kevsf

I am buying my first road bike (technically second because I impulsively bought one too big (58cm) and it strains my neck).

The online guides seem to give a 53-55cm range for 5'6"-5'9". I am 5'7" tall and wear 30x30 in pants size.

Can I buy a 53cm, 54cm or 55cm frame? I read that I should aim for a 54cm but I'm buying second hand so I feel like I can't be picky.

Does the wheel size factor into sizing? 700cc vs 26in

Bob the Mech

(Wheel) Size matters... Here are some general sizing charts.

There are other factors involved like top tube length, reach, stack height, seat lay back, stem length...

Iride01 

If you are buying a new bike, I recommend going with the manufacturer's suggested size for that model bike. Some actually do have different sizing recommendations for various models. I'd even apply the same to an old bike if you can find the recommendations.

If a manufacturers size recommendation is between two size bikes, then generally, the smaller frame will feel more sporty and you might actually make more power on it. The larger frame will feel more stable at speed and depending on your specific body dimensions might be more comfortable, but could be less comfortable if your dimensions go the other way.

If you want to run calculators and stuff on the web that supposedly pick the perfect frame size for you, then you really are obsessing too much about your perfect pick for a bike. Hopefully it's your first road bike. Not your last road bike. As you get experience, you'll realize things you want different in your next bike if you pay attention.

Bob the Mech

The bigger the frame the longer it gets. Inside leg sizing only factors for standand over height and saddle to pedal distance. Reach factors for torso and arm distance. Stack factors for how low or high the front end of the bike is. Low stack means a short head tube and a more agressive riding postion in road bike terms, puting the rider in a lower flater postion. a higher stack means a longer head tube, puting the rider in a more up right postion.

If you are going down the used bike route and your not armed with a list of measurements then it's doing it the old fasioned way...Get on the bike see how it feels. It's probably the case of trying a few before you find the right fit.

kevsf

When I was testing out the 58cm road bike I bought, it felt alright. Maybe its the excitement of buying something that made me think I can "make it work".

Bob the Mech

Like buying a really nice pair of shoes one size too big and wearing two pairs of socks to make them fit...

icemilkcoffee 

I am surprised you could clear the top tube on the 58cm frame.
Anyways if you are shopping for older used bikes with quill stems- you can find replacement quill stems in many different height and reach combinations, so you can easily make a smaller frame fit you. Whereas with threadless stems there is a limit to how high you can relocate the handlebars.

jon c. 

The short answer is yes. Any of those should work. You could probably go to 52 or 56 and make it work. Depends on the frame geometry as well as your own.

But 54 +/- 1 is no problem and can almost always be adapted with only simple tweaks.

Personally, I'd go for a bit too large over a bit too small. But I'm out of step with modern sizing and most people now feel the opposite.

berner

I'm the same heigth as you and I ride a bike with a 54cm effective top tube. Most of the time this size is fine, especially about mid summer when I get into my best physical condition after a winter layoff. Often though, I would have preferred a slightly smaller frame, say ETT of 52cm. It works out that if a frame is too big there is no adjustment that will make it fit well and the longer the ride, the more that misfit will become apparent. A frame that is toward the small side had many adjustments possible.

For example, in a too large frame it may not ever be possible to find optimal saddle position which is totally dependent on the bottom bracket. On a frame toward the small side, there are several choices to get the saddle in the best location.

jadocs

If we are talking standard geometry - 53cm would be ideal considering your inseam with your height. Anything 55cm or above is too big.

Everything else depends on manufacturer, you need to know what the geometry is on the bike you are looking at. If you are unfamiliar with stack and reach, you want something that has a virtual top tube (effective top tube) measurement (TT) 52cm-54cm range. You will need to fine tune your reach with a stem of appropriate length.

JMO

kevsf

I was wondering about the different stems I was seeing on old vs newer bikes but didn't know the terminologies so didn't know where to start. thank you!

I have a quill stem on my current 58cm bike but I won't mess with it since its not a smaller frame.

kevsf

I also had read a post somewhere that a bike shop owner preferred to recommend going a size up on bikes. But I think I'll go with a bit smaller instead to avoid neck pain from over stretching.

kevsf

Do you have your saddle higher than the handlebar? And did you have to move it higher when you changed out for the longer stem?

kevsf

Sorry, what does ETT mean?

At our heights, with a 52 or 53cm frame, would the adjustments be minor things like changing the saddle height and/or stem height? Or would the adjustments be buying/changing out hardware like a new stem?

kevsf

Thanks! I will aim for a 53cm frame.

I briefly read up on stack and reach and it seems tough to measure. Do people use two measuring tapes at once?

I just measured my old mountain bike's TT using this image guide and it's 54cm. I find I get a little back discomfort after an hour of riding on it so maybe I'll aim for a TT of 52cm-53cm on a road bike. Thank you!

Carbonfiberboy 

Your height doesn't matter as much as the length of your torso. ETT means Effective Top Tube. https://www.bikecad.ca/effective_top_tube_length

To get your recommended ETT, go to: https://www.competitivecyclist.com/S...ulatorBike.jsp
and have someone help you get your measurements.

When sizing a bike, go by ETT length, not nominal size, either in cm. or S/M/L. ETT is the critical measurement. Saddles go up and down easily.

Iride01 

But you aren't saying to disregard the seat tube length or nominal size cm or S/M/L.........right?

I can imagine some with really long arms and torsos with short legs not being able to reach the pedals properly on some of the old bikes with horizontal top tube that increase stack by simply increasing the head tube and seat tube length. Even maybe some newer geometry bikes to with sloped top tubes.

jadocs

Not as critical on sloping or compact frames. Standard frames are when you really need to pay attention to the ST height, especially if you are short.

The geometry of S,M,L,XL can vary from manufacturer. So if one is unfamiliar with stack and reach, the ETT is what you should pay attention to. It will usually jive with manufacturer recommendation....but not always. I could be a Small on one bike and a M on another.

Carbonfiberboy 

For horizontal top tubes, look at standover height. If you have that, seat tube length should be fine, but if it's close you're getting into the issue that you might not have the saddle-bar drop you want. So yes, you want to check stack height and I am saying to disregard seat tube based and S/M/L sizing, the former because it's outdated and the latter because it's imprecise.

berner

Sorry. I'm generally against acronyms because they are not always understood. ETT is Effective Top Tube. This comes about because in earlier years the top tube on bikes was horizontal. Modern frames today have a sloping top tube so that if using the top tube as a reference dimension we use a horizontal measurement because today's frames will have varying amounts of slope in the top tube. Thus, ETT provides a consistant reference across various frames.

Mojo31

I would careful about blindly going by manufacturer’s recommended size. When I was looking at Trek Domanes, Trek’s recommended size for me was 58cm. But, with the saddle in the lowest position I could barely reach the pedals, and the reach was too long. I could hardly ride the bike. Went to a 56cm bike, and the fit was much better. I’m 6’.

Iride01 

I wouldn't recommend going blindly either by the manufacturers recommendation or even the effective top tube length. But for those that have nothing else to go by, it's still a good start. My only caveat would be if they know ahead of time that they have exceedingly long or short legs and arms. But conversation usually never gets to that point of asking here.

I'm surprised though that you had so much trouble on a 58 cm frame at 6' of height. I'd have to suspect that you go opposite of me and have short arms and legs for your 6 foot height. I have long legs and long arms for my 5'-11" height. I used to ride a 65 cm frame with no issues. I could even straddle the completely horizontal top tube flat footed.

headwind15

As a road cyclist for over 40 years, bicycle store owner for over 12 years and frame builder for the past twenty years, and a simple guideline according to Greg LeMond is to make sure that there is more seat post sticking out of the frame than size of the head tube. I

Carbonfiberboy 

Maybe for him. I have over 2" less than that on my 52cm race frame with a horizontal top tube. It's a perfect fit for me and I'm 5-6". Greg was 5''10".

I've been a road cyclist for over 65 years, which has absolutely nothing to do with it. One's physical dimensions have a lot to do with it and the rest is up to the mass marketplace. Unless I were going to have a custom carbon bike built of course. I doubt the builder could do better than what I have, though. I had a pro fit last year. The fitter raised me up a bit - my hip angle was too closed with my -17° slammed stem.

Mojo31

Nope, normal inseam and arm length for my height. The Trek rec was based on height and inseam. I was surprised how big it was compared to my Specialized bike with 58cm ETT. Like I said, I was really having to stretch my legs at the bottom of the stroke.

I'm sure there is an explanation, but I haven’t worried about figuring it out.