If you have been looking at purchasing an e-cargo bike and have been confused about the various drive options then this blog post is for you.
Most people are familiar with how an analogue (non-electric) bikes works. You have a chain that connects to a rear cassette that has a selection of cogs. The larger the rear cog then the easier it will be to pedal and the smaller the rear cog then it will be harder to pedal. So when going up a hill you will want to shift the chain on to a larger cog and when zooming down a hill you will want a smaller cog.
With e-cargo bikes you will find that as well as the traditional chain and rear cassette combination you also have chain (or belt drive) and internal hub gears, (gears inside the rear wheel's hub). So what is the difference and how can you choose the best option for your requirements?
Internal Gear Hubs (IGH)
Internal Gear Hubs, or IGH are a popular option for e-cargo bikes. Instead of having an external cassette the magic happens inside the rear hub. Protected from the elements and road grime, this is one of the many advantages of an IGH system.
There are a few main companies that specialise in IGH systems, the bikes we tend to stock are equipped with Shimano's Nexus or a system from Enviolo.
Gate's Carbon Drive
You may have read e-bike descriptions and come across Gate's Carbon Belt Drives. A carbon belt drive doesn't have a traditional chain that turns the cogs but a carbon fibre belt. The advantages of carbon belt drives are:
- low maintenance, no need to oil the chain
- clean, as no oil the belt drive remains clean
- long life, belt drives last far longer than chains (approx 5 times as long)
Some e-cargo bike manufacturers give you options regarding what brand IGH you can select and if the drive chain is a chain or a carbon belt. It may be confusing trying to decide what the best option is for you. Your available budget is also going to have an influence on the bike specification.
If you're on a limited budget then the traditional cassette and chain option (so not a IGH) is going to be the cheapest option and will perfom perfectly well.
Benefits of Internal Hub Gears
We've already discussed the fact that IHG are internal so protected from the elements. This will prolong the life of the system and reduce maintenance. Other benefits include:
- protected from elements
- low maintenance
- smoother operation, no more clunky gear changes
Nexus vs Enviolo
Selecting from the available options will come down to budget, available gear range and if you are looking for an automatic system - yes you can now get e-bikes with automatic gearing!
The easiest way to compare systems is to work out the gear ratio. On a traditional road bike the rear cassette may have a smallest rear cog of 11 and a maximum of 34, (these numbers represent the teeth on the cogs). So the range is (34/11)*100 = 309% The larger the % then the larger the gear range, therefore the bike will be more suited to a range of riding conditions, i.e. more suited to hills.
If you live in flat region then the range of gears isn't so important. However that little hill on the way to the station is going to feel like a very big hill when you are transporting yourself, your work bag a couple of toddlers as well as your shopping!
Enviolo Gear Ratio
The gear ration for the Enviolo IGH is 380%
The gear ration for the Shimao Nexus 5E IGH is 263%
The Enviolo system is also available with an automatic gear box, the Automatiq. The advantage of this is the same as with a car, no more gear changes.
IGH are more expensive than a traditional cassette and the Enviolo Automatiq is the most expensive option. You will need to balance the additional cost of an IGH with the benefits outlined above.