Bike Review: Santa Cruz Heckler SL

There is an almost bewildering level of choice available in E-Bikes these days, with competing systems offering various levels of motor torque, battery capacity and ride feel to create a range of bikes suited to different demands and riders.

Originally all E-Bikes were what are now termed ‘full fat’ bikes, using a high torque motor and large capacity battery to create systems which prioritise power and range giving a rider the maximum uphill assistance. The compromise required to achieve that assistance however is increased weight with the majority of true full power models weighing upwards of 23kg, even with carbon frames and good quality parts and many above 25kg. With a chunk of that weight coming from the battery in the downtube, handling is inevitably different to a regular mountain bike, with big E-Bikes carrying momentum incredibly well, but harder work​​ to manoeuvre on tight and steep trails, especially for smaller riders. 

In more recent years another whole class has emerged, commonly referred to as SL E-Bikes. These new versions generally use a mid torque motor, coupled with a smaller battery to create a bike which handles almost like a regular MTB on the descents. Giving a familiar mountain bike feel and lighter overall bike weight, most weigh in at around or under the 20kg mark depending on battery size. While they might not provide the climbing speeds of the full power bikes, they still give a solid amount of assistance, essentially doubling climbing speed for the same effort compared to a normal bike. Recently, both motor torque and battery capacity in the best SL bikes have increased, further reducing the gap between the two styles.

The choice between prioritising power or handling often presents a tricky dilemma for potential buyers with no one bike able to give win in every aspect, so it’s now a case of understanding what the strengths of any individual model are and trying to match them to what you personally value when buying something. 

Very much a model in the light and agile camp, the Santa Cruz Heckler SL is an out and out riders bike, designed with its downhill performance in mind. With the whole motor and battery system weighing barely more than 4kg and the battery sitting low in the downtube and near the centre of the bike, the weight is not just reduced but also in the best possible place to allow for quick changes of direction or lofting of the front wheel. Just the battery alone in the full power Heckler weighs 4kg, which should help to give some idea just how different the SL version is in terms of weight and handling. 

Using the Fazua Ride 60 motor system, it supplies up to 60 nm of torque on the climbs and carries a 420W battery in the downtube. Both those numbers sit towards the upper end of the category for SL bikes, making the Heckler SL both long ranged and relatively powerful within its class. Modelled around the super popular Bronson, it pairs a 160mm travel fork with 150mm of VPP suspension out back. As with the Bronson, that amount of travel should create a very well rounded bike, with enough suspension in reserve to take on some very hard riding, while still remaining firm enough to be responsive on easier terrain or at lower speeds. All sizes of the Heckler SL also make use of an MX wheel setup, a choice that is becoming almost universal on harder riding E-bikes as it improves agility even further with the motor there to compensate for any minor loss in climbing efficiency compared to a full 29’ bike.

Geometry is very close to the new Bronson V5, with a Medium bike combining a  64.3 head angle, short for an E-bike 443mm chainstay, 457mm reach and generous BB drop to create a 1239mm wheelbase. Those numbers look like a great set on paper, and as with the Bronson V5 we liked so much recently, should make for a neutral and balanced bike, easy to load and corner while still being slack and stable enough to really ride hard. 

Ride Impressions

Pick up a Hecker SL to go for a ride and you’ll notice the weight difference to most E-Bikes even before you’ve gotten aboard. At just over 19kg lifting it out of the van or down from a rack is much easier than with the big bikes, especially for smaller riders - we’ve had numerous friends who have regular mountain bikes approaching these weights so it’s really not that heavy in the grand scheme of things! 

Motor startup is quick, requiring just a flick of the ring controller and can be done with the bike already in motion. Once it’s up and running, battery life and power are both displayed from the top tube mounted LED hub with three power modes to choose from. All can be customised by the user but in stock form the bike offers a fairly normal spread. 

In “Breeze”, the Fauza system supplies just a light touch of assist giving the maximum possible range. Used in this mode, the Heckler SL is still faster uphill than a regular enduro bike, but very much feels like a normal mountain bike to ride, needing your usual effort to keep it going. Bump up a mode to “River” and the bike now feels like a real E-Bike. Climbing speed ramps up dramatically and effort reduces, with what would be impossible grades now becoming climbable with effort. Unlike some full power bikes in their middle power mode, you’ll still need to put some watts in to move at a decent speed, but do so and you are rewarded with a solid level of assistance. Finally “Rocket” is perhaps a little misnamed, but provides either something close to a shuttle mode for forest road climbing where you can sit back onto the motor much more, or try to climb up truly silly grades. Uniquely to the Ride 60 system there is also a “super assist” mode available, where a double click in rocket will give even more power for a 20 second window adding an extra 100W of peal power to rescue you from a bad gear choice or blast over a steep crest.

Compared to something like a full power EP801 or Bosch Cx motor, the Fazua Ride 60 does demand quite a bit more effort from the rider but by the standards of SL motors it feels really torquey with a solid amount of assist. Overall climbing speed is lower than the full power systems but more than double that of a regular bike. It’s also less cadence dependent than many others, still delivering good levels of power at lower cadences which can be super helpful after a stall, when caught in the wrong gear or for technical climbs where you might not want the cranks whirling away to help time pedal strokes around obstacles.

It's also a quiet motor, making very little noise indeed at lower torques and only really becoming audible when pushing harder on the cranks. Power delivery is especially well modulated in the lower modes giving a bike that has quite a natural ride feel, like riding a regular mountain bike but impossibly quickly. Range is also good with the SL delivering close to the full distances we’d normally see from a full 600W battery Shimano bike, so whatever Fazua have done with the motor tuning has worked extremely well at getting the best out of their 420W battery. It’s not something we’d regularly plan on doing, but the motor is almost completely drag free so pedalling without assistance is very much possible should a rider end up out of battery and needing to get home. That does also help when sprinting the bike downhill above the motor cutout speed with less of the feeling of ‘hitting the wall’ than is present on many full power bikes. 

In terms of climbing position, it’s a comfortable bike to log uphill miles on. The seat angle is set at a middle of the road 76’ creating a great position for spinning up forest road climbs and traversing sections without the perched on top of the BB feel that some very steep seat angles bikes can have. That angle, in combination with the shorter chainstays, does mean that on the steepest climbs the bike requires a bit more effort to keep the front wheel planted than some others, but then that willingness to get the front wheel up would come back in all the right way on the descents. 

If so far the Heckler SL is sounding like a bike of slight compromises, then all that ends the moment it crests the top of the hill and gets its teeth into any kind of a descent. Not just good for an E-Bike, it’s straight up one of the best descending 150mm bikes we have ever ridden full stop. 

The balanced geometry coupled to the mid travel suspension makes for a very easy bike to ride indeed, with weight nicely centred between the wheels and incredible cornering grip. As with the Bronson, the VPP suspension does an excellent job of muting out small trail chatter while still supplying plenty of support to pump from. Small trail gaps can be picked up for just like a regular bike and quick manuals are easier to initiate than on any other E-Bike we’ve ridden. Bigger impacts are also handled well, with plenty of bottom out resistance and no obvious ramp or harshness in the rear suspension stroke. If there is a limit to how hard the bike can be pushed, it’s more that the generally excellent 160mm Lyrik just can’t quite keep up with the punishment the rear end of the bike can deal with, eventually becoming overwhelmed when braking through steeper, rougher ground. 

The slight lag when initiating direction changes that can be present in most e-bikes simply isn’t here, with the Heckler SL responding instantly to rider input, weaving through the corners like a regular enduro bike. For riders who are used to, or who prefer the feel of a regular enduro bike it’s an absolute treat with no learning curve or adjustment required to get up to speed. For smaller riders, that quickness of response is even more noticeable, with Janey at 58kg instantly loving the lighter and quicker handling chassis compared to her normal full power Heckler. 

Add to that the extra stability that comes from the low centre mass of the motor and the grip levels are off the charts. It might even be better than a regular enduro bike in many places, with the small amount of extra weight actually acting as a positive, helping to mute out the smaller impacts and steady the bike without ever becoming a chore. It’s very rare to get a bike that simultaneously feels stuck to the ground yet still can pop and pump well but this one does. At its absolute best when linking corners and pumping through fast trails, it’s also more than capable of downhill runs and steep enduro terrain. For the kind of riding that suits a 150mm platform, it’s virtually faultless.

Any more questions on the platform, keen to arrange a demo or looking to pick up a Heckler SL at a bargain price? Get in touch and we’ll see what we can do for you.

☎️ 01896 831429

📧 shop@tweedvalleybikes.co.uk