Shimano and FOX are to produce a new 15mm through-axle hub system in combination with a 100mm Over Locknut Dimension (OLD), which they’re aiming at all mountain, cross country and marathon riders. Shimano will be providing Deore XT and XTR level hubs as well as a Deore XT level complete front wheel for the new system.
The idea behind the new size over the current 20mm platform is a lighter, more rigid link between the hubs, axles and the fork lowers.
FOX will be producing 15mm specific forks and claim that with the new system the 15mm through axles are 15% stiffer torsionally and 25% stiffer in transverse shear than a traditional 9mm quick release front axle system.
The XTR 15mm through axle hub HB-M978 is more than 100 grams lighter than the 20mm version HB-M976. HB-M978 has been developed with the Center Lock system just like HB-M778, the new front hub with 15mm through axle at Deore XT level. HB-M758 is a Deore XT level 15mm through axle front hub for 6-bolt rotors.
Shimano is also introducing a complete Deore XT front wheel WH-M778 with this new 15mm x 100mm technology. It has 24 double butted spokes and uses the 23mm rim used on the current 9mm QR XC wheelset. A new sealing design on the wheelset is said to improve bearing durability by 400% with less seal drag than cartridge bearings. Combined with a WH-M775 Deore XT XC rear wheel it weighs 1702 g for a set.
When’s all this available? June 2008 for the HB-M978/778/758; September 2008 for the WH-M778.