We do a lot of Ag. Not a lot of margin on a % but decent money for the time it takes. We run between &100-200 markup on rears plus labor. The one thing to remember is they have more than just tractors.
Tires were the only thing we did until about 3 years ago. the money part is a hard thing to get but you need to sell yourself and quality not on price or some one will always be cheaper than you (car dealers, big box,ect.) and for shaving i have not heard that term in 10 years. the best way to stop cupping rotate and shocks,Struts.
tom do you go with a % of sale or a flat fee i was thinking of it my self. one of my wholesalers offers it but the first thing you lose is 2/32 off the top witch is hard to tell a customer that has a rd/hzd on a new tire but it is still better than new price thanks for your input