You may want to re-think and go with an 85mm fork. The difference in axle to crown between a 50mm travel fork and a 100 is going to be quite large. It will lift up the front of your frame a lot more than the designers intended and could easily make your steering feel "floppy" at lower speeds due to the change in the steering geometry that raising the head tube will cause. Generally longer forks of 100mm's or more travel shoudl be used on frames with higher located steering head tubes intended for use with such forks.