I live a bit north of Chang Mai Land Rd along Chiang Khlan Rd, not far from Shangri La hotel. I used to go to the O2 Gym that was next to DK Book Centre (near corner Loi Kroh and the Moat). That was a few minutes by scooter but it's shut now.

 

I'm first and foremost looking for a place with bikes and cross training machines. Weights and punching bags would be bonus but not necessary. Any suggestions appreciated.

Don't know if the Shangri La itself is an option for you.

 

The Shangri La gym is very good and the locker room is heavenly, nicely stocked with all the supplies you need to get yourself looking good after a workout.  They charge a day rate, so I sometimes treat myself to a workout if I'm on that side of town and have a few hours to share.

 

The fitness center at Duang Tawan hotel on Loi Kroh Rd. is much more reasonably priced and probably worth a look if it's not too far. 

The O2 gym didn't just close.   It moved to a larger location which is actually closer to you now.   Its just behind the Suriwong bookstore.    Go north on the Changklahn and turn left at Pantip plaza.   Make the next left (Gekko) and it about 50m up on the right. 

Rati Lanna Hotel serves the purpose and not far from you on Changklan.

The Rati Lanna although not huge was very nice when I first used it about 4 years ago.

 

The is also an outside pool you can use too as part of their gym membership.  Loved their steam room too.