Yes, you need a bike. However, your trusty mountain bike will suffice. If you can afford to invest a little, a set of slick (non-knobbly) tyres will make you ride faster. As long as it is road-worthy and fits you properly you are all set.
If you want to ride a road bike you can consider borrowing from a friend or renting one - if you do this make sure that you have trained on it beforehand and ensure a good fit and working order.
State-of-the-art lycra race suits that leave nothing to the imagination are an option. But comfort and getting kit that's fit for purpose should guide your initial wardrobe choice.
Close fitting shorts or trousers that don't flap around without ties and ribbon (that may get caught in the bike) are ideal. Cycling shorts with a small pad (chamois) can be comfortable on the bike and you can also wear them for running.
A close fitting top will work well for running and biking and if the weather is cool remember to have a light-weight jacket to hand as it's always a little colder on the bike than you expect.
The key is to select a race distance that is realistic for you and to train accordingly. There are novice, sprint, Olympic and long distance races to select from. Something for everyone.
The beauty of a triathlon is that you may be more prepared than you realise. There is no escaping the fact that the event demands that you ride a bike and run. However, for training purposes this does not mean that you have to get out onto the roads and burn rubber or hit the local running track and join the athletics club. Successful training is the kind that you can incorporate into your lifestyle in a manageable way.
Think laterally – can you go on a family bike ride at the weekend? Is there a spin class at the local gym that you can do a couple of days a week? Can you run in your lunch hour or use a treadmill at the gym? As the event gets closer you may want to consider increasing the specificity of your training: go for a bike ride, leave your running shoes at the front door and go for a quick run when you get back. You can also do this session at the gym by quickly nipping onto the treadmill after your spin class or jumping from the stationary bike onto the treadmill.
I find that I often need a little extra motivation for training and I get this from my training partners. Misery loves company! A date in the diary will get you out the door – after all you don't want to let someone down. Some friendly banter and competition will make you dig deeper and get more out of that training session. And don't underestimate the social and emotional benefits of having someone to chat to before and after training – advice, inspiration and a shared experience.
The fact is that by taking up a new challenge you are already winning. Yes, there will be people 'racing', against themselves or others. This can be off-putting for some but everybody has different motivations and goals.
As long as you keep your own goals in mind and rise to your own challenges you need not be distracted by others. If you are a first time duathlete it can often seem quite daunting but you will be surrounded by like-minded people who will support and encourage you on the day, so embrace the challenge.
Above all, if you are entering this race for Macmillan Cancer Support then you are likely doing so to support friends and loved ones or to honour the memory of someone close to you. When things start to get tough remind yourself of this and you will find that you have extra wind in your sails.