Sales of electric bicycles were on a roll even before the pandemic, but ever since the health crisis changed attitudes to public transport, demand has gone through the roof.

Demand is outstripping supply which means that many dealers have run out of battery-assisted two-wheelers and customers often face a long waiting list for the model of their choice.

So is buying a used e-bike a viable alternative?

"There is nothing to be said against buying a pre-owned e-bike and you can save money by doing so," says Rene Filippek from Germany’s huge ADFC cycling club.

However, the pitfalls are plenty and it’s as well to understand a little about how e-bikes work if you want to avoid landing yourself with a lemon. Many older e-bikes were not built to last and in some cases, repairs to them will exceed their worth.

Benjamin Topf, who edits the German e-bike magazine Downtown, thinks it's great that many people want to buy a used electric two-wheeler, but warns that finding a bargain is not easy. "At the moment there is very little on the market to choose from."

The battery is the heart of any electric bicycle and if its rechargeable cells are not up to the job, any joy you find in biking to work will be short-lived.

Fillipek suggests buying a used e-bike from a reputable shop or online dealer with at least a year’s guarantee or money-back clause if serious problems arise.

Fellow expert Topf warns against buying privately since battery cells lose capacity over time, something which the seller is hardly likely to admit. This means the battery will not hold a full charge for long and quickly deplete.

Expect an e-bike battery to last up to five years but replacing one which has reached the end of its useful lifetime can easily cost hundreds of euros.

Buyers should also steer clear of e-bikes which may have been tuned to run at higher speeds. Such modifications are illegal in many countries and they void any warranty on the machine. The power boost also leads to excessive wear on brakes and tyres.

Like with any bike, a road test is essential and if you think the bike feels like a good fit for you in terms of frame size and geometry, it's time to listen for any tell-tale noises.

The gears should change smoothly, without any jerkiness and there should be no grinding or clattering. Mid-mounted motors emit a constant low whine when working properly and any deviation from this is a sign of potential trouble.

Many e-bike dealers lack the facilities to check motors, which in some cases have to be returned to the maker for repair. Examining battery health is possible however.

The ADFC expert recommends asking the vendor to supply a battery report, which will tell you how much life is left in the cells. Private sellers will usually not be able to offer this.

"The battery concept is even more important," says Topf. Buyers should ask themselves what range they need between charges, both whether they need a more powerful battery for hills or mainly want to ride on the flat and also where they want to charge up their e-bike.

Battery packs come in myriad sizes and buying an e-bike which has more power than you need usually means paying more in the first place and carrying around excess weight.

A broken e-bike can also mean a long walk home since many machines are too heavy to be pedalled without power assistance.

"On some models the gearbox is also a permanent part of the drivetrain which means you have added mechanical resistance when pedalling," says Topf. "It might be OK for short distances but makes for an uncomfortable ride."

So are there are real savings to be made by buying second-hand?

The rule of thumb here is to pay as much as you can for a quality, used e-bike, says Topf. "Buying cheap means paying twice."

Filippek estimates that like conventional bikes, electric two-wheelers lose around a quarter of their value in the first two years and around 15% annually after that. "So a good, mid-engined e-bike with a tried-and-tested, mid-mounted motor is going to cost at least 1,500 euros ."

That is still cheaper than many new models but since e-bike battery technology is advancing rapidly, older bikes may be quickly rendered obsolete.

In some cases a replacement battery or electrical fittings for an older e-bike may simply be unavailable.

"If you invest in a five-year-old e-bike and have to replace the battery three years later it's a bad buy," says the expert.

Battery cells can be rejuvenated at some cost but "swapping the original battery for one not designed to fit from the start can cause overheating and even start a fire."

 - dpa