pepperbelly

I am trying to understand fit and sizes compared to my height. The sizes fit a range of heights.
Is it generally better for the bike to be slightly short or slightly tall?

I have been looking at bikes on facebook and have 2 or 3 I might checkout.

genejockey 

It's not just height. There's also inseam. Not trouser inseam, but rather floor to crotch when in bare feet. Then there's flexibility. Wrench Science has a fit calculator, but there are others, that can help you figure out what size is likely to fit.

You can make a smaller bike fit with longer seatpost and stem. Too big is more challenging.

pepperbelly

I have been trying to learn about reach and the other stuff.
I meed to measure my inseam, not just pants inseam.

delbiker1 

The bottom line is that it is better if the bike fits properly. A "good deal" is not so good if the bike does not fit you properly. As for purchasing and riding a bike that is too tall or too small, that is a personal preference. If it is really necessary to pick one, I would not be surprised if it is about 50/50 on whether cyclists prefer too big or too small. I personally would prefer a bit too big, and, in fact, have a bike like that. I use a shorter stem, lower the saddle and move it forward a bit. I am quite comfortable on it. However, I do not ride it that much any longer as I have bikes that actually fit, and I prefer them.

bruce19

Exactly. Back in the day the pros went with the smallest frame that worked because it was lighter.

bruce19

FWIW I have used the LeMond-Guimmard formula for 40 years and it works for me. But, thanks to the modern sloping TT you have to use a level to find the virtual TT intersection with the Seat Tube to do this. Basically, it's your inseam in cm X .665 = frame size. This should get you in the ballpark. Of course an actual fitting is optimal.

shelbyfv

Calling Moisty, bike fit expertise needed....

DaveSSS 

Stack and reach are the two dimensions that matter. Once you get those figured out, picking the right size is simple, except that reach can only be compared directly at the same stack height. When one frame has a 20mm shorter stack, subtract 6mm from the reach, assuming that 20mm of spacer will be used to get the same stack.

The type of fit you want also makes a big difference. Even though I'm old, I still use a 10cm saddle to bar drop. With my 72-73cm saddle height, I look for around a 525mm stack and 365-380mm reach. Those wanting less saddle to bar drop often look at endurance frames with 20-40mm more stack. My frames always use a headset top that is 15mm tall. With a minimum stack of 540mm, I use no spacers and a -17 stem. A -6 stem will raise the bars by about 2cm.

Maelochs

https://www.competitivecyclist.com/S...ulatorBike.jsp

This is good for getting a ball park figure but a lot depends on your specific proportions, and your comfort levels in different positions.

I have unusually long limbs and a stunted torso so I can ride a smaller frame with a longer seat post than most people with my inseam, and am too stretched on what most people would say is the "right" size for my height .... also, as I get older, I am less comfortable leaning far forward.

Some peope are more comfortable in a racier position. It depends on your build, your native flexibility, your fitness, and your preference.

There is no "right" size. I have a 52 cm bike which was given to me as a gift which I can ride. The seat post in about 18 inches long, the stem is a boat tiller, but I can ride it if I need to. Another of my bikes I bought as a garage queen .... a really nice bike someone bought and never rode---it is a little too big for me, but with a micro-stem and almost no seat post iI can use it pretty well.

The best thing is to buy a bike which is as close as possible to "right' for you and then to adjust it as you go. I find that the more I ride, the lower I can ride, so at the start of the season I might have to suffer or raise my bars a little, and later readjust.

The Really important things, IMO, or saddle height and saddle position relative to bottom bracket (the place the pedals attach. Every person, as far as I know, has a "right" arrangement of height of saddle, and distance of saddle behind the BB, where leg length (both upper and lower) and foot length and cleat placement or foot placement on pedal, all fall into some optimal range for power and comfort.

You might have to experiment to get this relationship, but once you have it it shouldn't change much unless you cut off part of your leg or something.

A lot of people Start with KOPS (Knee over pedal spindle---google it) but that is just a place to start. Fine-tune that relationship and Then start thinking about where you want your handlebars.

Some people move the saddle and bars to get the "right" position and then either hurt their knees or never get an efficient pedal stroke, or have too much weight on their hands, or whatever, because they started with the handlebars and not the pedals and bottom bracket. Fact is, for most of your ride, most of your weight will be on the pedals, Not on the saddle and certainly not on the handlebars. Get the saddle/BB relationship right first.

In My Opinion.

freeranger

When it's figured out, please let the rest of us know. As no two bodies are identical, it's very difficult to tell by a chart what will work best for you. At one time, I was considering a hybrid. One brand's chart had me on a "medium". Went to the LBS and it felt and looked like a toy with me on it. Large was the correct fit for me. Yes, you can get a general idea from charts and you may luck out and the chart be a good judge of size for you. But there is no substitute for sitting on a bike and trying it out.

pgjackson

You should be able to ride multiple sized bikes easily with minor adjustments. I'm 5'8" and currently ride a 52. It's on the smallish side. My previous bikes were a 54 and a 56. All were just fine. Don't think you HAVE to have a 54 or a 56 just because some calculator said so. Bikes are adjustable to fit many body types. Get it close enough then make adjustments. The worst thing you can do is fall in love with a particular bike, then pass on it just because it isn't the exact perfect size you think you need. Especially in this market right now, buyer's really can't be overly picky because inventory just isn't there. If you think a 54 is just right, but the bike shop only has a sweet 52 or 56...get it.

Sy Reene

Only other suggestion is to be wary of sizing that FB sellers might use in their descriptions. Likewise if the seller is accurately telling you the manufacturer size, realize that manufacturers vary how they label their sizes.

genejockey 

Great point. After a lot of looking, I'm usually able to tell the size on steel, traditional frames from the length of the head tube and the angle of the seat stays at the seat cluster. A number of times I've looked at bikes listed as '58' and realized it was more like a 54. Sometimes, they measure, but then they don't tell you that they measured center to top, instead of CTC.

cyccommute 

I have trouble seeing how picking out the “right size” could be simple if you use stack and reach. Do you pour over geometry charts of thousands of different bicycle models to find “just the right one”? Do you keep a data base of frames so that you can compare all of the different bikes? That’s a whole lot of effort. It’s far easier to just go out and try a few bikes to see how they fit.

Let’s look at some examples of your measurements. The Trek 50 cm Émonda SLR 9 for example has a stack for 521mm and a reach of 370mm. But if you look at the Domane AL, the 44cm frame is the only one in your range (510/360mm stack/reach). The 49cm Domane frame has a 540mm stack with a 368 reach. If we switch over to Specialized, the Tarmac SL7 has a 517/383mm stack/reach in the 52cm bike. Which one is the “right fit”?

If we compare the standover…I know, how gauche!…the Émonda has a stand over of 711mm, the 44cm Domane has a standover of 657 mm, the 49cm Domane has a standover of 717cm, and, finally, the Tarmac has a stand over of 746cm. That’s an 88 cm range or almost 3.5”. Someone using just stack and reach is going to find themselves either needing a very long seatpost or being split in half when they try to get off.

Maelochs

I think most of the people suggesting only stack and reach matter, forget how many years of cycling they have, and how many bikes they have ridden, and how long it took them to be able to figure how a bike would fit by looking at the geometry chart.

Like @cyccommute, I recommend sitting on a bunch of bikes of varying sizes, and then looking at seat post exposure, spacers, stem length and angle, and handlebar reach. It might take a while to start to get a feel for what might work just looking at it, if you don't have any idea at all what a bike properly fitted to your body actually looks like.

pepperbelly

I will be going to a couple of bike shops and figure it out.

DaveSSS 

Once again you're making a big deal over nothing. If I want a new frame, it only takes me a few seconds to look at the two sizes that might produce the fit I want. With today's sloping top tubes and my long legs, standover is never an issue.

If you read more closely, you'd notice that I said that IF I was looking for an endurance frame, those would typically have 20-40mm more stack height to produce a more upright position. Then the stack I'd be looking for would be at least 545mm instead of 525mm. After that's found, all you can do is see what reach is offered to go with it. I have no clue exactly how I might change my fit when I get so old I can't tolerate the 10cm saddle to bar drop I've been using for the last 13 years. I'm 68 and I have no need for an endurance fit. I wouldn't even look at Domane. Don't forget about changing stem length and angle or using a little spacer to get the desired fit.

My current Cinelli superstar frames have a 509mm stack and a 373mm reach. I could ride it with no spacers and a -6 stem, but to keep the steering tube a little longer for resale, I put a 30mm headset top on it instead of the standard 15mm and use a -17 stem.

I had this all figured out in a couple of minutes when I replaced my Colnago frames with a 527mm stack and 383mm reach.

Maelochs

If I read closely, you have about six decades of riding experience and for almost a decade-and-a-half have dialed in exactly what you like.

As I said above ... This guy is just starting cycling after a long layoff, on a bike he inherited, and he has Zero clue about bike fit. You have spent longer knowing exactly what you want than he has been riding in his whole life.

There are riders that can go to the top of a mountain and just ride down, through rock gardens, root beds, mud, massive drops, slaloming through trees with inches to spare. if one of them stood next to you at the top and said "It's easy," would you just plunge over the edge?

I have tried .... and it hurt a lot and I ended up with a battered body, walking a broken bike back to my car .

Not everyone has the same capacities.

pepperbelly

This has more math than scuba.
Y’all have given me a lot of info. Thank you.

Bald Paul

Is there a local bike shop (one that actually has some bikes in stock) you can go to? Tell them you're looking for a bike, ask them to recommend what size, and then swing a leg over one or two. If possible, take a test ride (some shops allow this.) You'll figure it out.

pepperbelly

I will be doing that tomorrow.

70sSanO

It really is a lot easier. You have a bike that you can measure. The stand over of the old bike will give you a starting point based on the size of Raleigh.

You also know the handlebar height and reach that doesn’t seem to work for you. Since you’ve had the bike a long time, you probably have a good idea where you would might want the bars to make things more comfortable.

You might also want to think if you really want a drop bar bike or a flat bar bike. Only you know if a faster more aero riding position is want you want going forward.

John

pepperbelly

I want a more upright position on the bike. Is that what flatbars give?

genejockey 

That, and your hands overly pronated, and one(1) position for your hands..

cyclezen

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start here:
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the internet is a wild and sometimes bewildering place, but it does have a lot of info
here's your fishun pole and hook, now go catch a fish...
Thx
Yuri