The last time we rode the Trek Rail we awarded it our 2021 E-Bike of the Year crown in the shop bought category. Since then we haven’t had another chance to ride one, mainly because they’ve been flying off the shop floor. Meanwhile, Trek hasn’t rested on its laurels – the front triangle has been lengthened and the extra space used to stuff in Bosch’s biggest 750Wh battery on all but the smallest frame size. So how does it perform and is it one of the best electric mountain bikes on offer?

Need to know:

• Mino link on the seatstay/rocker interface gives high and low geometry settings – useful if you want to run a 27.5in rear wheel
• Knock Block steering limiter uses interlocking stem and headset spacers, while steerer tube gets oversize 1.8in taper
• Top tube System controller and wireless remote are available to buy aftermarket, but they should come as standard
• M, L, and XL frames get 750Wh battery, while S gets a 625Wh

This updated Rail is called the Gen 4, but you can still buy the old Gen 3 model. It gets the smaller 625Wh battery, non-Smart System-compatible electronics and a shorter reach. Although buying the Gen 4 seems like a no-brainer, the new large frame is a really big bike, with a 490mm reach and a yawning 35mm gap to the medium. So some riders may achieve a better fit on the old Gen 3.

It’s disappointing that Trek hasn’t fitted the latest Bosch System Controller (as found on the Mondraker) to the top tube. Instead you get a measly blanking plate. To enjoy the improved integration and reduced clutter you’ll have to fork out an extra £1,600 for the next model up, which seems pretty stingy.

Suspension

Trek claims the Rail delivers 150mm travel, but we only measured 140mm (3mm less than the last Rail we tested). However, we didn’t notice this shortcoming on the trail, mostly because the long wheelbase of the Rail gives it excellent stability at high speeds on rough ground.

Where we found it wanting was in terms of grip and sensitivity. It struggled to trace smaller bumps, so not only did it lack some comfort on long rides, but it needed more effort to hold a line on off-cambers, through slow turns, and in the wet. Having said that, there’s plenty of support, so as long as we had the energy, we could ride the Rail like a runaway train.

Our bike came with a RockShox Zeb in place of the advertised Domain RC. With 38mm stanchions it perfectly matches the hench proportions of the Rail frame, but it wasn’t the smoothest or most supple fork on test. In that respect there was a symbiosis between the Trek’s front and rear suspension, even if it wasn’t quite the fairytale relationship we’d hoped for.

Components

Trek proffers two brake specs on the Rail 9.7 – Shimano Deore or SRAM Code R, both in four-piston guise. Given the choice, we’d take the Shimano brake option, as the SRAM levers on our test bike needed a judicious squeeze to extract full power.

The in-house Bontrager wheels came tubeless out of the box, and Trek certainly doesn’t skimp on sealant. We also liked the smooth, silent, fast engagement of the freehub, but the rear wheel de-tensioned badly after about 100km.

The Bontrager Arvada saddle was unanimously hated by all our testers for its lack of cushioning, and the TranzX dropper post remote suffered from an overly stiff action compared to some of the other test bikes.

Performance

If the last Rail we tested was a monster truck on the trails, the new bike’s longer sizing and extra payload (in the form of that big, heavy battery) makes it even more of a juggernaut. Long and low, once up to speed there is no stopping it, steamrolling high-speed descents with poise and confidence. At certain points its pace was breathtaking, not only because we were going so fast, but also because we were working so hard to hold on with the constant pounding.

More supple, forgiving suspension would reduce rider fatigue and increase mechanical grip, making the Rail a better all-rounder. Perhaps getting rid of its proprietary Thru Shaft damper has deprived the Rail of its early magic.

That extra length in the front end also makes the new Rail more cumbersome through rapid direction changes. So we swapped the stock 50mm stem for a 40mm model, which reduced the reach, moved our centre of gravity back, and helped with getting the front wheel off the ground. On the other hand, the long chainstays and steep seat angle, combined with the rapid response and instant torque of the Bosch motor, make the Rail an absolute hillclimb demon.

What alternatives do we recommend? Check out our guide to the best electric mountain bikes, thoroughly tried and tested by MBR, or the best budget eMTB.