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The Cannondale HollowGram R45 wheelset can cope with everything from roads to gravel, and the 45mm-deep rims give a usefully compliant ride on rough surfaces. Bladed spokes and a smooth 32mm-wide profile mean they hold speed well, though their relatively high weight and slow-to-engage freehub mean climbing is not their forte, either on road or off. They're not the most competitive on price, either. Check out our guide to the best road bike wheels and off.road.cc ’s guide to the best gravel wheelsets for more options.
The dimensions of these rims – a reasonably wide 21mm internally and 32mm externally – tell you there's a fair amount of carbon fibre here. Prime's road-only Primavera 44 wheels, for comparison, have a broader 23mm internal width yet a narrower 30mm outside measurement.
As a result, the transition from tyre to wheel is not as smooth as some – though for their intended use (road and gravel) the fractional aero loss is largely irrelevant – and the weight is a little higher. With 28mm tyres there's a slightly 'lightbulb' effect to the cross-section, though with the thick rim it's actually more like a figure of eight, with a bit of a waist at the bead.
We weighed our set at 1,780g, and while the 50g extra over the claimed figure is likely to be the rim tape, that's still relatively heavy. If it's weight reduction you're after, there are lighter alloy wheels at less than half the price: the Vel 28RL Alloy Tubeless Disc wheels weigh 1,620g and cost £399, for instance.
What these chunky R45 rims do offer is a confident and plushly damped ride on poor surfaces. I've got some truly terrible tarmac on my local lanes, and these really are a benefit on the faster sections – they noticeably take the edge off vibrations and impacts, without ever making you fear for their integrity. It's a big help for reducing fatigue on long rides.
Feedback from the road is still good, though – it's soft-edged, not dead or dull.
Once up to speed they roll well, and those smooth 45mm sidewalls and bladed spokes at least feel like they're helping you slip through the air. At the same time, the rims aren't so deep that sidewinds are any more of a problem than with shallower wheels.
Inevitably, acceleration is nothing special, and they're not going to add anything to climbing – especially if you're on a steep, loose surface where you might break traction. This is because the Formula internals of the rear hub are noticeably slow to engage. That lagginess doesn't do your control, or your chain, any favours.
It's less of a problem on the road, but still annoying if you're wanting to get back on the power out of a corner smoothly. Also, on an entirely personal and subjective note, I found the sound of freewheeling disappointing... more like the basic clicking of a budget hub than the authoritative, neatly machined and watch-like tick I was expecting of a £1,000 set of wheels. The £350 Mavics I swapped these for actually sounded far more special.
Still, it is at least pretty quiet, and you may well love it.
The R45s arrived straight and true and stayed that way throughout the test, spinning easily on their bearings. The 24 front, 28 rear straight-pull spokes – double butted with a noticeable step down in thickness for a bit of weight reduction – stayed evenly tensioned, too. Having those extra few spokes at both ends over many wheels isn't intrinsically light, of course, but it does shore up their strength.
These come tubeless ready, and I found setting them up easy. All the tyres I tried went on with minimal fight using just plastic levers, and they sealed – oozing just a little goo around the odd spoke and stretch of rim – the first time. I've only used a track pump to seat the beads, as well.
The R45s are Center Lock disc and 12mm axle only, but you can choose between a Shimano driver body or SRAM XDR.
At £1,000 for the pair (£400 front, £600 rear) these seem on the expensive side for the performance. Hunt's 50 Carbon Aero Disc Road wheels are not only £250 less at £749, for instance, but considerably lighter, too – a claimed 1,487g.
Of course, the R45s are capable of gravel use. Sticking with Hunt, the 40mm-deep Carbon Gravel Race wheelset is still cheaper than the R45s at £899... and weighs a full 397g less at a claimed 1,383g.
Alternatively, the Prime Orra 700C Carbon Gravel wheelset is £599.99 and a claimed 1,636g.
If you're only planning to ride on tarmac, the Prime Primavera 44 Carbon Disc wheels mentioned earlier are £899.99 but again considerably lighter, while the Scribe Inception Aero Wide 42-D Carbon wheelset is now £695 (down from £720 when George tested the set last year) and weighs 1,640g.
Overall, the R45s feel strong, relatively plush over bad surfaces, and are happy to venture off the road completely. The rather average rear freehub and highish weight are a bit disappointing for the price, though – there's some (literally) stiff competition out there for wheels like these.
Tough and smooth on poor surfaces, but not the lightest or the quickest-engaging either
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road.cc test report
Make and model: Cannondale HollowGram R45 wheelset
Size tested: 700C 100x12mm
Tell us what the wheel is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Cannondale says: "Easy to ride, easy to choose. We took all our aerodynamic expertise and put it at an incredibly enticing price. This 45mm deep carbon wheel covers all the bases of road riding from tough climbs, to winding descents. Available in disc brake only with Formula rear hub internals, double-butted spokes, and a full-carbon rim."
Tell us some more about the technical aspects of the wheel?
Where it thrives - Open roads, gravel roads
What it's built for - Performance, versatility
45mm depth, 21mm internal width, 32mm external width
Full carbon rim, tubeless compatible, 1730g (pair)
SRAM XDr/Shimano freehub options / centerlock disc brake only
It's a neat and solid build with 24 spokes front and 28 rear.
Give a pleasingly smooth, well-damped ride on rough tarmac, though their ability to deflect – useful in the rough – means they're not the stiffest laterally. The highish weight means acceleration is nothing special, and hub pickup is a little laggy.
At 1,780g these aren't especially light. They're 50g heavier than claimed, too, but that could be the rim tape.
It's not hard to get cheaper and lighter carbon wheels, both for gravel and for road use.
Did the wheels stay true? Any issues with spoke tension?
Took a battering from badly frost-damaged tarmac and stayed completely true and evenly tensioned.
How easy did you find it to fit tyres?
Pretty easy – plastic levers got tyres on without issue.
Tell us how the wheel performed overall when used for its designed purpose
These deal particularly well with very rough tarmac at speed, and while they're not incredibly stiff laterally it's rarely obvious, and they track accurately. Hub pickup is slow, though.
Tell us what you particularly liked about the wheel
Compliant over poor surfaces, roll well at speed.
Tell us what you particularly disliked about the wheel
Not that light, slow freehub pickup.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
There are plenty of comparable wheels at the same price (or more), but most are considerably lighter and some have faster engagement.
Did you enjoy using the wheel? Yes, for its comfort.
Would you consider buying the wheel? No – I'd want something lighter.
Would you recommend the wheel to a friend? Maybe
Use this box to explain your overall score
These are intended as solid all-rounders, and they are. The high weight and entry-level feel of the rear hub detract overall, however, given the price.
About the tester
I usually ride: Vitus Zenium SL VR Disc My best bike is:
I've been riding for: 10-20 years I ride: A few times a week I would class myself as: Experienced
I regularly do the following types of riding: general fitness riding, mtb,