When we don't have snow, our dogs pull a car tire, Kickbike, a mountain bike, a moped or an ATV. Because we now have enough dogs for pulling the ATV, we mostly use this vehicle. ATV has good brakes and you can help dogs by using the engine.
For one or two dogs Kickbike Cross G4 is an excellent choice. You can nowadays consider Surly Pugsley for pulling. This bicycle has very wide tires and can be equipped with efficient disc brakes. We don't have any experience of this bicycle, but it seems very interesting to sled dog owners.
In the snow time our dogs pull Kickspark, a skier or a sled. Kickspark suits for one or two dogs. You must be able to cross-country ski without a dog before you try skijoring. There are many kind of sleds for different purposes. Danler sleds are nowadays probably the ultimate choice for racing. Swedish Björkis sleds (slädar in Swedish) are popular among safari tour entrepreneurs in Lapland. Risto Kamunen makes good sleds in Hirvas near Rovaniemi. There are many other excellent sled builders.