I'm training for a series of TT races and didn't do so great in the first race. It was suggested that I add some aero bars to my road bike. I am considering doing this, but before I plop down a chunk of change, what can I reasonably expect to gain from this addition? If it's simply shaving a couple of seconds off due to being in a more "aero" position, I think I'll pass.

If you install it and can use an aero position properly, you will be close to 1 mph. I remember gaining about 3/4 mph when I started doing tri's and did test with and without the bars.

Given that 90% of the wind resistance is coming from the rider, any difference in posture is significant. In this case, aero bars give you the opportunity to narrow your torso/arms quite a bit, and be lower.

You will improve your Fred Street Cred*™

I wonder is that due to having less wind resistance, or does that aero position ergonomically place the body in a more powerful position. I've read that if I use the aero bars that I'd have to adjust the seat to accomodate a new riding position.

I just found this. It's been posted here before and comes from a test in a German cycling magazine.

So you gain 37 watts with aero bars as opposed to the drops

Understood, but until I can afford a proper TT bike I might just have to deal with a significant Fred-factor.

Is that a lot? I have no idea how to convert watts to effort.

Yes, that is a lot. Most riders are happy to gain 20 watts or so in a year of training.

Think of it as it took 465 watts going all out for this rider to do 28 mph or 406 in the drops. That's almost 10% at that speed.

OK, that sounds like a good reason. Payday is tomorrow, my birthday is Friday and Performance Bike is on my way home from work.

I gain about 1-1.5 mph with my TT bike over my road bike. I wouldn't gain anything close to this though by putting aero bars on my road bike because I wouldn't be able to put out the same power output for any length of time being in this awkward position.

For example, I am in almost the same body position on my road and TT bikes just rotated more forward on the TT bike. The geometry of the TT bike allows for this more forward rotated position without changing my overall body position much (as if I was on my road bike and someone lifted up my rear wheel a foot or more). Aero bars on a road bike would be a completely new and less efficient position.

I would guess that 37 watts is close to a 15-20 percent improvement for you, based on the other reports you have written.

it's the wind resistance. Most people will put out less power in the more aero position, until they train in the new position and adapt to it.

I'll give it a shot. I'm a stocky guy with broad shoulders. I don't cut the wind very well on my hoods or in the drops.

You should seriously consider getting a proper fit as well. Odds are you'll need to push the seat very far forward and lower the stem. A longer TT in a bad position is likely to be rather uncomfortable and might impede your ability to produce power.

It also takes time to learn how to control your bike properly when you're in the drops. I wouldn't use the aero bars in an event until you feel fully confident.

Sage advice: Before you start another TT thread, click here.

The next event is October 9th. Time enough to get used to the bike set up. My seat is currently all the way back so there's plenty of room to push it forward and I'll try dropping the stem a spacer or two.

Lots of props for the aero bar.

I gain about 1mph with the same wattage output (~250watts) when I get onto my aerobars, and I didn't move my seat at all from my standard road position.

Did you ride your entire TT that you recently completed in your drops?

I remember a thread here a while back saying pretty significant gains were made from those goofy aero helmets too - moreso than aero wheels IIRC.

I think those helmets are cool.

probably wouldn't wear one if I were given one. But, I like the look on someone else

I've not noticed a huge speed different with aero bars on my road bike in terms of speed. What it does do is provide an additional position to rest my hands and arms that typically bother me on a long ride. I can be just as "aero" on the horns.

Probably about 90%.