Everything You Should Know About The Nautilus U618 Upright Bike [A Review]

The U618 is Nautilus’ highest-end upright bike to date and as such, it’s packing some rather impressive features.

Highlights of this model include 29 built-in workout programs, 25 levels of magnetic resistance, bluetooth, and an included chest strap heart rate monitor.

It’s also pretty heavy-duty for a bike in this price range and backed by a great warranty.

The biggest downside I see is that it’s packing a pretty light flywheel, but users still generally agree that this bike provides a smooth ride.

If you’re looking for a budget upright that offers more features than most, I think Nautilus’ U618 is a pretty smart buy – but you still need to do your homework to ensure it’s the right option for ya.

And that’s where I can help.

In this review, I’ll go over everything the U618 has to offer – we’re talking specs, features, warranties, and really anything else you’d want to know.

After reading, you’ll know everything you need to in order to decide for yourself whether or not this is the right bike for your home.

The Nautilus U618 Upright Bike

You don’t hear much about Nautilus these days.

As a brand, I feel like they’re pretty low-key.

Maybe I’m missing something, but I know I don’t see any commercials or marketing from them. And I can’t remember the last time they had a new product out either.

Well, if it’s not broken, I guess you don’t fix it.

These days, Nautilus’ lineup is pretty small, but they still offer some solid cardio machines in the budget price range.

They’ve got a couple of treadmills, ellipticals, and recumbents to choose from, as well as a pair of upright bikes.

Speaking of which, the U618 is one of 2 uprights in their lineup, with the other being the slightly more affordable U616.

The differences between them are quite subtle, but more on that down below.


  • 25 magnetic resistance levels
  • 29 workout programs
  • 4 user profiles
  • Fairly heavy-duty frame
  • 325 lb weight limit
  • DualTrack console
  • Bluetooth
  • Chest strap heart rate monitor included
  • Built-in speakers
  • USB charging port
  • Quick touch resistance buttons
  • Fully adjustable seat
  • Cooling fan
  • Great warranty


  • Flywheel could be heavier


Let’s start this review with a look at the most important thing to consider – the resistance system.

This not only gives you something to pedal against during workouts, but it also determines how smooth your pedaling action is going to be.

Most bikes in this price range should be using magnetic systems, so we’ll skip the friction brake talk for now (the key takeaway is that magnetic is better anyway).

With a magnetic system, the resistance is created through a spinning metal flywheel and a series of magnets that can be moved closer (increasing resistance) or farther away (reducing resistance) from the flywheel.

This is how the resistance on the U618 works.

The U618 comes with 25 resistance levels, which is a lot for any exercise bike.

Having a lot of resistance levels gives you more play with fine tuning the resistance, but it doesn’t necessarily mean you get more total resistance… if that makes sense.

But back to flywheels.

Nautilus doesn’t report the flywheel weights for any of their bikes on their website and different sources tend to report different values for their flywheels.

This makes it a bit difficult to determine the actual weight of the flywheel for the U618.

That said, according to the Nautilus representative that I contacted, the flywheel for this bike weighs about 13 lb.

I’ve seen other sources stating that it weighs 10 lb and others even stating that it weighs 30 lb (which is ridiculous).

I’m going with what the Nautilus rep told me and saying that it weighs 13 lb – which makes sense, considering that’s the same weight of Schwinn’s 170 (Nautilus and Schwinn are owned by the same parent company).

Yes, 13 lb is pretty light when compared to higher bikes that are packing 20 – 30 lb flywheels, but affordable bikes are affordable for legit reasons.

And having lighter flywheels is one of those reasons.

I haven’t come across any upright bikes in this price range that are packing heavier flywheels, so I can’t hold this against the U618 too much.

Overall, I think this bike scores pretty highly in this department. I like that it comes with so many resistance levels to work with and folks seem to agree that the flywheel does a good job of providing a smooth workout.


Moving on, let’s take a look at the bike itself.

We all want a heavy-duty bike that’ll feel stable and secure during our workouts, but unfortunately most budget bikes are pretty lightweight.

Some are better than others though, but how can you tell online?

I suggest you check out the assembled weight and weight capacities.

These 2 specs tell ya a lot about how heavy-duty the bike really is.

Higher weights and higher weight capacities will indicate stronger, more secure bikes.

With this in mind, the U618 comes with an assembled weight of 83 lb, which is pretty heavy for an upright in this price range.

More expensive uprights will weighs well over 100 lb, fyi.

But at 83 lb, the U618 is a good 20 lb heavier than Schwinn’s 170, which is another popular upright in this price range.

Most decent budget upright bikes weigh somewhere between 50 – 70 lb, although a lot of those really cheap “bikes” weigh a lot less.

At 83 lb, the U618 is heavier than most, which I think is a good thing.

This bike also comes with an impressive weight limit of 325 lb.

I like to see at least a 300 lb limit on a bike to ensure decent construction and the U618 easily hits this mark.

FYI, one of the biggest differences between the U618 and U616 is that the U618 is quite a bit heavier and has a slightly higher weight capacity.

Overall though, the U618 is about as heavy-duty as you’ll see in this price range.


Nautilus backs their U618 upright bike with the following residential warranty:

  • 10 year frame
  • 3 year parts
  • 1 year labor

So, I think this is a great warranty for a bike in this price range.

It’s unlikely you’ll find better than 10 years on the frame and 3 years is about 3x longer than what most other budget brands are offering.

One year on labor is pretty standard operating procedure for even high-end brands (and most competitors in this price range don’t offer any labor warranty).

Overall, a great home warranty (Nautilus offers the best budget warranties around).

FYI – this is the same warranty found on the U616.


The Nautilus U618 comes with the following included features:

DualTrack console- the console is divided into 2 LCD screens that allow you to view your workout profiles and see all of your workout stats at the same time. Both are blue backlit for better visibility.

29 workout programs- this bike comes with a ton of workouts to choose from. These include a dozen standard workout profiles, several heart rate guided workouts, custom workouts, as well as a quick start and several fitness tests.

Bluetooth- this bike is bluetooth friendly, allowing you to connect with popular fitness apps for scenic routes and metric tracking and all that jazz.

USB charging port- the built-in charging port allows you to keep your phone or tablet up and running during workouts.

Heart rate monitoring- the U618 comes with built-in grip monitors as well as a included chest strap for even more accurate readings during workouts.

4 user profiles- you can save up to 4 user profiles on this bike, making it easy for multiple family members to save their settings.

Quick touch resistance buttons- these buttons make it easy to rapidly switch between resistance levels- a handy feature for interval training.

Fully adjustable seat- you can adjust both the height and fore/aft posting of the seat, making it easier to find a comfortable riding position. The seat on the U618 comes with a gel cushion for added comfort too.

Cooling fan- there’s a 3 speed fan built-into the console for added comfort during harder workouts.

Speakers- the built-in speakers allow you to hook up your mp3 player and listen to your workout jams through the console.

Water bottle holder- this hi-tech device allows you to conveniently store your beverage of choice.


Ok so the U618 comes with an impressive selection of features, but it’s time to talk price.

At the time of writing this review, the U618 costs $699 when purchased directly through Nautilus (it costs the same through Amazon too).

The price on this bike is pretty stable, but it’s always a good idea to shop around for the lowest price.

In this price range, the Schwinn 170 is probably the U618’s biggest competitor, although that costs about $150 less.

There’s also Nautilus’ U616 that goes for about $500, which I dare say is the better buy…

When you compare the 2, you find that the U616 has all the same performance specs- same flywheel, same resistance levels, same workouts.

The U618 is 20 lb heavier and comes with a slightly higher weight capacity. It also has a few other subtle upgrades like nicer handles and a softer seat.

Are these upgrades worth $200?

Well, that’s a judgement call, but definitely something to consider.

Otherwise, there aren’t that many direct competitors for the U618 in this price range.

There are a few off brand bikes on sites like Amazon that are comparable, but none of them come with a warranty that’s even close to what Nautilus offers.

There is one other competitor that I can think of and that’s ProForm’s 8.0 EX.

The 8.0 EX comes with a slightly heavier flywheel (16 lb), similar features, and a good warranty (Nautilus’ is still better though), making it a tough call between the two.

Final Thoughts

Ok, it’s about time to wrap this review up.

I like the Nautilus U618 and I think it has a lot going for it.

It scores higher than most when it comes to the flywheel and resistance system and it’s also heavier-duty than most in this price range.

When it comes to features, it has everything most riders are looking for and then some, including a ton of workouts to choose from.

The extended warranty is the icing on the cake though (it’s still the best I’ve seen in this price range).

If considering this bike, I would encourage you to take a close look at Nautilus’ U616 too – there aren’t many differences between these bikes and it might be worth it to save that extra $200.

Overall though, when it comes to budget friendly upright bikes, the U618 is easily one of the best around. Highly recommended.

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