Saturday, September 24, 2011

Tri Bike vs. Road Bike Or Race to Place vs. Race to Race

Over the last two years of doing triathlons, at some point people started talking about triathlon specific bikes. And I notice that a lot of people that pass me are riding really nice bikes, and when I look them up they're sport specific. I have wondered to myself (and really anyone who will listen) if a sport specific bike is more mental than actual. Does a bike really make that much of a difference?

My Current Bike
I have a mid-range road bike. It's a Giant TCR II from 2003, it's got an aluminum alloy frame with Shimano 105 components, it came with a set of Mavic rims, and Michelin Pro Race 3 tires. Overall this bike has treated me very well. I got it when I upgraded from my first hybrid bike, and to be honest I think it's a pretty decent bike. I just wanted a bike that would let me go out and get some mileage without killing myself. Because let's face it, it's a lot more satisfying to ride 15 miles in an hour instead of an hour and a half.

For the uninitiated, the difference between a decent road bike and a hybrid bike is difficult to describe. But imagine that when you step on the pedals on your bike it responds as if all of that effort you just put into pushing the pedal is directly translated into forward progress. They're lighter, they are less cushy, they absorb less of the energy put into them (both by you and the road - so a more bumpy ride :) It is basically like upgrading from a sedan to a sports car.

I've had this bike since about May 2004 - so it's the only bike I've used in my triathlons. The only upgrade I've made to this bike is to go through two GPS bike computers, and put on a pair of clip-on aero bars. Up until recently I've been reluctant to think about getting a triathlon specific bike. Really for three reasons
  1. The bike does not make the rider. If I can't muster a decent speed on a decent road bike, plunking down a few thousand for a new bike isn't going to catapult me onto the podium
  2. I was not convinced that there was significant difference between a road bike and a triathlon bike
  3. If you're going to throw down a bunch of money on a bike you'd better either be committed to the sport, or have tons of extra money laying around. And I do not fall into the second category :)
What Makes a Tri Bike Different
When scouring the internet you can find many descriptions of what makes a tri bike different. First things first, it's not obsenly lighter than a road bike, in fact it may weigh more. It's also not even really any more expensive than a road bike. But they are designed differently - the purpose of the two bikes is a lot different.

Triathlon is a non-drafting sport, meaning that when you ride your bike you're not allowed to ride close enough to someone else to benefit from their presence. In a bike race, or even group ride, drafting is part of the deal. Riding in a group has a major impact on the amount of wind resistance you have to deal with. Riding within two or three feet of even just one other person is significantly easier than being out on your own. So the triathlon bikes are designed to help you cut through the wind. This is accomplished in a couple of ways
  • Aero bars - Instead of putting your hands on your bars and riding around in a more or less upright position you bend WAY over and put your forearms on the bars. The biggest factor in a bikes wind resistance is the huge piece of meat sitting on it. So the goal here is to get that big sail of a body tucked in a nice small ball that is resembles an arrow more than a flapping wall. One side effect of this position, it's uncomfortable for extended periods. If you can't hold this position, you're likely to plop back up on your hands and "engage the meat parachute"
  • Bike Geometry - To solve the problem of aero bars being uncomfortable, the way the bike is built is different. Basically, a tri bike pushes your whole body forward on the bike. The result is that it's more comfortable to ride in that tucked position for longer. It also changes what muscles you use to power the bike. Now it's very easy for me to write that, I have read it a hundred times. I have also heard more technical descriptions. A tri bike has a steeper seat tube angle, a shorter top tube, and a shorter head tube. Oh yeah, that's the stuff, just imagine that in your head.
  • Aero components - Things are tapered and tucked to get out of the wind. When you look at an extreme aero bike head on it's very skinny. Heck, when you see them from the side they look all jammed together.

I was convinced it was all just marketing, "Hey put your rear up here and you'll be winning Kona in no time! The seat tube is steeper, how can you help but go a million miles an hour?!" I mean seriously, why can't someone put together a nice graphic to show me how a tri-specific setup is different. Or show me some real numbers about how riding a tri bike is somehow faster than riding a road bike in normal tri conditions (e.g., by yourself.) It must mean it's all hype, and as I like to say, don't believe the hype.

So I finally found an article that shows bike geometry differences and while I don't like the graphic they have because the bikes look the same with just different words written on them, here's my graphic that shows those two bikes on top of each other.

Blue = Tri Geometry
Red = Standard Geometry
So there we have it, a tri bike definitely moves you forward on the frame, apparently to the tune of 70/30 split instead of 50/50 weight distribution. Some of the side effects are stability and handling, but if you're riding by yourself and basically in a straight line - who cares right? Other side effects include comfort in the aero position and using different leg muscles to turn the cranks. The goal is to go as fast as you can while cutting down on the effort to do it. Because when you're done with your amazingly fast bike leg, you need to hop off and do another fast running leg.

So how much benefit do aero bars give you (and the position they put you in?) Again, there are lots of anecdotal conversations, and I personally feel like it's actually more comfortable, but I wanted to see some actual numbers. And then I found this guy basically doing the comparison I wanted. The numbers are a little tricky, because he does things like sets up a road bike with aero bars, but then doesn't use them. At first I was frustrated by this, but then I realized that in fact after about 10 miles of riding I get up off my aero bars to stretch my back, so you could say that a road bike with aero bars at some point or another will force you out of aero into the normal riding position. If you look at his last little graph, he basically says that the difference between a road bike and a full on tri-bike is 3 miles per hour (for a guy who is already averaging 25 miles per hour.) That article is basically contending that an aero road bike may suffice as your triathlon bike, but if you buy the argument that a tri bike is more suited for triathlons due to it's different geometry then what you gather from this is that the aero position clearly has big benefits.

So it's clear that a tri-bike isn't just hype. They are designed for a different sport, and that design can have great benefits. So the question is, when should I get one?

Tri Bike or Road Bike
This conversation is as old as the bikes I'm comparing. If you search the internet for this topic it's full of opinion and comparisons. It almost always boils down to a few points
  • The bike doesn't make the rider. A good rider can go fast on any decent bike, so if you're just looking for speed then look in the mirror. I read this as - if all you want is speed spend more time on the bike you have.
  • Don't bother with a tri bike if you're not going to be doing a lot of triathlons. A tri bike is a great bike, but its designed for triathlons which are ridden basically by yourself on mostly flat terrain with a small number of turns. If you're planning on lots of group rides, or rides with challenging climbs or lots of twists and turns, then a tri bike is not for you
I am a personal believer in the first point. When I started riding this season my average speed was in the mid to low 17s,  I would be happy to be able to hold 18 for 10 miles. When I ended the season I was up over 19 miles per hour. To put that in perspective, the people who usually podium in my age group average around 21 to 22 miles per hour. So let's say I had run out and bought a tri bike at the end of last year, and for arguments sake let's say it made me 2 miles per hour faster. So without any additional work I would have been .. where I am. Except a little poorer.

I am also a believer on the second point. I am not someone who jumps on a wagon as soon as it starts going. Before this season I had done four triathlons the year before, and one before that. So to buy a tri bike at the start of this season seemed a little premature. What if I got back to MN and the tri scene was non-existant or my motivation died? That would have been pretty rediculous.

I actually believe I'm now getting dialed in on those two big points. I have completed 10 triathlons, and have a tentative race schedule planned for next year that has 17 potential races on it. I have also seen significant gains in my overall speed, and my goal is to get very close to being able to close that bike speed gap next starting with the base I developed this year.

Verdict
So I'm sold, clearly a tri bike is more than just a set of aero bars and some nice wheels. They can bring you a lot of speed if you use it right, and if you're racing to win and are going to be doing it for the foreseeable future, it's probably worth the investment.

2 comments:

Amy said...

I want one too.

Jeremy said...

Oh boy, if you get a new bike before me I'll be green with Envy!