RichinSC1

Hello all. I'm new in here. Wife and I had a 2005ish KHS Tandemania that we liked but quit riding it and sold about 10 years ago. Wife and I want to start riding again so I bought a 1990 Burley Duet for $200 with plans to strip her, paint her and add all new components. It has the ugly heavy drum brake on rear and it has front and rear rim brakes (front and rear rim brakes are operated by one brake lever which I find odd). In trying to modernize her I want to get rid of the drum brakes and add disk brakes front and rear controlled by separate brake levers. Since the Duet was made for drum brakes do you think the frame can handle the load of disk brakes on the rear? How about the front forks, can they handle disc brakes? Reason on wanting to change to disk is I understand they dissipate heat better than rim brakes and will not heat up the tire on long downhills which can cause blow outs. I'll hang up and listen to your answers on the radio. Thanks

L134 

I don’t know the answers to your questions but could be interested in that drum brake if you are looking to get rid of it.

Otherwise, are you expecting to ride beyond the limits of the original brake system? Unless you are just wanting a fun project or you will be riding at the aggressive end of the scale, I should think the existing system should be safe and adequate if all is maintained and adjusted properly. I did a fully loaded tour in the mountains on a similarly braked tandem and survived. If I were thinking aggressive tandem riding I would probably be thinking a different starting point.

RichinSC1

I live in Charleston, SC which is extremely flat. No mountains and no hills. I would not consider this aggressive riding.
This will be a fun project that will hopefully end up with a cool looking bike that performs better than it did from the factory.

Joint Venture

We started on a new 1990 Burly Duet back in the day, equipped with braking like yours. I did remove the drum brake and separate the front/rear canti brakes to each on one lever. You can use that double pull lever still to pull just one cable. Along with some Kool Stop salmon pads, that will make a world of difference in braking.

Now for the bad stuff. Although we rode that bike for 9 years, the “woven truss” frame design of the 1st gen Duets was really flexy! Easy to induce stoker steer and the bottom bracket area of the frame in the captain’s position deflected a startling amount under any significant pedaling force! We were shocked by how much more stable a better designed frame was when we upgraded to a new ride.

I’d enjoy the bike as-is or with modest upgrades to get back into riding a tandem. If you need speed control and heat capacity for long/steep downhills, leave the drum on and let the stoker control it with a bar end shifter. IMHO the frame is not suitable for a lot of money spent on upgrades - especially disc brakes. You’d need to reinforce the rear triangle and add a disc mount. For a front disc, you definitely need a new fork and hub, and if I recall, the bike uses a 1” headset (I could be wrong) and it would be tough, if not impossible, to find a tandem-rated disk fork with a 1” steerer. You can buy adapter “donuts” to spin onto your threaded rear hub to mount a 6-bolt rotor ... assuming you have clearance at the stays for a suitable size rotor. The rear spacing on this bike is 140mm.

Plus the frame has a relatively short stoker top tube as well, if that’s an issue for you. If your bike is still sporting the original components (27-inch wheels, 3x6 Suntour shifting with half-step-plus-granny gearing, freewheel rear hub, bolt-on rear axle... etc.), your list of components you want to replace may be extensive.

It’s a lot of work, time and money to spend on a frame/fork with some shortcomings. I still think it would make a fine bike as-is for easy cruising type rides. We even did some flat metric centuries on our 1990 Duet! However, a more robust (yet lighter and more comfy!) and more modern frame is a whole different experience! Your old tandem was probably an overall better ride than a 1st gen Duet, so you may be bothered by the flexy frame. Note: The redesigned Duet frame of the mid-90’s (with the mitered joints at the bottom bracket and stays ... etc., instead of the bent tubes of the woven truss design) was quite nice!

Paul J

if you live in Charleston you could just take the drum off and switch to individual action brake levers. The cantilever calipers would be fine for your terrain with upgraded pads. Our touring bike has V brakes and we have two sets of wheels, one with the drum and one without so we can ride whatever the terrain. With just the change in levers you could lighten the bike and see how you enjoyed riding again as a couple on a tandem.

RichinSC1

thanks for your reply. I’ll post some before and after pics when I’m finished with the upgrades and painting.

Joint Venture

One change I made to our 1990 Duet after a few years was to swap the original brake levers for Dia Compe 287V Aero levers. This allowed me to pull enough cable to use long-arm MTB V-brakes without any adapters for the road levers. The combination made for some most excellent braking! I still see the 287V levers on eBay at times.

Leisesturm

I happen to think post #4 had some sage advice for you. Most of your planned upgrades are simply not going to be possible. If you want disc brakes you'll have to buy a tandem that has them or at least the mounting tabs. It really is the best way. Your Stoker is not going to be happy with you if you throw too much money and time at this bike and it still ends up being a dog. But you will do what you will do. At least we warned you.

RichinSC1

I appreciate all the responses. The brakes as is is a no go. The springs are broken and they are totally non operational. So I will replace them with something new, either new calipers or fit for disc brakes. You may have missed the part where I posted that the bike has original drum brakes (also non functioning) so a mounting tab is there from the factory, is it in the exact correct location to mount disc brakes, I won't know until I retrofit, IF I go that route. I'll post some pics when I am completed with it and y'all can weigh in on what a terrible mistake I made. LOL. I'm kind of use to that. I've been married to the same woman for 30+ years. . Hopefully it will turn out as planned and will provide many years of enjoyment for us. Or it may fall apart on the first ride and leave us in a tangled heap of bike parts. If that is the case my only hope is that someone can capture it on video in hopes of us winning some cash money on Funniest Home Videos.

bwebel

Before you go too far down the disc road, you might want to mount wheels with disc rotors on them just to confirm that the rotors even fit. I was planning to get disc mounts brazed on a fork when I was getting the bike repainted, but then realized that because of the taper of the fork, the rotor would hit the fork.

WheelsNT

To answer the question you asked — The frame handle a disc in the rear. The fork probably can’t handle a disc in the front.

About the two brakes on one lever, something I have posted previously about that setup:

“Absolutely move the drum to a thumbshifter and put the rim brakes each on their own lever. The drum is a drag brake that you will apply to a level and leave at that level until you are done descending. It is not intended to stop the bike, just to control your speed and safely dissipate heat. When you have the drum applied, you are using up some of your rear tire’s traction, but not using any of the front tire’s traction. If you need to apply the rim brakes while the drumis applied, and they are both on the same lever, you may unexpectedly skid the rear tire while not using all the front braking you have. With the rim brakes on separate levers, you can apply the front fully and the rear partially when applying while using the drum.”

Joint Venture

The drum brake mounting tab won’t work for discs. With a drum, the entire brake mounts on/over the rear hub and that tab on the frame is there just to secure the arm that prevents the shoe assembly from rotating. Best of luck with your project!

WheelsNT

This is correct. I see I didn’t write very well — what I meant was that the frame was strong enough at the drum brake location to support a disc, that it is designed to take braking forces there. Actually mounting a disc to that location would require the services of a framebuilder to remove the drum mount and add a disc mount.

A better path would be to put new rim brakes with new pads on it, each on their own lever. Then get the drum brake working and put it on a thumbshifter. Arai drum brakes are exactly intended to answer the heat dissipation concern that you raised. When you begin to head down a significant hill, you apply the drum brake to an appropriate level using the thumbshifter and leave it there until you get to the bottom of the hill. The drum brake can dissipate massive amounts of heat without damage. The rim brakes are for stopping the bike; the drum brake is for controlling speed down hills. That system of rim and drum brakes will work fine if it is in good repair.

This is not to say there are not advantages to disc brakes. But if you really want a disc brake tandem, you should probably buy one designed for that.