現在MTBでの一般的なリアエンド幅、142mmに、 6mmをプラスして148mm幅としたのがBOOST 148だ。これはリアハブのフランジ幅を広げてスポーク の組み角度を大きくすることで、さらに剛性高く組 まれたホイールが装備可能となる。さらには太いタイヤ を履くクリアランスを設け、チェーンステーも短く できる。嬉しいのは、リアエンド幅は広がるが、クラ ンクのQファクターは広がらないよう新デザインの クランクアームスパイダーを装備すること。変わらぬ 走り心地で走りの質を変える新規格である。
サイズ3. 0、太めのタイヤを履く『プラス』規格だ。太めの タイヤには、多くの空気量＝エアボリュームがある。このため 空気圧を下げてもパンクせず、やわらかなタイヤがしっかり と路面をつかむ。登りでさらにトラクションを高め、ドロや 岩場など不安定な路面でも安定したグリップ力を発揮 する。つまり大きな自信を持ち、オフロードをこれまで以上 に楽しく走れる、タイヤの太さなのだ。
All our frames and forks are tested continually to meet or exceed (in some cases, well exceed) EN standards 14764, 14765, 14766 and 14781 as well as the new ISO 4210 standards. We conduct these tests at our frame manufacturing facilities, but we also use EN accredited testing laboratories such as Intertek and SGS to verify the results of our own tests. If these tests aren’t telling us everything we want to know about our bikes, we increase the loads and cycles, or we determine another way to test. Where current hydraulic testing machines, jigs and hardware aren’t up to the task of emulating some of the forces and impacts our bikes might be subject to, we’ve designed our own.
We relentlessly cycle test for fatigue from pedaling and torsional forces on every single frame size, with deflection tests for stiffness at every point of the frame. Brutal impact tests with massive weights dropped on fixed frames or forks are performed. Then reversed, with weights attached to the frame, the frame hoisted to a given height depending upon product type, then released.
This destructive testing is enormously instructive and important. And it is in continual process. But it’s our ongoing non-destructive testing of frames and forks fresh off the factory floor that’s just as vital.
For our carbon fiber frames, EVERY frame is weighed to make sure it’s neither resin rich nor resin deficient. We also measure the stiffness of each frame in 6 critical areas as a check on lay-up production. Each deflection test must fall within 5% of the standards our machine and field-testing have established. This weighing and stiffness deflection testing guarantees every single frame we produce meets all Jamis manufacturing protocol and will
deliver the ride qualities we defined and demand.
A 27.5x3” tire measures out to a 29” diameter and a 26x3” tire measures out to a 27.5” diameter. Combining them with a 40mm rim, results in the ultimate combination of traction, roll-over and versatility without being too heavy, too bouncy, too tall or feeling lethargic on the trail.
Riding fast with control requires steering precision, which starts with the front of the bike. Stiffening this area results in less wheel deflection, more wheel control. A full 1.5” head tube and steerer would achieve this, but would add unnecessary weight and bulk, and limit stem choices. But a tapered 1 1 /8” to 1 1 /2” head tube serves up a significant increase in rough terrain tracking and stability without much of a weight penalty compared to standard 1 1 /8” systems.
The rear wheel tucks in with short chainstays. With a 12x148 rear hub, you’ve got a stiff and responsive rear end.
A 12x148 rear hub with 3mm offset chainrings minimizes the chance of chain to tire contact with short chainstays and “mid-fat” tires without compromising any pedaling efficiency to a wider q-factor.
Securing the rear wheel to the frame by threading a 12mm axle into the rear drop-outs is not only safer, it’s stiffer. The rear wheel tracks directly in line with the frame, for more precise handling, so you can go faster with more confidence. The increase in stiffness of a 15mm fork axle improves steering & handling significantly. It also puts less stress on the fork’s internals, improving fork durability and performance. The hub drop outs provide a self centering feature for the wheel for fast, easy installation.
A one-piece bottom bracket shell and drive-side chainstay yoke provide a strong and lightweight solution for the potential clearance issues of 3” tires and double chainrings.
Benefits of a tubeless set-up are reduced rotating weight and the ability to use lower inflation pressures for greater traction without the risk of pinch flats. WTB TCS rims feature a tubeless UST “On-Ramp” profile providing a consistent fit between the rim and the tire for easy installation and inflation.
Bigger wheels and tires generate more rotating mass and traction once they are up to speed. So it only makes sense to use larger rotors to help control that larger wheel in the most efficient manner possible. Sure, 160mm rotors will stop the bike. But when you’re riding like every second counts, braking for the shortest time possible while keeping the bike under control is the goal. And a larger 180mm rotor up front let’s you do this.
A 35mm seat tube with 31.6mm seat post assures the stiffest possible pedaling & steering platform, with a sloping top tube for low stand-over.
|Frame||Triple-butted 6061 aluminum, 1.5 - 1 1/8” tapered head tube, post mount disc brakes, 12x148mm thru-axle drop-outs, High Direct Mount (HDM) front derailleur with front-pull internal cable routing, internal dropper post routing, replaceable derailleur hanger, Formula axle|
|Fork||SR Suntour XCR 32 LOR 29/27.5+, coil spring , external rebound, lockout adjust, 32mm stanchions, tapered aluminum steerer,15x110mm axle, 120mm travel|
|Headset||FSA Orbit 1.5 Zero-Stack internal cup, 8mm cone spacer|
|Wheels||WTB Scraper i40 TCS tubeless 27.5" rims, Formula 15x110mm front & 12x148mm rear sealed bearing 6-bolt disc hubs, stainless spokes|
|Tires||WTB Ranger, 27.5 x 3.0”|
|Derailleurs||Shimano Deore Shadow rear & Deore front|
|Shift levers||Shimano Deore, 2x10-speed|
|Chain||KMC X10, 10-speed|
|Cassette||Shimano HG50, 10-speed, 11-36T|
|Crankset||SR Suntour XCM, 36/22T, 170mm (15”), 175mm (17-21”)|
|BB Set||SR Suntour External|
|Pedals||ATB alloy platform|
|Brakeset||Tektro M285 hydraulic disc, 180mm front & 160mm rear 6-bolt rotors|
|Handlebar||Ritchey Trail 2X, 31.8 x 9˚ x 720mm x +/- 5mm rise|
|Stem||Ritchey Trail, 60mm (15"), 70mm (17"), 80mm (19"), 90mm (21")|
|Seat Post||Ritchey Trail, 31.6 x 400mm|
|Saddle||WTB Volt Sport|
|Sizes||15”, 17”, 19”, 21”|
|SIZE||TOP EFFECTIVE||HEAD ANGLE||SEAT ANGLE||CHAIN STAY||WHEEL BASE||BB DROP||HEAD TUBE||STANDOVER||STACK||REACH|
|15||22.8 / 580||68˚||73˚||17.1 / 435||43.6 / 1108||1.9 / 47||3.5 / 90||30.0 / 763||21.9 / 557||15.5 / 395|
|17||23.6 / 600||68˚||73˚||17.1 / 435||44.5 / 1130||1.9 / 47||4.3 / 110||31.1 / 790||22.6 / 575||16.1 / 410|
|19||24.4 / 620||68˚||73˚||17.1 / 435||45.3 / 1151||1.9 / 47||5.5 / 140||33.9 / 861||23.7 / 603||17.6 / 448|
|21||25.2 / 640||68˚||73˚||17.1 / 435||46.4 / 1179||1.9 / 47||5.5 / 140||33.9 / 861||23.7 / 603||17.6 / 448|
FIT & SIZING