Mondraker has gone for the no-holds-barred approach with the e-Prime Carbon RR+, with a spec list that is dripping with high-end parts and a carbon frame featuring the brand's much admired Forward Geometry.
This model tops a four bike e-Prime range, with a less spendy carbon version and two alloy ones. It is, on the face of it, an odd machine. Lightweight XC parts are matched with a plus wheelset, something we’re more used to seeing on trail bikes, as the heavier wheels and tyres, run wider and softer, are more suited to more aggressive riding. In some ways though, has Mondraker made the obvious connection between plus and electric?
Specced to the hilt
This e-Prime is based around a carbon frame, with claimed benefits of associated low weight and maxed-out stiffness being particularly welcome things on an e-bike. The rear stays are flattened to again increase compliance, but when paired with the plus tyres this effect is hard to quantify, because the vast noticeable majority of the bike’s comfort comes from the high-volume rubber.
The high-volume Maxxis Ikon out back is prone to a little spinning under motor power on slippery climbs
Mondraker’s Forward Geometry has been around for a few years now, and is popular with BikeRadar testers. In our Large frame it combines a long reach (480mm) with a short stem (30mm), reasonably steep seat angle (73.5 degrees) and a long wheelbase (1234mm). The head angle isn’t overly slack at 69 degrees. See table below for a full comparison of geometry across sizes.
The result is a bike that is incredibly stable at speed, but still has slow-speed flickability. Forward Geometry bikes do take a bit of getting used to, riding style-wise, because you need to weight the front wheel more than you might usually do, but the result is an incredibly quick ride.
The head angle is steepish at 69 degrees
The RR+ version comes with a RockShox RS1 fork, SRAM Guide RSC brakes and XX1 drivetrain. The rest of the kit is decent quality stuff, including Mondraker’s own carbon bar and own plus wheels. Maxxis Ikon and Rekon treads finish the package, in 2.8in width.
Ok, let’s cut to the chase. This thing climbs like nothing else I’ve ever ridden.
Yes, the motor is without doubt a large part of that, and the 250W Bosch Performance CX unit with the 500 Wh battery is a top performer. But that’s only one part of the story.
The e-Prime is quite simply a fantastic climber
The Maxxis tyres might not be the most aggressive, but set at low pressures (17psi on our test ride) there’s a fair amount of grip in most conditions, and the added float over soft, choppy ground (horses hooves, anyone?) means that the bike was far more surefooted than my riding compatriot’s regular tyred e-bike when riding up heavily cut up, almost boggy climbs. Then there’s the Forward Geometry, which sits your weight centrally for a really well balanced feel, enabling you to easily control rear wheel traction and front wheel accuracy.
So far, so good on the climbing front – but it’s not infallible. The Ikon out back does lack tread, so when the mud is greasy, or over rocks and roots, grip levels are thin on the ground – and with the added power from the motor, I found myself spinning wheels or slipping out more than I'm used to.
On the descents, again the Forward Geometry comes into play, along with the plus wheels. Stability at speed is exceptional, allowing you to carry far more speed into sections, and brake later than you’d imagine – fortunately the Guide RSC brakes pack a fair punch in the stopping game.
Many of our testers have found RockShox' RS-1's flexiness outweighs its merits
The wheels came set up tubeless, and this is no doubt a good thing, as the Maxxis rubber wrapping them doesn't have the sturdiest of sidewalls to get the weight low. The only thing that limits the e-Prime's performance down the hill is the RS1 fork, which we’ve not really got on well with in the past.
The slight harshness from the damper is negated by the suppleness of the plus tyres, but the fork’s inherent twistiness, when matched to the relatively vagueness of a plus tyre means this isn’t one for high precision riding – the front end has a definite vagueness about it in high-load situations.
The plus tyre condundrum
We need to spend more time on the e-Prime – it’s a funny bike in some respects. In the UK we feel that more aggressive tyres would be far better suited, as save for the balmiest of sunny days, there are usually muddy trails to contend with.
The Mondraker is exceptionally stable at speed
Okay, on a normal plus bike, and certainly an XC orientated one, you want to minimise rolling resistance, but when you’ve got a motor backing you up why not go for a sturdier, heavier tyre with a more aggressive tread to fully maximise its climbing potential?
The only downside would be on gently flowing trails where your natural speed is just above the assistance level, where you’d be riding a heavy, draggy bike. But for climbs, and steeper descents, we reckon a bit more bite would be a big benefit.
Geometry across sizes
|Head Tube Angle||69||69||69||69|
|Seat Tube Angle||73.5||73.5||73.5||73.5|
This article was originally published in What Mountain Bike magazine.