For nearly 3 years now, I have been using a 21-inch hybrid bicycle (Fuji Absolute 1.9D).

My use of the bike is primarily for aerobic exercise. I ride about 20 kilometres in the morning for about an hour.

Now I'm planning on switching to a road bike. The purpose of use remains the same - aerobic exercise.

I ride only on tarred roads. I don't go off the road.

Now, my questions are:

  1. Am I making the right decision?
  2. My bike dealer tells me that the size of the road bike should be one less than a hybrid. That is, if my hybrid is Large then my road bike should be Medium. Do you agree?

Thank you.

  • 51 inch is huge, usually largest production bikes are around 25. There is plenty of information about sizing on the internet and if you have no idea what you are buying, you should do test rides.
    – ojs
    Jan 28, 2019 at 8:39
  • I'm sorry, it was a typo. The size of my hybrid is 21 inches.
    – Ali
    Jan 28, 2019 at 9:58
  • How tall are you? Jan 28, 2019 at 12:41
  • Consider starting with a used road bike for a couple of months, rather than spending bigger money on a new one. Just to see if it feels okay. You can always onsell the old bike later.
    – Criggie
    Jan 28, 2019 at 13:37
  • It's all a question of "bike fit", and that can only be judged by actually seeing how well you and the bike fit each other. Definitely test ride -- more than just around the block -- 15 or 30 minutes. Jan 28, 2019 at 14:10

3 Answers 3


Road bike sizing seems harder to get right than more upright bikes. Your dealer may be right, but only as a starting point - that's a good size to test ride first. If your dealer wants you to buy the next size down without trying it first, you don't need a new bike, you need a new dealer.

You have to think about your goals. Road bikes are more aerodynamic and therefore more efficient. So you'll get less exercise for the same distance, or go further in the same time. You may want to go further if you enjoy it more.

  • 1
    51 inch was a typo. I meant 21 inches. No, the dealer did not ask me to buy one size down without testing it. He is a good friend. As regards the intensity of exercise, what if I ride a road bike the same distance as the hybrid but at a higher speed (cadence)? Wouldn't that compensate for the higher efficiency of the former?
    – Ali
    Jan 28, 2019 at 10:04
  • Higher cadence over the same distance won't change much, as you'll have lower torque, so the power is about the same.
    – Chris H
    Jan 28, 2019 at 12:35
  • You can ride a higher cadence in a lower gear and wind up going the same speed or slower, on the same bike or a different one. Assuming you are more efficient on the road bike, then riding a higher cadence in at least the same gear, or riding the same cadence in a higher gear, will roughly compensate for that change in efficiency (although we'd need to hook you up to a power meter to be more specific).
    – Adam Rice
    Jan 28, 2019 at 19:37

Am I making the right decision?

In my opinion, yes. A hybrid bicycle is just that - a hybrid. It's designed to be able to do both road and off-road riding.

As a result of the compromises necessary to do that, as a road bike hybrids make really good mountain bikes, and as a mountain bike hybrids make really good road bikes.

Given you posted this:

I ride only on tarred roads. I don't go off the road.

I think it's safe to say a road bike will probably fit your needs better.

If you wind up going faster, that just means in your one hour ride you go 25 km instead of 20.

Just be careful how you set up a road bike. You're probably not used to riding a road bike in an aggressive aerodynamic position, with your saddle way above your handlebars, your body rotated forward with your head and shoulders low, trying to present a small frontal area to reduce drag. The added speed you feel riding like that might feel great on a five-minute test ride. 30 minutes later you might not feel so good, with weight on your hands and arms that you're not used to and a saddle causing "problems"...

So, don't get very aggressive with your bike fit - yet. The drop bars on a road bike aren't there just so you can be aerodynamic. They also give you a lot more hand positions that you can use over a long ride, improving your comfort. You can always modify your position later.

My bike dealer tells me that the size of the road bike should be one less than a hybrid. That is, if my hybrid is Large then my road bike should be Medium. Do you agree?

In general, I don't think I'd agree with that but your dealer is saying that with a lot more information about you than we have. He can probably just look at you and tell what size road bike would most likely fit you, and it's not clear from your post exactly how your dealer meant that. Did he mean it for everyone, or just for you?

Your best fit will depend on how you want to set it up, and different road bikes do have different dimensions that can affect the proper size.

For example, if you have shorter legs and a torso that's relatively long for your height, if you wanted a full racing-style road bike with a really low aerodynamic fit, you might need a larger size in order to get the long top tube required to fit your relatively longer reach because of your longer torso.

But you'll probably want more of a "comfort" road bike initially - one with a more relaxed, upright fit. The easiest way to identify those will be by head tube height - that's the tube between the handlebars and front wheel. The taller/longer that tube is, the more upright your position on the bike will be. And a small difference here - even just 2 or 3 cm - will probably make a big difference in how the bike fit feels.

Don't go too far into the "comfort" road bike setup, though. You don't want a high head tube on your first road bike to limit you from getting more aerodynamic later if you want to. I'd recommend a first road bike be fit so that you have a few spacers needed under the stem, with the stem set up with a slight upward angle. That way you have the option later of adjusting your fit by lowering your handlebars. If you buy a full-comfort style road bike that already has your handlebars set as low as they can go, you won't be able to adjust your fit by lowering your bars later.

  • While it may be the case that some comfort road bikes provide little opportunity to increase the seat to handlebar drop, my experience with the Cannondale Synapse is that it came with three spacers, and a 17 degree rise stem. It would be trivial to remove spacers, flip the stem, or to swap in a stem with less rise/drop angle, to be used in whichever orientation achieved the target drop. Maybe the Synapse isn't what you mean by comfort road bike. It's sold as an "endurance" road bike.
    – DavidO
    Jan 31, 2019 at 5:04

Am I making the right decision?

We can't answer this definitively, but if you feel like you want a drop bar road bike: sure why not?

We don't know where you are located but in many countries bike stores offer test rides. Go test ride a bunch of bikes and see how you feel. Beware that you may feel uncomfortable at first as your torso will be leant forward more, and you may feel 'bunched up' as your knees come closer to you chest.

Be aware that there is a spectrum of drop bar 'road' bikes available. At one end are bikes with less aggressive hand positions and more stable steering geometry sometimes called 'adventure' or 'endurance' bikes; at the other end are more aggressive racing bikes. You probably want the former.

My bike dealer tells me that the size of the road bike should be one less than a hybrid. That is, if my hybrid is Large then my road bike should be Medium. Do you agree?

On it's face that statement is nonsensical. Maybe you hybrid is too big, maybe it's too small. What is a hybrid anyway? There is a great deal of variation in bikes that are labelled 'hybrid'.

It's a good idea to arm yourself with some basic bike fitting knowledge so you have a basic idea if a bike fits you when you try it out. With seat height and fore-aft position set right you want you torso you be no more than 45 degrees from vertical and angle between torso and arms about 90 degrees when on the hoods where you will spend most of your riding time. To ball park seat hight and fore-aft: heel should touch pedal with butt on the seat and leg straight (wearing the shoes you will ride in); line from kneecap to pedal axle should be vertical.

Also check out this video from the Global Cycling Network YouTube Channel:

  • Thank you. Your input was very helpful. Thanks again.
    – Ali
    Jan 29, 2019 at 4:50

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