4 ms·

You should also keep in mind that the articles are slightly dated, so technical improvements may have changed the equation. For example in the comments thread f

You should also keep in mind that the articles are slightly dated, so technical improvements may have changed the equation. For example in the comments thread for the disc brake article, people mention that they cannot find disc rotors with sufficient size for tandems. With the rise of cargo and electric bikes, disc brakes with pretty massive stopping power have come to market. Mine can safely stop the bike, me, plus 100kg of extra load for a total of about 250kg [1], the R+M Load Cargo has an S-Pedelec version with a powered top speed of 45km/h. Those brakes will work for any tandem as well. [1] yes, I tried.

jacquesm 5y ago
On tandems the problem hasn't been stopping power for years (every since we had hydraulic brakes this has been a solved problem). The bigger issue on a tandem is that when you're going downhill you will end up overheating your brake, whatever kind of system you are using. There is just too much kinetic energy to get rid of as heat for your normal brake system to be able to deal with.
- Xylakant 5y ago
  The kinetic energy depends on weight and speed. Cargo bikes easily come into that range, especially the fast 45km/h electric ones. Energy dissipation depends on the size of the rotor and sizes have been increasing substantially. When I bought mine, the standard disk size was 160mm, I opted for the upgrade to 180mm. The current generation of Riese-Müller Load uses dedicated cargo bike brakes with thicker rotors (2.3mm instead of 1.8) and a 223mm diameter on the rear wheel, 160mm on the front. Those brakes have substantially more staying power before they fade. Edit: Generally, developments for cargo bikes seem to help tandems and tandem developments benefit cargo bikes. There's now an option to use the tandem version of the Rohloff internal geared hub for RM cargo bikes. That's a serious upgrade to all previous internal hubs, especially since you can combine it with a belt drive. It's a tiny bit expensive, though...
  - jacquesm 5y ago
    Yes, that Rohloff stuff is nice, and indeed a tiny bit expensive.
- nikau 5y ago
  With proper technique disc brakes wont overheat, especially now heatsinked pads and 203mm rotors are available. People who overheat brakes typically lack confidence and drag them constantly on descents causing overheating.
  - jacquesm 5y ago
    I take it you've never been on a tandem going downhill for a long stretch? That's not a matter of confidence, that's purely a matter of safety.
    - nikau 5y ago
      I've been on a touring bike with a total weight of 130kg down massive hills in Japan
      - jacquesm 5y ago
        They why would you comment on what it's like to go downhill on a tandem? I've got a Koga TwintySix, a trekking tandem, fully loaded it gets up to 180-200 Kg (two adults+camping gear, the 200 Kg is the maximum allowed load), the brakes are super good and yet, by the time you reach 70 kph downhill they are no longer capable of stopping the bike, safely or even at all. A drag brake is a must in a situation like that or your brakes will start fading within minutes during speed reduction (short bursts of braking to reduce your speed to something safe and allow for ample cooling), and long before you really need them.
        nikau 5y ago
        My comment was around experience of a reasonably heavy bike and braking down steep hills. Like I said, its about technique, if you are getting up to 70kmh with bad brakes then you have bad technique. The braking energy dissipated goes up square vs speed, so in that case you brake earlier and keep the speed down. With that said, I have no doubt a large rotor with out heat soak can easily stop a 200kg bike from 70kmh to zero.

jacquesm 5y ago

On tandems the problem hasn't been stopping power for years (every since we had hydraulic brakes this has been a solved problem). The bigger issue on a tandem is that when you're going downhill you will end up overheating your brake, whatever kind of system you are using. There is just too much kinetic energy to get rid of as heat for your normal brake system to be able to deal with.

Xylakant 5y ago
The kinetic energy depends on weight and speed. Cargo bikes easily come into that range, especially the fast 45km/h electric ones. Energy dissipation depends on the size of the rotor and sizes have been increasing substantially. When I bought mine, the standard disk size was 160mm, I opted for the upgrade to 180mm. The current generation of Riese-Müller Load uses dedicated cargo bike brakes with thicker rotors (2.3mm instead of 1.8) and a 223mm diameter on the rear wheel, 160mm on the front. Those brakes have substantially more staying power before they fade. Edit: Generally, developments for cargo bikes seem to help tandems and tandem developments benefit cargo bikes. There's now an option to use the tandem version of the Rohloff internal geared hub for RM cargo bikes. That's a serious upgrade to all previous internal hubs, especially since you can combine it with a belt drive. It's a tiny bit expensive, though...
- jacquesm 5y ago
  Yes, that Rohloff stuff is nice, and indeed a tiny bit expensive.
nikau 5y ago
With proper technique disc brakes wont overheat, especially now heatsinked pads and 203mm rotors are available. People who overheat brakes typically lack confidence and drag them constantly on descents causing overheating.
- jacquesm 5y ago
  I take it you've never been on a tandem going downhill for a long stretch? That's not a matter of confidence, that's purely a matter of safety.
  - nikau 5y ago
    I've been on a touring bike with a total weight of 130kg down massive hills in Japan
    - jacquesm 5y ago
      They why would you comment on what it's like to go downhill on a tandem? I've got a Koga TwintySix, a trekking tandem, fully loaded it gets up to 180-200 Kg (two adults+camping gear, the 200 Kg is the maximum allowed load), the brakes are super good and yet, by the time you reach 70 kph downhill they are no longer capable of stopping the bike, safely or even at all. A drag brake is a must in a situation like that or your brakes will start fading within minutes during speed reduction (short bursts of braking to reduce your speed to something safe and allow for ample cooling), and long before you really need them.
      - nikau 5y ago
        My comment was around experience of a reasonably heavy bike and braking down steep hills. Like I said, its about technique, if you are getting up to 70kmh with bad brakes then you have bad technique. The braking energy dissipated goes up square vs speed, so in that case you brake earlier and keep the speed down. With that said, I have no doubt a large rotor with out heat soak can easily stop a 200kg bike from 70kmh to zero.