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2021 Kona Process-X enduro bikes bring 161mm of mullet-able travel, plus new 153

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Kona have gone big on enduro for 2021, releasing two new 170mm forked bikes with 161mm rear wheel travel. The 2021 Kona Process-X and Process-X DL both roll on a 29″ wheelset but Kona have designed them to be mullet-able. OK, you can chuck a 27.5″ wheel on the back of any 29er. However, Kona have added some key design features that should allow you to take full advantage of running a smaller wheel out back.

2021 Kona Process-X & X DL

The 2021 Kona Process-X & X DL enduro bikes are two models of the very same 161mm travel carbon frame. The Process-X models are Kona’s biggest enduro bikes yet, pairing that substantial rear wheel travel with 38mm stanchion 170mm forks. 

161mm of mullet-able travel 

What interests us about the new Process-X is the fact that, despite being a 29er, Kona have actually designed the frame to work well as a mullet too. Those key design features alluded to earlier are as follows:

  • Flip-chip at the rocker-seat stay interface
  • Adjustable length chainstays

kona process-x flip-chip allows riders to run 27.5" rear wheel mullet setupYou’ll be more familiar with flip-chips in the context of geometry changes. Heaps of brands use them to allow riders to switch between “high” and “low” geometry. On the 2021 Kona Process-X, the flip-chip is key to running a mullet setup.

Basically, it allows riders to switch out their 29″ rear wheel for a 27.5″ while maintaining the geometry figures of the 29/29. So the BB height stays the same, as do the seat tube and head tube angles. Neat.

kona process-x adjustable length chain stays 435mm 450mm mullet setup
Kona seem to have done a neat job on the internal cable routing

Chainstay length of the Process-X is 450mm across the S-XL frame size range. That’s considered to be pretty generous, particularly for smaller frame sizes, and should give the bike good stability at high speeds. Kona give riders the option to shorten the chainstays to 435mm, to give a more nimble, playful ride feel.

kona prcoess-x 435mm chainstays 2.5" tire clearance 29" rear wheel
Crucially, switching to 435mm still allows riders to run 2.5″ tires on a 29″ rear wheel

Is it obligatory to run the shorter 435mm chain stays in mullet mode? Ian Schmitt, Kona’s product manager behind the Process-X says yes, yes it is. The shorter stays are essential in delivering the geometry figures Kona were aiming for with the mullet setup. 

The resulting shorter wheelbase and the fact that the rider is now positioned a little closer to the rear axle should (I haven’t ridden a specifically designed mullet yet) give the rider an easier time through tight corners.

Process-X Geometry



Just one geometry chart is published for the 2021 Kona Process-X, despite the fact that it can be run as a 29/29 or with a 29/27.5″ mixed wheel size setup. That’s because the flip-chip and ability to shorten the chainstays to 435mm, mean the bike’s geometry is largely uncompromised by the switch to a smaller rear wheel. 

That point aside, what are the actual geometry figures?

2021 kona process-x has 63.5 degree head angle 170mm fork travel short offset
170mm forks run a 44mm offset, both for the Fox 38 on the Process-X and the ZEB on the Process-X DL

Slack where it matters, and steep where it counts.

The head tube angle sits at 63.5°, consistent across the frame sizes. The angle at the seat tube is refreshingly steep at 78.2° in S and M, 78° in L and 79.9° in XL. This should put riders in a relatively powerful position with respect to the bottom bracket, which will be key to pedaling comfort.

2021 kona process-x generous reach figures 440mm-525mm
The large Process-X sports a reach of 490mm

The 2021 Kona Process-X and X DL models boast generous reach figures, stretching from 440mm in small, up to 525mm in XL. Seat tubes remain short, allowing riders to make full use of super long travel dropper posts. For example, the small and medium frames run a 380mm seat tube, both sold with whopping 170mm droppers. 

2021 kona process-x has short seat tube runs long travel dropper posts

The large frame runs a 420mm seat tube, while the XL sits at 450mm. Both run 200mm droppers.


Process-X & X DL Pricing

2021 Kona Process-x £5,499

The Process-X will set you back $4,999. It gets a Fox 38 Performance fork with GRIP damper, a DPX2 Performance Elite shock, 12s Shimano Deore drivetrain and 4-piston brakes. It rolls on WTB KOM Trail rims (30mm internal width) on a DT SWISS 370 hubset.

x dl is top end process x 2021 carbon enduro bike gets zeb fork

The flagship Process-X DL model is priced at $6,999. It gets Rockshox’s new 38mm stanchion ZEB fork, Super Deluxe Ultimate shock, SRAM XO1 Eagle drivetrain, Code RSC brakes and WTB KOM Trial rims on DT350 hubs.

2021 Kona Process 153

2021 kona process 153 goes aluminium 29er deluxe model
The 2021 Kona Process 153 29 DL (Deluxe model)

The Process-X and Process-X DL bikes are available as carbon frames only so if you prefer the ride feel of aluminium, it’s worth taking a look at the new Process 153. Get it in both a 27.5″ or a 29″ version.

That 153mm of rear wheel travel is paired with a 160mm fork. The aluminium frames are updated for 2021, now based around the tubing of the 134 and Process-X. The new tubing shaves 150g off previous year’s models. 

The leverage curve is also updated to bring more progressiveness and a bottomless feel to the travel. It is said to be very similar to that of the 134 models with around 13% progression from 30-95% travel.

2021 kona process 153 29er dl aluminium frame
Cable routing is external but Kona do a neat job attaching the cable outer to the main pivot hardware

Unlike the Process-X bikes, the Process 153 doesn’t offer mullet-ability. Its geometry, chainstay length and wheel size options are fixed.

The 29er(s)

The 2021 Kona Process 153 29er chainstays measure up at 435mm

Kona offer the new Process 153 in two 29er models, both available in sizes M, L and XL. For 2021, the frameset is updated with fresh geometry, now longer, and much slacker out front compared with the 2019 carbon frame.

29er process 153 deluxe yellow gold gloss colorway

Reach spans 455mm in medium to 515mm in XL. The head tube slackens out 1.5° to 64.5° while seat tubes steepen up by around 1° to 76.9° in medium. In line with those changes comes a shorter fork offset of 44mm. 

external cable routing my21 process 153 29er

Seat tubes are much longer than what we saw on the carbon framed Process-X. In medium, the seat tube measures 410mm, stacking up to 450mm in large and 485mm in XL. That said, the medium will still run a 170mm dropper while L & XL get a 200mm drop.

2021 process 153 geometry kona mtb 29er

The 2021 Kona Process 153 29 DL (Deluxe model) is priced at $3,699. It gets a 12s Eagle drivetrain made up of SX, NX and GX componentry, a RockShox Lyrik Select RC Charger fork, Super Deluxe Select Plus shock, SRAM G2 RS stoppers and WTB KOM Trail rims on Formula hubs.

new kona process 153 29 budget model gets yari fork

At the budget-friendly end is the Process 153 29 model, retailing at $2,999. It differs from the DL model with an RS Yari RC fork, Deluxe Select Plus shock, and SRAM Guide T brakes.  

The 650b


The 27.5″ Kona Process 153 is available in sizes S-XL. For 2021, some key geometry figures remain unchanged from 2019’s iteration. The head tube still sits at 66°, the seat angle at ~76.5°, and the reach still spans a 425mm to 510mm range.

kona process 153 27.5" tire clearance 2.5"
The 27.5″ Process 153 can accommodate tires up to 2.5″

The major change for this model year is the BB height, now at 342mm as compared to the 355mm on previous years’ models. Chainstays are fractionally lower at 427mm for 2021.

The MY21 27.5″ Kona Process 153 will set you back $2,999, sporting the same spec as the above mentioned 29er. 


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