First Impression: KHS SixFifty 2500

By Karl Rosengarth

There’s no denying the buzz surrounding 27.5-inch mountain bikes. Color me intrigued, as I begin my first long-term test on a tweener. I’m ready to clear my mind of preconceptions, ride and learn.

KHS offers two 120mm and two 140mm-travel models in their SixFifty lineup. All four models employ a Horst-link rear suspension, which KHS has been licensing for many years. For this initial report, I’ll simply mention that this is a tried and true suspension platform, and leave it at that.

My first foray into the B-side finds me astride the 120mm-travel SixFifty 2500. With its $2,149 price tag, the 2500 is the company’s entry-level SixFifty dually. Our size medium test bike weighed in at 33.2 lbs with my Time X-ROC S platform pedals.

Before I hit the trails, I wondered how the geometry would translate to on-trail handling:

  • effective top tube length = 23.2-inches
  • chainstay length = 17.5-inches
  • head tube angle = 69.5 degrees
  • seat tube angle = 73 degrees
  • BB height = 13.3-inches.

After shredding some sweet singletrack, I breathed a sigh of relief. The 2500 handled intuitively, and immediately put me at ease. The 2500 felt responsive, and more playful than monster truck-like. It’s solid XC-oriented handling.


Up front the bike sports an RST 650B Air fork, with adjustable rebound damping and a lockout knob atop the right leg. The fork has 30mm diameter uppers and a conventional Q/R skewer, which may account for the flex and imprecision that I detected under strain. The fork didn’t feel as plush as I’d have liked either. The RockShox Bar R air shock in the rear has been hunky-dory.

The 3×9 drivetrain on the SixFifty 2500 features Shimano SLX/Deore derailleurs F/R, mated to Alivio shifters, with an Alivio 44/32/22T crankset and 11-34 cassette (and, interestingly, a SRAM PC-951 chain). So far so good on the drivetrain.


Rubber is courtesy of Maxxis, with an Ardent 2.25 up front and a Crossmark 2.1 on the drive wheel. Both tread designs work well under a wide range of conditions.

The Bengal Helix 7.0 hydro disc brakes (with 160mm rotors) were new to me. My initial impression is that they lack stopping power, compared to hydros from the major name brands.

Look for the long-term review of this bike in an upcoming issue of Dirt Rag. Subscribe now to make sure you don’t miss it.