Originally Posted by
AlaskaGrizzly
My guess right now is have a tire (or tires) that are larger circumference on left. They travel farther every revolution and make you pull to the right.
Making sure all are at the same pressure is the first thing to do. If you are willing pull all the tires off and measure the circumference of all of your tires inflated to the same pressure. You might be surprised to find how much difference there is. With my 2015 HDI with the 25" tires size ranged from 75" to 80". I like to run them biggest to smallest on each side starting from front to back. If you want to "tune" it some inflate the tires on the side it is pulling to and you can get it to track straighter.
Checking the brake drag is also good advice. Block it up so all the tires are off the ground and spin each side by hand. You'll likely be able to feel it. Run it on the blocks too and see if one seems to drag more.