Will the Empulse R90 fit your wheelchair?

1. A

   Check A. Rigid or folding frame

   Try to fold the chair in from the sides, the way you would to put it in a car. A folding chair collapses narrow and has a cross brace under the seat shaped like an X. A rigid chair does not fold at all, and under the seat it carries one straight bar running across from one rear wheel to the other. That bar is the camber tube.

   Most rigid chairs still fold their backrest down flat. That is not the same thing, so judge it by whether the frame itself folds in from the sides.

2. B

   Check B. Camber tube diameter

   This one is for a rigid chair. Look under the seat for the single straight bar that runs across the chair and carries both rear wheels. Measure straight across the bar, at its thickest, the way you would measure the thickness of a broom handle.

   The standard clamp takes tubes up to 1.26 inches. The large clamp takes 1.38 to 1.77 inches. Any ultralight rigid chair fits if the tube measures in one of those ranges.

3. C

   Check C. Axle distance

   This one is for a folding chair. Take both rear wheels off if they come off easily, or reach under the chair. On each side there is a flat metal plate with a row of holes where the rear axle bolts in. That is the axle plate.

   Measure from the inside face of one plate to the inside face of the other, straight across the chair. Any ultralight folding chair fits if the number lands in one of the ranges on this page.

4. D

   Check D. Axle plate height

   Still on a folding chair, and on the same plate you just used for check C. Measure the plate itself from its top edge to its bottom edge.

   Measure the plate only. The frame tube it is bolted to is not part of this number.