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