Author Topic: wheel swap disc to drum.  (Read 4143 times)

0 Members and 1 Guest are viewing this topic.

Offline jeepurz

  • Enthusiast
  • **
  • Posts: 138
wheel swap disc to drum.
« on: November 19, 2008, 04:22:26 PM »
bike is 78 550, wanna swap disc to drum, before I get into it how much of a PIA will this be?? I searched through some threads but couldnt find what I needed. Not sure what the drums off of other than its honda.  also is there an easy swap to longer swingarm  thats not major mod type thing.  shooting for ratrod/cafe lookin thing  ;
 thanks jeep.



Offline sinister902

  • Hot Shot
  • ***
  • Posts: 512
    • Anger Street Kustoms
Re: wheel swap disc to drum.
« Reply #1 on: November 19, 2008, 05:33:34 PM »
here are some pics of it mounted on my cb550, minus the sprocket that is.....this is the entire rear from a 750(swingarm, brake caliper and mount, caliper brace, rim, tire, etc.) all untouched from previous bike just mounted on the bike as is. All I did was pull the swingarm pivot bolt from the 750 out, and remount the entire rear end on the 550, no fab, direct bolt in. Just have to use some modern sportbike rearsets to work the rear brake now.








Offline Alan F.

  • We remember the Night Rider, and we know who you are.
  • Really Old Timer ...
  • *******
  • Posts: 7,351
Re: wheel swap disc to drum.
« Reply #2 on: November 19, 2008, 06:04:03 PM »
I remember a certain member a few years back running a drum front on his 750, he said it was no problem considering the type of riding he does.  Here's a thread I found in a quick search:
http://forums.sohc4.net/index.php?topic=8819.0    this one has info on front brake cables.

if you run the search for front drum you'll get about a dozen pages of threads to search through.  it seems like it's more popular than I thought.

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
Re: wheel swap disc to drum.
« Reply #3 on: November 19, 2008, 06:22:49 PM »
Currently doing that now to my CB750....  got a drum from a CB450 at a salvage yard for $40

Axle diameter and bearings are the same as the stock disc.   I just got it laced up last night.
I think it will bolt right up.  My only concern is that maybe the CB450 triples were narrower....not sure
In that case, you'd just have to get some spacers made up.

I'll post some pics later this weekend if I get that far.
Yep, I'm the kid that figured out how to put things back together...eventually.

Offline moham

  • .fnord.
  • Expert
  • ****
  • Posts: 1,108
Re: wheel swap disc to drum.
« Reply #4 on: November 19, 2008, 06:29:10 PM »
bike is 78 550, wanna swap disc to drum

I'm just curious...Why? It seems that for all practical concerns, everybody (mostly) is going the other direction. Not that I'm calling for everybody to be herded sheep, but it seems a fairly significant practical matter. Discs are superior to drum for braking performance, right? Are the aesthetics worth the downgrade in   safety and handling? I don't mean to judge, just trying to understand...

78 750K-The Ocho
74 550-The Cherry Picker
70 750K0 motor-Dick in a Box

Offline jeepurz

  • Enthusiast
  • **
  • Posts: 138
Re: wheel swap disc to drum.
« Reply #5 on: November 19, 2008, 06:44:14 PM »
bike is 78 550, wanna swap disc to drum

I'm just curious...Why? It seems that for all practical concerns, everybody (mostly) is going the other direction. Not that I'm calling for everybody to be herded sheep, but it seems a fairly significant practical matter. Discs are superior to drum for braking performance, right? Are the aesthetics worth the downgrade in   safety and handling? I don't mean to judge, just trying to understand...



WhY?  because I have it, its there, its a look I like , and im to old for stoppies. it must be a  character flaw ive alway put skinnie tires on when everyone else is going fat tires too.

thanks for the input and Ill check the other thread. ive got the forks for the wheel to il  meas those,  If im correct for tubes are 35 mm on later 450's? as are these.

Offline moham

  • .fnord.
  • Expert
  • ****
  • Posts: 1,108
Re: wheel swap disc to drum.
« Reply #6 on: November 19, 2008, 07:05:12 PM »
bike is 78 550, wanna swap disc to drum

I'm just curious...Why? It seems that for all practical concerns, everybody (mostly) is going the other direction. Not that I'm calling for everybody to be herded sheep, but it seems a fairly significant practical matter. Discs are superior to drum for braking performance, right? Are the aesthetics worth the downgrade in   safety and handling? I don't mean to judge, just trying to understand...




WhY?  because I have it, its there, its a look I like , and im to old for stoppies. it must be a  character flaw ive alway put skinnie tires on when everyone else is going fat tires too.

thanks for the input and Ill check the other thread. ive got the forks for the wheel to il  meas those,  If im correct for tubes are 35 mm on later 450's? as are these.

Cool. Like I said, just curious.
78 750K-The Ocho
74 550-The Cherry Picker
70 750K0 motor-Dick in a Box

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
Re: wheel swap disc to drum.
« Reply #7 on: November 20, 2008, 04:44:21 AM »
Yep, this is one of those things that you just can't argue for....I was just going for an "older" look.
Hopefully, when I'm finished, it will be one of those bikes that everybody (except us CB guys) will wonder about

Jeepurz - The fork diameter is the same, I'm pretty sure.  It's the distance that they are apart in the triples that I'm not sure of...
« Last Edit: November 20, 2008, 09:14:11 PM by greenjeans »
Yep, I'm the kid that figured out how to put things back together...eventually.

Offline ct_racer

  • Enthusiast
  • **
  • Posts: 117
  • ""
Re: wheel swap disc to drum.
« Reply #8 on: November 20, 2008, 02:18:58 PM »
Well if you're getting rid of your disk setup, would it fit on a stock 500k2 rim with the drum.  Sorry, I don't know anything about that setup.  If the parts were in anyway interchangeable i mean...  though I know its quite a long-shot. 

Offline Geeto67

  • A grumpy
  • Old Timer
  • ******
  • Posts: 2,823
Re: wheel swap disc to drum.
« Reply #9 on: November 20, 2008, 05:26:12 PM »
ditching the disc for a drum is kinda like bailing out on the prom queen for a fat hooker.

If you are going to bother doing this DOWNGRADE, might i suggest actually getting a drum that will at least stop the bike, like one off a GT750/550 perhaps? The 450 drum was inadiquate for stopping a cb450, putting on a bike with 100lbs more girth is plain stupid.

A drum is superior in stopping power but sucks in repeatabilty, a disc is mostly consistent. the more stops you make with a drum the longer it takes you to stop, this is called fade and why (among other reasons) drums are largely obsolete.
Maintenance Matters Most

Offline moham

  • .fnord.
  • Expert
  • ****
  • Posts: 1,108
Re: wheel swap disc to drum.
« Reply #10 on: November 20, 2008, 05:44:15 PM »
bailing out on the prom queen for a fat hooker

Ahhh yes, terms I can understand...
78 750K-The Ocho
74 550-The Cherry Picker
70 750K0 motor-Dick in a Box

Offline hapsh

  • Enthusiast
  • **
  • Posts: 178
    • Listen to the latest tracks from JazzCancer
Re: wheel swap disc to drum.
« Reply #11 on: November 20, 2008, 06:25:04 PM »
ditching the disc for a drum is kinda like bailing out on the prom queen for a fat hooker.

If you are going to bother doing this DOWNGRADE, might i suggest actually getting a drum that will at least stop the bike, like one off a GT750/550 perhaps? The 450 drum was inadiquate for stopping a cb450, putting on a bike with 100lbs more girth is plain stupid.

A drum is superior in stopping power but sucks in repeatabilty, a disc is mostly consistent. the more stops you make with a drum the longer it takes you to stop, this is called fade and why (among other reasons) drums are largely obsolete.

I've done it and there is plenty of power, especially with a Twin Leading Shoe that is adjusted properly.  Just because you ASSUME it will be stupid doesn't mean it is.  Yes, there is fade, but only on repeated max braking over and over, like on a track.  You most likely wont notice any fade on the street.  Plus you don't loose any power when riding in the rain as opposed to the stock un-drilled rotors of that era; those things can be downright scary in a downpour.
'71 CB500/550, '72 CB450, '79 RD400 Daytona, '90 FZR600R

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
Re: wheel swap disc to drum.
« Reply #12 on: November 20, 2008, 09:17:15 PM »
Geeto, you just don't appreciate what a fat hooker will do....sometimes experience counts ;)

Points taken - this one is strictly for the look....
Yep, I'm the kid that figured out how to put things back together...eventually.

Offline Geeto67

  • A grumpy
  • Old Timer
  • ******
  • Posts: 2,823
Re: wheel swap disc to drum.
« Reply #13 on: November 21, 2008, 07:30:07 AM »
ditching the disc for a drum is kinda like bailing out on the prom queen for a fat hooker.

If you are going to bother doing this DOWNGRADE, might i suggest actually getting a drum that will at least stop the bike, like one off a GT750/550 perhaps? The 450 drum was inadiquate for stopping a cb450, putting on a bike with 100lbs more girth is plain stupid.

A drum is superior in stopping power but sucks in repeatabilty, a disc is mostly consistent. the more stops you make with a drum the longer it takes you to stop, this is called fade and why (among other reasons) drums are largely obsolete.

I've done it and there is plenty of power, especially with a Twin Leading Shoe that is adjusted properly.  Just because you ASSUME it will be stupid doesn't mean it is.  Yes, there is fade, but only on repeated max braking over and over, like on a track.  You most likely wont notice any fade on the street.  Plus you don't loose any power when riding in the rain as opposed to the stock un-drilled rotors of that era; those things can be downright scary in a downpour.

I am not assuming anything, the 450 drum is inadiquate for a cb750 and at the ragged edge of inadiquate for a 550. I should have clarified something above, a properly sized drum brake is superior to a disc in sheer stopping power, an dundersized drum will fade fast.

What are the stopping distances for your setup? Have you ever done a real comparison? I have seen both setups in action (against each other as specified for braking classes) and the disc brake bikes routinely outbrake the drum. The guys that run drum brake classes will tell you for any bike over 300 lbs you need a big brake (like the GT series brakes). As far as whether the 450 brake is a good brake even on a 450, most of the roadracers I know who run 450s ditch them in favor of T500 drums, gt550/750 drums, and basically anything other than stock because the 450 drum is generally regarded as weak. It is a stupid idea because it is a downgrade from stock in performance. Yeah the stock disc isn't that great but it is a long sight better than the 45 drum. 

Now before you go and claim that racing is hard on brakes, well that may be true but the harshest situation for brakes is always going to be the street. I am sure the 10 miles a year you ride your bike or what have you probably doesn't make it an issue but frankly I would not want to be on any cb750 with a 450 front drum and have to make a panic stop. There is more constant sue of the brake in varying degrees than on the street than on the track, also the likelyhood of fade is greater in street riding than for on the track.
« Last Edit: November 21, 2008, 07:55:16 AM by Geeto67 »
Maintenance Matters Most

Offline Geeto67

  • A grumpy
  • Old Timer
  • ******
  • Posts: 2,823
Re: wheel swap disc to drum.
« Reply #14 on: November 21, 2008, 07:46:19 AM »
Geeto, you just don't appreciate what a fat hooker will do....

what? besides give you crabs and various other diseases that may or may not be pronounceable.

FYI, just throwing any drum on there "for the look" is kinda dumb. Any person worth his salt will look at a bike with a crappy drum and say "well, it is a nice bike but what a crappy drum" - I know I do this at shows all the time with brit bikes (and often I am talking about some cafe custom running the stock crappy drum). It impresses no-one. Just because the unwashed masses kind of expect our bikes to have drum brakes because they are old looking does not mean you should go out and throw any old turd of a drum on there.  Do a little homework, do things right, don't half ass it. With brakes it is always better to over engineer than under engineer.

If you are going to put a drum on a bike, don't be a cheap bastard and just grab any drum, make is something impressive. Moto Guzzi drums are huge, setup for stopping large bikes, and have finned covers and such, plus they are common in the guzzi world. GT750 drums are 4 leading shoe and seeing four arms working in unison is impressive. Grimeca drums are still out there being produced, sure they are spendy but I have never seen a person look at a grimeca drum with anything but amazement - it is an impressive piece. Really there are some cool looking drums out there, a cb450 drum, a stock triumph drum, even a kawi h1 drum, not impressive pieces and woefully underpowered for these large and in charge inline-4s.

Any idiot can stick an old piece of garbage on the bike and say it now looks period, but to really sell it, for the look aspect of it, it should be up to the task, otherwise you have done nothing but build a bike that nobody but those ignorant in motorcycles is going to even say looks right.
Maintenance Matters Most

Offline mlinder

  • "Kitten Puncher"
  • Really Old Timer ...
  • *******
  • Posts: 5,013
  • Stop Global Tilting now!
    • Moto Northwest
Re: wheel swap disc to drum.
« Reply #15 on: November 21, 2008, 08:04:45 AM »
Saw a BMW r75/5 drum brake on ebay the other day.

Good brake, but dunno how hard it would be to make it fit.
Stops the 470lb r75/5 pretty well.
No.


Offline hapsh

  • Enthusiast
  • **
  • Posts: 178
    • Listen to the latest tracks from JazzCancer
Re: wheel swap disc to drum.
« Reply #16 on: November 21, 2008, 01:14:53 PM »

What are the stopping distances for your setup? Have you ever done a real comparison? I have seen both setups in action (against each other as specified for braking classes) and the disc brake bikes routinely outbrake the drum. The guys that run drum brake classes will tell you for any bike over 300 lbs you need a big brake (like the GT series brakes). As far as whether the 450 brake is a good brake even on a 450, most of the roadracers I know who run 450s ditch them in favor of T500 drums, gt550/750 drums, and basically anything other than stock because the 450 drum is generally regarded as weak. It is a stupid idea because it is a downgrade from stock in performance. Yeah the stock disc isn't that great but it is a long sight better than the 45 drum. 

Now before you go and claim that racing is hard on brakes, well that may be true but the harshest situation for brakes is always going to be the street. I am sure the 10 miles a year you ride your bike or what have you probably doesn't make it an issue but frankly I would not want to be on any cb750 with a 450 front drum and have to make a panic stop. There is more constant sue of the brake in varying degrees than on the street than on the track, also the likelyhood of fade is greater in street riding than for on the track.

I don't see any reason for you to insult my riding experience.  I have been riding for over 30 years and put at least 7000 miles a year on my bikes.  What kind of track riding do you do that puts less stress on the brakes than on the street, parade laps ::)?  When I am doing track days on my R6 I use very close to max braking before almost all the turns around the track.  Yes a 450 drum may be a bit small for a 750 but it works absolutely fine for street use on a 550.  I'm done wasting my time with this.
'71 CB500/550, '72 CB450, '79 RD400 Daytona, '90 FZR600R

Offline jeepurz

  • Enthusiast
  • **
  • Posts: 138
Re: wheel swap disc to drum.
« Reply #17 on: November 25, 2008, 04:17:46 PM »
ditching the disc for a drum is kinda like bailing out on the prom queen for a fat hooker.

If you are going to bother doing this DOWNGRADE, might i suggest actually getting a drum that will at least stop the bike, like one off a GT750/550 perhaps? The 450 drum was inadiquate for stopping a cb450, putting on a bike with 100lbs more girth is plain stupid.

A drum is superior in stopping power but sucks in repeatabilty, a disc is mostly consistent. the more stops you make with a drum the longer it takes you to stop, this is called fade and why (among other reasons) drums are largely obsolete.

its gonna be a bar hopper (err coffee shop hopper , quit drinkin), it is simply a look. I put dual disc on the last two projects (xs's) so that should get me a free pass for the drum , right??

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,086
Re: wheel swap disc to drum.
« Reply #18 on: November 25, 2008, 04:35:56 PM »
guys, dont throw mud at drums so fast.... people in classic racing with drum braked G50's, Manx Nortons and a certain CB450T guy named Henning could outbrake you all.

Question is of course WHAT drum. Wouldnt mind fitting a magnesium 250 mm Fontana 4 LS on mine. It's only about 2000$ after all.

If someone is looking for some excitment when he REALLY NEEDS to do an emergency stop, that's he's choice no?

:-)

TG

Offline pablo78cb550

  • Hot Shot
  • ***
  • Posts: 318
  • mmmph.
Re: wheel swap disc to drum.
« Reply #19 on: November 25, 2008, 04:41:39 PM »
guys, dont throw mud at drums so fast.... people in classic racing with drum braked G50's, Manx Nortons and a certain CB450T guy named Henning could outbrake you all.

Question is of course WHAT drum. Wouldnt mind fitting a magnesium 250 mm Fontana 4 LS on mine. It's only about 2000$ after all.

If someone is looking for some excitment when he REALLY NEEDS to do an emergency stop, that's he's choice no?

:-)

TG

i agree, dual leading shoe front drums can be very effective.
i have them on my XS400 and they are very good.
Bikes in hand:
1977 Yamaha XS650
1978 Yamaha SR500 #119!
1978 Yamaha XS400
1978 Honda CB550K
1965 Ducati Monza 250

Sold off:
1992 Yamaha FZR600
1978 Yamaha SR500- I miss it so much.
1981 Yamaha Seca 550

Offline Geeto67

  • A grumpy
  • Old Timer
  • ******
  • Posts: 2,823
Re: wheel swap disc to drum.
« Reply #20 on: November 25, 2008, 06:19:29 PM »
guys, dont throw mud at drums so fast.... people in classic racing with drum braked G50's, Manx Nortons and a certain CB450T guy named Henning could outbrake you all.



I am almost certain that henning isn't running a 450 drum on any of his racebikes, and if he is it is a severly re-worked drum with new liners, mechanism, and pads - it would be in no way shape or form anything that resembles a stock cb450 drum. Most dracers forced to take a drum for a racing class use the Gt550/750 drum for the larger bikes, and the t500 or worked 350 drum for the smaller bikes (some of the really small ones use 350 honda drums). Most of the racers I talk to would rather have discs if the class allowed it because of a drums heat sensitivity.

I was going to let this just die out since someone had to get the moderators involved and all but since it is being resurrected.....

Quote
I don't see any reason for you to insult my riding experience.  I have been riding for over 30 years and put at least 7000 miles a year on my bikes.  What kind of track riding do you do that puts less stress on the brakes than on the street, parade laps ?  When I am doing track days on my R6 I use very close to max braking before almost all the turns around the track.  Yes a 450 drum may be a bit small for a 750 but it works absolutely fine for street use on a 550.  I'm done wasting my time with this.

comparing a track day on a dics brake R6 with a vintage racebike drums shows you are pretty inexpirenced and oblivious as to how both these systems work and feel. Comparing a modern disc brake setup to a drum is like comparing apples to pencils. First off the amount of work that goes into a racing drum is far and away more than would go into your track day R6. Plus a racing drum will be mazimized for maximum stopping power and minimal drag, something that is not optimal for a street drum. Some setups won't even stop the bike until some heat is built up in the shoes (sintered metallic shoes espically).

As far as that crack about your riding is concerned you must not be logging very many of those 7000 miles on your drum brake cb. If I were to ride a cb550 with a 450 drum brake into work everyday instead of my 750 I can pretty much gaurantee there would be at least once per day an incident where that drum would have exceeded its limit - as it stands my 750's disc brake is at its limit once a day between the cabs and the other traffic. I actually have a 550 chop with a drum on it and it is the bike I use the least because of the brakes alone. I am locked into using a drum because of the narrow springer front end, but I would ditch that drum in a heartbeat if I could.

Now, recommending a 450 stock drum for use on a 550 is stupid advice plain and simple. The 450 drum was inadiquate for the bike it came on, the cb450 and is one of the bigger complaints about those bikes - to then recommend it be used on a larger inline four is just reckless. 1970s honda brakes in general are not that great to begin with, even the stock cb750 discs are a bit lacking, why anyone would want to give up stopping power for the sake of looks is beyond me, espically when the cb450 drum is not eye candy - it is just an ugly drum that won't win you anything in the looks department.

If you want to take your life into your own hands with it that is fine, but don't recomend it to people who don't know any better.

I don't have an intrinsic problem with drums, as i said in an earlier post there are plenty of appropriate sized drums, if you can't be disuaded, most of them designed for bigger bikes. Gt550/750 4 leading shoe drums, moto guzzi drums, bmw drums, grimeca aftermarket drums, etc....

Maintenance Matters Most

Offline pablo78cb550

  • Hot Shot
  • ***
  • Posts: 318
  • mmmph.
Re: wheel swap disc to drum.
« Reply #21 on: November 25, 2008, 06:44:45 PM »
Suzuki T500 dual shoe front wheel.


Bikes in hand:
1977 Yamaha XS650
1978 Yamaha SR500 #119!
1978 Yamaha XS400
1978 Honda CB550K
1965 Ducati Monza 250

Sold off:
1992 Yamaha FZR600
1978 Yamaha SR500- I miss it so much.
1981 Yamaha Seca 550

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
Re: wheel swap disc to drum.
« Reply #22 on: November 25, 2008, 06:59:17 PM »
Entertaining thread, but to answer the original question,

I just put my wheel into the forks yesterday, and it looks like the axle for  the CB450 drum is too short...but, if you use the axle from your CB750 or 550 It will bolt right up - You WILL need to have a spacer made for each side, but if you still have your origial hub, you can take one out of there and cut it to fit.   Don't know if I'll get that far this weekend, but when I do, I'll get some exact measurements (at least for 750's) for the width of the spacers.

I wish this thread had come up BEFORE I bought, cleaned, polished & bought new shoes for this 450 brake....
Luckily, I'm a conservative rider in my old age and have ridden a few that only had a rear brake (can't help it - I'm an
old chopper) 
Yep, I'm the kid that figured out how to put things back together...eventually.

Offline jeepurz

  • Enthusiast
  • **
  • Posts: 138
Re: wheel swap disc to drum.
« Reply #23 on: November 26, 2008, 10:08:24 AM »
Entertaining thread, but to answer the original question,

I just put my wheel into the forks yesterday, and it looks like the axle for  the CB450 drum is too short...but, if you use the axle from your CB750 or 550 It will bolt right up - You WILL need to have a spacer made for each side, but if you still have your origial hub, you can take one out of there and cut it to fit.   Don't know if I'll get that far this weekend, but when I do, I'll get some exact measurements (at least for 750's) for the width of the spacers.

I wish this thread had come up BEFORE I bought, cleaned, polished & bought new shoes for this 450 brake....
Luckily, I'm a conservative rider in my old age and have ridden a few that only had a rear brake (can't help it - I'm an
old chopper) 



im gettin it figured out,  I think your right. ill either make spacers or shave existing ones.


also the two #s inside the drum, the stamping stating ASK10375R2FF is on brake pad, is this a part ref #? inner drum states 363Y2.Id like to order new shoes.


oh and same here on the chop thing , but too old for that.
« Last Edit: November 26, 2008, 10:10:31 AM by jeepurz »

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
Re: wheel swap disc to drum.
« Reply #24 on: November 27, 2008, 09:05:04 AM »
Not sure about the part number - I got mine from a local shop that used to handle a bunch of the vintage stuff...
Just happened to have them on the shelf.  I'll try and look later this afternoon and see if there is a part number.
They should be readily available
Yep, I'm the kid that figured out how to put things back together...eventually.