Reserve's new 48|53 GR gravel wheels bring differential rim depths of 48mm at the front and 53mm at the rear, combined with a wide 44mm external dimension in line with the trend for wider, aero-optimised rims.The shift towards wider aero rims started with Zipps revolutionary 303 XPLR SW design, which combines a 54mm depth with a huge 32mm internal width.Hunt followed with the Limitless Gravel rim, bringing a 40mm depth and 27mm internal width. Newmen then upped the ante with the Streem G.62, blending a 62mm-deep rim with a massive 45mm external width and 27mm internal.ENVE has pushed the boundaries even further with the 67mm-deep G SES 6.7 Pro, which has a huge 35mm internal width. The new 48|53 GR wheelset combines a 48mm front and 53mm rear rim depth. Reserve wheels Reserve says the aero shape is a development from its road-going wheelsets, as used by Team VismaLease a Bike, which have differential rim depths front and rear.It also claims to have combined the aero knowledge gained from the Tour de France with the toughness of Reserves wheels, as used by the Santa Cruz Syndicate downhill team and the Cannondale Factory Racing XC team.That includes details such as the asymmetric spoke offset to increase the bracing angles, to provide a stronger, stiffer wheel build, along with the carbon fibre construction at the heart of the rims.The new gravel wheels are built around an all-new rim design Reserve is calling 'hollow hook' construction. It claims this semi-hook rim shape shaves weight from the outermost section of the rim without sacrificing strength.Reserve backs up its claims with not only a lifetime warranty but also by putting no rider weight limit on the wheelset. The 48|53 GR wheelset makes for a smooth transition between rim and tyre. Reserve wheels The wheel construction is kept simple and user-friendly, with external spoke nipples and off-the-peg Sapim spokes, and tubeless compatibility with the semi-hooked rim design.Rim details The new semi-hook rim profile has a 30mm-wide internal dimension. Reserve wheels The rim has a broad 30mm internal width that helps the tyre to sit wider. Reserve claims this means a wider contact patch for enhanced grip.The brand says the problem with gravel wheel rims is the sport has shifted to ever-wider tyres. On traditional narrower rims, this means the tyre lightbulbs, where the sidewalls taper in narrower than the widest point of the tyre. This makes the tyre more unstable on rough terrain and reduces the contact patch, limiting grip. The premium model comes with lightweight DT Swiss 180 Dicut hubs. Reserve wheels The new 48|53's rim is also very wide externally, at 44mm. This means the transition between rim and tyre is much smoother, reducing drag, which means more speed.Its a similar design solution to the Streem G.62, and G SES 6.7 Pro. Reserve 48|53 GR specs Rim 30mm internal/44mm external width 24 spokes front and rear XDR or HG freehub Standard model: DT Swiss 350 hubs, Sapim CX-Ray Aero spokes, 1,528g pair Premium model: DT Swiss 180 hubs, Sapim CX-Ray Aero spokes, 1,433g pairPricing Reserve 48|53 GR / DT 350 1,599 / $1,599 / 1,799 Reserve 48|53 GR / DT 180 2,399, $TBC / TBC Rim only: 599 each / $TBC / TBC