If you have changed your tires and you feel a pulsing in the steering wheel while on smooth hard pack or pavement...and you have checked that the tires are not out of round, are mounted properly and all front end parts are tight, you may have what I believe is called "Cow Toeing" happening. This happens with some tire tread designs that have angled bars for mud use along with too much toe-in. Basically each tire is headed for a point in front of the machine that crosses each other less then 75 yards away which allows one wheel at a time to hold traction until it is forced to slip and restart which at that point the other tire gains traction. This produces a fast rocking action as each tire makes and breaks traction making the wheel or bars shake like a tire balancing problem. You can sometimes cure or drastically reduce this by adjusting the toe of your machine closer to zero. This will stop the loading and unloading of the tire traction caused by toe-in.
I found I had this problem with mine while in Gallina. The Zs and Us are easy to set with the string procedure. It cured mine by reducing the factory toe setting from almost 1/2" (which is way too much anyway) to 2/32". Reducing the toe-in will also cause quicker steering responses but can also increase road wander at high speeds so just be aware.