It's cooled off some, forcast for today is highs in the 80's, low 90's later in the week. Had some rain in Sturgis last night, felt pretty good and cooled things off a little. Actually was supposed to get down into the 50's last night!
I've never ridden it, but the Centennial trail is supposed to be a great mountain bike trail. It starts at Bear Butte, but you can pick it up right by the National Cemetery, one exit east of Sturgis. The section from the horse camp in Ft Meade recreation area heading south is supposed to be a real nice section (I plan to hike that section this fall). I've hiked quite a bit of the Centennial, and it seems a little too much for me to bike it, I'm more of a bike path kind of guy
The Mickelson Trail is great, I've ridden it end to end in 2 days on my Mountain Bike, pulling a Bob trailer with my camping gear in it. It's about 115 miles long, the first 12 miles heading out of Deadwood are all up hill

The section south of Crazy Horse is real nice, as is the section north of Hill City.