My grandparents bought this Samsonite 55/20 spinner carry-on 10 years ago. They don't know the model name; the receipt merely states '99023476-SAMSONITE-N1'. The warranty expired, but money isn't the issue, as they're willing to pay for bigger sturdier twin wheels.
The carry-on can't be rolled effortlessly; my grandparents must drag it tiresomely; its teeny wheels don't rotate smoothly. They haven't overloaded it; airlines have always weighted it under 10 lbs.
A cart with bigger wheels is easier to push because its greater-diameter wheels work like bigger levers, multiplying the pulling or pushing force and making it easier to turn the wheels around their axles—in exactly the same way that a long spanner makes it easier to loosen a nut.
But EVEX (Samsonite's authorized repair corporation) and Samsonite refused to fasten them, alleging that the carry-on can't fit each double-wheel part, regardless of how much they can pay.
So how can my grandparents fasten the twin wheels themselves?
If they oughtn't, what kind of trustworthy professional in Toronto, Canada can help them?