Cannondale HollowGram R45 wheelset review

The HollowGram R45 wheelset is positioned as the more affordable sibling of Cannondale's £2,000 KNOT 45 SLs, which sit alongside the deeper KNOT 64 SL wheels at the top of the company’s range.

However, don't be fooled by the R45s' more modest price point.

While it may suggest that these are not high-performance road bike wheels, the details indicate all may not be quite as it seems.

Cannondale HollowGram R45 wheelset spec details

Crucially, both the HollowGram R45 and KNOT 45 SL wheels share the same tubeless carbon rim, although the R45 rims each have four more spoke holes.

Where the KNOT 45 SL has DT Swiss 240 rear-hub internals, the R45 has a Formula hub with a traditional three-pawl design.

The R45 has a HollowGram front hub with 24 double-butted spokes, with 16 spokes crossed twice on the brake side, and eight radial spokes on the other side. The rear wheel has 28 spokes, crossed twice on each side.

Cannondale claims a pair of R45s weigh 1,730g, but including 12mm thru-axle end caps and rim tape, on our scales the front weighed 804g and the rear 964g, totalling 1,768g.

The KNOT 45 SLs have a claimed weight of 1,540g. The savings over the R45 are due to having eight fewer of their lighter DT Swiss Aerolite spokes, and different hub internals.

The blunt-nosed rims are 45mm tall, 21mm wide internally and a bulbous 32mm externally, which could cause clearance issues on certain frames.

They were designed by Nathan Barry, who designed Cannondale’s SystemSix aero race bike, and are intended to make the most of larger-volume tyres.

Cannondale HollowGram R45 wheelset performance

A pair of 28mm road bike tyres needed a little coaxing on to the rims, but inflated easily with a track pump, sealed quickly and measured 30mm wide.

The wide rim is said to optimise airflow around a wider tyre, so when the air is parted, it reattaches cleanly to the following rim and lowers drag.

The R45s are a lesson in not judging wheels on total mass alone. With 21 points of engagement, the rear hub picks up fairly quickly, and the additional spokes make for a taut, lively wheel that appears keen to accelerate.

The R45s gain speed with ease, and their aerodynamic efficiency helps sustain it, feeling noticeably quicker than expected when coasting.

Long climbs aren’t a drag, and despite winter’s best efforts to unsettle my bike, the R45s seem impervious to gusting winds.

Since you can use lower tyre pressures in wide tyres, they roll smoothly, conforming well to the road surface, and corner with assurance, thanks to excellent sidewall support.

The HollowGram R45s enjoy the same two-year, no-quibble crash replacement and lifetime warranty as Cannondale's premium wheels.

Cannondale HollowGram R45 wheelset bottom line

With its rim profile and dimensions, not to mention its competitive price and product support, the R45 is well suited to gravel riding, as well as all types of road use.

Although priced as a budget carbon wheel, the R45s outperform cost expectations. They feel like a more expensive road bike wheelset, providing an engaging and rewarding ride.