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The massive head tube area yields expected dividends in front triangle rigidity for sharp handling(Image credit: James Huang)
The Isaac Sonic offers off-the-charts frame rigidity that should satisfy the most discerning riders(Image credit: James Huang)
The egg-shaped head tube profile adds to the stiffness without adding much weight.(Image credit: James Huang)
We're accustomed to seeing bulbous bottom bracket shells but this one is simply huge.(Image credit: James Huang)
The top tube flows smoothly into the full-length dual seat stays.(Image credit: James Huang)
The giant front end is matched with a similarly proportioned rear triangle.(Image credit: James Huang)
All of this material requires a few extra grams but it's a worthwhile tradeoff in this case(Image credit: James Huang)
In keeping with its 'natural design' motif, the frame is virtually devoid of any sharp creases.(Image credit: James Huang)
Isaac says the frame is made of ultra high modulus tubing and in this case we believe them(Image credit: James Huang)
The dropouts are arguably a bit clunky in appearance but they get the job done.(Image credit: James Huang)
The seat tube is capped by a rather sizeable collar.(Image credit: James Huang)
The matching carbon fork uses a tapered-and-oversized 1 1/8"-to-1 1/4" steerer(Image credit: James Huang)
The Campagnolo Record Ergopower levers provided their usual excellent performance.(Image credit: James Huang)
The same can be said for the Record rear derailleur(Image credit: James Huang)
The carbon cage on the Record front derailleur matches the look of the frame well.(Image credit: James Huang)
Campagnolo was late with external-bearing bottom brackets but its Ultra-Torque design was worth it(Image credit: James Huang)
The dual-pivot front/single-pivot rear brake calliper combination gave excellent brake modulation(Image credit: James Huang)
The front rim on the Campagnolo Neutron Ultra wheel uses a symmetric spoke drilling…(Image credit: James Huang)
…while the rear is slightly offset for more even spoke tension.(Image credit: James Huang)
Both rims are milled in between the spoke holes to shave a few grams.(Image credit: James Huang)
There's more carbon to be found in the front hub shell…(Image credit: James Huang)
…as well as the rear. (Image credit: James Huang)
The included Veloflex 'open tubular' clinchers provided a stellar ride.(Image credit: James Huang)
The Deda Newton 31.8 cockpit is a well-proven design.(Image credit: James Huang)
The Selle Italia SLR Gel Flow saddle is comfortable but the Isaac seatpost was disappointing(Image credit: James Huang)
Isaac is a German company both in origin and philosophy:
The Isaac Sonic impresses you right out of the box with
Our 57cm sample came
Total as-tested
The presentation leads to one overwhelming expectation: this
Ride & handling: total stiffness
The Sonic’s overall ride is one of the stiffest I’ve ever
Heading uphill, the bike felt rock solid and light while
On most bikes a bit of bottom bracket flex almost seems to
The solution was to go to a bigger gear and stay on the
The Sonic’s giant front end also provided very precise and
Not surprisingly, the combination of the high drivetrain and
But how is all of this stiffness on rough roads, you ask? The
Even so, few will ever describe this bike as ‘plush’ but the
In short, the stiffness of the Sonic is such a huge
Frame: go big
These days there are a number of sub-900g frames (and even
The Sonic’s extra-large tubing sizes and joints results in a
Isaac’s hand-laid carbon frames proudly bear the technical
The frame is first molded in three sections (front triangle,
Isaac also constructs
One small niggle with the frame was that the downtube cable
The front derailleur cable needs to run up though a small
To be fair, Isaac isn’t the only company to do such a thing
Equipment: Italian form & function
A bike is more than just a frame and fork, and as a mechanic
The dual-pivot front/single-pivot rear arrangement on the
The Campagnolo Neutron Ultra wheels were a pleasant surprise
One last observation on the wheels is that the Neutron Ultra
The Veloflex ‘open tubular’ tyres have their roots deep in
The supplied Deda Newton oversized bar and stem are ProTour
The Isaac carbon seatpost was nicely crafted and lightweight
Summary: benefits of not being the lightest kid on the block
The Sonic is a super stiff, precise and confidence inspiring
Rock solid and race ready with the complete Italian parts
