Breaking down the lengthy name gives the Pro quality level designation (and price), while VR-SF stands for the shape of the drops — variable radius shallow flare. Following on from the bump-taming IsoSpeed elements of several Trek framesets, IsoCore is described as continuous inner-laminar technology, which in layman’s terms means the company has added something to the bar’s OCLV carbon layup.
Our 42cm example weighs just 240g and has wide tops with a very square bend in to the short reach, mildly flared drops. Bontrager offers a compact drop version for the same price, but my shallow bend has a slightly deeper, more rounded shape that proved comfortable for large palms, with brake and shift levers easily in reach.
The front of the tops has an indentation to route two cables, completing the bar’s round profile, although electronic shifting users might need to add empty housing to maintain the shape. Another hollowed section on top is angled slightly towards the rider for two EVA IsoZone pads, which are L-shaped to provide cushioning from the hoods and across most of the tops, and weigh a mere 7g together.
Taping the cables in position partly bridges the pads’ intended location, but their adhesive backing keeps each pad firmly positioned before taping the bar. When complete, there’s no visible trace of the pads or cables beneath the tape, although the tops are pleasantly chunky, which I like.
The bar is claimed to reduce road vibration by 20 percent compared with traditional carbon. Isolating vibration reduction to one component is difficult, as there are so many ways to achieve improvements. With a PRO Vibe 7s stem, 25mm tyres, cushioned polymer bar tape and compliant frameset I was already well equipped, but the Bontrager bar added ride comfort, converting our favourite corrugated tarmac sections to mere bumps. Swapping from hoods to tops only multiplied the improvements, the firm EVA foam helping grip and wrist comfort.
There’s all the stiffness you could want for climbing or sprinting, and the minimal amount of flare helps avoid forearm clashes when on the drops. But this isn’t an uncompromising girder-like bar, it transmits positive road feel while permitting fine control, and with a sensible bike set up, can leave you feeling less fatigued after a hard ride.