Get your mum and dad to logon to 50+. Any problems they come across in choosing a "New" bike can easily be answered on here. And we are not all ultra fit cyclists that have been riding for years with $2,000 bikes.
We may not be able to help your parents on choosing a bike or help them get fit and lose weight- but me can provide advice that has been well earned from our experiences.
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How long was I in the army? Five foot seven.
Spike Milligan