A collapsible wheelchair convertible between a collapsible beach wheelchair and a collapsible all-terrain wheelchair, comprising:
- a folding frame carrying a foldable seat, a foldable back, a right side frame structure, and a left side frame structure, the right side frame structure having a right side armrest, a right side back frame member, a right side front frame member, and a right side rear frame member, the left side frame structure having a left side armrest, a left side back frame member, a left side front frame member, and a left side rear frame member;
- a rear right side all-terrain tire of a first diameter rotatably mounted to the right side rear frame member and having a rear right side all-terrain tire axis of rotation;
- a rear left side all-terrain tire of the first diameter rotatably mounted to the left side rear frame member, and having a rear left side all-terrain tire axis of rotation that is co-axial with the rear right side all-terrain tire axis of rotation and which together define a rear all-terrain axis of rotation whose height from ground is substantially equal to a radius of the first diameter;
- a front right side all-terrain tire of a second diameter that is less than the first diameter mounted to the right side front frame member and having a front right side all-terrain tire axis of rotation;
- a front left side all-terrain tire of the second diameter rotatably mounted to the left side front frame member, and having a front left side all-terrain tire axis of rotation that is co-axial with the front right side all-terrain tire axis of rotation and which together define a front all-terrain axis of rotation whose height from ground is substantially equal to a radius of the second diameter, whereby the foldable seat is substantially parallel to ground when the folding frame in un-folded;
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- conversion components that, when installed on the folding frame with the front and rear all-terrain tires, convert the all-terrain wheelchair into a beach wheelchair, the conversion components including:
- a rear axle sized to be received through the rear right side all-terrain tire axis of rotation of the rear right side all-terrain tire and the rear left side all-terrain tire axis of rotation of the rear left side all-terrain tire, the rear axle defining a rear beach axis of rotation;
- a rear right side beach tire of a third diameter rotatably mountable on the rear axle;
- a rear left side beach tire of the third diameter rotatably mountable on the rear axle, the rear beach axis of rotation having a height from ground that is substantially equal to a radius of the third diameter;
- a pivoting front right side beach tire of a fourth diameter that is less that the third diameter receivable in place of the front right side all-terrain tire;
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- a pivoting front left side beach tire of the fourth diameter receivable in place of the front left side all-terrain tire;
- the third diameter of the right and left rear beach tires relative to the fourth diameter of the right and left front beach tires making the foldable seat slant upwardly relative to ground from the rear of the folding frame to the front of the folding frame when the folding frame in un-folded.