Living at sea level, it is not so easy to simulate pulling an alpine sled such as required on big climbs like Denali. I poked around the internet, and saw examples of people pulling everything from spare tires to igloos but wanted something a bit more elegant and portable. I logged quite a bit of sled time on my recent winter Rainier climb so I know what a real sled feels like, and this setup appropriates it very closely.
To start with, I picked up a set of 5/8 x 7ft galvanized steel weight lifting chains from Amazon.
The chains are 7′ long, come in a set of two and weigh 30lbs each for a total of 60 lbs. As you can see they are very large links, something like I would expect a large ship to use as an anchor chain.
In addition to the chains, I picked up a Multi Purpose Training Sled & Lead Harness so I could pull the chains without my pack to give me a bit more flexibility.
I connected both chains the the center ring of the 3 pull rings. Then I walked around the neighborhood to see what it felt like, and was amazed at how closely it matched an actual sled. I could close my eyes and imagine myself back on Rainier leaning into that familiar tug. Maybe later I might double up on the chains, but for now the resistance feels just about perfect to me.
I drug it on concrete, dirt and grass and it felt pretty consistent on all surfaces with a slight increase in resistance on dry grass. Of course if you drag it only on concrete it does wear the chain, but the material loss seems minimal.
If you try this setup let me know how it worked out for you.