I seem to be built similarly. I'm 6'3", but have a 32" pants inseam. My sleeve length by comparison is 37". I'm riding a 60cm frame with a 59 cm top tube, and I'm using a 140 mm stem with that. If the Giant feels good to you, go ahead and get it. IME getting a good fit on a bike is a mixture of objective and subjective. There rare different method & formulas and it's not at at all unusual for several bikes to all use different fit criteria. IMO if you get fairly close re: fit, and it feels good to you - do it. Personally, I like to sit back a little and be a little "stretched out" on the bike. I have a commuter bike that only fits "OK." the problem I have with it is the same as I have with many bikes. The distance from the center of the seat to the bars is too short. I ride it a lot and feel pretty comfy on it, but when I ride my race bike it's like sitting in a Barcolounger by comparison.

 

You and I have almost the exact same measurements as far as total height and inseam. I also ride a medium Giant (TCR though). I started on a Large Giant because that's what I was told was the right size. After almost a year and a half of fiddling becuase it never felt quite right, I settled on a very short (60cm) stem that made it acceptable to ride. Now on my med TCR, it feels natural.

 

I to have almost the same measurements as you, except I'm about about a 1/2" taller. LeMond fits me great with a longer top tube lenght then normal and I ride a 54cm.

 

I to have almost the same measurements as you, except I'm about about a 1/2" taller. LeMond fits me great with a longer top tube lenght then normal and I ride a 54cm.

From what I have read Lemond would be a logical place for you to look for the best fit. Flexibility is a big factor in fit also. Only the LBS or someone local can help you with that.

 

I'm similar in size at 5'11" with a 32.5" inseam.

I've found that Top Tube does make a difference, but for me the seat tube angle is much more important. I need a minimum of a 73.5 degree seat tube with a 0 degree setback post to get my knee in proper position. Ideally I need a STA of 74 - 74.5 degrees (short femurs with short legs).

Most 56cm frames come with 73 degree STA's which narrows my choices.

The other problem I have is with the shorter legs, the head tube tends to be too tall on most bikes. My current race bike is a Scott S20 but I run a -17 degree stem and still ride in the drops 90% or more of the time.

So I need not only a bike with a 73.5 degree STA but a head tube that's no taller than 15cm and preferably 14cm....Those are hard to come by in a 56cm frame.

However dropping down to a 55cm or a 54cm frame with a longer TT can get those dimensions for me....basically I can get by with a frame that has a 55 cm TT as long as it has a steeper STA and shorter head tube and make up some of the difference in the shorter TT with a longer stem.

Another way to cheat STA problem is to run 170mm cranks instead of my normal 172.5mm cranks...but that still doesn't cure the head tube height.

Anyway....a 54 with a longer TT or a 56 can work for you....A 58 will probably feel too big and have too slack of a STA.

As for Lance...As with most Pro Cyclists they are all leg and arm...kind of spider like so they fit much differently than most normal people on bikes. Some go with smaller bikes to get a large saddle to bar drop, some go with larger bikes to get more stretched out. It's a personal preference.

In the end, buy the bike that feels good to you and not what somebody else tells you should feel good...however, down the line what you might like now, you might not like later because your needs may change. I have a great bike now that I don't ride much because I'm racing a lot now and participate in very fast group rides and the bike just doesn't fit my needs any longer.

 

Fit is a subjective thing. Different shops have different notions, sometimes they have good reasons, over times it half cocked nonsense.

It is not just a matter of height and reach. Flexibility has a huge roll as well. I have friends of similar size who ride with reaches of ~4cm difference and different rise - one is gumby and the other can't touch their toes.

How strong your back, trunk and arms are also come into play in making a comfortable position. Fit is a full package and you need to ride what is comfortable, not what someone tells you you ought to ride.

The other thing to remember is that not all bikes are measured the same and that things like seat post angle and setback additionally complicated the situation. Find a fitter who will work with you if you are having issues. Otherwise, just use a position that works and transfer it to other bikes.

 

I've had a terrible time migrating from mountain to road! I started out on this journey back in July and I think I may just be coming out of the coma that I've been in thanks to the LBS.

Your advice and comments are greatly appreciated!

I am exactly 5'10" tall - 178cm - weight 80kg

My inseam is 31.5" - 80cm. I get to .5 by really jamming a book up my shoot and then marking the wall!

I am most comfortable with a saddle height just a hair under 28"

I understand calculating frame size is a "guideline"... So by the numbers I should start somewhere on a 53-54cm frame...right?

For reference I ride a 17" mountain bike - 44cm -- and it feels like its a part of me.

My crisis: I made the move to a road bike and purchased a Scott S20. The dealer insisted that I needed a large frame - 56cm. He stated that because I have a long torso the longer top tube was more important then the seat tube measurement.

OK I thought. During the test ride I felt like I was riding on a fence post. I had the shop lower the seat several times. The end result...I found my 28" saddle height without a tape measure and there was less then a fist of seat post showing...the mechanic has to raise the seat to get the bike on the work stand.

I was fitted to the bike. It "OK" but I still feel something is off. In the drops I am stretched out across the bike, and even when riding up at the top of the bars it feels odd...but I can't put my finger on what is wrong. The Scott is up for sale...

I went to get fitted on a Giant Defy...compact road frame. I found myself on Giant's medium frame. Giant says this frame fits people 5'7" to 5'10"....so I am on the high end of the range. The shop owner initally recommended a M/L, next size up based on my height...but after playing around I ended up on the smaller frame. The shop set the saddle and changed the stem to a 110mm and am perfect on this thing. The seat is centered on the post, knee right over the pedal...and it "Feels" perfect. For me if I don't notice anything then its OK.

Does any of this make sense?

I guess what I am asking here is --- Is sizing purely objective and based on the LBS opinion? It seems like you can go one place and they will recommend a 56cm, and then the next guy will say 54cm.

One of my buddies says "Lance is 5'10" and ride a 58cm" How is that possible? Is he all inseam?

I am looking for some concrete explanation on how I can determine appropriate frame sizing. Thanks for listening to my rant!

Your problem is not abnormal. Top cyclists and good athletes in general tend to have longer extremities and shorter torsos. So, bikes a built for long legged, short torso longed armed people.

We, average dweebs are built all wrong for the bikes they sell. we have short legs and long torsos so we need little bikes with long top tubes. They aren't available.

However, someone invented compact frames. Aha. Then, you get a bike with lots of clearance and a longer top tube.

So, you could look at a bike size large with compact geometry. In the size large, they may have a 56 to 58 cm top tube and they will still have tons of clearance for your legs.

 

We, average dweebs are built all wrong for the bikes they sell. we have short legs and long torsos so we need little bikes with long top tubes. They aren't available.

However, someone invented compact frames. Aha. Then, you get a bike with lots of clearance and a longer top tube.

So, you could look at a bike size large with compact geometry. In the size large, they may have a 56 to 58 cm top tube and they will still have tons of clearance for your legs.

I have the same dimensions and my bikes are now very well fitting. It took awhile to get there.

Compact frames. (Ridley/Orbea). Right seat posts, and varying the stem size.

Out-of-the-box sizing will get you in range of what you want. Final tweeks are
up to you.

 

Hey, I resemble that remark

I'm 5'10.5" tall and have a 32" inseam. I fit quite well on 56cmx56cm bikes. The fist-full of seatpost is a rule of thumb, if that. I like my bars close to the level of my saddles. I found handlebar height to be as much a factor in bike fit or comfort as any other factor. Bikes that feel good on a short test ride won't necessarily feel good after 100 miles.

Two options to objectively determine the right bike size for you are (1) your subjective sense of the fit and (2) a fitting by a good, professional bike fitter.

 

I read somewhere that one of Boardman's bikes was up for sale. 52cm ST and a 57cm TT Try finding someone else in the world that fits that!!!

Me? I've got the same issue as the OP. Shorter legs, longer torso. I have a tendency to ride bikes with between 54 and 55cm TTs with 11-12cm stems on em.

That Giant that you're so comfy on has a 55.5cm TT, so its not *that* much shorter front to back than the original bike, its just built differently. If it fits, run with it.

I'll warn ya now tho, you *may* find that as you progress as a road rider, your fit preferences will probably change. I'll bet you go back to a longer TT as you get more comfy on the road bike. Whether you'll stick with the min. seatpost showing is another story...

HTH

M

 

From what I have read Lemond would be a logical place for you to look for the best fit. Flexibility is a big factor in fit also. Only the LBS or someone local can help you with that.

not sure about Lemond... slacker STA/longer TT might not be good for short legs. long torso (w/ normal legs), maybe, but it depends not just on proportion to one another. most bikes are made to fit people w/ relatively normal proportions. it's moot anyways since Lemond is gone

 

Thank you!

Awesome replies and greatly appreciated. I spent the day at the LBS talking about sizing and Giants compact frame.

I also came across a formula -->

--------------------------

The top tube length of your bike should be proportional to a combination of your trunk length and arm length. For these measurements you need to be seated with your back pressed firmly against an upright surface such as a wall. Trunk length is measured from the seat you are sat on to the top of your shoulder with you sitting fully upright. The forearm length is measured from the back of the elbow (with the back of the elbow pressed against the upright support and with the forearm horizontal) to the centre of your clenched fist. Total arm length is obtained with your arm straight out in front and measuring from the upright support to the centre of your clenched fist (keep your back firmly against the support). The measurements are used in the following equation: top tube length = 75.25% trunk length + 7.8% forearm length + 7% total arm length - 1cm (1/2"). The answer should be rounded out to the nearest 1/2cm (1/4").

-----------------------------

OK...so I had my wife help me with the measurements and came up with a 57cm top tube. LOL!

I think what I have learned here is anyone can be right when it comes to sizing. Scotts 56cm frame with a 56cm top tube almost makes sense considering the 54cm has a 54.5cm top tube length.

Giants compact road seat tube is 50cm but is compared to conventional 55-57cm frames...and the top tube is also 54.5cm. We're talking about centimeters but the they feel like two different animals.

I am pretty flexible and could stretch out across the Scott...but gettin out of the drops was another story. I had to pull myself up. The Giant Medium with a 11cm stem feels just right.

I think the irony here is I probably could have made the Scott work with a shorter stem and some more tinkering.

The LBS owner seems to think that as I progress in cycling I will move toward the smaller frame. He recommends larger frames for more relaxed riding. What are your thoughts on this?

Either way you cook this I think the next frame I will go compact design 54cm and look for a longer top tube. I can always buy a longer stem to compensate. For right now I am going to enjoy this Giant and perhaps turn the Scott into a stationary trainer or mailbox post.

 

The LBS owner seems to think that as I progress in cycling I will move toward the smaller frame. He recommends larger frames for more relaxed riding. What are your thoughts on this?

I'm not sure how to explain the specifics, or even if I'm right, but I think he's referring to the geometries of different styles of bike in which for a given size a larger frame might be more associated with a touring or brevet style bike and a smaller frame being more associated with a racing style geometry. I've actually progressed in the opposite direction - from a smaller style frame to a larger style.

 

I also came across a formula -->

--------------------------

The top tube length of your bike should be proportional to a combination of your trunk length and arm length. For these measurements you need to be seated with your back pressed firmly against an upright surface such as a wall. Trunk length is measured from the seat you are sat on to the top of your shoulder with you sitting fully upright. The forearm length is measured from the back of the elbow (with the back of the elbow pressed against the upright support and with the forearm horizontal) to the centre of your clenched fist. Total arm length is obtained with your arm straight out in front and measuring from the upright support to the centre of your clenched fist (keep your back firmly against the support). The measurements are used in the following equation: top tube length = 75.25% trunk length + 7.8% forearm length + 7% total arm length - 1cm (1/2"). The answer should be rounded out to the nearest 1/2cm (1/4").

That top tube formula strikes me as overly simplistic as it doesn't include the seat tube angle. Each degree of STA will change the position of the headtube relative to bottom bracket by roughly 1 cm, so if you're comparing different sizes/brands of bikes with different STA's you need to factor that in.

 

That top tube formula strikes me as overly simplistic as it doesn't include the seat tube angle. Each degree of STA will change the position of the headtube relative to bottom bracket by roughly 1 cm, so if you're comparing different sizes/brands of bikes with different STA's you need to factor that in.

Thanks...

You're saying the down tube increases in length as the angle decreases? I'm visual so I need more description on this if you don't mind. I am interested in what you are saying here.

Is there a "one stop" for formulas? LBS recommended Andy Pruit as a resource. Can anyone recommend books?

 

I've had a terrible time migrating from mountain to road! I started out on this journey back in July and I think I may just be coming out of the coma that I've been in thanks to the LBS.

Your advice and comments are greatly appreciated!

I am exactly 5'10" tall - 178cm - weight 80kg

My inseam is 31.5" - 80cm. I get to .5 by really jamming a book up my shoot and then marking the wall!

I am most comfortable with a saddle height just a hair under 28"

I understand calculating frame size is a "guideline"... So by the numbers I should start somewhere on a 53-54cm frame...right?

For reference I ride a 17" mountain bike - 44cm -- and it feels like its a part of me.

My crisis: I made the move to a road bike and purchased a Scott S20. The dealer insisted that I needed a large frame - 56cm. He stated that because I have a long torso the longer top tube was more important then the seat tube measurement.

OK I thought. During the test ride I felt like I was riding on a fence post. I had the shop lower the seat several times. The end result...I found my 28" saddle height without a tape measure and there was less then a fist of seat post showing...the mechanic has to raise the seat to get the bike on the work stand.

I was fitted to the bike. It "OK" but I still feel something is off. In the drops I am stretched out across the bike, and even when riding up at the top of the bars it feels odd...but I can't put my finger on what is wrong. The Scott is up for sale...

I went to get fitted on a Giant Defy...compact road frame. I found myself on Giant's medium frame. Giant says this frame fits people 5'7" to 5'10"....so I am on the high end of the range. The shop owner initally recommended a M/L, next size up based on my height...but after playing around I ended up on the smaller frame. The shop set the saddle and changed the stem to a 110mm and am perfect on this thing. The seat is centered on the post, knee right over the pedal...and it "Feels" perfect. For me if I don't notice anything then its OK.

Does any of this make sense?

I guess what I am asking here is --- Is sizing purely objective and based on the LBS opinion? It seems like you can go one place and they will recommend a 56cm, and then the next guy will say 54cm.

One of my buddies says "Lance is 5'10" and ride a 58cm" How is that possible? Is he all inseam?

I am looking for some concrete explanation on how I can determine appropriate frame sizing. Thanks for listening to my rant!

I have similar measurements and rode a Giant M and it worked well.

 

Thanks...

You're saying the down tube increases in length as the angle decreases? I'm visual so I need more description on this if you don't mind. I am interested in what you are saying here.

Is there a "one stop" for formulas? LBS recommended Andy Pruit as a resource. Can anyone recommend books?

What I was saying is that you can't look at TT length as the sole deciding factor in selecting a bike. Your bike fit is based on three fixed contact points - feet, butt, hands. Those three points should always the be same relative to the BB, regardless of what size/geometry frame your ride.

Here's how to visualize it. Pretend you took your existing bike and made its STA lower, while keeping the saddle position relative to BB the same (thus you moved the saddle a bit more forward on seatpost). The handlebars will get closer to the saddle, i.e., you'll be less stretched out. Thus to get the same hands position you'd need a longer stem. Therefore, bikes with low STAs will have a lower "reach" than their published TT lengths might indicate (every one degree of STA corresponds to about 1 cm)

Looking at some real-world numbers, consider the Giant TCR size M/L which has 57 TT and 72.5 STA, and a Cannondale SuperSix size 56 which has 56 TT and 73.5 STA. You mentioned before that the formula indicated an ideal TT length of 57 for you, so based on that you might think the Giant has better geometry. However when you factor in the one degree difference in STA the two bikes actually have virtually identical "reach". I'm not suggesting one bike or another, just saying you can't only look at TT length.

 

What I was saying is that you can't look at TT length as the sole deciding factor in selecting a bike. Your bike fit is based on three fixed contact points - feet, butt, hands. Those three points should always the be same relative to the BB, regardless of what size/geometry frame your ride.

Here's how to visualize it. Pretend you took your existing bike and made its STA lower, while keeping the saddle position relative to BB the same (thus you moved the saddle a bit more forward on seatpost). The handlebars will get closer to the saddle, i.e., you'll be less stretched out. Thus to get the same hands position you'd need a longer stem. Therefore, bikes with low STAs will have a lower "reach" than their published TT lengths might indicate (every one degree of STA corresponds to about 1 cm)

Looking at some real-world numbers, consider the Giant TCR size M/L which has 57 TT and 72.5 STA, and a Cannondale SuperSix size 56 which has 56 TT and 73.5 STA. You mentioned before that the formula indicated an ideal TT length of 57 for you, so based on that you might think the Giant has better geometry. However when you factor in the one degree difference in STA the two bikes actually have virtually identical "reach". I'm not suggesting one bike or another, just saying you can't only look at TT length.

OK...this I understand. I need to compare apples to apples so to speak. If I have two frames both with the same STA then I can compare top tubes

 

advice...

Get a frame that will fit your legs and use a 130-140mm stem if needed, plus long reach handlebars. Also, don't let someone shove the saddle far forward to achieve KOP. That will make the situation worse. Try placing the knee 1-2cm behind the pedal spindle.

Buying a frame that is vertically too large with the silly idea that reach (or TT length) is more critical is stupid.

If the person fitting you thinks a 130-140mm stem is too long, they are wrong.

Based on your saddle height, a frame in the 51-53cm size (c-c) is appropriate. Your saddle height of 71cm is 2.5cm lower than mine and I'm just over 5'6" tall. I ride a 51cm LOOK 585.

 

Your problem is not abnormal. Top cyclists and good athletes in general tend to have longer extremities and shorter torsos.

One word: Michael Phelps

Well, that would be "michaelphelps".

BTW, your response is implausibly dopey.

 

One word: Michael Phelps

Well, that would be "michaelphelps".

BTW, your response is implausibly dopey.

Interesting...I'm glad you mentioned Phelps.

My arm span in about 72". At 5'10" my inseam is 31.5". My wife calls me a gorilla.

I have yet to meet another person that shares exactly the same measurements. Everyone seems to be "special" in their own way.

 

One word: Michael Phelps

Well, that would be "michaelphelps".

BTW, your response is implausibly dopey.

Michael phelps is an exception in the other way. Long torso shorter extremities. Makes good swimmers but not so good runners, cyclists.

 

Interesting discussion, and very revealing about how "one size fits all" does not work in cycling. I have similar proportions to you, except I'm a little taller at 5'11". I have settled on 57 cm frames as my best size, with the top tube depending on the seat tube angle. My 57 Merckx fit just right with a 57 top tube and 72.5 STA. My 57 De Bernardi has a 56 top tube and 74 STA. Like PDX, I like to run my handlebars about level with the height of the saddle, so I've got about a "fistfull" of seatpost showing, and that works for me. One of the key measurements for me in a frame is the headtube length. I'm opposite Wookie in this regard -- I look for the longest headtube I can find.

 

My arm span in about 72". At 5'10" my inseam is 31.5". My wife calls me a gorilla.

Fitting cartoon out of John Schubert's 1988 Cycling for Fitness book.

 

Either way you cook this I think the next frame I will go compact design 54cm and look for a longer top tube. I can always buy a longer stem to compensate. For right now I am going to enjoy this Giant and perhaps turn the Scott into a stationary trainer or mailbox post.

I'm thinkin you're going too small. *I* ride a 54cm bike and I'm 5'8". With 2" on me, you'd be better off looking for something longer in the TT.

Steep STAs help with us folks with stubby legs to keep things 'right' with the torso.

BUT... its YOUR bike. Do whatcha want.

M