New cart tires
 

I have a 2013 4-seater Yamaha with 17,000+ miles. Original tires, still with tread. This is the firm ride model. Would radial tires improve the ride?

Steel Belted? Yes

Good information here:

Bias Ply vs Radial: What'''s the Difference for Your Golf Cart | GCTS

Thank you. Is there a company that comes to the house to change tires? Or where to buy tires?

Our 2014 Yamaha needs new shoes. I’d welcome recommendations from others who have had positive experiences with 10 inch steel belted radials (not low profile) tires.

The Tire Guy sold me new ones for my cart. He comes to your house and does it on site. Good work and fair price.

In my opinion, changing to radials would not make that much of a difference. Have you tried simply reducing the air pressure in the tires?

Tires
 

The Kenda brand radial tires have the best ride I've experienced in a golf cart. That said, they cost about $140-155 per tire installed, and you'll need 4 of them. I just purchased 4 Ocelot radials from Amazon and had them mounted at a total cost of $75 per tire. The ride is a little stiffer than the Kenda, but still better than the non-radial bias ply tires. Half the price, works for me. I got about 8500 miles on my original Kenda tires...now we wait.

Can’t answer the question about the tires but can suggest changing your springs. I have a 2016 Yamaha that had firm springs. Todd Casey Golf Cart Repair changed the springs and my ride is much smoother now.

Firm tires
 

Yes, but why not try letting some air out first.... Try asking a local Yamaha dealer