Pivot Cycles' Mach 4 cross-country and marathon racing flagship has undergone a much needed diet for 2011, dropping a substantial 300g and bringing the total frame and shock weight down to a much more appropriate 2.5kg (5.5lb).
Even so, Pivot Cycles president Chris Cocalis says torsional frame stiffness has actually gone up by about 20 percent over what was already a remarkably true-tracking chassis.
Changes to the front triangle include a tapered 1 1/8"-to-1 1/2" head tube, a more curvaceous top tube shape borrowed from the longer-travel Firebird, and slimmed-down shock mounts and cable guides.
Out back the updates are even more extensive with newly forged uprights on the rear triangle, a much more dramatically relieved chain stay yoke, and asymmetrical chain stays, all whilst retaining the previous version's carbon fibre upper link, wide-format machined aluminum-and-carbon fiber lower link, and cartridge bearing pivots all around.
Cocalis says changes to the Mach 4 suspension geometry yields a more efficient ride, both in terms of pedaling performance and bump-eating capabilities. Shock stroke shortens across the board as compared to the 2010 version - making for slightly higher leverage ratios than before - but the Fox RP23's revamped valving supposedly makes for a more dynamic range of ride characteristics across the ProPedal adjustment range.
According to Cocalis, the changes will be most noticeable in the higher ProPedal positions where riders will notice similar resistance to bob as before but lower blowoff thresholds when actual bumps are encountered.
Last year's Mach 5 trail bike extends its reach a bit for 2011 with a slight 5mm bump in rear wheel travel and a subsequent name change to the Mach 5.7 (though it's a bit misleading as last year's Mach 5 actually had 5.5" of travel). As with the Mach 4, the Mach 5.7 also drops a sizeable 230g of weight from before and yet improves torsional stiffness - and thus handling precision - by a claimed 20 percent.
In comparison to its predecessor though, the more significant updates are the revised frame geometry - which now includes a 10mm-lower bottom bracket and slackened head tube for improved high speed stability - and the new rear suspension geometry that's designed to sit a bit further into the travel than before.
Again like the Mach 4, the new Mach 5.7 also gains a tapered head tube, a Firebird-like top tube, and a completely revamped rear triangle with forged uprights, heavily machined yokes, and asymmetrical chain stays.
Updates to the versatile Firebird all-mountain machine are more subtle, including a beefier carbon fibre upper link that more readily accommodates coil-sprung rear shocks - and the more aggressive riding styles that generally accompany them - and a revised front derailleur pivot mechanism that runs quieter than before.
The ISCG tab positions have been tweaked too, while an improved chain guide system offers better chain retention off the inner ring.
Finally there's the recently introduced Phoenix DH, which uses the same dw-link rear suspension design as on the rest of the Pivot Cycles range but with revamped pivot positions to yield 207mm of travel and an overall feel better suited to its World Cup downhill racing intentions.
Frame construction is suitably robust with healthily proportioned aluminum tube sizes throughout plus an especially stout central chassis that houses both the upper and lower links as well as the coil-sprung rear shock.
The 17mm and 19mm pivot axles plus dual-row cartridge bearings throughout keep flex at a minimum and despite the rear shock's tucked-in positioning, logically placed cutouts and openings still leave all of the adjustments readily accessible.
Geometry is highly customisable with interchangeable thru-axle rear dropouts that allow for tunable wheelbase and bottom bracket height and the front end with also come with a Cane Creek Angleset headset that can provide 2.75 degrees of head tube adjustment.
The Phoenix DH won't be available to consumers until January but the rest of the Pivot Cycles collection - which includes the unchanged Mach 429 full-suspension 29er - is currently in production and available for purchase now.