Review: Lenz Mammoth

By Jon Pratt. Photos by Justin Steiner.

Devin Lenz built his first full suspension bike in 1996, and started selling his frames the following year. Lenz started with mid-travel cross-country and trail bikes and quickly dialed up the squish with his gravity rigs. Lenz entered the 29er market in 2004 when he saw an emerging niche he could fill.

What are Devin’s goals when designing a bike? Simply put, simplicity, lightweight, and stiffness. It’s pretty straightforward thinking. Devin puts these design principles into all his bikes, including the Mammoth: a sturdy 5-inch-travel trail bike built around a linkage-driven single pivot.

The Mammoth inherits its DNA from two popular Lenz 29er models: the Behemoth, the first long travel all-mountain 29er, and the more cross- country oriented Leviathan 29×4.0. The Mammoth is designed to tackle technical terrain while still being light enough for all-day epic rides.

Lenz would rather not build a complete bike, preferring to sell the frame and shock to a shop and allowing it to be customized to the rider’s needs. That said, he will sell a complete build when one is requested. My complete Mammoth came with: a Fox RP23 shock, White Brothers 140mm LOOP fork, Terry Fly Saddle, Maxxis Ardent tires, Truvativ XO brakes and drivetrain, and DT Swiss XM 490 wheels. A very respectable build.


I had the pleasure of riding the Mammoth over varied terrain and found the bike to perform as advertised. Being the kind of rider who takes the more aggressive technical line whenever possible, and loving to sprint up hills when I’ve got gas left in the tank, the Mammoth was well suited to my needs from our very first outing. It glided over my favorite trails, and responded confidently when I ventured off the beaten path and encountered the unexpected trail feature.

The simple suspension design mated with the LOOP and RP23 worked well. The LOOP is incredibly stiff and responsive, even if it’s pretty noisy during its rebound stroke. Once I put it through a few rocky sections I never wondered if I would be sent flying off in the wrong direction…just point and go. The rear suspension design felt pretty spot-on as well. Because of the low placement of the main pivot, the rear wheel maintained traction during technical climbs, and the RP23 was able to handle larger bumps at speed. I didn’t notice any significant pedal bob while climbing.

The 69° headtube angle isn’t too slack to prohibit efficient climbing, but is slack enough to encourage forays down the mountain at speeds not comfortable, or safe, on steeper bikes. The 444mm chainstays felt perfect on the Mammoth, keeping the bike stabile during descents but never adversely affected the front end on tight, switchback climbs.

It’s worth mentioning that the bottom bracket is pretty high for this type of bike. The Mammoth’s high bottom bracket is not ideally suited to carving through corners. Its strength is in ground clearance. A half-inch can make the difference between getting through a tough section and hitting a pedal at the most inopportune time.


There are some things that I’d like to see in the next generation of the Mammoth: a rear thru-axle, which Lenz is planning to include, and water bottle cage mounts that allow me to run a standard cage and bottle under the downtube. The high placement of the mounts on my large frame forced me to use a shorter bottle in the cage than I’m accustomed to. Lenz told me he is looking into this. That being said, the medium and small frames will not accommodate a water bottle.

I really love the anodizing and the extremely low-key graphics on the Mammoth. Unfortunately it sounds like the anodized graphics are going to be replaced with a similarly designed sticker. It turns out the etching of the logo and graphics is an incredibly difficult process. I hope Lenz can find a way to either mimic the subtle graphics or figure out a way to keep doing what he’s been doing. Time will tell.

I dig this bike, in all its simplicity and toughness. The Mammoth is ideal for the rider who takes the technical line while everyone else chooses the easy route. Add in its climbing prowess and this is a great all-around trail bike that’s incredibly fun to ride. 

Vital stats

  • Wheelbase: 46 inches, 1168mm
  • Head Angle: 69 degrees
  • Seat Tube Angle: 73.8 degrees
  • Bottom Bracket: 13.75 inches, 349mm
  • Chainstay Length: 17.5 inches, 444mm
  • Weight: 6.5lbs., 2.9kg (frame and shock); 28.3lbs., 12.8kg (as tested)
  • Sizes: S, M, L(tested), XL, XXL
  • Specs based on size tested
  • Price: $2,350 (frame and shock)
  • Made in United States


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