Slash 2

[datchew]

Originally Posted by danedg

What?

Sorry brother. I'm very bad about not thinking about how some of my posts come across at the other end.
I wasn't laughing at you, but more at what Vech told you.
It just doesn't make sense.

Yes, if you shave off huge amounts from the drum, you affect the circumferential position of brake shoe engagement (clock position of where the shoe touches the drum) but you would have to remove alot of metal before it became a serious concern.

In extreme cases of turning the drum you simply begin to lose some % of the pad engagement surface area, but this doesn't mean you can't turn the drums.

Single leading shoe and twin leading shoe designs all have a history of being successfully turned and still working quite well. I don't know which is more prone to symptoms from drum turning, but that certainly doesn't mean that the answer is "you can't do it."

[crazydrummerdude]

Originally Posted by datchew

that certainly doesn't mean that the answer is "you can't do it."

Especially considering I turn my trucks drums. It's the same theory in that regard. Is there something else we're missing, to justify Vech's answer?

[Carl]

As previously clearly stated, it can and has been done successfully many times.

There are definitely several concerns to remember so as to not botch the task for those competent to do the hub liner machining. One is to machine the contact surface in a mode that allows it to remain concentric to the steel bearing retainer hub. This tends to be more of an issue w/ '70 and up rear hubs. The tension of the spokes can change the shape of the liner.

Another issue with the 55-69 twin hubs is the 30204 bearing race journal ID. Between sidecar use and improper PM, the bearings races are often, or become, loose in the hub. This can also be fixed, yet if brake lathe cones are used w/ the bearings races that have a loose fit for the machining task the brake liner can be improperly machined.

Carl

[danedg]

I believe your first attempt at an emergency stop, will justify Vech's response.

[Carl]

Originally Posted by danedg

I believe your first attempt at an emergency stop, will justify Vech's response.

Your response is both 'Horizontally Suppressed' and 'Horizontally Oppressed'.

Not everyone is a kool-aid drinker.

Carl

[Carl]

...I'll add for safety purposes, what some consider an update to these machines w/ a 'modern' more aggressive brake lining should rethought out. They're trying to squeeze 20 kilos of food in a 10 kilo bag. The design of the brakes both mechanically and material wise is not always user friendly to brake lining composition changes.

Carl

[danedg]

Not everyone is a kool-aid drinker.




What does that mean? Where did that expression originate?

[SlackerSteve]

drums have been turned and shoes have been arced to for superior performance in drum braked automotive applications for years. On a /2 it is a safety hazard?

Maybe somebody doesn't own a brake shoe arcing machine.

[danedg]

There's too much hearsay and second hand smoke clouding the air on these BMW pre-70 technical items.

Precisely the reason for starting this thread. I've spent 1000's of hours sifting through the hoohaa, and reading everyone's comments regarding this and that, and have come to realize that there are truly only about 7 people on the planet that really know what they are talking about. Craig Vechorik is one of 'em.
I am not. But I'm hoping to cut through some of the hoopla, to make it easier for the 4th hand owner, such as myself, to easier understand and appreciate these bikes.
I welcome, all the input and knowledge that the participants in this thread have to offer. I stand corrected most of the time, but I put myself in that position on purpose, to jumpstart a conversation that might never have happened, or to clear up some deep dark mystery, that's as plain as the nose on your face.
I'm glad to know that it is possible to freshen up the front drum on my bike. Perhaps Craig misunderstood my question. Maybe the right question wasn't asked. But I'd thought long and hard about it.
It seemed like an eternity the other day as I whiteknuckled that bike to a safe stop around the codger trying to kill me. I had plenty of time to contemplate the feeble friction coefficient, to wonder how much better the brake would be, if the drum and shoe were in tip top shape. Heck , I even had time to regret owning a motorcycle with such a primitive braking system, at the very instant that I could've REALLY used 4 discs and ABS...I'd just replaced the front brake cable, and was very happy about that!
So I thought I'd mention my experience on my own thread, maybe try to clarify some thoughts and recommendations on how to cope with /2 brakes in a modern driving situation. Heck, if I'd asked that question over on Yahoo/ 2, I'm sure I would have gotten some crusty old fart to call me an idiot, if I'd gotten an answer at all....

[bergermeister]

Originally Posted by danedg

Heck , I even had time to regret owning a motorcycle with such a primitive braking system, at the very instant that I could've REALLY used 4 discs and ABS...

fyi - you could fit yours with a dual disc. I just took such a system off of mine and went back to an original front wheel.

[crazydrummerdude]

Originally Posted by bergermeister

fyi - you could fit yours with a dual disc. I just took such a system off of mine and went back to an original front wheel.

Any pictures?

[danedg]

Tell us more!

[bergermeister]

pretty nice custom installation by the prior owner in Japan. basically an early 70's Kawasaki setup with a /5 master cylinder under the tank. the calipers bolt to brackets welded to the underside of the swingarm.

[Ze Red Baron]

Wow. better practice that one at low speed. Those used to grabbing all the front brake they can get might find themselves flying over the handlebars

[crazydrummerdude]

That looks like something I might have to add to my vw conversion if I ever get it going.