Coming in just under the MT65 wheelset the brand new MT55's pack in a whole lot of features to make this a quality mountain bike wheel, and for under $300 for the pair you'll be hard pressed to find anything that comes close to the quality of these. Part of the 2012 Shimano lineup, the MT55 wheelset is available in both 26" and 29" versions and features an optional QR15 thru-axle front hub for those riders looking to pair some new hoops to their QR15 fork. Mirroring the industry's move to wider rims, the MT55 feature a 24.6mm external width for increased strength and the 19mm internal width provides a more stable platform for 1.9"-2.35" wide tyres.
If you're looking for a well-engineered, feature-packed set of hoops, the Shimano wheels lineup is very tough to beat. Although Shimano have always had a reputation for building solid wheels for road and MTB, they have set out to redefine their range in order to encompass the high performance and precision engineering that all of their components are renowned for. The latest Shimano mountain bike wheels utilise wider rims, 24 spokes instead of 16, faster engaging hubs and a more conventional 2-cross lacing pattern. For 2012, the new Shimano wheelset range is now stiffer, lighter, stronger and easier to maintain.
 

Rims

Taking cues from the latest XTR wheelset, the MT55 gets a wider profile rim that maintains a stiff box-section design. The 19mm internal width allows for use of tyres between 1.9" - 2.35" wide, and provides more traction and stability through increased casing volume compared to using the same tyre on a skinnier rim. By using the wider rim, Shimano have also reduced the chance of getting pinch flats with the MT55, and because of the wider footprint achieved with the tyre there is more protection for the rim sidewalls. 

 

Spokes

The MT55 gets straight pull spokes for increased tension and less chance of breakage thanks to the elimination of the elbow from traditional J-bend spokes. Although they're not quite as light as the butted versions on the XT and XTR wheels, the 2mm straight gauge spokes are impressively strong. Both front & rear wheels get 2-cross lacing and 24 spokes per wheel.

 

Hubs

Featuring similar internals to the SLX hubs, the MT55 gets a Centrelock hubset for use with either Centrelock rotors, or 6-Bolt rotors and the necessary adapter. Like all Shimano hubs, the MT55's use sealed Angular Contact Bearings for the highest level of lateral and radial support on the bearings and feature a system of Labyrinth and Contact sealing to keep grease in and muck out. Stout steel axles keep the MT55's nice 'n' stiff and contribute to the overall rigidity of the wheel. A durable steel freehub body houses the cartridge freehub mechanism inside that provides faster engagement over previous Shimano wheels. And while the hub is easily pulled apart for maintenance with a couple of basic tools, spare parts are readily available should you need to replace anything over time.