 has a big ring around the outside and looks kind of like an early Ford backing plate.

and here we can see them all.
Mechanical plate
First generation hydraulic - which shares the same drum as mechanical
and 63-72, big ring around the outside and uses the wider drums.

https://live.staticflickr.com/65535/...59e07d11_b.jpg
https://live.staticflickr.com/65535/...1073cdcf_b.jpg
https://live.staticflickr.com/65535/...39ea8984_b.jpg



Think I got all this right and hope it helps someone else looking for this information.

VonWegener 11-12-2019 07:30 PM

Re: Confused about brake drums
 

Very good JP. I think this thread will be helpful to a lot of guys who want to convert to rear hydraulic brakes.

Stormin 11-22-2019 08:12 PM

Re: Confused about brake drums
 

Great post! I have been thinking about changing the timken hub I currently run and installing either a mechanical or a hydraulic drum brake set up. I have a wishbone frame so it would make sense to use a mechanical brake but if I wanted to run a juice drum what are my best options? Should I replace the let axle flange? I don't want it to look out of place.

[JP] 11-25-2019 03:17 AM

Re: Confused about brake drums
 

Well, for a juice drum the easiest is just to add the bit of plate to the bottom of your axle plate.
I believe you can buy a plate that is bolted on and then has the whole for the juice anchor bolt.
Or.. you can weld a plate (or get someone to) to the bottom of axle plate and give it a cast finish look by beating it small and a lot.

VonWegener 11-26-2019 12:29 AM

Re: Confused about brake drums
 

1 Attachment(s)
John at Hardtail Choppers makes the neatest little brake tab. V-Twin offers a piece of plate with the elongated hole needed but it is just a plate that you could make at home with a hacksaw, file and a drill.

The Hardtail Choppers tabs are $50 directly from him.
Photo is that Hardtail choppers hydraulic brake tab installed by 47 Industries. Note that it looks like the slot that the axle rides in. Just a neat design.



http://www.hardtailchoppers.com/repair-tabs.html

rhysmort 11-26-2019 03:42 PM

Re: Confused about brake drums
 

Quote:

Originally Posted by VonWegener (Post 2063602)
John at Hardtail Choppers makes the neatest little brake tab. V-Twin offers a piece of plate with the elongated hole needed but it is just a plate that you could make at home with a hacksaw, file and a drill.

The Hardtail Choppers tabs are $50 directly from him.
Photo is that Hardtail choppers hydraulic brake tab installed by 47 Industries. Note that it looks like the slot that the axle rides in. Just a neat design.



http://www.hardtailchoppers.com/repair-tabs.html

Very nicely done Mike, I made my own when I went to juice on my panhead. Personally though, I much prefer mechanical! Simple and super effective when they're set up right.

Stormin 11-27-2019 11:45 PM

Re: Confused about brake drums
 

Thanks, that looks good, but might be a little annoying to adjust the leading shoe with the mechanical tab in the way unless it was removed. The mechanical may look cleaner from what I see in the picture. Good enlighten post and ended some confusion.

richbob 11-28-2019 01:49 AM

Re: Confused about brake drums
 

I have a mechanical and locks up fine but heavy bike keeps moving forward
pressure is applied with fore foot which is not a lot of pressure.
i can understand the benefit of a disc hyd brake, but why would you want drum hydraulic?
(easy to apply pressure with foot, i could understand if it was lever operated by fingers)

[JP] 11-29-2019 05:16 AM

Re: Confused about brake drums
 

Quote:

Originally Posted by richbob (Post 2063660)
I have a mechanical and locks up fine but heavy bike keeps moving forward
pressure is applied with fore foot which is not a lot of pressure.
i can understand the benefit of a disc hyd brake, but why would you want drum hydraulic?
(easy to apply pressure with foot, i could understand if it was lever operated by fingers)

Hyd brake also has wider brake shoes, so surely more stopping power when compared to the narrower on mechanical?

rhysmort 11-29-2019 12:39 PM

Re: Confused about brake drums
 

My mech brake has never been anything but spot on. I also find it less bitey than juice drums.. The pan used to lock up all the time... the mech I can feather much easier!

Shaneo40 05-30-2020 06:38 AM

Re: Confused about brake drums
 

Hey Guys, anyone in this thread able to describe the breakdown and sequence of a juice drum on a mid star hub?
Also looking for clarity on axle length (11.5”?) for rigid frame and axel diameter.
Sequence would be ideal from one side of axel plate to the other with size of spacers etc.
Thanks in advance

Dutch Dennoz 05-30-2020 07:35 AM

Re: Confused about brake drums
 

Nice collection jp, parts...never have enough of them.

rhysmort 05-30-2020 10:07 AM

Re: Confused about brake drums
 

Quote:

Originally Posted by Shaneo40 (Post 2067960)
Hey Guys, anyone in this thread able to describe the breakdown and sequence of a juice drum on a mid star hub?
Also looking for clarity on axle length (11.5?) for rigid frame and axel diameter.
Sequence would be ideal from one side of axel plate to the other with size of spacers etc.
Thanks in advance

I can do one better than that.

See attached. This is for BT's

rhysmort 05-30-2020 10:09 AM

Re: Confused about brake drums
 

1 Attachment(s)
SDee attached

Shaneo40 05-30-2020 06:59 PM

Thanks Rhys. I’ve got a similar diagram from my Clymer manual and it’s real good for showing the brake set up, then I found a diagram of the hub setup in a VTwin catalogue but so far no luck with seeing the sequence of it all coming together.

Reason I’m in a pickle is i think I’ve mixed my juice setup with something else. Would be ideal to see setup from one side to the other with Sizes of spacers, bearings, sleeves etc.

I‘ll post a pic soon of what I’ve got and my interpretation on how it goes together. Cheers


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