Trek Marlin+ 8 Review | Electrifying A Popular MTB

The pairing of the Bosch Active Line Plus and the CompactTube 400 made for a very efficient e-bike. Because we often review e-bikes with 750W hub motors, for which 400Wh won’t go far, we understand that, at first, 400Wh may not sound like much capacity. But 400Wh isn’t a measure of range; it’s only a measure of how much capacity the battery has—that is, how much work it can do.

Trek has paired the 400Wh CompactTube battery with a 36V, 250W motor, which draws much less current than a 48V, 750W motor. Think of it like the size of a gas tank. A 20 gal. tank in a Sprinter van won’t take it far, but in a Prius, you’ll be able to drive all day and not stop for gas.

To find out just what the Trek Marlin+ 8 is capable of, we performed two different range tests, one on the lowest assistance level (Eco) and the highest assistance level (Turbo). Plot spoiler: It performed very well in both tests.

Trek doesn’t publish range estimates, but we used Bosch’s web-based E-Bike Range Calculator, and after selecting from a number of variables including rider weight and riding environment, it suggested that the Trek Marlin+ 8 might have a range of up to 57 mi. in Eco and 29 mi. in Turbo. Let’s see how it did.

When we took the Trek Marlin+ 8 out for its max assistance range test (Turbo), we went 30.7 mi. at an average speed of 17.1 mph with 530 feet of climbing. It’s a remarkable result.

For the Eco test we saw a whopping range of 71.2 mph at an average speed of 13.2 mph over 1475 ft. of climbing.

Remember when I said this was a remarkably efficient e-bike? This is what I was talking about. We’ve seen e-bikes that offer a range of 70 mi. or more; they aren’t hard to find. What is hard to find is one that can cover that much distance with a 400Wh battery. That’s not common.

Let’s put this in perspective: When figuring out a car’s efficiency we look at miles per gallon, which is simply miles traveled divided by fuel used. Well, we do the same thing with batteries. We’ve calculated this for more than 260 e-bikes we’ve reviewed. How good is the Trek Marlin+ 8? It scored eighth on our minimum assistance test and 14th for the maximum assistance test. This is even more impressive when we consider that our speeds weren’t pokey. We’ve seen e-bikes achieve impressive ranges in Eco, but go so slowly it defeats the purpose of having an e-bike. The Trek Marlin+ 8 impressed us at every turn.

Justin, our dedicated hill tester, took the Trek Marlin+ 8 up Hell Hole, the local bike path that runs a third of a mile at a grade of 12 percent. He recorded a time of 1:48, which gave him a 10 mph average speed.

Let’s put this performance in perspective, as we’ve definitely had quicker climbers. Justin does all the tests at a moderate effort. He’s not going all-out because, well, most folks don’t see going as hard as possible on a hill as much fun. E-bikes with cadence sensors don’t care how hard you go; set to their max PAS, they are putting out their maximum wattage. With e-bikes with mid-drive motors, the torque sensor responds to rider effort—you go harder, it goes harder. The upshot is that a moderate effort on an e-bike with a mid-drive motor (or any e-bike with a torque sensor) will result in a moderate output from the e-bike.

What this means is that the Trek Marlin+ 8 is capable of climbing faster than this. Many motors we test produce more than 50Nm of torque, and while it may seem like a lackluster number, it’s important to keep in mind that e-bikes with mid-drive motors don’t need to produce as much torque because they use the mechanical advantage of the drivetrain, which effectively multiplies the torque. And the drivetrain is very effective in this regard. Like un-motorized mountain bikes, the Trek Marlin+ 8 has a 12-speed drivetrain—Shimano’s remarkably good Deore group—which gives riders a 510 percent range of gears—more than double what we see with many e-bikes at the value end of the market.

What this adds up to is an e-bike that didn’t fully show its abilities in this test; it is a most capable climber.

An eMTB has a different sort of ride than other e-bikes. They tend to be remarkably maneuverable at low speeds—though not as maneuverable as e-bikes with 20-in. wheels—while offering terrific stability at higher speeds.

The Trek Marlin+ 8 is built with an aluminum alloy frame, what Trek calls Alpha Gold aluminum. This is a relatively thin-walled aluminum that is butted—tubes are thicker on the where they are welded—and also hydroformed to give the tubes the shapes they take. What this adds up to is a frame that is lighter and stronger than what we find at lower price points.

Trek produces the Marlin+ 8 in five sizes to truly fit nearly anyone. Two sizes, the small and extra small, roll on 27.5-in. wheels to keep the standover height and reach reasonable for people of modest height. The medium, large and extra large roll on 29-in. wheels, which allows them to make the most of this eMTBs ability to roll over rocks and roots. Trek says that the Marlin+ 8 should fit everyone from 4 feet 9 up to 6 feet 5 and that is a range you can believe … thanks to five sizes. The two smallest sizes also get a narrower bar than the bigger sizes.

The fork is RockShox’s Recon Silver RL, which is an air-spring fork with adjustable damping, adjustable air pressure and preload, plus lockout. It also offers 120mm of travel; compare that with the 60, 80 or 100mm of travel we often see on more cost-conscious e-bikes. The difference between this fork and the suspension forks with coil springs we see on value-targeted e-bikes is significant; it will do more to soak up little bumps while also doing a better job of absorbing bigger hits.

For riders looking to ride singletrack trails who also need to stick to a budget that won’t max out a credit card, the Trek Marlin+ 8 is an outstanding option. It will offer a level of performance that is unlikely to be matched by anything going for less than $3000. This is a different world of performance from the fat-tire, all-terrain e-bikes that are so heavily advertised. And while it’s made for off road use, there’s nothing to say you can’t commute to work on the Marlin+ 8.

One detail that would be easy to overlook that will definitely affect the ride quality is their tire choice. The Bontrager Gunnison Pro XR tires are tubeless ready which means that a bike shop can remove the tubes and set the tires up to be run tubeless. This does several things for your experience. First, it improves the ride quality by allowing the tire to flex more. It also allows you to run lower tire pressure, which also improves ride quality. Running tires tubeless also cuts rolling resistance which means that running lower tire pressure won’t slow you down. Finally, it improves flat resistance because should the tire be punctured, sealant inside the tire will usually plug the hole before it goes flat.

We’re beginning to see some eMTBs at lower price points and one thing they don’t offer is the ability to set up the tires for tubeless riding. It’s easy to underestimate how this improves an eMTB’s ride quality.

One last detail not to overlook is the presence of a dropper post. Of the many technical innovations in mountain biking over the last 25 years (and there have been many), dropper posts changed the experience of going down steep descents by allowing the rider to press a lever with their thumb and with their body weight push the saddle down, allowing them to get their body down to lower their center of gravity, making downhills entirely more fun than they would be with the seat all the way up.

I’ve been riding the Marlin+ 8 for a few weeks now and my biggest takeaways were, in no particular order: I love the feel of this e-bike. The handling is very natural and it’s easy to control even when there’s a dusting of sand on top of the trail. That it comes in five sizes means that I was able to find more comfort than happens with most one-size e-bikes. The operation of the motor may be the biggest story here. The Bosch Active Line Plus motor operated seamlessly with my pedaling and rather than leaving me feeling like it was doing all the work for me, I’d say it encouraged me to give a bit more than I would have on other e-bikes.

The Bosch Flow app allows for a great deal of adjustment to customize the motor to your preference, plus it converts your smartphone into a large display that allows you to see more data as you ride.

The componentry is great considering what you pay. There may be nicer stuff out there, but not at this price. And because this is a Trek product, it is possible to get a test ride before you buy it and when the day comes that your e-bike needs service, Trek dealers are easy to find.

The majority of e-bikes we review weigh more than 60 lbs. With an eMTB more weight is a penalty, so manufacturers try to keep them as light as possible, relative to their price—less weight always equals mo money. With the Trek Marlin+ 8, the weight was kept to a surprisingly low 49.6 lbs. Considering what this eMTB goes for, that’s a terrific weight.

Trek knows that some buyers of the Marlin may want to run errands or commute with their e-bike. The Trek Marlin+ 8 comes with mounts for a kickstand, fenders and a rear rack should you want it to serve double, or triple, duty.

For anyone who is on the fence about whether to buy a fat-tire e-bike or make a bigger investment and buy the Trek Marlin+ 8, we recommend the Trek Marlin+ 8 for anyone who wants to focus on off-road riding and plans to ride technical trails. This is an e-bike for someone who looks at a hiking trail and thinks, “That would be more fun on two wheels.”

For the person who wasn’t a mountain biker in the past, but wants an e-bike that will grow with them and reward both increasing fitness and ability, the Trek Marlin+ 8 is a great place to start. This is an eMTB that won’t prevent you from taking the singletrack trails you encounter, and it will still be loads of fun on the road, whether that road is paved, or not.

Happy Riding! Make sure to let the Electric Bike Report team know if you have any questions or if you think we left anything out in this review of the Trek Marlin +8 down in our comments section.