A triplet bike is lighter and has less resistance per person, so is more efficient than a tandem, which is more efficient than a regular bike. Does this trend hold however long the bike? (continued)
Peter Mynors, London, UK
In 1962, I was one of five undergraduates who cycled from the UK to Greece 鈥� two of us on a tandem and three on a triplet bike.
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On level roads and moderate uphill slopes, the triplet was noticeably more efficient than the tandem. On steeper hills, the main influence on progress was how soon one of the riders needed to pause for breath and that team had to stop.
Restarting either a tandem or triplet on a steep uphill section can be difficult, so we often continued pushing that bike all the way to the top. With a solo bike, you can more easily remount and ride on, which is one reason why tandems are often regarded as poor for climbing hills.
On the unsurfaced roads through Yugoslavia, the longer wheelbase of the triplet gave a generally more comfortable ride, at least for the middle rider.
With a well-matched team of riders on the triplet, we found it more efficient to have the pedals displaced by 60 degrees relative to the rider ahead, rather than the usual arrangement for tandems in which both riders鈥� downstrokes occur simultaneously, as the 60 degrees setting provides constant power.
Matt Chamings, Barnstaple, Devon, UK
Steering is one problem associated with extending a bike for more than one person. Turning a bike involves leaning into the turn. With more weight shifting off the centre of balance, the person holding the handlebars would need enormous strength to stop the whole thing toppling over.
Adam Osen, Harlow, Essex, UK
The previous discussion on tandems focused mainly on the hardware. The software is important too. A few years ago, my daughter and I rode a tandem. When we got back, I remarked that it was surprisingly hard. She smiled. Apparently, I had been doing all the work, while she enjoyed the ride. On the other hand, when I rode up a hill with my son on the back, it was like having an electric motor. Perhaps an app that displayed the power being provided by each rider might help the efficiency gains of the tandem to be better realised.
鈥淥n steeper hills, the main influence on progress was how soon one of the riders needed to pause for breath鈥�
Richard Ellam, Bristol, UK
The discussion about multi-person bicycles assumes that triplets are more efficient than tandems, which in turn are more efficient than solos. Practical experience suggests that this isn鈥檛 always the case. The truth of the claim rests on the definition of 鈥渆fficiency鈥�.
. So, with about twice the power available, it can be ridden faster than either rider can comfortably pedal a solo when air resistance is dominant, for example on flattish roads and when riding into a headwind. But not when it comes to hill-climbing.
The ability to climb steep hills depends on the power-to-weight ratio of the bike and its rider or riders, not on the power-to-air resistance ratio, because most of the riders鈥� efforts are devoted to increasing gravitational potential energy, not pushing the air aside.
The fact tandems climb poorly suggests that their actual power-to-weight ratio is less than that of good solo bikes. That is probably because of increased losses in the transmission due to the chainsets being coupled and difficulties in the riders synchronising their physiological efforts, despite being mechanically coupled.
My wife and I rode a tandem for several years. When riding with solo cyclists, it was common for the solos to pass us on climbs.
On the descent, we would catch up and overtake them in short order as we were much faster downhill. Even with very low gear settings, climbing our local hills, which we can do quite comfortably on our solo bikes, could be pretty purgatorial on the tandem.
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