Specialized Turbo Tero X 4.0 review

The Tero X is listed by Specialized in its ‘active’ and ‘mountain’ ebike product lines, and it certainly deserves its place in both categories.

It’s a versatile machine for commuting and more leisure-orientated trekking, but it certainly doesn’t embarrass itself if you venture much further into full-on mountain bike riding now and again.

The Tero X is a bike that packs in a lot of riding capability and versatility.

Specialized Turbo Tero X 4.0 frame details

The Tero’s design is certainly interesting. Specialized has opted for a very compact and low-slung profile. It's intended for easy mounting and dismounting, and for manoeuvring the bike on more challenging routes and terrain.

It’s a full-suspension design with a single-pivot rear end. The suspension travel is controlled by a RockShox Deluxe R shock.

The shock has pre-set compression damping to smoothly control the 120mm of rear travel. That means you only need to worry about adjusting the rebound (how fast the shock returns to its full extension) to your preference via a dial on the shock body.

Up-front, RockShox provides a Recon Silver SL 130mm-travel fork. It makes for an incredibly smooth bike to ride, whatever the surface.

The other interesting element of the design (on larger-sized bikes) is it uses a mullet setup. At the front is a 29in wheel, while at the rear it’s 27.5 inches.

The benefits here are three-fold, enabling a ‘shorter’ rear end, which can liven up handling, improve rear-end clearance (both yours and the bike’s), and potentially improve reliability of the rear wheel.

The ride position is fairly upright, as with most mountain-bike derived designs (and the Tero X is much more mountain bike than most).

It means the Specialized works as an urban commuter bike just as well as it does when you want to get a bit more involved.

The Tero’s 67-degree head angle puts it firmly in the all-rounder camp (trail bikes will be more relaxed), while the 77-degree seat angle positions you straight over the pedals.

Specialized Turbo Tero X 4.0 build

The Specialized Tero X 4.0 is the most affordable of the Tero X range. However, aside from the more 5.0 and 6.0 having a larger 750Wh battery compared to the 4.0’s 530Wh model, the frameset and motor system are essentially the same.

The 1x drivetrain combines SRAM’s SX Eagle shifter pod and rear derailleur with a Praxis forged E30 chainset, with a 38-tooth chainring driving a wide-spread 11-50 tooth cassette at the rear.

The shifting quality is excellent, and the gear range combined with the powerful motor meant I never once baulked at any ascent on- or off-road, confident I’d have the power and gear to match.

SRAM also provides the brakes, with the electric mountain bike specific GR RE hydraulic disc system using a huge 200mm rotor up-front and a 180mm model at the rear.

The wide (750mm) upswept bar is clamped by a short stem (60mm), which helps the bike feel stable to steer without being sluggish.

The RockShox Recon Silver SL fork feels smooth and controlled in its suspension movement.

The fork has a dial to control the low-speed compression (how quickly and how far it moves). Turn the dial full-on and it locks out the fork, which is great for riding on smooth roads or climbing uphill.

At the rear, a TranzX dropper post (200mm drop) is topped by Specialized’s comfortable Bridge Sport saddle.

The dropper is controlled by a bar-mounted remote and became very handy when pulling up to traffic lights and dismounting (especially when the bike was loaded up with panniers).

It also came in very handy when riding off-road on some properly testing terrain.

Specialized has chosen its own Ground Control mountain bike tyres in a wide 2.75in size.

The 4.0 also packs in integrated Lezyne lights front and rear, a low-profile rear rack and full aluminium mudguards.

Add in super-comfortable grips, a bell and a kickstand, and the Tero X wants for nothing straight out of the shop.

Motor assistance and Mission Control app

The Tero uses Specialized’s own mid-drive 2.0E electric bike motor.

It’s noticeably smooth in its power delivery, compared to many other urban bikes.

Unlike the RadRunner and Engwe ebikes, which have a big power dump from their rear-hub motors, the Specialized feels much more refined and considered in its delivery. However, it doesn’t feel any less powerful.

The Canyon Pathlite:On’s Bosch system can’t match the progressive feel of the Specialized’s motor either, but it certainly surpasses it for power and torque.

That said, I never felt underpowered on the Tero X.

The bar-mounted remote, combined with a colour screen, is simple to use and very informative. Multiple screens can be scrolled through, showing all the relevant metrics you’ll need for a ride.

On the default (speed) screen, you get a bar that changes colour depending on how hard you’re working the motor, and shows your current pedalling cadence. Combined, they have the potential to help you ride in the most efficient way.

Range-wise, the Tero X impressed, taking in 45.24 miles (72.8km) with 2,813.3ft/857.5m of punchy off-road climbing.

Further recreational rides, mainly on tarmac, saw between 51.2 miles (82.4km), with 3,207ft/977.5m of ascent and 55.06 miles (88.6km) with 1,953.94ft/595.56m.

This proved easily a match for the larger-capacity battery of the Canyon Pathlite:On, but with less weight to carry.

The 530Wh battery charges in just shy of five hours and can be charged either on or off the bike.

The Turbo system combines with Specialized’s Mission Control app to record rides (piggybacking your phone's GPS signal).

You can also use the app to ‘tune’ the motor, setting up your own parameters on power settings, diagnose any issues with the bike and log servicing.

It also has a useful ‘Turbo lock’ function, which pairs your bike to your phone and if the bike is moved while not paired (when you’re not with it), it initiates an alarm, locks the motor system, and notifies you immediately.

Specialized Turbo Tero X 4.0 ride impressions

Often with the extra weight of an ebike system, a bike comes with some element of compromise over its handling. Even with the increase in power, some heavy electric bikes still feel heavy and ponderous to manoeuvre. The Tero X doesn’t suffer any of those traits.

At 26.54kg, it’s not exactly light, but compared to most ebikes designed for commuting, it’s not heavy either.

The Tero is nearly 3.5kg lighter than Canyon’s new Pathlite:On, even with a full-suspension design. If anything, it rides even lighter than its 26.54kg would suggest.

The Tero X’s ride was sublimely smooth on pretty much any surface I could chuck at it. On tarmac, potholes, speed humps and kerbs can be all but ignored.

Off-road, the Tero X is capable of going as far as you're willing to. I rode the bike on tight technical singletrack right through to downhill runs and it was composed everywhere.

The main advantage of going with single-pivot suspension on a bike of this type is simplicity – there’s only one pivot point for maintenance (rather than any complex linkages, etc), which is a good thing on a bike that’ll be used mostly as a workhorse.

The pivot point is also placed on the chainline to limit the effect of your pedalling on the suspension. It works, because I couldn’t feel any sense of movement or bobbing when I was sat down and pedalling, further feeding the composed ride feel.

The chunky tyre tread, with its pronounced shoulder blocks and offset blocks running through the centre, is excellent off-road and rolls fast considering its size.

On tarmac, it feels ponderous compared to a proper broad road slick, as you might expect.

If I was using the Tero X predominantly as a commuter, I’d probably invest in a less treaded tyre such as Schwalbe’s Big Ben or Specialized’s own Nimbus 2.

Specialized Turbo Tero X 4.0 bottom line

The Tero X 4.0 may not be a slimmed-down urban commuter, hauling utility bike or SUV-like cruiser, but it’s quite simply one of the best all-round ebikes I’ve ever tested.

The handling is superb on- and off-road, the ride is comfort and composure personified, and it's masses of fun and very versatile.

I’ve used it to cycle to work, travel to the supermarket and to thrill seek on some demanding off-road rides.

I simply can’t think of another bike that can do all of those things and do them so well.

The price of £4,000 is certainly not cheap, but when you’re getting as much bike as the Tero X 4.0 for your money, it could look like good value to some.