twin sprocket carrier

CarlHungness

Well Known and Active Forum User
VOC Member
This may be useful: http://www.vintagebrake.com/mastercylinder.htm

One Track, he say, "Keep 'em Standard!"
HI: Great information. I want to see the Keep 'em Standard folks ride through downtown Chicago on I94 and have a cellphone operative switch lanes and jam on his brakes in front of you. I ain't cuttin' nothin', and the standard brakes will be well protected from the dust they gather in a safe box.
 

Magnetoman

Well Known and Active Forum User
VOC Member
ride through downtown Chicago on I94 and have a cellphone operative switch lanes and jam on his brakes in front of you.
Disk brakes have many attributes to recommend them (lower force on brake lever, progressive feel, fade resistance, etc.), and I certainly understand why someone might want to convert front drums for circumstances like you describe. However, the "need" to convert the rear drum is less obvious to me.

Not that anyone wants to lock up a wheel, but a properly set up rear drum easily should be capable of that. Given this, the attributes of a disk in that location become much less obvious. Yes, a rear disk would be "better" in some sense (as would an electric starter, heated hand grips, electronic traction control, ...), but given the amount of work required to make this conversion it's not clear to me that the additional "betterness" would be merited. One could even argue that with all the rider's attention on making sure not to lock up the front wheel with its disk in a split-second emergency situation, being able to tromp on the back brake hard without worrying about locking it up would be a benefit in reducing overall stopping distance.

Hey, it's your bike so I'm not saying you shouldn't do this. I'm just asking the question whether the effort to do the conversion of the rear brake would result in an improvement in actual operation when the major concern is minimum stopping distance in emergency situations (rather than fade resistance).
 

vibrac

Well Known and Active Forum User
VOC Member
I would agree with magnetoman
When racing we found that even slowing down for a hairpin a single Vincent brake was sufficient I only had one drum on the first Egli I raced (but that was when disc brakes were only fitted to jet fighters:)) we certainly up to the present day only fitted one drum to the Comet or the Grey Flash and the wheel will still often lock under heavy braking if care is not taken.
We fitted a disc brake to the Egli the smallest we could find but it was still over braked and easily lost traction. In fact just last week Ben fitted a smaller caliper and lower(higher?) lever ratio to his flying brick to reduce the braking force that could be applied -and thats a big lump.
 

CarlHungness

Well Known and Active Forum User
VOC Member
Disk brakes have many attributes to recommend them (lower force on brake lever, progressive feel, fade resistance, etc.), and I certainly understand why someone might want to convert front drums for circumstances like you describe. However, the "need" to convert the rear drum is less obvious to me.

Not that anyone wants to lock up a wheel, but a properly set up rear drum easily should be capable of that. Given this, the attributes of a disk in that location become much less obvious. Yes, a rear disk would be "better" in some sense (as would an electric starter, heated hand grips, electronic traction control, ...), but given the amount of work required to make this conversion it's not clear to me that the additional "betterness" would be merited. One could even argue that with all the rider's attention on making sure not to lock up the front wheel with its disk in a split-second emergency situation, being able to tromp on the back brake hard without worrying about locking it up would be a benefit in reducing overall stopping distance.

Hey, it's your bike so I'm not saying you shouldn't do this. I'm just asking the question whether the effort to do the conversion of the rear brake would result in an improvement in actual operation when the major concern is minimum stopping distance in emergency situations (rather than fade resistance).
Hi:
I surely agree regarding having a disc on the rear, it seems like a lot of work for no reward. When you consider that very nearly all of the stopping power of a vehicle in motion is on the front, asking the rear to assist in stopping is almost pointless. Far too many motorcycle riders do not understand the effectiveness of the front brake and I've heard every argument from "it'll throw me over the handlebars" on down to "I just really like the rear brake." I intend to install one dual pot Kawasaki style front brake on the left side. I think I'll keep the right front brake plate only to run the speedo cable. Thus when an onlooker sees the bike when it is parked, it will take a sharp eye to see it has a disc. I also plan to hide the master cylinder between the forks so I can retain my stock caliper/cable.
 
Top