Hi. New here.

I just started riding recently because I want to do a sprint triathlon later this summer. The bike part is 12 miles, hardtop, some hills. Right now I'm riding a mountain bike I got from Walmart and it takes me about 40 minutes to do 6 miles on similar terrain.

What I'm wondering is about how much of a difference I should see if I went to a road bike. (Basically I would have to try to find something from a yard sale.)

Would the difference be neglible over that distance or should it be X% easier to ride?

at 9mph (your current speed) it would take you 80 minutes to do 12 miles. If you got a road bike you could probably up your speed to 15mph (thats a fairly conservative estimate) which would translate to a 49 minute bike section.

But are you really gonna drop that money on a bike for one 12 mile ride? Get one if you want one.

Agree with above. Try to borrow a bike for the event and see how it goes before you drop the $$ on a new bike.

The jump won't be anywhere near that big based on bike alone. Two things about mountain bikes really slow people down, aerodynamics and rolling resistance.

At 9mph, the aero resistance is minimal. Rolling resistance is going to be noticeable, but even that won't be insane. I'd guess you may pick up 2mph, but I'd guess you could get that simply by putting more air in your tires. Most n00bs ride with their tire pressures way too low.

What's holding you back more than the bike is your physical condition, so if you just ride more, you'll speed up fast. The faster you go, the more difference you'll notice between a road bike and an MTB. Since you want to do this triathalon in the summer, I'd guess that you could probably get in good enough shape to do the cycling part at 15mph or maybe a little higher on a road bike, probably closer to 13mph if you stick with the MTB.

I'm with NTF on this one, maybe not all the way to 15 mph but definitely 13+.

The ultra cheap bearings and races, cleap poorly lubricated chain, freewheel filled with a glue like substance vaguely resembling grease, and all the rest could be lowering your drivetrain efficiency from 98% to 90%. Simply swapping knobs for slicks is worth 2 mph on top of that. Add another mph for skinny slicks. And although weight is rarely as important as the weenies would like you to think, I get about 0.1 mph for every pound lost. Mal-Wart bike at 35 lbs. -> road bike at 20 lbs. = another 1.5 mph. Drop a few pounds from the waistline and and add riding on a regular basis to your training for a few months and there's another 2-3 mph. 9+1+2+1.5+2.5 and 17 mph could potentially be within reach given a few months. After that it gets tougher. The next 1-2 mph could take a year or more to achieve.

As far as the bike goes, rent one, borrow one, beg one, buy one, whatever. You could be a trust fund child for all I know. Our LBS has been known to rent for a day ($30-$50) and let the renter apply that to the purchase price after the race or even a month or so later.

use the right tool for the job.. get a road bike. +1 to borrowing one first, and if you like it, then buy your own and dial it in.

40 minutes for 6 miles? Hell, people can run faster than that.

Get a CHEAP TT bike. It's all about position. You should be able to do 6 miles in under 20 minutes.

I would borrow or rent a bike, unless you can find a good deal somewhere.

My wife did her first triathlon last year out in the mountains of Western North Carolina. There were several people riding mountain bikes or hybrids, and many of them put in competitive times. The bicycle should not hold you back at all.

If he's riding at 4:00/km, it's definitely not the bike that's holding him back, and I'm betting he couldn't hold a TT position too well either without some major stretching work between now and then

You could also put skinnier tires without knobbies on your current bike and pump them to full pressure. They won't be as fast as road bike wheels, but for a single event, it's a cheap way to gain some improvement.

+ 1.

Assuming this is an occassional thing and the OP doesn't want to sink a lot of money into it, skinny slick tires will make a big difference on the rolling resistence side of things.

And some cheap clip on aero bars will help the aerodynamics a lot.

I bet you can find an old pair on Ebay or Craig's list for $25 or less.

I just changed from a mtn bike to a road bike over last summer. Would be able to ride 10 miles in about 34-36 min. On my road bike I only dropped about 3-4 min off that time...maybe +1 mph average.

Will a road bike make you faster? NO.
Will a road bike make your time better? Yes, due to less rolling resistance/better aerodynamics.

The only way to become faster is to ride more. Train and use the mtn bike for now and when you can ride that route in under 45 min on your mtn bike, look into a road bike if you want to keep riding and racing. I was averaging 16+ mph on my mtn bike for 20-25 miles before I bought my road bike.

Sad, but true. I would not say I am in any kind of phenominal shape but I am training to run a half marathon next weekend. This weekend I ran 12 miles in 1:35:00 - that works out to 7:51/per mile. Biking at 6:40/mile is slower than a lot of guys run half or even full marathons.

If I were you I would at least borrow a better bike and do some rides to see how much of a difference it makes. Then get some miles under your belt and I bet the time just gets better and better.

Good luck!

I agree with those that say the difference won't be dramatic. I also agree that changing the tires and modifying your position will get you really close to the time you're going to get on a road bike.

Proof that you can go fast on a MTB

I'm going to buck the trend here and say get a road bike. No you don't need it, but you probably aren't wearing hiking boots for the run section are you? Use the right equipment for the job, even if it is cheap / older stuff.

This proves only that he can go fast on a mountain bike.

The advice I've seen with regard to Tris is do a few Sprint/Oly distances and then see if you're still interested, and then get a tri bike. Bad idea to spend $300+repairs on an old beater for your very first race, find out you love it and have to spend even more to replace it with a proper Tri rig

wut

Ok, you've got a point there.

Not sure if this is a troll or not, but the people who think a road bike is going to make that big of a difference is amazing. My average speed on the mountain bike is about 75% that of the road bike, if the mountain biking is done on rough and rutted terrain with 20% grades and sharp corners to navigate. Sheesh.

Meant to say stronger...just buying a road bike isn't going to make you a FOP rider. Sure, the aerodynamics/rolling resistance will give you some speed but not in the sense it makes the rider better. Only way to become a FOP rider is to ride more

+1

Just put slick tires on your current bike.This was the standard advice given to new triathletes among the group I used to train with.

Triathlons can be a very expensive sport to compete in. Do a few Sprint/Olympic tri's first before deciding if you want to take the plunge. Besides, most people's goal in their first few triathlons is to just get across the finish line, not to seriously compete. A MTB from Walmart will get you across the finish line.

Good luck, and enjoy it. Tri's can be lots of fun and no worries; there will be others with MTB's from X-mart also.

my boss at work did one of those sprint triathlons on a bit of a whim. his enthusiasm peaked a couple of weeks after his event but since dwindled. going fast hurts.

I am going to go against the grain and say a rode bike even a cheap one will do much faster than a mountain bike. A cheap road bike with 700-23 tires at 110 psi on hard blacktop you should be able to ride the 10 miles in 30 minutes. I am a runner first and while I have great edurance I am not a fast runner. I do ride serious but on my son's cheap Sekia 1000 I could easily go 20mph for 30 minutes if not faster. I am not sure what kind of shape your in but if you can run miles at 8-9 minute pace training you can ride road bike at 20 mph for 30 minutes. A mountain bike is like running in your wing tip dress shoes they work but are not nearly as smooth and fast. Borrow a bike and try it. 12 miles you should be able to do easily in less than 50 minutes.