O.K. here's another question I need help with. I'm 5'10" tall but my inseem is only 31" (sounds a lot worse than it looks!). I currently have a 56cm frame and the reach is fine but when I stand off the saddle over the top tube "the boys" rest on the top tube, a little scary. Should I go for a 54cm frame and use a longer stem or keep my current set up. BTW my seatpost is only 2" above the crown of the seat post. I do not have problems with any pain with my current set-up, of course that could all change should I come down on the top tube.

I am 5' 11" 33.5 in inseam and ride a 57 (center to top) and the fit is good. If you use the inseam (in centimeters) X .67 for a frame sized center to the top of the top tube it would suggest that your frame is too big...53 or 54 may be better. Stem length, saddle set back are also very important. I would suggest that bike shop with someone who is really knowledgeable about fit. refer to the Colorado Cyclist fit guide as a good basic source https://www.coloradocyclist.com/bikefit/#properframesize

What length stem are you running on the 56? It's probably only a one to two cm difference in top tube length, so if you aren't already running a longish stem, it sounds like a 54 cm with a slightly longer stem (& possibly higher to counter shorter head tube), would suit you.

If your bike fits, keep it. I am 5'11" with only a 31" inseam and I ride a 57cm frame. The issue for me isn't stem length but seat tube angle. I have long thighs and even with a setback seatpost need a 73 (or less) degree angle.

If your saddle isn't all the way back and your stem is currently shorter than 120mm, you could probably get away with a 54. However with all the knee problems and back aches I've had from bikes that just wouldn't fit, I'm an advocate of riding whatever fits, and my boys rest on the top tube as well.

I have another 56cm that I ride, mind you it's vintage (1982) and it has a 110mm stem, I find I have no issue with this bike except I feel that the stem could be shorter with more rise as I prefer to sit up more than lay over the top tube. I also find that relieves pressure from the nose of the saddle. My seat is set in the middle and not all the way back. I did have a Large Devinci Bike prior to this but I had no issue since it was a compact geometry with a sloping top tube. My new frame (being older) is not. My biggest fear with a 54cm is I will feel cramped in it's normal set-up and if I move the seat back and go longer on the stem I will be in the position I do not like (laying over top tube). Any of this make sense?

Makes sense, but as long as you can make all the important dimensions the same (saddle position in relation to bottom bracket, saddle height, saddle back to handlebar, and saddle to bar drop) the only thing that should feel different would be the bike's handling. You would obviously need to have the bar higher in relation to the frame on the smaller frame.

the 54 with a longer stem should fit you better.

If you're comfortable, don't mess with it. That said, if you want a new frame or are nervous about crashing into the top tube, that's fine, but much of the advice you get here will be useless. Anybody who tells you what size you should be riding knowing nothing more than your height and inseam with no information about the frame you are considering is giving you advice that is dubious at best.

Frame sizes aren't like sock sizes where you can take a single measurement and have a size that will always work. Geometries and how sizes are measured vary greatly between manufacturers and even models from the same manufacturer.

Also, the further your measurements fall outside the norm, the more physical limitations you have and the older you get, the more important a decent fit becomes.

Good advice, well said.

Bikes are for riding, not for standing over. I'm a bit under 5'10, and the road bikes with traditional geometry that fit me the best are in the size 57 to size 61 range. With traditional geometry, the top tube of a size 57 will be lightly brushing against my crotch when I stand flat-footed over the bike. And, on a size 61, the top tube would be pressing into my crotch to an uncomfortable extent if I stood flat-footed over the bike.

But, those bikes fit me perfectly when I riding and I NEVER stand flat-footed over a bike during a ride. At a stop light, I put just one foot down and keep one foot on a pedal. No problem.

If you buy a "too small" bike, the bars are likely to end up two, three, or four inches lower than the top of the saddle, shifting your weight to your hands, and leading to pain in the hands, wrists, neck, and back on long rides.

Thanks for the advice. I will stick with my new frame and build it out as planned.

My advice is find a knowledgable bike shop and have someone take a look at you on the bike. As others have said, opinions on this forum from people that ahven't seen you are mostly useless.

My first bike was a 58 and now I know it was too bike. I've since gone with 56 and could tell a difference from the first even though the geometery was similar to a couple I now have.

I just remembered something from your OP. Since you have only 2" of seatpost showing, you really need someone experienced to closely look at you on that frame. It likely is too small. If you look at most of the pictures of members bikes posted on this forum, you'll see a range of 6"-10" inches of post showing.

Bad advice. First we have no idea if OP has his saddle height correct. Secondly, he's riding traditional geometry instead of the compact geometry usually favored here. Six to ten inches of seat post on traditional geometry is usually an indication of bad fit while it is normal on compact frames. Two inches is a bit less than ideal on a traditional frame, but often very workable. Back in the day, three to four inches was the norm.

Yep, here's my bike with very little seatpost showing. It's a little on the large side, but I needed a relaxed seat tube.



Find someone who can look at you on the bike and decide if you're fitted properly or not.

Scroll through all the bike pics. Skip the compact and sloping top tubes. You'll find just about every bike has 6" showing.

The greatest cyclist of all time with somewhere around four to five inches of seat post:
https://www.allposters.com/View_HighZ...&imgheight=819

Maybe you prefer someone more recent:
https://www.velonews.com/images/cyc/7321.9802.f.jpg

Or someone more French:
https://www.cyclesmenet.com/2007/vista2.jpg

Or the French guy when he was younger:
https://www.velo-club.net/nicolas/hinault1978.jpg

Six inches is pushing it for seat post exposure on a traditional geometry frame and the fact that your informal polling of bike weeinies in the throes of the little bike and massive drop fad shows that most of them don't go any further ought to tell you something. Certainly, a six inch minimum is bunk.

you can't determine proper fit by looking at someone else (or some racer's) bike. You should determine fit by your own standard of comfort. If you do not feel you have enough knowledge, get a real person to help you.

wrenchscience.com had a fit system to determine the proper size by your specific body measurements. That would help you get in the ballpark but this is where I feel the internet cannot help you all the way.

I am religious about my bike fit, but it has been determined through my personal comfort and control on the bike, never how a pro is setup.

Please don't follow photos of someone with no relation to your phisiology, skeletal structure, musculature, flexibility or a million ergonomic factors. That person is not you. Your fit may change as your body changes as well. It is very important because cycling is a repetitive motion, and could cause real injury if you are improperly fit.

good luck!

Cruiserhead, I don't think the pics are meant as a guide. They are meant to ease the mind of the OP that there is nothing wrong with a bike that's set up that way. As mentioned before again and again, he should ride what feels right. We just want him to know that "right" could mean 4" of seatpost or 14"

14" of seatpost on a traditional frame is stupid. I don't even have 14" showing on my compact-frame mountain bike.

Even hard-core old-school pursuit bikes would rarely have more than 8" showing, because they'd have downward-sloping top tubes; even after all that the rider's hand positions were only a bit lower than normal drops.

I have about 6-7 inches of seatpost showing after the lbs fit me. I need to go back and get the fit modifies a little because I get a little lower back pain on longer rides.

For comparison, I'm 5'10 and I have a 32-33ish inch inseam. I used to ride a 56 motobecane and I got shoulder pain on longer rides. I'm now on a 54 cannondale.

There are a lot of variables. It could be that the saddle height and positioning is correct for you, but the 'bars are not in your best position. You can do a rough assessment of the saddle height based on the numbers, but ultimately it's your legs and butt that make the decision. 'bar height is much more subjective, and you really need to either experiment on yourself to understand where your limits really are, or get input from a real person who can watch you moving on the bike and has the knowledge to see what's right and what's not.

Road Fan

You are correct! Of course, we haven't even addressed the basic fact that exposed seatpost is a ridiculous fit metric in the first place.