How important is the weight of an e-bike when it comes to the ride experience? Does less weight really give a more agile ride, or does extra mass and more stability hold the trump card? Those are two of the questions we set out to answer recently, the results of which you can watch in the video above. As we found out, it’s not quite as simple as we’d hoped!

Our two steeds for the video were the Merida eOne-Sixty 875 (left) and CF 10k (right), sharing the same motor, travel, wheel size, and geometry.

There’s a lot of focus on headline weights in e-bike marketing, with the best SL e-bikes compromising on power and range to hit weights from 15-20kg, and the best full-fat electric models giving riders maximum grunt and vert with weights starting at 20kg. One brand that’s gone one step further with its e-bike range is Merida. The Taiwanese brand’s eOne-Sixty model is available in multiple configurations to suit varying rider priorities. There’s a chunky alloy bike with a removable 750Wh battery to cover the biggest days in the saddle, and a much lighter carbon bike with a smaller, fixed battery. Theoretically, the carbon bike should be more manoeuvrable and dynamic than the alloy bike, since there’s a 3kg (11%) difference between the two models. But is that actually the case in reality? We got hold of the Merida eOne-Sixty 875 and the eOne-Sixty CF 10k to find out.

The eOne-Sixty 875 on the left uses an alloy frame that weighs almost 2kg more than the carbon version, with the rest of the extra weight mainly down to the bigger battery.

The vital stats

Both bikes run the same travel (170mm F/174mm R), same MX wheel size, and share the same sizing and geometry, but the alloy bike weighs 26.2kg and the carbon bike weighs 23.2kg, both in size Long.

170mm fork, 174mm rear travel with P-Flex flex stay suspension and a removable 750Wh battery – those are the headline stats for the £6k Merida eOne-Sixty 875.

Weight distribution

We also measured the front to rear weight balance, but both bikes were remarkably similar. The 875 has a 48.2/51.8% balance, and the CF 10k has a slightly more forward weight bias with 48.6/51.4%. This makes sense given that the Shimano EP801 motor is the same, and the difference in battery capacity between the two bikes is done by adding a row of cells, rather than increasing the length of the battery. They are both the same length, just the 750Wh unit is fatter than the 600Wh in the carbon bike – something obvious by just looking at the size of the down tubes.

Carbon frame, carbon wheels, wireless gears, and a £10,500 price tag – the 23.2kg Merida eOne-Sixty CF 10k uses a non-removable 600Wh battery.

Add the circa 1kg difference in battery weight to the almost 2kg variation in frame weight (the alloy frame weighs 4,750g while the carbon is 2,825g) and we get to that 3kg bike weight difference. So in this example, it’s a global weight increase, where the weight balance is barely affected and the difference is spread across the whole bike. In fact, it was the variation in wheel weights that made the biggest difference to the weight distribution. The alloy bike has a lighter front wheel and a heavier rear wheel, which gives it a slightly higher rearward weight bias. Weird, considering the CF 10K also comes with carbon wheels.

Some brands – such as Canyon here – offer larger capacity batteries that are longer, putting more weight onto the fork.

Other e-bikes, such as the Canyon Spectral:ON and Torque:ON, use different length battery options (the 900Wh battery adds nearly 1kg of weight over the fork compared to the 720Wh option), which will affect even things like fork sag and air pressure. But on the Meridas we were able to set up the suspension with the same sag front and rear without compensating with higher pressures in the fork.

Even with the range extender fitted, it’s obvious that the COG of the Whyte E-Lyte Evo is really low and central.

The centre of gravity of the bike also plays a huge part in how the bike handles. This is something Whyte has been spending a lot of time optimising on its latest E-Lyte model, particularly with the optional range extender fitted. The goal being to keep the heaviest parts on the bike (the motor and battery) as low and centred as possible. A low centre of gravity helps with keeping the bike stable, and easy to lean over – like a reverse pendulum – while a centred mass means the front and rear of the bike have less inertia and require less effort to change direction and get the wheels off the ground.

Whyte has even built a jig to measure the COG both its own bikes, and competitor models. Making it easier to compare in relative terms and see how changes to the chassis design influence COG.

When it came to tyre pressures, we couldn’t help but get a bit geeky. The overall system weight difference (with rider) is 3%, so we added an extra 1psi to the tyre pressures in the 875.

How much climbing you can do on an e-bike is largely dictated by battery size, while as the motor power can compensate for small differences in system weight (bike +rider).

Climbing

If you were climbing up Ventoux and someone asked you to carry a 3kg feed bag, you’d tell them where to go, and it wouldn’t be polite. Because weight really matters when it comes to climbing. Power-to-weight is the ultimate metric for climbing speed, and on a conventional bike your power is effectively capped. Your body can only produce so much power, so reducing bike weight is the best way you can manipulate your speed in the short term.

Merida’s range extender adds over 50% more range for a 2.9kg weight penalty.

With an e-bike it’s very different, because you have so much more power. Up to 600w more to be precise, so the power-to-weight ratio between our two e-bikes becomes less significant than it would be on two conventional bikes with a 10% weight difference.

Both these two Meridas use the Shimano EP801 motor with the latest Race Tune firmware. This gives more support, faster response, adjustable overrun, and the chance to change how the power cuts out at the speed limiter. It’s available free to any Shimano EP801 owner and it makes a big difference to the feel of the motor.

Yes, the Rotwild R.X275 is actually an e-bike, and it’s one of the lightest we’ve ridden at just 15.3kg.

Given the same motor, same tyres, and same travel, the difference in how many metres of vert you’ll be able to climb on these two bikes comes down mostly to the battery size. The 750Wh battery in the alloy 875 will give you more range and more potential vert on every ride. How much? Well, in Boost mode, our range tests have shown that 1,200-1,300m of climbing is achievable out of a 600Wh battery, while the 750Wh unit in the alloy bike should give you an extra lap in the same power mode. That’s a UK lap – so 2-300m – not an alpine lap though!

Merida’s eOne-Sixty CF 10k is a good looking bike!

Which is appealing, right? Except that maybe you’re going to be more fatigued from hustling those extra 3kg around the whole ride? Maybe that extra party lap is going to be more like a passenger lap.

Except it depends on the terrain. On a technical descent where you’re having to make lots of direction changes, or a bike park trail where you’re throwing the bike around, you’re going to use more energy than on a fast, rowdy natural trail. Arguably it’s here that the heavier, and more stable bike, might actually be less tiring to ride? It’s never straightforward!

Think about it. Lifting a 3kg dumbbell is easy, right? But try lifting it repeatedly, even just a few centimetres, for two hours, or the length of a typical e-bike ride, and it’ll soon become very tiring.

Sizing can make a big difference to agility on an e-bike, since they have an inherent stability advantage over conventional bikes. For more agility, try riding a smaller size.

Agility and stability

As two sides of the same coin, agility and stability are subjective traits, and come with their own pros and cons, but weight is one of the factors that can influence them.

A lighter bike is generally considered to be a more agile bike, or at least the two are more likely to go together. And most of us would say that a heavier bike is going to be more stable. But it’s not always the case. A lighter bike with heavier wheels, a forward weight bias, or more damping might feel less agile than a heavier bike with a centralised mass, lighter wheels, and faster damping.

But sometimes you can go too far, and a smaller bike can feel less planted and confident.

Dynamic bikes might be more fun to throw around on smooth bike park trails, but they might be more of a handful and less confidence inspiring on gnarly, rough tracks. A stronger, heavier rider might be able to compensate more easily for the weight of a heavier e-bike when moving it around, but a lighter, weaker rider probably won’t have that luxury. So rider weight and strength also plays a part in deciding the importance of bike mass in the equation.

For a 60kg rider, a 20kg e-bike is 30% of their bodyweight, whereas for a 100kg rider it’s only 20%. So the weight of the e-bike will be more significant if you’re at the lighter end of the rider scale.

And it depends on your background, too. If you’re used to riding a motocross bike, then you probably won’t care about the difference between 23kg and 26kg. But if you’re coming from a 13-14kg trail bike, then it will be pretty noticeable.

Suspension plays a huge influence on how lively or poppy a bike feels. Don’t underestimate its ability to mask the weight of a heavier bike.

Ultimately it comes down to working out your priorities, test riding different models, or reading/watching reviews to find out how a bike performs. The numbers on the scales can only tell you so much.

Cost

There’s no getting away from the fact that weight saving is an expensive hobby. Looking at the two Meridas here, one is £6k and weighs 26kg. The other is £10,500 and 23kg. That’s a £4,500 difference in cost and a 3kg difference in weight, or £1,500 per kilo. Merida does have a eOne-Sixty 6000 with the same carbon frame and 600Wh battery as the 10K for the same price as the 875. So that’s six grand, and while it’s a bit heavier than the flagship model (23.6kg) you can actually get a 2.6kg lighter e-bike for no extra cash (there are obviously some lower spec parts on the carbon bike).

Some e-bikes also let you save money and weight by opting for the smaller battery. For example, the Canyon Spectral:ON (before the battery issues), or the Orbea Wild, to name just two. Both these bikes offer discounts on the smaller battery options, although you will have to accept less range as a result.

Canyon’s Spectral:ON CFR rides astonishingly well with the biggest 900Wh battery option, and is still an easy bike to manual and bunny-hop, even if battery issues have plagued it recently.

Generally though, lighter frames and components cost more money than heavier ones. So the weight of your e-bike is going to be dictated, to a large degree, by the depth of your pockets. Equally, spending money on better suspension, or more powerful brakes, will make a bigger difference to the ride and handling than a lighter saddle or stem.

Other variables

Weight is just one influence on handling and performance. And it’s not even the most important one. Taking our two bikes here, one has a carbon frame, the other has an alloy frame. One has carbon wheels, the other alloy wheels. Both materials have completely different flex responses. Ditto the wheels. Riding them for the video highlighted these variations, where the eOne-Sixty CF was sharp and precise, but not as forgiving as the alloy 875. The CF would get deflected more by bumps, while the 875 could be ridden with a more relaxed grip on the reins.

While some of this was probably down to the materials used, it’s impossible to exclude the influence of the suspension. While they both have the same kinematics, one uses RockShox parts, while the other uses Fox. So the stiffer, less compliant ride of the eOne-Sixty CF could also be down to the Fox suspension having more damping, and vice versa.

There are a lot of preconceptions about weight on an e-bike, but as with most things, its complicated!

Conclusion

If there’s one thing we can be sure of at the end of this experiment, is that it’s very difficult to make black and white statements about weight without equalising every other factor. On the face of it a lighter bike is always better. But start drilling into the details and it becomes obvious that this is not always the case. For one thing, it depends on your priorities. Choosing the right bike depends on where you ride, how you ride, your skill level, height, weight, and strength.

It also depends on your budget, and while lighter sounds better on paper, the actual ride characteristics of the bike are influenced by so many other factors that it’s impossible to draw conclusions without actually experiencing how a bike rides on the trails.