A wheelset as burly as the Enve M70Thirty 29" DT 240 XD1 Wheelset has no business being this light. There are bikes lined up at XC start lines everywhere weighing more, and there are wheels on DH bikes the world over with much less impact resistance. Enve's 70Thirty provides DH strength at trail weight for the most challenging enduro-style riding you can find.
Each M-Rim model is optimized and designated for specific riding styles, loosely indicated by the amount of time spent (or importance placed on) descending vs. climbing. In this case 70Thirty represents the rider who would be on a downhill bike but doesn't live near a chairlift, and is placed between the Trail/Enduro 60Forty and DH race 90Ten models. Across the M line-up, carbon lay-ups, rim widths, and hole counts vary to best exploit the wheel's performance for it's intended application. Bead hooks will not be found anywhere, however, as today's precision tire manufacturing processes and better rim design ensure a secure interface between tire and rim. Eliminating the bead hook obviously saves weight, but also allows greater impact resistance. Further, each M model rim is specifically tuned to provide a balance between vertical compliance and stiffness appropriate to it's intended use. Rest assured, however, these rims are plenty stiff, and will provide unbelievable steering accuracy and maximize deflection resistance, while still doing their part to reduce rider fatigue as much as possible.
Interestingly, M-Rims share much of the same DNA with their SES-series road rims. During the research and development of the road rims, Enve discovered that their design provided more strength than the current series of mountain rims. Armed with this new data, Enve's engineers were able to create an MTB rim that was both lighter and more resilient than anything that has come before in the M-rim.