Is it possible? Does it yield a benefit? I may not be getting a new road/tri bike this year, but I was able to take the broken(couldn't figure out what was wrong. I tried everything, and I'm pretty resourceful) fd off my mtn bike and turn it so it would give me the large front chainring instead of the small one. After a quick test ride to make sure all 5 gears worked w/o any scraping of the derailleur, I already see a huge speed increase. If there is no way to acquire a road/TT bike (still hopeful), can aerobars be added to the mtn. bike to give that aero benefit? The top tube is rather short already and i actually place my wrist in between the brake levers and the handlebar b/c I am too scrunched up otherwise. Any thoughts?

You can do anything, the only benefit may be to pull you out of the wind a bit, but considering the geometry of a mountain bike it may not be comfortable. That and Mountain bikes are as aero as a brick so there won't be much aero benefit. I wouldn't bother.

You can add aero bars. I've seen people riding that way - mostly commuters. But you still have two problems. One is the fit. Like you said, you end up scrunched up. The other is you still have knoby tires. You need to but slicks to get faster.

The problem is you have sunk money for aero bars and new tires and have a faster bike but still is maybe 2 mph slower than just a regular road bike. Save your money and buy a used tt/tri bike that fits.

I am srunched up as it is...won't aerobars let me lay out a little more?

Mountain bikes have a more upright riding position. Adding aero bars will make you a little further forward while still upright.

Save your $$ for the new rig. And totally get some (cheap) slick tires. That you will notice a difference from.

I've seen sooo many people with aero bars on MTBs - but without any kind of aero advantage - total waste of money.

I would suggest just going to the smallest mountain bike slick you can safely put on your rims. Slicks will make a big difference.

Not worth it. Probably get back pain.

It mostly depends on the speed. Aero benefit does not happen under about 20 mph, and most mountain bikes won't get you much faster than that. Also the rest of the aero position would be ruined by the set up of the bike. My advice is get a $150 bike on craigslist from 1983, and that should do better than a mountain bike. Or just save your money and get something better.

Lots of bad advice in this thread. Mountain bikes are aero as a brick because of the flat bars and upright position.

This is precisely why aerobars on the MTB will make a significant difference in your speed on the bike leg.

Get the cheapest slicks, and aerobar you cand find, and for $75 bucks you'll get at least 50% of the speed increase you would get by buying a high end TT bike.

The rider's position is the most important thing for speed in a TT,a nd you can get a decent position putting aerobars on a MTB with some trial and error.

And as for "It doesn't matter if you're not going 20mph plus" being more aero is always good, and aerodynamic improvements measured by total time are actually more significant for slower riders. i.e. if you ride a 40k in 1:20, a 2% improvement is a bigger time gain, than a 2% improvement is for someone who rides a 53 minute 40k.

Sure, it would be great to have a P4, but if all you can afford is $50-75 bucks think slicks and a used aerobar from Ebay.

So I have not yet competed in a triathlon but I do commute to and from work everyday. One of the bikes I ride is a steel 80s gt mountain bike. I have put slicks on it (certainly the best improvement I made) and then because of the wind and I wanted more speed I picked up a set of aero bars from craigslist for $25 and I love them. The bars get me low and out of the wind and puts me in a position where I feel I get more leverage on my pedal strokes. I have definately noticed a difference with the bars...... I say find cheap bars on Craigslist and go for it....

I have a Specialized mtn bike with slicks and aerobars. I found it more comfortable to ride in an aero position on longer rides. I have only done a few sprints, but averaged ~19mph in each one.

I say, buy if it is all you can afford.

Yes there is bad advice, and you're giving it.

And since you think aero is always good, then you try going up the biggest hill in your area in aero and tell me what happens. Then try it in normal position.

You should find that although the aero may lower your wind resistance, it also lowers your ability to breathe and pedal efficiently. The aero position was designed to increase aerodynamics at the cost of power and is only meant for downhill and fast flats.

Really, a 150 dollar road bike even without aero bars will be much more efficient than 75 dollar aero bars on a mountain bike.

Thanks for that reply, couldn't have said it better myself.