When choosing an e-bike it can be a bit of minefield with the different varieties available, power modes, motors batteries etc. so this is a summary of what to look for in terms of electric bikes.

Drive systems

There are two main drive systems with electric bikes; these are either central crank driven systems or hub driven systems.

Crank Drives

Crank driven motors are located in the middle of the bike frame, where the bottom bracket normally sits. The drive system propels the bike through the chain with the use of the rear wheel gears. This is a highly efficient system, because it can increase its own torque through the use of wheel’s cassette. To put it simple, it can allow the bicycle to climb up very steep hills.

Crank drives are what is known as a pedelec bike which means it will only work when the rider keeps pedalling by rotating the cranks. They are more intuitive than hub driven motors because they are equipped with a torque sensor, which recognizes when the rider puts more effort on the cranks. The higher the rider’s effort on the cranks, the more power is supplied by the motor and the faster the bike goes. , these make them very efficient and are great for hill climbing. But because they work as a pedelec only, the rider needs to keep pedalling to make the assistance work.

Various Crank drive systems are available, so the ones to look out for are Bosch, Yamaha, Shimano and Panasonic.

Hub Drives

On hub driven systems the motor is located inside the hub, this propels the whole wheel independently from the bike chain or cassette so works from power on demand. With Hub motor systems they can be driven in two modes. Either pedal assist mode or via throttle. With many models you can select different levels of pedal assist modes and the power will come in based on the level set whilst pedalling. The throttle mode will be just a twist and go or thumb throttle, this mode does not require the rider to pedal. It is important to note that there is a limitation on the speed the throttle can go as of the 1st January 2016 which limits the speed to 6kph in line with European law. Hub driven bikes are great for riders which do not want to worry about the need for exertion as with crank drives. Whilst the crank drives give you a more seamless sense of riding, with hub motors you can just select the power mode you want so is a more effortless means of cycling an electric bike.

There are different types of hub motors, with the main types being direct drive only, and the ones using an internal gearing system:

Motors

Motors come in two different styles, brushed or brushless, whilst brushed motors require maintenance and require replacing after a certain period of use, brushless motors are generally maintenance free and prove to be maintenance free in the main. For on road use in the UK the motors need to be limited to 250w

Direct drive hub motors

The direct drive hub motors are very reliable and quiet but can be quite large and heavy. The direct drive motors need to be big in order to generate sufficient amount of torque. Due to the weight this can be a downside when fitted to an electric bike when trying to reduce the weight of the actual bike itself.

Geared hub motors

The geared hub motors ae constructed differently whereby they are smaller in size and weigh less than the direct drive counterparts. They have an internal gearing system that allows to generate higher torque which will allow superior hill climbing ability. The only downside is that they can be a little louder than other drive systems but have proved to be very reliable.

Batteries

There have been advancements in batteries in recent years with the current mainstay of lithium batteries proving to have a greater lifecycle than the old lead acid counterparts, please find below a description of the different battery types available.

Sealed Lead Acid

These are old style battery technology now and only had a lifecycle of approx. 120 recharges. They are also extremely heavy which is obviously detrimental to cycling some lead acid batteries carry memory which means they tend to lose their capacity over time.

NiMh batteries

Nickel Metal Hydride batteries are still used in a small amount of electric bikes. They are lighter than the lead acid batteries but heavier than Lithium. They do like to be drained down as opposed to topped up.

Lithium-Ion battery

These are the mainstay for most electric bikes these days. They are lightweight when compared to previous styles of batteries and can last for approx. 800-1000 recharges before it starts to degrade.

LiFePO4

Lithium Iron Phosphate battery also utilises a lithium based mixture but with the addition of iron cathodes. The LiFePO4 battery has a very long lifetime but is not widely used in electric bicycles due to the power density being lower than the standard lithium batteries.

Which bike is right for you?

There are several things that can determine the correct bike for you. The first being the style of bike you wish to ride i.e. step through, crossbar, mountain bike, folding etc. once his has been ascertained you need to look at your height as many bikes on the market will not be sufficient for those of a slighter stature, 5’6 and under you will be looking at a maximum frame height of approx. 17”.

The next consideration is the power outage from the battery, The voltage will determine the torque and power you have and the amp hours the distance the battery will give you. For good hill climbing ability a 36v battery or higher would be the best choice, there are 24v and 26v batteries on the market that are perfectly fine however you will need to put a little more effort on steep inclines. Where distance is concerned. Anything with an 9Ah -10Ah will give an approx. 25-35 mile range on pedal assist, whilst a 15Ah - 16Ah between 60-70 miles on pedal assist.

We here at E-Bikes Direct deliver free and assembled products and should you have any questions relating to electric bikes or what you should be looking for then please contact us via email at info@e-bikesdirect.co.uk or alternatively please call us on 01580 830959 and our dedicated team will be more than happy to assist.

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