As a triathlon coach, I do my best to promote the sport - which often includes converting my personal training clients and runners into beginner triathletes. In doing so, I have to answer a slew of questions - how much training does it take, how hard are they, how do I conquer my fear of open-water swimming . . . all valid inquiries, and as you might imagine - I provide a slightly different answer for each person.
Lately, though, I have been bombarded with the question of "what bike should I buy?" I initially provide my typical response to any fitness/nutrition question that "it depends." And bike choice is highly dependent - bicycles can range from $50-$15,000 in price, can get you from point A to B, down the Kamikaze at Mammoth, or 112 miles across the Hawaiian desert.
To better answer the question, though, I ask a few questions myself:
1) How much do you have to spend?
When discussing price, I recommend to set two limits: a "soft" limit (how much you would like to spend) and a "hard" limit (the amount you absolutely can not exceed). These limits are imperative when walking into a bike shop - in fact, this will be one of the first questions they will ask you. Some aspects of a bike are more more important than others; for example, it's worth spending a little extra money on the components (brakes, gears, shifters) than on race wheels. In short - select a bike with Shimano 105, Ultegra, or DuraAce components or any SRAM components. Shimano Tiagra and Sora components are of much lesser value. And for an entry-level bike, either an aluminum or carbon frame will work well.
Good bicycles (worthy of triathlon races) start around $1,000, but if you want a competitive bike that will will be happy with for multiple years, expect to spend in the $2,000 range. The good news is that is somewhat levels off from there - the difference between $1,000 bike and a $2,000 is pretty significant; however, the difference between a $2,000 bike and a $10,000 bike is rather small (unless you are an elite athlete).
Note: do not forget to consider sales tax, pedals, shoes, and helmet when planning your finances.
2) What distance of triathlon do you plan to do?
If you want to just try out a triathlon and plan to do one sprint-distance race (bike course is 15 miles or less) before committing to anything else - a mountain bike (or borrowed road bike) will service you just fine. If you do race on a mountain bike, though, it is well-worth spending $30-$40 on "road slicks" (smooth tires) as they will save you a considerable amount of time and energy. If you plan to compete in an Olympic distance race (or greater) or try a season of triathlon racing - you will need a road or triathlon bike (more on those differences below).
3) What other riding do you plan to do (bike racing, century rides, commuting)?
This question has to do with the type of bike you purchase. The three main types of bicycles are Mountain Bikes, Road Bikes, and Triathlon (aka Time Trial or TT bikes). Mountain bikes are suitable for short commutes or off-road riding. Road bikes are the most versatile - they built for a combination of comfort and speed ("comfort" is a relative term, especially if you have never ridden a road bike) and can be used in a triathlon or road race. Triathlon bikes are built for speed, but are not legal in road bike racing and might be uncomfortable for longer rides (over 70 miles). Frame geometry is the main difference between road and triathlon bikes. If you are unsure what you want to do - buy a road bike. If you know you only want to race triathlons and want to go as fast as possible, buy a triathlon bike. Most enthusiasts, though, have at least one of each, so if you get bit by the endurance-sport bug, chances are you will have three+ bikes within three years.
4) How long do you plan to keep the bike?
This question related to the price question. If you are satisfied with upgrading to a new bike in a year or two - it's okay to spend $1,000 or less (for a used or new bike with lesser components). For the average athlete, spending $2,000 will get you a ride that you may never outgrow.
Most Important Part!
Above all, the absolute most important factor in bike selection is the "Bike Fit". A carbon-frame bike, with SRAM Red components, and Zipp 808 race wheels is useless if you are uncomfortable on it. Getting fit to a bike is much more complicated than standing over the top tube and making sure you have 4-fingers of clearance (frame size, in fact, is only a small consideration of the fit). A bike fit (by a certified professional) should be the first step in selecting a bike. Most shops can narrow your choice of bikes to 3-4 based on your fit and price range.
San Diego has a plethora of quality bike shops - I recommend two: Moment Cycle Sport (Point Loma) or Nytro (Encinitas). Browse through either of their websites to read more about bike-fitting philosophy.
To summarize, selecting a bike depends on a number of factors - the two most important are your budget and the bike fit.
I hope this helps - the discussion of how to get into triathlon is a lengthy one, but the coaches at CEC are always happy to offer advice.
Justin Robinson, MA,RD,CSSD,FAFS,CSCS
Triathlon, Running Coach
Catalyst Endurance Coaching