I want to buy a mountain bike to ride off-road at weekends and improve my fitness. The shops seem to have lots of different types of bike and a massive price range. What kind of things should I look out for, and what's a good price to pay?
Mark Hopgood, Glasgow

Matt Hart answers: If you want a mountain bike for fitness you're probably best off buying a 'hardtail'. These bikes have suspension at the front and not the back, and tend to be lighter and less expensive. The most important part of the bike is the frame, with the more expensive and lighter frames made of special alloys, carbon fibre or titanium. Cheaper frames are made of steel or heavier, less refined aluminium. On cheaper bikes other components such as wheels and bearing surfaces tend to be less durable too.

The most you need to spend as a first-timer is £500, and you should be able to get a good, reliable entry-level bike for that. But if you get the mountain biking bug, be prepared to part with some serious cash.