The pivot arm initially positions the tire on the wheel such that the wheel partially protrudes through {HEAD ~ the center aperture} of {TAIL ~ the tire} 
The pivot arm initially positions the tire on the wheel such that the wheel partially protrudes through { HEAD ~ the center aperture } of { TAIL ~ the tire }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL