Actually the STEMCO site is the BIG Rig Site!
The actual site is:
http://www.rvedition.com/size.html
The unit to buy for the TM's is either the:
K - 0700 for 14 inch tires, like the TM 3326 or
K - 0702 for 13 inch tires.
The price is $81.99, plus $10.00 shipping and comes with a mounting kit that will fit over the hub.
Looks like a good unit!
Just my 2 cents worth.
Jeff