Let’s be honest, one of the key reasons for having an e-mountain bike is to take the labour out of climbing. From short sharp uphill stings, to hour-long fire road drags, e-mtb's don't make climbs disappear, but they can make them fun; almost as much fun as descending. In full power mode on loose, dry uphill turns in your Turbo setting, you can actually drift an e-mtb through uphill turns!
To chug or to blast?
Whether you’re content to chug up the hills or blast them, you have to concentrate on a few things to make the best progress. Firstly, figure out what sort of assistance you want; do you want a workout, or a thrill ride? Lower energy settings will mean you’re putting more through the pedals, high power settings mean you’re getting the full benefit of the battery, with the feeling of having an invisible force pushing you up the incline with far less pressure on the pedals. This decision will be determined by other factors, such as the severity of the terrain, the length and steepness of the climb and of course the amount of energy the battery has in reserve.
Remember, using all the remaining battery charge to get up a long climb in the highest power mode might be both fast and fun... but if it leaves you at top of the hill with a ten mile unassisted pedal home on a 45lb bike, then it might be better to do the climb in a less power intensive mode to leave something for the ride home!
When you arrive at the foot of a climb, especially the fairly short and sharp ones that you might typically find on British trails, it’s good practice to use the approach to build some speed so you can glide into it as muhc as possible before having to lay down more power against gravity. You’ll have read the best line to ride on approach, selected a power mode that will get you up the hill at the speed you want/can afford to, and selected a gear that gives a good balance between cadence and torque.
Predicting the right line
When climbing under power, especially if you’re hitting a short hill with turns at speed, an e-mtb will have a tendency to understeer (run wide). This depends a little on the level of positive camber you have to help you round the corner. The more positive camber, or ‘berm’ you have, the less the oversteer is a factor. It’s often not a problem for a single corner, but it can have a compound effect when you have four or five turns like this in quick succession. The effect of running an inch or two wide in each corner could result in you being wildly off-line by the time the last corner arrives.
For these situations, it’s a good idea to fractionally oversteer (terrain-permitting), to account for the power understeer and natural lateral drift of tyres on loose or wet dirt. With practice, you can hit twisty sections flat out and remain bang on the right line until the trail straightens out again.
The sensors on your bike are actually switches set to respond to pre-set input data from cadence and torque supplied by you through the pedals. Sometimes when hitting the foot of a climb these can get a bit overloaded with what it is you're asking of them. Choosing the right gear is important, not only for your comfort but to give the motor the best chance of giving you the power you want.
Choose a gear that is too light will mean the motor sensors don’t register that you want help, leaving you with a time gap and power lag as they try to make sense of what you’re trying to achieve. Choose too heavy a gear, and you can find the high pedal pressure/slow cadence combination causes you to get bogged down with a low torque power delivery. It's best to compromise on a gear that you are able to spin at (around 70-80 rpm), against a sustainable pedal pressure. This asks the motor for power and torque in useful amounts, which is ideal for getting you over obstacles on climbs or through turns without fear of stalling the bike.
When you get the gearing right, you’ll find you’re pedalling at almost a constant 70-80 rpm everywhere as you end up judging your pedal input to be just enough to get the maximum assistance from the motor. This results in a surprising ability to maintain a remarkably constant speed through open singletrack. This also means you’re probably pedalling more consistently than if you were on a standard mtb, where the lighter weight means you can use the ‘freewheeling glide’ between pedal strokes more... for those who think e-mtb’s are for the lazy, think again!
To a degree, climbing on a e-mtb requires some of the same body positioning that you’d use on a regular mtb. You need to keep both wheels adequately weighted to maintain grip for the tyres, steering for the front tyre and drive for the rear. Some of this job will be taken up by the added weight of the centrally positioned battery and motor. That said, you’ll still have to ease your body weight back and forth as required.
While standing on the pedals to increase the force you can place on them is a normal and natural thing to do for short periods on steep climbs, it’s not so useful on an e-mtb. The added weight of the bike and the fact that you’ve got power assistance means it’s more efficient to remain in the saddle. Just spin your prime gear at 70-80rpm and let the motor fill in the extra power you’d get from standing. It’s one of the few small areas where technique between mtb and e-mtb really does differ.