Abstract: A wheelchair is provided which has a seat height adjustment comprised of a in-line turnbuckle that allows infinite adjustment of the length of a turnbuckle assembly. The assembly includes a handgrip with a longitudinal recess having a first end with smaller internal threads that mate with the external threads of a smaller diameter cylinder. This cylinder can telescope with a recess formed in a second hollow cylinder having oppositely threaded external threads that mates with a second larger diameter set of threads in a second end of the longitudinal recess of the handgrip. The smaller diameter cylinder includes a snap button on a spring, which catches an annular shoulder on the recess formed at the transition between the smaller and the larger diameter areas. This inhibits the turnbuckle from over-extension. Further, the assembly has a restraint, which inhibits the turnbuckle assembly from working out of its selected position during use. The restraint can be pop detent or jam nut.