Yes, the SumoSprings Rebel Custom Helper Springs part # SSF-170-40-2 comes with springs for the front passenger and front driver side of your 2015 Forest River FR3 Motorhome. If you are looking for the rear passenger and rear driver as well then you can use the SumoSprings Maxim Custom Helper Springs part # SSR-187-40-1. view full answer...
Yes, the Timbren Rear Suspension Enhancement # TFRF53A contains 2 add on springs. You will get one spring for each side of your 2016 Forest River FR3 30DS.
You will need to raise the rear axle of your FR3 slightly off the ground to install these as per the instructions that I have linked below. view full answer...