JEFFSY vs STUMPJUMPER 15: Which Trail Titan Deserves Your Dollars?

Posted by Team at Day Zero on 7th Aug 2025

JEFFSY vs STUMPJUMPER 15: Which Trail Titan Deserves Your Dollars?

JEFFSY vs STUMPJUMPER: Which Trail Titan Deserves Your Dollars?

We’ve spent real time on the YT Jeffsy Core 4, and we’re impressed. It’s fast, planted, responsive, and comes spec’d with components usually reserved for builds well north of 15 grand, and up $20,000! So when Specialized launched the new Stumpjumper 15 EVO Expert AXS, we naturally took a closer look.

Now, straight up, we haven’t ridden the new Stumpjumper. But we’ve lined them up on paper, spec-for-spec, and here’s what we found.

Price Check: Who’s Already Ahead?

  • YT Jeffsy Core 4: NZD $11,499

  • Specialized Stumpjumper 15 EVO Expert AXS: NZD $12,900

Right off the bat, that’s $1,400 in your pocket with the Jeffsy. Let’s see what you get for it.

For reference:

@ DAY | ZERO

@ Specialized NZ

Component Showdown

Jeffsy Core 4 gives you:

Stumpjumper EVO Expert AXS gives you:

  • SRAM GX Eagle AXS Transmission (good, but not XO)

  • FOX FLOAT 36 Performance Elite + GENIE Shock (great, but not Factory)

  • Specialized alloy wheelset (good, but not DT SWISS Carbon)

  • Butcher / Eliminator tires (good)

So here’s the thing: Jeffsy wins the spec battle. Easily. From carbon wheels to the upgraded drivetrain, it’s spec’d to shred without any compromise.

Geometry + Ride Intentions (On Paper)

Both bikes sit in that do-it-all trail-to-all-mountain category, "THE ONE BIKE". The Jeffsy leans into enduro-lite, stable at speed, pedals surprisingly well, and gives you confidence on steep descents.

The Stumpjumper EVO 15 adds their new GENIE shock, promising big traction and control. It looks trick, no doubt. But from what we’ve seen and read, the ride character sits in a similar space as the Jeffsy.

Real Talk From the Trail

We’ve got real hours on the Jeffsy, and it just works. On tech trails in Rotorua, park laps at CAP in Christchurch, fast singletrack, and off-camber roots, the platform is composed. The XO Transmission shifts like a dream, and the carbon wheels keep you online and shoot you out of corners.

As for the Stumpy, we’re waiting to swing a leg over it, but reviews speak well of the GENIE shock’s traction and tunability. Still, at the JEFFSY Core price level, it’s GX, not XO. Alloy, not carbon wheels. Performance Elite, not Factory. For more money.

Our Take: Go Hard, Save Money, Ride YT

We respect both bikes. Specialized builds quality rigs. But when it comes to pure value and trail-ready performance, the Jeffsy Core 4 is hard to beat.

If you’re the kind of rider who values top-tier components, killer ride quality, and wants to keep a few grand in your wallet, Jeffsy’s the clear winner.

Pro Riders: See Each Bike in Action

Jack Moir rides the YT Jeffsy and Capra, and his footage shows the bikes being taken to serious levels. Check out his run here: Jack Moir Metal Monday

On the flip side, Charlie Murray from ChazmazTV has extensive footage aboard the Specialized Stumpjumper, bringing it to life on some chunky New Zealand terrain: Bielsko-Biala Practice day | CHAZMAZTV

Watching both riders handle legit trails helps you see how each builds rides and stands up under real-world conditions.

Do Your Homework

Don’t just take our word for it. Check out:

Two great bikes. Two great brands. But if you’re hunting for value and ready-to-ride performance? The Jeffsy might be your next ride.