drum brake improvement

[AdminGuy]

Wow! Good job. Your making me hurt for a lathe with an auto center chuck. Or by golly - just a lathe!

Please remember- I know nothing.
Question: Do the shoes contact equally from the cam action? Theoretically they should -shouldn't they? Or do they float and settle in after a bit of use.

Also - I'd think someone with alot of time may already have such a jig. Maybe a racer?

Is the whole thing of cutting the shoe pads way over the top for street riding? Couldn't you just drag them a bit and 80 percent contact good enough? I guess each to there own. Oh well.

How about that first question?

[Paps]

NO !!!! You are absolutley right !! 80% is more than good enough. Most folks will just leave the shoes wear in on their own to the circumference if the brake backing plate assembly and shoes will drop into the drum in the beginning. [automotive technology] Filing is adaquate also to obtain this percentage of fit. You know me already ........ I just had to point out the most perfect way of obtaining the best fit. Used to get *****ed at from my employers for being to accurate!! The way I pointed out will give you the altimate fit and wear possible. Basically a lifetime of never changing brake shoes again!! For that matter your drum would outlast you too. There are easier ways to optain the optimin fits as I explained but a person must have the tooling and the time in the first place to do it. Readouts will eliminate the need to set indicators thus saving hours of time. The best that can be achieved in the conventional way is 50% contact. Usually the contact ends up around 25%. This is all well and good for most mechanics and I myself settle for this on all of my automobiles but on my until I die personal ride I am a perfectionist. All of these technics work as far a adaquate braking power goes but as I said in the beginning..........if you want 100%......???? do it this way. Disc brakes do the same thing that I have pointed out but they do it from a different angle and with less work to accomplish it. I owe you the beers this time. Paps

[Paps]

I am sorry......the first question?? I have heard quite a lot of good feedback concerning the new dual cam front brake systems. My wife Kat sells them as a rep for 45" Parts Depot and she has received no complaints, only praise for them. They basically double the stopping power at the front wheel compared to the single cam conventionals. Paps

[AdminGuy]

It was really cool reading about the set-up. Would make a good little additional winter project for alot of guys I hope.

Thanks for percentage info also. Interesting stuff.

I guess my thoughts were around how the shoes may accually settle or be engaged in function. Over how they may be cut in a jig. I just kinda had a feeling that they may shift around a bit as they bed in. But the amount is really negligable - so forget I said that.

I think one of my shoes (scout) is not seating properly (worn) not square. So I'm reminded by all this to take a closer look, and address it now.

I scared the willies out of myself on the little 500 triumph with the single cam. Double makes a huge difference. Safety first. Well, honestly it has saved my life a couple of times. Once that front brake starts to work you start to really notice how your front susspention functions -or doesn't properly. So if I had a nice Knuckle or 45 that I really enjoyed rideing around I sure would slap one on. Someone could easily swap it out in 15-20 min. for show if need be.

I think some guys in Germany came up with a heavy duty front drum for Indians also. Ahhh ya, it's thicker. More surface.
http://www.indian-service.com/Anglos...ewpartsVB.html
Heavy duty cable helps on the front also. That's from ahhhhh...Steve...ahhh...Johnson? Ohio I think.

OK, I'm done now.

Music for this post- Kenny Chesney, -She thinks my tractors sexy.
I couldn't get that song out of my head on the road run.

[Paps]

Your thoughts are in the right place. That is why I said the fixture would have to basically duplicate the action of the brake backing plate. This is the best way to insure that the setup for arching the lining would place the lining in the exact location as the lining would be in the drum. I used the word fulcrum but probably should have used the words pivot pin. One end of the shoes never makes solid contact with the drum surface if the arching is correct. Funny thing about fitting lining though is.... the low points are not always in the center of the lining. Sometimes they are on the ends.
The percentages are pretty accurate. If you think about disc brake pads verses drum brake shoes you will no doubt agree that the disc pad makes 100% contact pressure with the rotor during braking but the drum brake lining never quite obtains this high of a percentage of equal contact pressure even though it has the same radius as the drum itself. The disc pad makes contact with only a very small amount of the rotors surface area but yet is much stronger than the drum /shoe setup. The drum systems brake shoes darn near cover the entire drum surface area yet the braking power is much less than the itty bitty disc pad. Dual cam is better than single cam drum brakes for sure because of this redistribution of shoe pressure. The perfect drum brake setup could have been made years ago but the cost was to high to justify it. This drum brake would have put the shoes on ways and gibs on the brake shoe backing plate at both ends of the shoes with hydraulic piston drive forcing the shoes out against the drum surface equally all around. Return would be conventional springs. The invention of the disc brake system made this idea obsolete anyway.
Man !!!!!!!!! We should chat about other topics as much as we chat about brakes. Oh Well.... I guess that's the brakes ! LOL Paps

[bobdo]

drum brake improvement

Hello Paps,
Wow, I'm out of breath too from reading, & my brain hurts. I'm going to have to read your reply a few more times to fully understand. I'm not sure at this point, which way I'll go. The "German precision" way or the " Hillbilly creative handwork" way. I have both in my genetic makeup.
I do appreciate your reply. This is an interesting topic, I'm sure others will find it helpful as well. Thanks again, Bob

[bobdo]

brake drum improvement

Hello again AdminGuy,
"thinks my tractors sexy" heh heh I love it.
Well the weather is turning cold & rainy, won't be long & snow will be deep.
I'll have plenty of time to work on my bike. Theres plenty to do, just painted the frame. Thanks to all who added to this thread. Happy trails, Bob

[AdminGuy]

OK, Welcome Bob. Paps and I were just getting the convo warmed up! hee-hee.

Of other interesting note I've bought alot of stuff from Andy Molnar over the years but haven't dug deep enough for one of his original hub castings. But they sure are nice, and may give someone a few ideas. Note how the arms are setup. Sadly doesn't show internal shoe setup.
http://www.manx.co.uk/products/hubs.htm

Yes Paps - I guess I was sort of heading toward the idea of shoes on way tracks/runners.

Paps - One of my back burner ideas was to put a mini floating disk setup including the resevoir into the front drum. They're making those mountain bike disk brakes ALOT stronger these days. Would retain antique look but would work like the dickens. Maybe save me/the bike from a close encounter with a deers' revenge.

[bobdo]

drum brake improvement

Hello Paps / AdminGuy,
I guess I'm still a rookie with this Forum. I didn't see there was a second page to this. You guys were way ahead of me when I wrote that last post. Good reading.
Hey Paps, you said your wife Kat is a sales rep? Is it possible to get the hardware on the dual cam in parkerized finish with black paint or does it only come cad? If she wants to contact me directly, rdorsey@ns-design.com
By the way, that Manx site is great Thanks.
Bob

[Paps]

Bobdo....go to the following link: www.vtwinrebuild.com
After the page boots....click on "Catalog"... After that page boots...click on "Shop Our Parts Catalog".....After that page boots....open the option window and select "Dual Cam Front Brakes".....From there you can view several pages of these brakes an their options. You can also enlarge the thumbnails to get a better view. Paps