New carbon fiber race machine for Giant’s resident big-wheel aficionado
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Carl Decker shows off the prototype Giant carbon XtC 29er at the team’s training camp in Santa Barbara, CA.(Image credit: Zach White)
A bottom view of the asymmetrical chainstays.(Image credit: Zach White)
A side view of Decker’s bottom bracket area shows the intricacy of the frame’s carbon layers.(Image credit: Zach White)
Decker runs his new Schwalbe tires tubeless.(Image credit: Zach White)
Giant’s PR guy, Andrew Juskaitis, states that both Decker’s prototype and the production version of the carbon XtC 29er will provide plenty of mud clearance, as seen here with a Schwalbe 2.25 Rocket Ron.(Image credit: Zach White)
Though the bent seat tube appears as if it'd be tough to mount a cage to, Decker states that it works fine.(Image credit: Zach White)
Decker prefers to run a saddle designed for triathlons, which allows him more comfort on the nose when shifting forward on steep climbs.(Image credit: Zach White)
One noticeable change from the prototype to the production sample is a slight reduction in chain stay asymmetry.(Image credit: Zach White)
A non-drive side overview of Decker’s Giant carbon XtC 29er prototype.(Image credit: Zach White)
Shaping on the tapered head tube is similar to Giant's TCR road range.(Image credit: Zach White)
The down tube is so wide that it’s asymmetrically shaped around the drivetrain, which causes an otherwise centered water bottle cage to appear offset.(Image credit: Zach White)
Opting for a little less weight than a lock-on style grip, Decker runs ODI Ruffian grips with the flanges removed and moto-style wires to keep them tight.(Image credit: Zach White)
Decker's bike was fitted with a RockShox Reba XX 29" when we caught up with him at the team training camp but he's likely on a new SID 29 by now.(Image credit: Zach White)
Giant prefers to use aluminum dropouts even on its top-end race bikes.(Image credit: Zach White)
The enormous, rectangular-profile, asymmetrical down tube suggests excellent front triangle and bottom bracket stiffness. And as a bonus, it looks like it'll make for a great built-in front mudguard, too.(Image credit: Zach White)
A production sample of the new Giant XtC Composite (left) as compared to Decker’s prototype.(Image credit: Zach White)
Decker will add the new Giant XtC Composite 29er to his current Anthem X 29 and Reign X for this season's races.(Image credit: Zach White)
Giant's new XtC Composite 29 will feature a press-fit bottom bracket shell.(Image credit: Zach White)
Decker prefers a 685mm-wide riser bar on his XC race rig.(Image credit: Zach White)
Giant Factory Off-Road Team racer Carl Decker raced last year's Sea Otter Classic on a prototype 29in version of the company’s Anthem X and he has followed suit this year on another big-wheeled prototype: the XtC Composite 29er.
Decker received the one-off prototype frame this January, though he admitted he hadn't ridden it much before the team camp in sunny Santa Barbara, California in late March. "I've been in ski mode basically until now, short of about one ride a week on it," he said.
Nevertheless, Decker hasn't wasted much time getting it on a race course, first using it at the Sea Otter Classic just a few weeks later, then again at the Whiskey Off Road in Arizona.
"It'll probably be my short track bike of choice," he said. "It's also going to be a great Leadville 100 bike. But I'll still race the Anthem X 29er quite a bit this year and I have a Reign X I may even race some burlier Super Ds on."
Decker will add the new Giant XtC Composite 29er to his current Anthem X 29 and Reign X for this season's races. Photo: Zach White
Decker’s bike is a true prototype and not just an early production sample, too - at least for now. While the public will get a production version later this year, Decker’s prototype test mule uses an experimental carbon fiber lay-up schedule that’s 80g lighter than what the public will get but unfortunately also slightly less tolerant of crash damage, too - something Giant isn't willing to compromise for general users.
"The Giant XtC Composite 29er is more of a price point bike and uses our Composite technology, versus our higher-end Advanced or Advanced SL carbon," said Giant global marketing director Andrew Juskaitis. "Production added about 50 grams to ensure strength where we felt the frame needed it."
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Decker’s prototype shares most of its features with the production version, including the Overdrive tapered head tube extra-wide Powercore press-fit bottom bracket shell, which are joined together with Giant's rectangular-profile MegaDrive down tube.
"It turned out so wide that we had to make the down tube asymmetrical to provide chainring clearance on the drive side," said Juskaitis.
The enormous, rectangular-profile, asymmetrical down tube suggests excellent front triangle and bottom bracket stiffness. And as a bonus, it looks like it'll make for a great built-in front mudguard, too. Photo: Zach White
Add to the asymmetrical design a pair of offset chain stays, twisted seat stays, and a kinked seat tube that allows for a shorter rear end.
Comparing the prototype to the production sample in terms of general design, they both look quite similar. Of course, paint, decals and polish can hide quite a bit, but one visible variation is a slightly less drastic asymmetry in the chain stays on the production version. The down tube is a bit different as well.
"The driveside chain stay on Carl’s proto ‘dips’ down about 15mm more than the production version - an early attempt at chain clearance which we decide wasn't necessary," said Juskaitis, according for the remaining 30g differential between the production and prototype frames. "Carl’s MegaDrive down tube is even more offset (to non-driveside) than the production version. We were able to equalize the production down tube a bit more although it’s still slightly offset."
Decker’s bike is impressively light at just 10.04kg (22.13lb) with alloy training wheels and pedals. While much of that is likely due to the new frame, there's also an almost entirely new build kit, too.
"For the last few seasons we were always told that our new bikes would be lighter than last year’s bikes before we got them, only to find out that they always weighed almost exactly the same when they got built up," said Decker. "This year, our bikes are legitimately lighter by at least a pound across the board."
Shaping on the tapered head tube is similar to Giant's TCR road range. Photo: Zach White
Switching over to SRAM's XX group with a 2x10 drivetrain played a key role in reducing weight. For Decker, it also switched up his gear ratio from the previous 3x9 he was used to.
"The crossover gear with 2x10 is awesome," Decker told BikeRadar. "At first I was a bit nervous as I'm a sewing machine guy when it comes to pedaling, but so far it's been great. There are a few race courses I'm nervous about but I'm hoping it'll just make me go faster on those climbs."
Reducing his prototype's mass even more will be DT Swiss's new XRC 950 T carbon tubular 29er wheels - said to weigh just 1,200g per set. In previous years, Decker has been known to cut his own tires to decrease rolling resistance and improve traction but this time around, Schwalbe will be doing the work for him, custom tuning tires to his preferences.
"Schwalbe has tons of SKUs," Decker said. "I think they offer three or four XC tires in three different compounds and several different widths. And they're offering us custom tires with our choice of tread pattern, compound, and width, too."
With Decker racing so many disciplines this year and knowing how particular he is with tires, we'll be surprised if he’s not on a special set of Schwalbes for each major race this season.
Opting for a little less weight than a lock-on style grip, Decker runs ODI Ruffian grips with the flanges removed and moto-style wires to keep them tight. Photo: Zach White
Rounding out Decker’s prototype set-up are a few oddball bits for a cross-country hardtail: a set of 685mm-wide Truvativ carbon riser bars and a fi'zi:k Arione Triathlon saddle.
"This bike was initially set up with 640mm bars but those just felt dumb so we switched them out with the wider Noirs," he said. "As for the saddle, I tend to ride way up on the nose and the Arione is made for that," said Decker.
Being the reigning 'All-Mountain World Champion', it’s not surprising that Decker runs relatively wide bars even on his cross-country bike. But a triathlete’s saddle? Hopefully he won't start racing in sleeveless tri-tops and brief-style swimsuits.
Frame: Giant carbon XtC 29er prototype, size L Fork: Rock Shox Reba XX 29", 100mm-travel, tapered steerer, 15mm thru-axle dropouts Headset: Chris King InSet Stem: Truvativ Stylo World Cup, 110mm x +5° Handlebars: Truvativ Noir carbon riser, 685mm Tape/grips: ODI Ruffians Front brake: Avid XX World Cup, 160mm disc Rear brake: Avid XX World Cup, 160mm disc Brake levers: Avid XX World Cup Front derailleur: SRAM XX Rear derailleur: SRAM XX Shift levers: SRAM XX Cassette: SRAM XX, 11-36T Chain: SRAM PC-1091 Crankset: SRAM XX, 175mm, 39/26T Bottom bracket: SRAM XX press-fit Pedals: Crankbrothers Candy 2 Wheelset: DT Swiss XRC 950 T (racing only) Rims: DT Swiss X470, 32-hole, 3-cross, set up tubeless (training) Front hub: DT Swiss 240s (training) Rear hub: DT Swiss 240s (training) Spokes: DT Swiss Competition, 14/15g Front tire: Schwalbe Racing Ralph, 29x2.25in Rear tire: Schwalbe Rocket Ron, 29x2.25in Saddle: fi'zi:k Arione Tri 2 Wing Flex Seat post: Truvativ Noir Bottle cages: King Cage Titanium
Critical measurements:
Rider's height: 1.83m (6' 0") Rider's weight: 72.6kg (160lb) Saddle height, from BB (c-t): 807mm Saddle setback: 90mm Seat tube length, c-t: 495mm Seat tube length, c-c: 440mm Tip of saddle nose to C of bars (next to stem): 575mm Saddle-to-bar drop (vertical): 20mm Head tube length: 110mm Top tube length: 615mm (horizontal) Total bicycle weight: 10.04kg (22.13lb)
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