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Pro bike: Tom Zirbel's Jamis Xenith SL

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Tom Zirbel (Jamis-Sutter Home) is making is return to pro cycling aboard the Jamis Xenith SL.

Tom Zirbel (Jamis-Sutter Home) is making is return to pro cycling aboard the Jamis Xenith SL. (Image credit: Jonny Irick)
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Tom Zirbel (Jamis-Sutter Home) uses classic-bend bars but they're tilted unusually skyward.

Tom Zirbel (Jamis-Sutter Home) uses classic-bend bars but they're tilted unusually skyward. (Image credit: Jonny Irick)
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Jamis-Sutter Home uses Shimano Dura-Ace mechanical groups.

Jamis-Sutter Home uses Shimano Dura-Ace mechanical groups. (Image credit: Jonny Irick)
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Tom Zirbel's (Jamis-Sutter Home) Speedplay Zero Stainless pedals look rather well used.

Tom Zirbel's (Jamis-Sutter Home) Speedplay Zero Stainless pedals look rather well used. (Image credit: Jonny Irick)
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Jamis-Sutter Home team bikes are fitted with neat carbon fiber number holders with nicely machined brass thumbwheels for easy plate installation and removal.

Jamis-Sutter Home team bikes are fitted with neat carbon fiber number holders with nicely machined brass thumbwheels for easy plate installation and removal. (Image credit: Jonny Irick)
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The Shimano Dura-Ace rear derailleur is bolted to a red anodized replaceable alloy hanger.

The Shimano Dura-Ace rear derailleur is bolted to a red anodized replaceable alloy hanger. (Image credit: Jonny Irick)
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The Shimano Dura-Ace rear hub uses adjustable angular contact bearings.

The Shimano Dura-Ace rear hub uses adjustable angular contact bearings. (Image credit: Jonny Irick)
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Tom Zirbel (Jamis-Sutter Home) plants himself atop Selle San Marco's Zoncolan saddle.

Tom Zirbel (Jamis-Sutter Home) plants himself atop Selle San Marco's Zoncolan saddle. (Image credit: Jonny Irick)
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The seat tube is essentially round from top to bottom.

The seat tube is essentially round from top to bottom. (Image credit: Jonny Irick)
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Tom Zirbel (Jamis-Sutter Home) uses an aluminum Ritchey WCS 1-Bolt seatpost.

Tom Zirbel (Jamis-Sutter Home) uses an aluminum Ritchey WCS 1-Bolt seatpost. (Image credit: Jonny Irick)
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Dual rotating barrels on the Jamis Xenith SL seatpost collar help ensure that the bolt isn't subjected to bending loads.

Dual rotating barrels on the Jamis Xenith SL seatpost collar help ensure that the bolt isn't subjected to bending loads. (Image credit: Jonny Irick)
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Jamis varies the tube diameters on the Xenith SL depending on frame size - a good thing since stays like this would likely be brutal on smaller riders.

Jamis varies the tube diameters on the Xenith SL depending on frame size - a good thing since stays like this would likely be brutal on smaller riders. (Image credit: Jonny Irick)
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Tom Zirbel's (Jamis-Sutter Home) Jamis Xenith SL features a tapered 1 1/8-to-1 1/2in head tube - especially useful in a frame of this size.

Tom Zirbel's (Jamis-Sutter Home) Jamis Xenith SL features a tapered 1 1/8-to-1 1/2in head tube - especially useful in a frame of this size. (Image credit: Jonny Irick)
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Jamis Xenith SL frames use BB30-compatible bottom bracket shells but as the team is sponsored by Shimano - who still doesn't offer a proper BB30 crankset - the team has to add threaded shell adapters.

Jamis Xenith SL frames use BB30-compatible bottom bracket shells but as the team is sponsored by Shimano - who still doesn't offer a proper BB30 crankset - the team has to add threaded shell adapters. (Image credit: Jonny Irick)
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Team Jamis-Sutter Home has generic alloy cages fitted to team bikes at Tour of California.

Team Jamis-Sutter Home has generic alloy cages fitted to team bikes at Tour of California. (Image credit: Jonny Irick)
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Jamis builds the Xenith SL with asymmetrical chain stays.

Jamis builds the Xenith SL with asymmetrical chain stays. (Image credit: Jonny Irick)
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Tom Zirbel (Jamis-Sutter Home) uses an all-aluminum cockpit.

Tom Zirbel (Jamis-Sutter Home) uses an all-aluminum cockpit. (Image credit: Jonny Irick)
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Tom Zirbel's (Jamis-Sutter Home) Jamis Xenith SL is equipped with 177.5mm-long Shimano Dura-Ace cranks.

Tom Zirbel's (Jamis-Sutter Home) Jamis Xenith SL is equipped with 177.5mm-long Shimano Dura-Ace cranks. (Image credit: Jonny Irick)
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Tom Zirbel (Jamis-Sutter Home) likely welcomes the Jamis Xenith SL's stout fork blades.

Tom Zirbel (Jamis-Sutter Home) likely welcomes the Jamis Xenith SL's stout fork blades. (Image credit: Jonny Irick)
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'Lawyer tabs' are filed off on Jamis Sutter Home team bikes to facilitate wheel changes.

'Lawyer tabs' are filed off on Jamis Sutter Home team bikes to facilitate wheel changes. (Image credit: Jonny Irick)
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Jamis is yet another company that has passed over wild tube shapes in favor of smoother and more organic forms that apparently produce better test numbers.

Jamis is yet another company that has passed over wild tube shapes in favor of smoother and more organic forms that apparently produce better test numbers. (Image credit: Jonny Irick)
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A red anodized clamp adapter is used with the braze-on Shimano Dura-Ace front derailleur.

A red anodized clamp adapter is used with the braze-on Shimano Dura-Ace front derailleur. (Image credit: Jonny Irick)
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Tom Zirbel (Jamis-Sutter Home) had 35mm-deep Shimano Dura-Ace carbon tubular wheels fitted to his Jamis Xenith SL in the days leading up to the start of Tour of California.

Tom Zirbel (Jamis-Sutter Home) had 35mm-deep Shimano Dura-Ace carbon tubular wheels fitted to his Jamis Xenith SL in the days leading up to the start of Tour of California. (Image credit: Jonny Irick)
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Vittoria Corsa Evo CX tubulars are mounted to 35mm-deep Shimano carbon tubular rims.

Vittoria Corsa Evo CX tubulars are mounted to 35mm-deep Shimano carbon tubular rims. (Image credit: Jonny Irick)

US cyclist Tom Zirbel (Jamis-Sutter Home) is making his major return to the professional ranks at this year's Amgen Tour of California after serving an eighteen-month doping suspension for DHEA. While some have invariably lambasted the comeback attempt, it seems that the majority have welcomed the affable Colorado resident with open arms.

Either way, one thing hasn't changed: the man is a tall drink of water, standing at a towering 1.96m (6' 5").

Obviously, the numbers reflect that fact, too. Zirbel is racing this year on a 61cm Jamis Xenith SL frameset with a 590mm effective top tube that still has to be paired with a 130mm-long stem. His saddle height is 862mm (measured from the bottom bracket spindle center along the seat tube axis), setback is a generous 96mm, and bar drop is a tremendous 139mm. Compare those figures to your own bike if they don't sound big enough on paper.

Zirbel isn't just tall, though; he's also very powerful, packing 88kg (194lb) of muscle according to his profile on the team web site. Helping harness that horsepower is Jamis's size-specific carbon tube diameters and shapes with supposed "100% super-high modulus M40 carbon fiber" content, a tapered 1 1/8-to-1 1/2in front end, and a large-diameter BB30-compatible bottom bracket shell.

Jamis Xenith SL frames use BB30-compatible bottom bracket shells but as the team are sponsored by Shimano - who still don't offer a proper BB30 crankset - they have to add threaded shell adapters. Photo: James Huang

As has been the trend the last few years, the Xenith SL also does without any wild shaping, preferring instead to go with mostly roundish cross-sections and smooth transitions that apparently help the chassis behave more cohesively and yield better numbers in the test lab. According to Jamis, tube shapes and diameters are also altered across the size range to help maintain consistent ride characteristics.

Zirbel's build kit is decidedly straightforward, consisting of a complete Shimano Dura-Ace mechanical group (with lengthy 177.5mm crankarms, of course), 35mm-deep Shimano carbon tubular wheels wrapped with Vittoria rubber, Speedplay Zero pedals with stainless steel spindles, and a pair of generic alloy bottle cages.

Not surprisingly, Zirbel has opted for an all-aluminum from team sponsor Ritchey, including a forged WCS 4-Axis stem, classic-bend bar, and stout seatpost with the company's handy one-bolt head. Finishing things off are a Zoncolan Team Issue saddle and grippy bar tape from Selle San Marco.

What is surprising, though, is the bike's total weight. Despite the size, Zirbel's complete rig weighs just 7.14kg (15.74lb) as pictured.

Jamis-Sutter Home team bikes are fitted with neat carbon fiber number holders with nicely machined brass thumbwheels for easy plate installation and removal. Photo: James Huang

This article originally appeared on BikeRadar.

Complete bike specifications:

Frame: Jamis Xenith SL, 61cm
Fork: Jamis Xenith SL
Headset: Ritchey WCS Carbon Drop-In, tapered 1 1/8-to-1 1/2in
Stem: Ritchey WCS 4-Axis, 13cm x -6°
Handlebars: Ritchey WCS Classic, 44cm (c-c)
Tape/grips: Selle San Marco
Front brake: Shimano Dura-Ace BR-7900 w/ carbon-specific pads
Rear brake: Shimano Dura-Ace BR-7900 w/ carbon-specific pads
Brake levers: Shimano Dura-Ace STI Dual Control ST-7900
Front derailleur: Shimano Dura-Ace FD-7900-F w/ clamp-on adapter
Rear derailleur: Shimano Dura-Ace RD-7900-SS
Shift levers: Shimano Dura-Ace STI Dual Control ST-7900
Cassette: Shimano Dura-Ace CS-7900, 11-25T
Chain: Shimano Dura-Ace CN-7900
Crankset: Shimano Dura-Ace FC-7900, 177.5mm, 53/39T
Bottom bracket: Shimano Dura-Ace SM-FC7900 w/ BB30 adapter
Pedals: Speedplay Zero Stainless
Wheelset: Shimano Dura-Ace WH-7900-C35-TU
Front tire: Vittoria Corsa Evo CX tubular, 21mm
Rear tire: Vittoria Corsa Evo CX tubular, 21mm
Saddle: Selle San Marco Zoncolan Racing Team
Seat post: Ritchey WCS 1-Bolt
Bottle cages: aluminum (2)
Computer: n/a

Critical measurements:

Rider's height: 1.96m (6' 5")
Rider's weight: 88kg (194lb)
Saddle height, from BB (c-t): 862mm
Saddle setback: 96mm
Seat tube length, c-t: 570mm
Seat tube length, c-c: 520mm
Tip of saddle nose to C of bars (next to stem): 631mm
Saddle-to-bar drop (vertical): 139mm
Head tube length: 200mm
Top tube length: 590mm (horizontal)
Total bicycle weight: 7.14kg (15.74lb)