datlas 

It’s WAY more complicated than that. Rules of thumb like KOPS or have bar obscure front hub may give you a reasonable starting point but may not really apply to you based on your flexibility and other factors. It’s gotta feel comfortable on the road. Talk to the best fitter at your LBS and find a time when you and they have spare time for you to test ride a few.

sumgy

As I said earlier, I would suggest a 58cm effective top tube is your starting point. I run a 120mm stem on both my 58s.
Stand bent over with your hands on your knees. That is about the position.

big john

I just thought the top tube length seemed a bit short, but I could be wrong.

I think any shop should be happy to let you try different sizes, but what feels good riding around the parking lot might not feel good 40 miles into a ride, or 6 months down the road. It takes time to find out what works and as you get more fit or flexible your fit may change, or, like me, when you get older.

Another thing is bikes from different companies will fit different even if they are the same "size".

The seat tube length is actually the least concerning of the measurements (within reason). Top tube, reach, and stack are more important. Again, 2 bikes that have the same seat tube size may fit completely different. I have a 62cm Gunnar and a 65cm Seven and the Seven has a shorter top tube.

Most forks are made with a 300mm steer tube. Big frames sometimes come with these steer tubes uncut. I like a frame with 230mm head tube so I don't have to use a ton of spacers to get the stem up as high as it will go. This gives me a drop of about 1 inch from the saddle to the bars on my Gunnar and more on the Seven because the bottom bracket is higher.

As I said earlier, the best thing to do is put some miles in and see what you like and don't like in your fit and adjust from there.
If you don't have a bike maybe you could rent or borrow one to get a starting point?

sumgy

Yes, it is only a good ballpark starting point.
SERIOUS bikefitting gets much more involved than stack and reach.
Then again I have had "serious" bikefitters who ultimately proved to me that they had NFI what they were doing.

diff

Definitely buy used. You will want a new bike right away in either case.

But go to shops and test ride.

Are you certain you want a road bike? Get a used hybrid with risers for like $250 (like a used sirrus) and go riding. If dead set on a road bike, still spend around that.

That calculator is a bit funky. I am shorter, but have a similar body type. The calculator recommends bike sizes that don't exist. Yours are a bit more extreme, though.

The best I can recommend would be a 58, shop cheap and smart, ride for a bit, then plan the next bike if you like cycling.

am0n

Thanks for the replies. I ask about those little rough ballpark things because since this will be my first road bike, and I'm looking to buy used, I'm trying to figure out how to quickly figure out if a bike would fit me. Not looking for a perfect fit on this bike, but I don't want a bad fit if that makes sense. And since I don't know exactly what I need, trying to figure out how to get close enough that if six months down the road I need to adjust it, I have the flexibility to do that.

My current plan is to hit the bike shop and try out some 56, 58 and 60 cm endurance bikes (roubaix, domane and synapse). From looking at geometry charts, the 60 cm domane has a 58 cm ETT and the other two have a 58 cm ETT on their 58 cm bikes. The synapse also seems to have the smallest stack to reach ratio (lower than the Trek Emonda). None of the rides will be long. I don't know anyone I can borrow from and the bikes they rent are a specific fleet of bikes, not necessarily what you want to try out.

I did see a 2013 Specialized Secteur Sport(everysingle.bike | 2013 Specialized Secteur Sport Compact) for sale. Claims to be endurance geometry. Lower ratio than the Domane and Roubaix, but higher than the Synapse. It's a 58 cm, so 58.2 cm TT. Seems promising, but given the shop isn't open tomorrow I won't get the chance to ride some others first, so doesn't seem wise to pursue it sadly. Other concern I have is the 51 cm ST and only 35 cm seat post length. Concerned that would be too short for me ( the fit calculator said a 82 cm seat to bb, and that bike would only have about 4 cm of post on the tube at that length).

What is considered a lot of miles on a bike? More curiosity. That one said like 2.5k miles, so not sure if that is well ridden and mech will need replaced or if that is still young.

horatio 

The Secteur is a nice bike. I chose mine over a carbon Synapse after comparing the two. Its ride qualities, to me, were on par with the Roubaix of that vintage (2011). My oldest son now rides it. Surely there's an aftermarket seat tube long enough to suffice.

And fit you get a longer seat post, make sure it's a two-bolt version. You can really dial in the perfect tilt with those.

Dean V

Check that the seat post is long enough but if it isn't as long as it is a standard round post you can get longer.
Also make sure the steerer hasn't been cut short.

big john

Like cars, the way a bike has been taken care of is more important than miles (within reason), and whether or not it has been crashed or abused.
Unlike cars,, bikes don't have an odometer so you can check the miles.

If you're looking at used bikes there are no guarantees, but look it over carefully. Are the teeth on the chainrings shaped like a sharktooth? If so you may need a new drivetrain. Spin the wheels and see if they wobble.

I have put 30,000 miles or more on several bikes and the frames were still ok. I also had a bike crack at the bottom bracket with 15,000 miles. Wheels, on the other hand, usually fail at about 8-10,000 miles (rear wheel).

The reason I suggested renting a bike is so you can get a baseline on your fit. If you rent a bike, it doesn't matter what brand, you can take a tape measure to it and discover things about what you like and don't like.

That Secteur looks like a nice bike but a 58 would be too small for me, the bars would be too low.

am0n

Thanks for the feedback. Two bolt seems standard from my quick look.

Seems 35 and 40 cm are standard. I've seen one 45 cm, but it was $200 carbon. I'll have to research brands to figure out who is trusted. As for steerer tube, I'll look. It's definitely not slammed from the photo, looks like 1 or 2 inches between stem and tube, but the stem already looks as high as it'll go.

Thanks. How do your measurements compare to mine? And what dimensions make you feel the bars would be too low?

big john

I actually don't know my body measurements except my cycling inseam is 38", I think. I could probably ride that bike if the steer tube was uncut so I could get the bars high enough. I looked at a geometry chart and I think that bike has a 194mm head tube for the 58 frame so with an uncut steerer (300mm) I would need 36mm more spacers than I have with my 230mm headtube. I don't like a huge stack of spacers or a super long seatpost so I use frames from 62 up.

am0n

The geometry chart I linked said 22.5 cm head tube for the 58 cm bike. There is also something between the tube and the stem. The zertz inserts? Not sure if that is part of the head tube length or not.

datlas 

If you are really looking for used, see if you can find a classic Italian or Italian style steel road bike. They typically run short top tubes.

datlas 

BTW you can go nuts with fit and geometry charts, so realize you will have to compromise and use your comfort as a guide. In case you, or anyone else with wacky body types like ours is interested, I am posting the schematic of my custom Habanero. Even this is a compromise, the head tube and seat tube should be slightly longer, but a longer HT would have severely limited my choices of forks as the streerer tube would be too short.

am0n

Took some measurements of my hybrid. Some eyeballing involved, but this was just to get a rough feel.

BB to ST top: 21 inches (53.3 cm)
BB to Saddle Top: 31.625 inches (80.3 cm, pretty much what the calculator said)
ST top to Saddle Top: 10.625 inches (27 cm)
I estimated the thickness from top of saddle to top of seat post was about 2 inches, leaving the seat post extending about 8.625 inches (21.9 cm)

Assuming that's not too far off, and the Secteur is indeed only 51 cm ST on the 58 cm size and to get the same height (both cranks are 17.5), I'd need an extra 2.3 cm to the seat post for a total of about 24.2 cm. If the post is indeed 35 cm, would leave about 10.8 cm on the tube, which seems fine? Only source I found said 15 cm or at least 9 cm as long as you are 2.5 cm below the bottom of the top tube.

Also tried to measure some of the reach dimensions, but since this is a hybrid not sure it is very applicable.

23.375 inch ETT (59.4 cm)
3.5 inch Stem (9 cm)
3.75 inch BB to Saddle setback (9.4 cm)
22 inch Saddle to Handlebar (55.9 cm)

Only, those dimensions aren't far off (recommended 2 cm longer stem and 1.5 cm longer setback, but that'd reduce the ETT by 3.5 cm to 56 which is almost spot on) even the Saddle to Handlebar is only off by about 1 cm.

Obviously, though, hoods on a drop bar are going to stretch me more. Roughly how much will the hoods stretch me out over flat bars?

noodle soup

@am0n, have you tried a 60cm Domane yet?

We have very similar measurements(though flexibility might differ), so I understand what might work well for you.

big john

I did not see that, I looked up a Secteur on a different chart. In that case I wouldn't have a problem with that frame. Very unusual for a 58 to have that length head tube, must be including Zertz. The question then is do you want the bars high like that? If you want them really low that could be an issue.
There are lots of different bar shapes and sizes as well as stems.

big john

Depends on the bars. They come in different shapes and sizes.

am0n

This is a starter road bike. If I decide down the road that I want lower, I'll factor that into the next one.

I was waiting for you to come yell at me. I have not. I was going to tomorrow, but they are closed. I did do a side by side on the 60 cm domane with the other bike over been taking about and it seems comparable. The smart move would be to wait and try out the 60 cm domane.

Edit: quick check of both bike shops websites and they don't have any 60 cm in stock.

noodle soup

I'm not yelling at you.

Our flexibility might be different, but I know what works for our dimensions. I never wanted to own a Trek bicycle when I bought the Domane, but it was the only stock frame that fit like my custom.

noodle soup

if you ever want to sell that frame, I got dibs.

am0n

Here is the side by side. What in particular would be concerning different between the two, besides the seat tube length.

noodle soup

add 5mm to the Trek's stack to compensate for the lower BB.

Go ride a 58 cm Secteur, and a 60cm Domane. Then tell us what you think fits better ,taking into account that the fit can be adjusted slightly

am0n

I thought stack was measured from BB? Wouldn't that take into account the difference in the drop already?

noodle soup

my mistake