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Nautilus T618 Review

Quick Summary

Nautilus recently updated its Performance Series of cardio trainers with a new top-of-the-line model, the T618 Treadmill. This $1299 treadmill for runners is meant to be a bargain even at full price: New owners get a 3.5 CHP motor, advanced cushioning, wireless pulse monitoring, Bluetooth data syncing, and compatibility with RunSocial — all with a five-year parts/electronics warranty. Get the details from FitRated’s complete Nautilus T618 Treadmill review.


Model Nautilus T618

Our custom rating considers all of the treadmill's features, specs, warranties, and 100's of user & expert reviews, to save you time!

List Price

Suggested retail price, typically higher than the price you'll pay with our recommended retailers.

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Treadmill Speed is measured in Miles Per Hour (mph). Average running speed is 5-9 mph.

0 - 12 mph

Treadmill Incline measures the angle of the deck, and how steep it is relative to the floor (0% is flat, and 15% is like a steep hill).

0 - 15%

The Treadmill Motor is what turns the belt as you run. We recommend at least 2 HP (Horsepower) motors, 2.5+ HP for jogging, and 3.0+ HP for running.

3.5 CHP peak AC motor

Treadmill Deck dimensions are measured in inches: Width x Length. The wider and longer the deck, the safer it is (55-60 inches long recommended for running).

20" x 60"

The Treadmill Belt is the surface you run on. The thicker the belt, the less impact on your joints. At least 2-ply (1 inch) recommended.


Some treadmills are designed to conserve space by folding up. This is a convenient option, but some features might be reduced.


Treadmill Programs allow you to complete a workout with changing speeds and inclines, without changing anything manually.

Max. Weight

Treadmill Max User Weight is the amount of weight, in pounds (lbs), that it can safely support, which can represent durability.

Heart Rate

Heart Rate programs allow you to track how many times your heart is beating per minute (bpm), and some control the workout for you.

Contact Grips

Dimensions are included to help you figure out if this treadmill will fit properly (Length x Width x Height and Height x Depth).

86" x 33" x 13"

Treadmill Display refers to the screen you'll look at to monitor workouts. LED and LCD displays are similar to TV screens.

Basic LED Display
Cooling Fans

Treadmill Cooling Fans are designed to help keep you cool during an intense workout.

Accessory Tray

Some treadmills include an accessory tray for holding items such as water bottles, wallets, keys, or MP3 players like iPods.


Treadmills that include a sound system allow you to listen to your MP3 player/iPod through built-in speakers (no headphones).

Quick Controls

Quick Controls allow you to select speed, incline and even workout programs with the touch of a button (usually on the handles).


The warranty is a very important part of your investment. The longer the warranty, the longer you can get free/discounted repairs by the manufacturer.

Frame & Motor: 15 years
Parts: 5 years
Labor: 2 years

Rating: 84.5%

Our Rating

Rating: 84.5/100. The Nautilus T618 Treadmill for runners hit the home gym market in late 2016. Priced at just $1299 and featuring some high-end parts, it seems almost too good to be the “real deal” — but so far we haven’t heard any complaints. This unit and a few other folding treadmills for 2016/2017 are challenging the old rule that if a treadmill can be folded, corners must have been cut. In fact the main drawback of the T618 could be its impressive heft: A powerful motor, large rollers and other substantial components help create a more than 250-pound machine.
Below we list and describe performance-related specifics, plus we explain the “mixed reality” or virtual reality workout programs that are available with the RunSocial mobile app.


  • Foldable to help conserve space
  • Four user profiles
  • 3.5 CHP motor
  • Top speed 12 mph
  • Workout area 20” wide x 60” long
  • Advanced cushioning
  • Automated incline up to 15%
  • 2.75” diameter belt rollers for quiet operation and longevity
  • 26 built-in workout apps
  • Compatible with RunSocial “mixed reality” training (described below)
  • Media shelf securely holds phone/tablet
  • Bluetooth enabled for wireless stats sharing
  • Chest strap for wireless pulse monitoring
  • Water bottle holder and towel rack
  • User weight capacity is 350 pounds


  • Heavy machine weight
  • Default display is ho-hum; workouts are much more engaging with the addition of a tablet computer and RunSocial
  • Motor warranty is below average


The new Nautilus T618 is a mid-priced treadmill for runners and walkers. Regarding performance, it’s loaded with above-average components for its price class. Regarding programming, it offers excellent variety with 26 built-in programs and the option to integrate RunSocial (tablet computer required). Here are details about the workouts and other features.

Workout Programs

The T618 Treadmill supports four user profiles. Main benefits of using a profile are 1) more accurate feedback (especially about calorie burn) and 2) the ability to track workout activity long-term.
The console holds 26 standard training programs. It also has a shelf for a tablet computer or smartphone (iPad or iPhone), which can be used as a display for RunSocial programming.

  • Standard programs automate the tread belt’s speed and incline to support efficient progress toward goals for weight management, endurance and interval training. Heart rate, calories burned, and other program data are shown in two wide windows with soft backlighting for easy reading. At the conclusion of each workout the treadmill assigns a fitness score.
  • RunSocial programs can be accessed with an iPhone or iPad. The RunSocial app is called a “mixed reality” platform because it combines users’ avatars with interactive video of real-life routes. As you exercise on the treadmill, your avatar moves through scenic video at the same pace. The RunSocial lets you choose from a walk or run in Tibet, a hike through the Scottish Highlands, a marathon route in London, and much more. You can download a free sample of any video and pay about $5 to download a full route. The visuals stream by at your workout pace, ambient audio can be included, and RunSocial tracks your performance stats. Your avatar is a somewhat realistic-looking man or woman. (Unfortunately you can’t change his/her physical features, but you can dress the avatar in your favorite colors.) The “social” part of the app refers to other avatars. If you like, you can plan a virtual run with your friends and family, or you can share a route with RunSocial users from around the world. By tapping on an avatar you can see the user’s profile picture and hometown.

Nautilus T618 Features

A full-sized treadmill for runners, the Nautilus T618 is approximately three feet wide and six feet long. It weighs more than 250 pounds. For space-saving the treadmill’s deck can easily be “folded” or pushed into a vertical position. When the deck is later released, it slowly and gently falls back into exercise mode.

The 3.5 CHP motor can support speeds up to 12 mph. The motor offers a good deal of power, but we wouldn’t necessarily count on it for marathon running. (A marathoner should generally opt for a treadmill with 4.0 CHP if possible, and we’d look for a motor with a lifetime warranty.)

A secondary motor powers the treadmill’s incline. It can push the track to a maximum 15% angle for extra challenge and to simulate outdoor routes.

Advanced cushioning on the T618 is firmer at the point of push-off and softer in the “landing zone” at the front of the track. Known as Rebound Cushioning, it’s the top Nautilus option for impact deflection.

The training surface is the standard size for treadmill running, 20” wide and 60” long. The belt is remarkably high quality for a treadmill under $1500: It’s three-ply and 2.5 mm thick. (For comparison, many home treadmills have thinner single-ply belts that bring noisy operation, require more maintenance and wear out quickly.) Also worth noting is that the belt moves over rollers with 2.75” diameter, which is relatively large for a home treadmill and helps prevent wear on the belt and motor.

This cardio trainer is shipped with a chest strap for wireless heart rate monitoring. The console can store workout data and has a Bluetooth connection for sending statistics to various fitness apps.

For digital distraction this cardio trainer has a media shelf and speakers.

Other amenities include a three-speed fan, a water bottle holder and a towel rack.

Warranty & Guarantee

The manufacturer’s warranty for the Nautilus T618 provides the following coverage:
– Motor and Frame: 15 years

– Parts and electronics: 5 years

– Labor:2 years

When a customer buys directly from Nautilus, returns are accepted within six weeks of purchase. Note that the buyer pays for shipping and other expenses though, so the trial isn’t completely free.


The Nautilus T618 Treadmill is designed to expertly serve an avid runner or multi-user household for at least several years. Although it’s a foldable treadmill, it has the same performance capacity as non-folding alternatives in its price class. Highlights range from a well-cushioned deck to a console with the option to integrate “mixed reality” training. We’re a bit wary of the substandard motor warranty (15 years instead of lifetime), but taking everything into account the T618 looks like a good deal for runners at $1299.

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