Review: 2020 Rocky Mountain Growler 40 Hardtail

Review: 2020 Rocky Mountain Growler 40 Hardtail

2020 Rocky Mountain Growler 40

The Rocky Mountain Growler is an aggressive hardtail with modern geometry: slack head tube, long wheelbase, and short chainstays.

If you are researching hardtails, looking for a bike with an entry/mid-level spec, or specifically interested in the Growler, this review covers the basics about what to expect from Rocky Mountain’s enduro hardtail offering. Note: although the Growler 40 is specifically mentioned in this review, anything about the frame and ride characteristics will apply to the Growler 20 and 50 too.

Rocky Mountain Growler 40 Review

Aggressive Hardtail Geometry

rocky growler 40

Sleek n’ slack aggressive geometry.

The Rocky Mountain Growler 40 is designed for stability at speed and descending with ease. These two riding characteristics define a hardtail as “aggressive trail/enduro style.” For more information about these kinds of bikes, check out Aggressive Hardtails: Modern Geometry Explained. But don’t let these “extreme” terms give you the wrong impression– you don’t have to be an aggressive rider to have fun on this bike.

The slack head tube puts the front wheel far out in front, and the large wheelbase makes it forgiving on descents and stable at higher speeds. The trade off for these benefits is slower steering response. To put the geometry in perspective, my last bike was an aggressive full suspension enduro bike (2017 Giant Reign Advanced 1) and the Growler is not only more slack, but has a longer wheelbase!

More hardtails are hitting the market these days, but many of them are “trail” style and designed to find a balance between being nimble, climbing efficiently, and descending comfortably. But the Rocky Mountain Growler 40, with its slack head tube angle of 64 degrees, is fully committed to the downs.

That being said, you don’t have to be shredding gnar to get something out of this bike–even on intermediate/blue trails the bike is extremely fun and rolls everything without a care.

The bike is still relatively responsive at slow speeds and while climbing due to the short chainstays, which put the rear wheel closer to the seat. This helps the bike respond to tighter steering inputs, and helps it cut into tight corners.

Rocky Mountain Growler 40 Base Spec

suntour raidon 34

The stock Suntour Raidon 34 on the stock Growler 40.

The stock spec for all versions of the bike are in the low to intermediate price range. Even the highest entry spec, the Growler 50, has the same wheelset as the lowest Growler 20 model and similar brakes as the Rocky Mountain Growler 40. 

However, for the price, the Growler is an excellent option for entering the enduro hardtail world, or for a budget entry level mountain bike. For intermediate riders wanting to get rowdy, the Growler is adequate.

Most specs come with WTB Vigilante and Trail Boss 29 x 2.6 tires, which have been excellent so far. These are wide tires and strike a balance between fast rolling and grip. I have not had any issues with them.

But, for Sasquatch Riders, the brakes and wheels will definitely need an upgrade. The stock Shimano hubs and resin brakes will struggle to perform on advanced/black downhill trails. Also watch out for the bottom brackets, the Growler 50 is the only one that comes with a higher quality Sram DUB. Although, changing the bottom bracket on the Growler 20 and 40 will involve a crank upgrade as well.

Work with your local bike shop to upgrade specific components, or sell the stock parts and browse local bike forums for used parts. I recommend The Bike Shop. This is what I did with my build. The only major stock parts left on mine are the frame, fork, tires, and seatpost. The fork will be upgraded at a later time and check out Suntour Raidon 34 Review to learn more.

If you want to check out my full build, go to Hardtail Canada’s Custom Growler.

Trail Performance

rocky mountain growler 40 hardtail

Downhill is where this bike shines!

The Rocky Mountain Growler 40 rides slack and fast.

On steeper descents the raked out front end, along with the 29″ wheels, floats and descends comfortably. I have zero issues rolling step downs or floating chunky sections, and with 29″ wheels the bike monster trucks far easier than my old enduro bike with its 27.5″ wheels.

However, it is a hardtail, and there are far greater demands on picking the smoothest line and using your legs and body to keep the back end tracking and engaged. This isn’t like a full suspension where you can relax and let your shock do the work.

As harsh as that may sound, the experience is rewarding: you feel connected to the trail and can take credit when you nail a line, instead of just sitting back on a plush La-Z-Boy suspension while you watch the world fly by.

At speed, this Rocky Mountain hardtail is extremely stable. The responsive, stiff frame never feels twitchy and the long wheelbase is confidence inspiring. Even on Blue trails you’ll notice a huge difference between this bike and something with a more trail/XC style frame.

On climbs, the relatively steep seat tube angle places you in an efficient pedalling position, and with the nimble back end makes for a surprisingly effective climber in spite of its wheelbase and stretched out geometry. On tighter switchbacks the precision definitely suffers; it does languish in tight corners, but 99% of the time the bike climbs better than you would expect. Due to the long reach and slack head tube, you have to put your body weight further forward on steep sections to keep the front wheel from wandering.

But what matters is the amazing “trail feel”, especially with clipless pedals. I have ridden the bike on everything from flowey Blues to chunky Blacks, and although the physical demands on more serious gnar are noticeable, the immediate trail feedback and responsiveness of the frame is something that has to be experienced!

On cross country and intermediate trails this bike is faster than my full suspension: without a sagging suspension it is so much easier to stay on line and choose how you get down the trail. When the Rocky Mountain Growler 40 gets up to speed it is a joy, and something any level of rider will appreciate.

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rocky mountain growler flat mount

The odd choice of a flat brake mount, requiring an adapter for any post mount caliper. Luckily, the bike comes with a flat to post mount adapter for a 180mm rotor.

The biggest technical issue for this Rocky Mountain hardtail is the flat frame mount for the rear caliper. To allow for a post mount caliper (the modern standard) on this frame, Rocky includes a flat to post mount adapter for a 180mm rotor.

Why does this matter? The maximum rotor size is 180mm, the bolts are tricky to access (making caliper alignment more work than it should be), and the cable routing for calipers with outside hose engagement is goofy.

rocky mountain growler 40 brakes

The initial install.

Why Rocky chose a flat mount standard, more common on road bikes, instead of a standard post mount on top of the seat stay, is one for people who know something I don’t. It is very likely this was done for aesthetic reasons: a caliper with a straight hose fitting looks very clean between the chain and seat stays.

But, this is a mountain bike, and performance should have priority over looks, especially something as trivial as caliper placement. I wouldn’t be surprised if Rocky installs post mounts on future frames.

Riders who value climbing efficiency and responsiveness over stability will find this bike cumbersome. The large wheel base and relatively slow turning (compared to a pure trail bike) makes technical climbing more difficult than it would be for a bike with a steeper head tube and shorter wheelbase.

But, I don’t want to blow the slow-speed steering issues out of proportion: take it for a quick spin around your LBS’ parking lot. This way you’ll get an instant impression about its steering responsiveness, and for most riders, the benefits of stability at speed will offset these minor challenges. Beginner bikers might not even notice a difference.

Who is the Rocky Mountain Growler 40 for?

rocky mountain hardtail

For anyone after a sub $2000 bike that’s rad at speed and in it for the fun, the Growler is an excellent option. In fact, the Rocky Mountain Growler 40 ($1900) comes with an air fork and SX Eagle drivetrain!

Riders interested in this bike for its aggressive, enduro style geometry will not be disappointed. The Growler makes no qualms about being big and slack. However, even the load out on the top-model 50 leaves much to be desired for aggressive or bigger riders.

At the end of the day the Growler, across all specs, offers a fast, stable hardtail bike at reasonable price points. Maybe in the future Rocky will  offer higher specs and correct the flat mount.

For any questions about the bike, comment below.

This review is an ongoing process and will be updated as I get experience with different components and terrain.

The next steps will be adding Cushcore and Nukeproof ARD inserts, and I will post updates after some time out on the trails.

Edit: these two tire inserts have made a noticeable difference to the handling and feel of the bike! I will be posting a separate article about them in the future.

Thanks for reading!


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Darryl Dirsten
Darryl Dirsten
3 years ago

Thanks for the review. I just started riding a Growler 50 and so far I love it.

Pocholo Grumo
Pocholo Grumo
3 years ago

Im planning to upgrade the fork on my growler 20 2021 bike. Which fork is compatible to it?

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