Maxspeed - does Graphhopper support the mph suffix?

I expect Graphhopper will utilize the maxspeed tag on ways. I am generating OSM data from a Shape file, and I have speed limits in miles per hour. Should I simply add tags with the mph suffix, as “maxspeed=25 mph” or do you recommend I convert to kilometers per hour and leave off the suffix?

Common units for maxspeed etc should be supported