Review: Tomac Diplomat

By John Herron

If you attended any of the big races in the 1990s, you had to love John Tomac. The date is a bit fuzzy for me, maybe 1994, but I can distinctly remember Johnny T. thundering down Mammoth’s Kamikaze downhill in a black skinsuit, riding a practically rigid frame with a booming Tioga disc rear wheel. He pushed a ridiculously large big ring and chattered through two-wheeled slides at 50mph sending dust and rocks flying. You couldn’t help but cheer him on while he rocked the DH, cross country and dual slalom races. Tomac would alternate National Championships in XC and DH over the next few years, and no doubt inspired many riders (like me) to start racing.

It’s this same admiration that company owner Joel Smith says inspires him to build bikes worthy of the Tomac name. The Diplomat attempts to bring together the best of big-wheeled rolling characteristics with the snappy nimbleness of a 26” rig.

The Bike

Fitting a robust 120mm of travel on 29” wheels introduces some obvious constraints when the goal is to mimic the ride of a 26” bike. As a result, the Diplomat sports some unique features. The chainstays are kept to a short 445mm by placing an arch in the seatstays around the seat tube, while the front derailleur is bolted to the chain stay yoke aft of the bent seat tube. The rocker-actuated single-pivot frame allows for a unified swingarm for stiffness. The rocker also provides subtle changes in the spring rate to keep small bump actuation and restrict harsh bottoming out.

The butted aluminum frame is respectably light at 6.8lbs. (with Fox RP23 shock), which, according to Smith, also passes the same strength standards as the company’s longer travel 26” bikes. It’s a high quality frame with purposeful bending, butting and a tapered head tube. The overall weight for the Diplomat 1 is reported to be 30.5lbs. I was pleasantly surprised when our size large test bike tipped the scale under 30lbs. with pedals and mud. The Diplomat 1 spec includes Easton EA70 wheels and EC70 handlebars, Fox F29 Fit RL fork, and Avid Elixir R brakes. It’s a parts mix that matches the bike’s intended use. The budget-friendlier Diplomat 2 build package (XT/SLX mix) is a nice option with only 2lbs. of additional weight.

The Ride

A fairly steep sloping top tube provides good standover clearance. With an unsagged bottom bracket height of 335mm, the Diplomat sat up very near in geometry to my 26” wheeled XC suspension bike, and didn’t induce the “Don’t look down!” acrophobia I’ve felt on other 29ers. The single-pivot frame gave no signs of lateral flex in the corners, while the 15mm thru-axle Fox F29 RL kept the front wheel as stiff as can be expected with big wheels. The 71° head tube angle is steep for a 120mm 29er, but felt very stable even on sustained downhills.

The light front end at slower speeds did require good form, but as long as I kept the weight on the outside pedal the bike corned well through the tight and twisty trails I most often ride. Pointed downhill, the big wheels and substantial suspension allowed me to let her roll with confidence. At breaks in the ride I was often surprised to see the O-ring at the bottom, having used all the rear suspension, but never felt it bottom out. Pedal bob was not an issue and what little I perceived could be dialed out with the Fox RP23 ProPedal adjustment. Once I swapped the stock Fizik Tundra saddle for my Barca-lounger-style saddle, I could slide up on the nose (rather than the nose sliding up my…) and more consistently cleared the steepest climbs on my test loop.

I had some initial concerns about the front derailleur position and tight fit up against the rear tire. The setup seemed ripe for mud collection and fouling the front shifting. But even after a very wet spring, I couldn’t find enough mud to clog the back wheel or affect shifting. I could see having to get my hands dirty if I hit the right sloppy mix of clay, but overall it wasn’t an issue. Like many 29ers, the back tire clearance is a bit limited, and while it fits some tires up to 2.5”, I found a tall 2.3” Bontrager that rubbed— something to keep in mind if you like to rock high volume skins. The stock Kenda Small Block Eights fit fine and seem like a good match for the bike.

Overall, the bigger wheels did require me to deploy a bit more leaning and body english, but they also propelled me through rough stuff at speeds I wouldn’t normally carry without more travel. While it’s true that the climbs are where you can best pull away from your riding buddies, it is a proven fact that it’s a lot more fun to try to make time on the descents. Twenty-nine inch wheels and 120mm of travel don’t magically turn rocks and roots to fluffy clouds, but the bike lived up to its intended design as a very nimble 120mm 29” bike that can handle abuse and speed like a 140mm 26” bike.

Final Thoughts

Tomac, the racer, crossed just about all categories of biking, and ruled the whole mountain. The Tomac Diplomat blurs the distinctions between wheel sizes and is a fine ambassador for big wheels, combining great descending, good slow speed handling, and ability to climb and roll over obstacles. Color options are black or white, with the two build packages, and a limited lifetime warranty. Skinsuit not included.

Bike stats

  • Country of origin: Taiwan
  • Price: $4,200
  • Weight: 29.5lbs.
  • Sizes available: M, L (tested), XL
  • Online:

Tester stats

  • Age: 39
  • Height: 5’11"
  • Weight: 160lbs.
  • Inseam: 33"