Gravel and adventure bikes are all the rage right now, offering versatility for cyclists who like to mix road riding with the ability to explore off-road on trails and gravel.
Many of the new breed of gravel bikes are designed to work with both standard 700c road wheels, or with slightly smaller 650B wheels.
Also known as 27.5" wheels, 650B have been used on touring bikes for some years but are growing in popularity as riders - and bike brands - discover their suitability for mixed-terrain riding.
650B wheels can be a little lighter and sprightlier than 700c, while they also allow for wider tyres to be run in most bike frames.
Here's a look at some of the best 650B wheel options available right now. All the wheels below are for disc brakes and thru axles, and they're all capable of being run tubeless or with standard clincher tyres and inner tubes.
Developed in collaboration with their pals at Mason Cycles, the Adventure Sport is one of three 650B gravel wheelsets offered by Hunt.
The tough 6066-T6 alloy rims have a generous 25mm internal width, and weight is competitive at 1594g for the pair.
They are of course tubeless-compatible (although you can run standard clinchers and inner tubes if you prefer), and come with tubeless valves and tape in the box. Hunt also offer to supply them fitted with a range of gravel tyres, including the WTB Horizon or Byway 650B x 47mm.
Looking to go lighter? Hunt's Adventure Carbon Disc wheelset (£799) feature a 24mm rim width in carbon, and weigh 1425g.
£339 from www.huntbikewheels.com.
The Alta is the first 650B wheel from Parcours, and with a rim combining 25mm internal width with an aero 35mm profile it looks to be a strong contender for performance-oriented gravel grinders.
Wheelset weight is a feathery 1360g - the lightest in our roundup - thanks in part to the use of premium Sapim CX-Ray spokes.
A dynamo build is also available using the benchmark Son Delux 12 dynamo hub.
£849 from www.parcours.cc.
Featuring DT Swiss 350 hubs paired with the Swiss brand's lightweight XR361 rims, these wheels are a great choice for riders seeking reliability and performance at a reasonable price point.
The rims aren't as wide as those listed above, but the 22.5mm internal width will allow you to run road as well as gravel or even MTB tyres without a problem.
We've used Bike Stacja for XC wheels and were impressed by the level of customisation on offer, as well as the good value and fast delivery from Poland to the UK (turnaround approx 2 weeks). They come with a 2-year warranty for added peace of mind.
At 1515g for the pair, you're getting a robust wheelset with excellent hubs that should stand up to many years of use.
£400.75 from www.bikestacja.pl.
If your idea of gravel riding is blasting through events like Dirty Reiver or Grinduro at full speed, then the Reynolds ATR Gravel wheelset might fit the bill.
Featuring deep-section carbon rims (23mm internal width) laced to Reynolds CNC-machined TR3 hubs, these wheels are built for speed. Sapim race spokes and 36-point freehub engagement ensure snappy acceleration, while brass nipples boost longevity.
At 1615g they aren't the lightest wheels in our roundup, but the 40mm aero rims mean they could well be the fastest.
£940 from www.wiggle.co.uk.
The lightest wheelset in the Vapour range, Halo say the GXC is "crafted for the longest distance gravel races, ultra-distance adventure riding, XC racing, road plus as well as lightly loaded touring."
Alloy rims (21mm internal) are teamed with Halo's new GXC hubs, which boast an impressive 120-point engagement along with sealed bearings and wide spaced flanges for increased stiffness.
The use of standard J-bend spokes is good news for long-distance tourers, with replacements relatively easier to find. The wheels come pre-taped and tubeless-ready.
At 1720g a pair the Vapour GXC strike a good balance between low weight and durability - and at a price that won't break the bank.
£409.98 from www.halowheels.com.