Kona’s scandium-framed, 29in-wheeled King Kahuna was the first 29er to ever win a US national series mountain bike race, which it did under team rider Ryan Trebon in Deer Valley, Utah during the 2008 season.
The go-to hardtail racer for the Kona Factory Team’s extra-tall ‘twin towers' (Trebon and Barry Wicks), it's half of a two-bike big-wheeled quiver that is completed by the full-suspension Hei-Hei 2-9.
While the factory duo get custom bikes to fit their proportions, the same butted scandium alloy material, tube shapes and geometry can all be found on the production model of the bike.
The stock King Kahuna boasts a decent frame – although we'd spec a slacker head angle for improved high-speed handling – but with its short-travel fork and a wheelset that's hard to convert to tubeless, the overall package requires too much modification to easily and cost-effectively reach its full potential.
Ride & handling: Lively and playful, but steep head angle makes it twitchy at speed
Kona’s butted scandium alloy tubing has a comfortable resilient feel, which we greatly prefer over a harsh riding aluminum alloy. The King Kahuna's 440mm chainstays and 73-degree seat angle make it easy to wheelie and manual, which adds considerably to the bike’s lively and playful feel. Despite the length of the chainstays, there's plenty of mud clearance around the 2.1in Kenda Small Block Eight tyres fitted.
The front end is adequately stiff despite sporting a standard 1-1/8in head tube and steerer. The big square top and down tubes are inevitably at work here, while the latter gives plenty of stiffness to the bottom bracket area for spirited sprints.
The front end tracked well even without a tapered head tube and fork steerer
All good so far, but the King Kahuna's ride falls down when it comes to the Fox F80RL fork up front. For starters, it's too linear in its tune. If we bumped up the air pressure to get the more progressive feel we were looking for, we hampered its ability to get full travel. This could have been taken care of by Fox, had Kona asked for more low-speed compression damping.
The next two issues actually have more to do with the geometry of the bike than the performance of the fork. Kona spec a 72-degree head angle on the King Kahuna, which is a common way of eliminating the truck-like feel often associated with 29ers. This does make the bike very agile, but in our opinion it goes too far. We'd prefer a head angle of 71 or even 70 degrees for a slower, more stable ride. Another, possibly better, option would be to bump the fork’s travel up to 100mm.
As it is, the 80mm-travel F80RL has a 44mm offset and short axle-to-crown length. This gave the King Kahuna an issue of gnarly oversteer in medium-speed, tight-cornering situations. It's a problem that reared its head on flat 180-degree corners – think short track racing – and it also made the bike skittish and twitchy on wide-open high-speed dirt road descents.
The faster you go on this bike, the more unstable it seems to become. We pored over the frame’s geometry to find some sort of fatal flaw and couldn’t come up with anything other than the too-steep head tube. In a final attempt to figure out our handling problems, we swapped the stock 80mm fork for a 100mm model with 2mm more offset (46mm, 2cm longer axle-to-crown measurement) and the King Kahuna rode much, much better. It was more stable at speed and didn’t oversteer nearly as badly on hairpins.
If it was up to us, we'd kick the head tube out a degree and add the extra travel. Kona’s technical product manager Doug LaFavor, aka Doctor Dew, tells us that the 2011 King Kahuna will feature a 100mm-travel fork as well as a slightly lower bottom bracket height, both of which, we think, will work wonders on the bike’s handling.
We wish Kona had used the 100mm Fox F29RL fork, but gladly accept the 15QR through-axle
Equipment: Quality drivetrain and finishing kit, but wheelset won't please tubeless fans
Kona build up the King Kahuna with a mix of Shimano XT (cranks, rear derailleur and shifters) and SLX (brakes, front derailleur and cassette) parts which are complemented by Easton’s XC2 29er wheelset. The cockpit is from Kona’s house line and the saddle is a WTB Rocket V Comp embossed with Kona’s name.
Even though the scandium frame offers a solid foundation for a race bike – our large (19in) sample weighs a respectable 3.88lb (1,762g), including bottle bolts, derailleur hanger and seat collar – the full build weighs in at well outside what would be considered competitive, at 26.82lb with the included 374g Shimano M520 clipless pedals.
The wheels are partly to blame for this, weighing in at 9.58lb/4,345g with 160/180mm SLX rotors and cassette, 2.0in Kenda Small Block Eight tyres and tubes. Converting to an alternative wheelset like Stan’s ZTR 355 (US$445) would allow you to save upwards of 2lb, and would make it far easier to go tubeless.
As it is, trying to convert Easton’s XC2s to tubeless is a frustrating task. The rims are drilled for Schrader valves so there's little chance of success with the lighter tape-based aftermarket conversion kits. NoTubes.com’s rubber strip conversion kit can be used, but it doesn’t allow for the greatest possible weight savings or the fastest changes, should you flat.
We've mentioned some issues with the Fox fork, but we will commend Kona for speccing the 15mm through-axle version. With the longer legs required for 29in wheels the beefed-up axle’s greater stiffness translates to noticeably better steering precision.
Easton XC Two wheels proved plenty strong, but presented a challenge to convert to tubeless
The flat, 710mm-wide Deluxe Energy bar (16in and 18in bikes get a 680mm model instead) opens up your chest for breathing and makes muscling the bike around fairly easy, but it can be a little too wide on tight singletrack. The XC/BC Deluxe stem (105mm/180g) is plenty stiff.
The 27.2mm seatpost (241g) has an easy-to-operate two-bolt micro-adjust clamp and looks sharp, but ours bent slighly during the test. LaFavor tells us that for 2011, the larger size King Kahunas (19in and up) will get a beefier 31.6mm post.
The Shimano parts performed flawlessly, though on a hardtail we feel we could have got away without the large 180mm front disc rotor, especially since the SLX brakes generate good power stopping. The Shadow rear derailleur design has a serious advantage over the conventional; its lower profile saves it from rocks and other obstacles that threaten to tear it off.
While the shifting performance was great, with the advent of 2x10 drivetrains, smaller big chainrings and 11-36T cassettes, 2010 will likely be the last year that manufacturers can get away with sticking a standard 11-34T cassette and 22/32/44T chainring combo on a 29er. The big wheels beg for a smaller large chainring and 36T cassettes – we’ll leave it at that.
Kona’s $699 Big Unit frameset sports the same scandium tubeset and geometry as the King Kahuna, but with a sliding dropout that allows for use with gears or as a singlespeed. Buy this and you'd have $2,100 left over with which to buy a 100mm-travel fork, lighter tubeless wheelset and 29er-specific gearing. We know which we'd choose.
The WTB Rocket V saddle is embossed with the Kona name, which is an elegant touch