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size issues once and for all(31 posts)

size issues once and for allET
Jul 13, 2001 4:54 AM
Is it just me, or is everyone way under-sizing their frames? It often happens that someone who is 6 feet tall comes on and asks what size bike to get, and the answers often seem to be like 53 or 55. Forget for the moment about all the niceties such as how a frame is measured (e.g. c-c or c-t), and even inseam variability. For now let's talk about a typical rider of typical height and presumably typical flexibility. After all, when offering advice, start with the norm and then deviate as appropriate. It seems to me that most of you are way under-sizing your bike. I used to think my reach wasn't as good as yours since many of you have 12 or 13 stems, but now I realize that many of you are accomplishing this by riding a way-small frame, and that maybe it's my flexibility that's outstanding.

In the traditional method for fitting a road frame with non-sloping top tube, the general rule was that your clearance over top tube should not exceed 2 inches, measured to a tight inseam, with some advocating closer to 1 inch. The way you guys are doing it, you must have more like Mtb clearance, perhaps closer to 3 inches.

The way it sounds on this forum, it's worded as Rivendell against the World, so there is a belief that for most people the World must be more right. (It's worth mentioning that even CC warns that as you approach 6', its formula goes too small.) It seems to me that for most of you, on what I perceive as your undersized bikes, your reach (tt+stem) is nothing special for your height, but that your drop to the bars is more severe. And, not surprisingly, many of you complain of back problems, hand problems, too severe a saddle/handlebar differential, etc. Fit more traditionally, I have only 1.4 inches of clearance over my top tube, and yet my saddle/bar differential (with a virtually horizontal stock stem) is still 2.8 inches. I could go for a lower drop but I don't feel like changing it just yet, as I'm still in my first year of serious riding (so call me a newbie and discount eveything I'm saying if you like). And my next bike might be 57 c-t instead of c-c. But many of you want to go further the other way, desiring saddle/bar differential closer to level, and yet, often based on advice of others with undersized bikes, you get those undersized, 2.5"+ clearance bikes, and then struggle to get the bars up high enough. Sure, if someone more at the tail end of flexibility and preference truly likes a 4 or 5 inch drop, an undersized (based on clearance) bike may even be preferred, especially if he's a serious racer. But this is more extreme. We're not all Doug Sloan. Heck, even Lance is not Doug Sloan (well, at least figuratively speaking :-)), riding more upright than most of the others in the Tour, and yet the increased air resistance did not destroy him (but maybe because he's just soooo good).

So just a thought that maybe many of you are under-sizing your frames. A typical cyclist 6' tall should no way be on a 53, a 55 is still way small, and even a 57 seems small to me, certainly c-t, maybe even c-c.
re: size issues once and for allPsyDoc
Jul 13, 2001 5:22 AM
Perhaps some people are riding bikes that are on one end of their "fit spectrum," and others are riding bikes that are beyond this point. I do not think that people are way undersizing the bikes they ride. Everyone has a range of sizes that they can ride, but I think the general tendency is to go with a frame size in the smaller range. Perhaps people purchasing frames that are on the smaller side of their "optimum" frame size comes from their own ignorance of how to choose the correct size frame, over-reliance on bike shop employees who are trying to move the inventory, trying to match the frame size/position of the pros, and sayings such as "you can make a smaller bike bigger, but you cannot make a bigger bike smaller" which lead people to think that they are better off with a smaller frame size.

One point regarding the 2" clearance issue...most of these recommendations are based on an inseam taken in bare feet, not in cycling shoes. So, perhaps the 1-2" clearance recommendation would be better served by taking the inseam measurement while wearing cycling shoes or a recommendation to add about 1.5 - 2cm to the inseam measurement taken in bare feet.

Your point about saddle/bar difference being at least one possible cause of discomfort is a good one. The 1993 USCF Bike Fit instructions state: "The top of the stem should be no more than 4 to 6 cm below the highest point of the saddle. Going lower than that will do nothing to improve aerodynamics, but will increase neck strain. Most riders have their stems too low and assume a greatly bent over position." I have seen many riders who go well beyond this 1.57" - 2.36" recommendation...and a recommendation is all that it is. I have no idea whether the USCF has modified this recommendation, though.

I submitted a post, "Thoughs on "Smaller" versus "Larger" Frame Sizes" around June 20th that raise the same types of issues that ended with some a few interesting questions: "Is the so-called trend toward smaller frames a function of what and how the pros ride? Were the frame fitting methods derived from the pro ranks? Should there be multiple methods of frame fit depending on one's goals and riding style? Perhaps one for aspiring racers, one for recreational riders, etc.?"
RE: the 2" clearanceET
Jul 13, 2001 5:45 AM
Thoughtful post, as are the others.

I am indeed considering standover clearance while in shoes and cleats, so one should know to add about 2 cms to the barefoot inseam. The switch to threadless has made raising the bars even more of a problem.

I think the main reason many who walk into an LBS (who, as you say, often want to clear inventory) end up on too small a bike is that when you eyeball the clearance when straddling the bike, it looks like you have a lot less clearance than you really do (it doesn't help either if you're wearing baggy weekday pants and not wearing cleats). One's, er, parts, could almost be touching the top tube and he would still have 1.5 inches of clearance to tight inseam, but he would think it's too little clearance and so sizes down.
The myth of standover clearance...Mabero
Jul 13, 2001 5:55 AM
What is so bad about the standover clearance is it doesn't account at all for the size of your torso...

Also I hate it when LBS's use the method of: get on the saddle and if you can see the front hub you are fine. Cause what happens if you and I have the same exact build 6'3'' and 170lbs etc etc. but you had a slighly smaller neck making you 6'2.5''. Should we have the same fit? Yes. With this method should we have the same fit? No.
re: size issues once and for allJofa
Jul 13, 2001 5:24 AM
The net of what you're saying is that in your judgement people are running their handlebars too low. This is not particularly linked to the number which a manufacturer chooses to allocate to a given frame, that number being more or less arbitrary, but I see your point; and to an extent I think you're right. There is a slight tendency for people to choose positions which they'd like to be in, based on seeing pro's speeding around, in place of the position in which they'd invariably be more comfortable (and productive).

But of all the myths we hear propogated, I don't think this is the worst one; for most bike fit queries, somebody will pipe up with a link to a sensible fitting website, or simply to say that they run their bars level with the saddle and like it that way.
Seems like gross generality to me.............Len J
Jul 13, 2001 5:31 AM
I understand your point about starting with an average but unfortunatly very few people are average.

I am exactly 6'0" tall and fit perfectly on a 55 Lemond. The reason is that my legs are short and my torso in long. I have less than 1.5 inches of clearance over the top tube but the long top tube of the Lemond fits my long torso perfectly. My Trek is a 56 (Equivilant to a 55 c to c) and on this I had to swap out the standard stem for a slightly longer one, but again, fits like a glove with less than 1.5 inches of standover clearance.

I think what you are missing here is two things (IMHO) 1.)Very few people are average and 2.)Every bike has it's own unique geometry. (well not every, but there are large differences).

Every article I've read on bike fit (The good one's anyway) seperate leg length from torso length measurements because standover height as well as tt plus stem length are both important to a proper fit.

The last thing I've observed is that fitting standards are a starting point, not an end. I tweak my fit for the first 3 to 6 mos of owning a new bike until it feels like part of me.

My .02.
Len
no, not grossET
Jul 13, 2001 5:56 AM
Sure, some deviate from the norm, and there are many factors contributing to fit; I totally accept your own explanation for you. But I claim those at or close to the average on all measures are, on average (:-)), undersizing.
I would contend that....Len J
Jul 13, 2001 6:05 AM
Many more deviate from the norm than are at or tightly bunched around the norm.
I would contend that....Howard
Jul 13, 2001 6:28 AM
if so, then you have just changed the definition of 'norm'!
Disagree...Len J
Jul 13, 2001 6:36 AM
Norm is an average. An average of multiple data points. None of which have to be the same as the Norm.
Me too!Howard
Jul 13, 2001 6:56 AM
Norm could be thought of as an average but it could also be thought of a as a nickname for 'Norman'! - both are besides the point. The classic shape of a normal distribution disproves your claim. Should you have data that shows the topic at hand to be distributed otherwise, a normal distribution is best assumed to hold in this case.
Biological systems exhibit large variation around the averageB. Bunter
Jul 13, 2001 7:53 AM
In a normal distribution the vast majority of measurements do not fall exactly on the mean. What is more pertinent is how much variation there is around the mean, which is reflected in the standard deviation. By defintion 68% (or about that, it's been awhile since I've taken basic statistics) of all measurements fall within a standard deviations of the mean for a normal distribution. So for systems with small variability (ie small standard deviations), most measurements should fall very close to the average. Biological systems typically display large variation ( See The Triple Helix by Lewontin). This variability is even more dramtic when attempting to couple two parameters such as inseam length and torso length (or height and weight). As a result, one would expect a fitting system based on measurements of body proportions to have a high standard deviation. Not to mention that such a system does not incorporate flexibility or riding style into the model, and both of these can have dramatic effects on fit.
you are only explaining why we see deviationET
Jul 13, 2001 8:23 AM
No argument there. It doesn't explain why we're not seeing enough frame selection closer to the norm. Unless you want to argue that the need for "freak" frame sizing (to use TJeanloz' terminology) is so great that we observe little in the normal range. I don't buy it. What I buy is the common fashion to undersize.
Biological systems exhibit large variation around the averageHoward
Jul 13, 2001 8:39 AM
I'll address the points in the order in which they were mentioned:

"In a normal distribution the vast majority of measurements do not fall exactly on the mean."

Quite true, not only for normal but for all distributions, but that's not the issue here. The issue, as you mentioned below, is where the points that are not 'average' lie.

"By definition 68% (or about that, it's been awhile since I've taken basic statistics) of all measurements fall within a standard deviations of the mean for a normal distribution. So for systems with small variability (ie small standard deviations), most measurements should fall very close to the average. Biological systems typically display large variation ( See The Triple Helix by Lewontin)."

The size of the variance and standard deviation says nothing about the type of the distribution itself. Case in point, one normal distribution can have a small variation while another normal distribution can have a large variation.

"This variability is even more dramatic when attempting to couple two parameters such as inseam length and torso length (or height and weight)."

Regardless of how these two parameters are distributed (and they very could be distributed normally), my original contention to Len J - I believe - still stands.

"As a result, one would expect a fitting system based on measurements of body proportions to have a high standard deviation."

Again (see above) not a factor in this discussion.

"Not to mention that such a system does not incorporate flexibility or riding style into the model, and both of these can have dramatic effects on fit."

I agree!
Population variability could have an effectB. Bunter
Jul 13, 2001 12:00 PM
I would like to politely disagree with your assertion that variability in the population is not a significant factor. In comparing a fit system based on inseam alone (old school) to one that utilizes inseam and torso (including arms), one would expect more variability in the result of the two parameter system. This is primarily due to the fact that 1) body proportions are not tightly coupled (ie torso length can vary dramtically for any given inseam length) and 2) torso length can be the dominate parameter (eg a short torso can lead to a smaller frame than based on inseam alone). Since the addition of the second parameter can lead to smaller frame sizes, but is unlikely to lead to larger frame sizes, then one would expect a trend of people riding smaller frames. This model is consistent with the apparent observation that frame sizes are getting smaller, but in no way a proof. I simply raise it as a plausability argument.

But regardless of why, it does seem that it's easier today to get a good fit, and that's what really matters.
I'm not being clear.......Len J
Jul 13, 2001 8:58 AM
Let me try again. I agree that a normal distribution does apply, however, my disagreement is with the statement that most riders are undersizing thier frame. I was using the variability that does exist around the mean to point out that everyone is different. And we are talking about multiple variables which exaggerates the differences. (Leg length, torso length, arm length, flexibility etc.) I think ET's contention might be valid if we were only looking at one variable (height), but we are not. It is the interaction of all of the differences in all of the factors that makes the generalization that "most riders undersize thier bikes" a gross generalization (IMO)

That being said, I do agree that there are probably more undersized bikes out there then oversized. Prior to threadless headsets, this was not that big an issue due to the ability to modify handelbar height easily. Now it is a different story. The penalty for undersizing is harsh (& expensive). ET raises a good point, I was just reacting to the generalization
Thank you for the clarification (nm)Howard
Jul 13, 2001 9:10 AM
GeometryB. Bunter
Jul 13, 2001 7:00 AM
I first size by top tube (around 54 cm) and then seat tube, which means there can be a substantial difference in frame sizes that fit me. For a classic European geometry I typically require a 54 cm - 55 cm (C-T) frame, whereas in a relaxed geometry the frame size is more in the 52 cm - 53 cm range. For me the relaxed geoemtry can sometimes be too much of a drop, so I prefer a European geometry. So depending on the geometry one prefers there can be a significant difference in seat tube size, even for the exact same person.
LBS shops fault mostly...Mabero
Jul 13, 2001 5:48 AM
I was riding a 58 cm Bianchi Brava before I bought my 63 cm Cannondale. What a huge difference. I was and am still aggravated with the my own naive attitude when I bought the Brava that the bike shop people were right, cause well they know more. I forgot that they were trying to sell a bike to a person who new nothing about road bikes. Consequently I bought a bike with a terrible fit with a saddle to stem difference of 6inches or so.

Now with my new bike and with an excellent fit I have no lower back pain, no knee pain, no hand pain, no shoulder pain, etc...

Oh my saddle to stem difference is a conservative 1-1.5 inches.
re: size issues once and for allJohnG
Jul 13, 2001 5:54 AM
What the heck are you talking about! I've NEVER seen anyone recommend a 53cm frame to a 6' rider on this site. Most of the comments I see about fitting are pretty close to the 'modern' norm. At best, there is a bias of perhaps -1cm and that has a lot to do with the silly standover issue that you mention. Sizing a bike by standover is a quick way to getting a wrong fit! There are also numerous references to fitting systems available on the net.

YMMV JohnG
58cm for a 6'3'' rider recommended for me...(savages!)Mabero
Jul 13, 2001 5:56 AM
Yes I am still pist about my first bike...
I am *not* advocating sizing by standoverET
Jul 13, 2001 6:06 AM
The discussion always seems to get distorted to imply one is saying this. Yes, top tube is more important. But if standover is too high, the reach to the bars is too low. And that's not a trivial point. The recommended 2" max is, among other things (possible oversteering?), a proxy to ensure the saddle/handlebar height differential is not too great. "Silly standover issue" indeed.
you've hit on a good pointbianchi boy
Jul 13, 2001 6:25 AM
ET -- I think you are correct that many cyclists are being steered toward buying frames that are too small these days. It all comes down to people wanting to look like the racers, when most people don't race and aren't really comfortable on a bike set up to race. A serious problem can result with new bikes because most of them now have threadless forks/stems in which the handlebars cannot be raised enough for comfort or proper weight distribution.

I have been riding road bikes for nearly 30 years (I'm 47), and the current trend toward smaller frames is a mistake in my opinion. When I bought my first Bianchi in 1985, most shops sized frames so that you cleared the top tube when standing by only a small amount (about 1"). Most bikes also were set up with the handlebars nearly level with the saddle or slightly lower. If you read older cycling books in a library, you also will find that they recommend keeping the handlebars nearly level with the saddle.

When I bought a new (used) bike last fall, I consulted various fit formulas and bought a frame that was correctly sized for me according to the Colorado Cyclist web site. I then proceeded to develop all sorts of problems with numbness in my hands that I hadn't had before. I now attribute these problems to the frame just being too small. My older bike (a 57 ctc Bianchi) was too large according to the formulas, but I rode it for 16 years with no fit problems other than feeling a little too stretched out. My newer bike (a 54 ctc Bianchi) also had a threadless fork and stem, and the bars absolutely could not be raised enough for my comfort without having to install a whole new fork and tons of spacers (3-4"). As a result, my weight was being shifted forward onto my hands, causing the numbness problem. I also didn't like the riding position, having to crane my neck to see the road ahead.

After fiddling around with various stem combinations, I finally threw in the towel and had a Serotta fitting done. It turns out that my old Bianchi was just about the correct size for me, but I would be better off with a frame with shorter top tube. My proportions are not that unusual -- 5'11" tall with 32" inseam. Anyway, I ended up ordering a new Gios with a 56 ctc seat tube and 55 ctc top tube. This bike fits me much better than my other bikes and my hands are getting better all the time. (Since the numbness presumably was due to nerve damage, I think it will take a while to totally go away.) However, hardly any manufacturers make bikes with quill stems anymore, so I had to order the Gios with an uncut steer tube and about 3" of spacers, which looks stupid to me. I have ridden the Gios for a month like this, and it is comfortable but stupid looking. So I called the dealer this week and had them order me a new Gios quill fork from Italy, which they said they would swap for no charge.

By the way, I also took all the new components, wheels, etc. off my new aluminum Bianchi frame and swapped them to my old steel Bianchi frame. At the same time, I put a new quill stem with a shorter reach on the old Bianchi, as well as wider handlebars. The old Bianchi now fits me like a dream, despite being too large according to the fit formulas. It is heavier than the aluminum frame, but rides much smoother and is much more comfortable.

Bottom line, don't believe everything you hear or read about going with the smallest frame possible. This may be good advice for racers as they need the stiffest possible frames and low handlebars for aerodynamics. But, for the average recreational or fitness rider, a small frame can not only be uncomfortable but unhealthy. I would not be surprised if there are a lot of cyclists who are developing hand and necks problems from riding undersized frames these days. Or, if they are new to biking, they end up quitting after a while because they just can't get comfortable.
and you tooET
Jul 13, 2001 8:10 AM
I think you're right that many want to "look" like racers, whatever they think that is, and figure they'll evolve and get used to the drop. "Real men have a huge drop." What they may not realize is that the lack of comfort and the fact that they might use their drops only rarely and briefly (some here have admitted to rarely using their drops) will hinder their racing performance as well.

I'm not advocating a babyish, inefficient upright riding stance for serious roadies. In fact, I'd guess my horizontal reach of around 68 cm (57.5 tt + 11 stem -.5 forward seat adj @ 72.5 STA) is way longer than that for a typical (I know some here hate that) 5'10" cyclist on this board more apt to ride a 55 c-t or 56 c-t and hence have a much smaller tt + stem combo (albeit long reach downward). I'm stretched out nicely and like it, but the shorter drop (and 2.8" isn't exactly level either) allows me to use my drops extensively and extendedly, something many here have said they're too uncomfortable to do. Who's better off in a race?
large bar/seat differential equals long distance comfortrailer
Jul 13, 2001 9:46 AM
This does require a certain hamstring flexibility and adapted neck muscles. It takes weight off your seat and disperses it out evenly. Another benefit is aerodynamics. Another is increased power.
huh?buzzz
Jul 13, 2001 8:11 AM
Tom, what the heck is a "quill fork"? If you meant threaded, I hope your ordered a new headset and stem as well. When you change you will probably still need spacers in the headset or an extra long (height-wise) quill stem to achieve the same height as threadless with 3" of spacers. One could argue that the extra long stems look stupid as well. Why not just flip the threadless stem to get some positive rise and reduce the numbers of spacers? If you already did this and still needed 3" of spacers, there is no way you will achieve the same bar height without a long stem. Another option would be a Serotta head tube extension. Regardless, seems like a lot of work and money just to alter the look.
quill = threadedbianchi boy
Jul 13, 2001 11:16 AM
I will need a new fork, headset and stem, but the dealer will swap all of the parts for me -- and refund the difference in price. So, I will actually save money going to a threaded (quill) fork and stem. As far as the look, it's all a matter of opinion, but I think 3" of spacers looks ridiculous. To me, a threaded stem just looks more sleek and simple and goes with the classic lugged frame. I am also sure that it is lighter because 3" of steel steerer tube has got to be heavier than 3" of aluminum stem. As far as positive rise stems go, they look alright on mountain bikes but I just don't like the look on a road bike. Have you ever seen a racing bike set up with a +17 stem -- not a pretty sight. Finally, as far as the height goes, it is much easier to raise or lower handlebars with a threaded stem. Different stems have different amounts of extension, but it is clearly easier to raise a bar with a threaded fork/stem. Although opinions vary on this issue, some mechanics say you shouldn't use more than 1.5" of spacers with a threadless stem. I don't really think this is a problem with a steel steerer, but 3" of spacers is definitely on the extreme side. Finally, I have ridden bikes with threaded stems for nearly 30 years without any problems. I have had nothing but hassles with the supposedly "improved" threadless stems. Sometimes new isn't better.
back to Excel?buzzz
Jul 16, 2001 7:02 AM
still seems like alot of time and effort involved... after passing you (I was on a Trek) and seeing the bike at the NCBC ride Sunday, I have no doubt that your front end looks ridiculous with 3+" of black spacers. The only problem is, with the minimal head tube protrusion of the Gios and that much spacer, I can almost guarantee that you will not be able to get your bars high enough with a normal non-high rise quill stem- without any spacers in the headset or a head tube extension (Serotta is the only mfger that I know of that makes it, and it is ti- won't match your chrome lugs). The only way I see you getting the bars that high is with a Nitto Technomic stem, which arguable looks as bad or worse than a stack of spacers (I don't even think the Technomic Deluxe with give enough rise). Of course, that assumes that you truly need your bars that high. BTW, we agree on threadless- duh.
I saw it too!dale c
Jul 20, 2001 10:30 AM
and yes, it looked ridiculous... there must be some flex with that many spacers.
I ride a small frame, like it a lot. AM I A FREAK?PingPong
Jul 13, 2001 8:28 AM
I am 6'2 ish and ride a 55cm centre - centre 99 Bianchi. It is not a sloping top tube model but is fairly compact with a 56 cm top tube.
The drop to the bars is fairly extreme, but I can ride for 3 - 4 hours without discomfort. The bike feels very nicely balanced and I am completely happy. The only disadvantage I see over my traditional steel frame with only a small drop is that heavy braking requires more effort. On the steel steed I can brake hard pretty much at will even when standing.

I am looking for a new frame and will look to match the position I have now.

I am not posting just to yak on about my own bike set up but to put across that people are all different.
(I am looking forward to checking Bartoli out in the tour breakaway tonight, that guy rides a tiny bike too!)
sounds normal to me, Mr. Octopus :-)ET
Jul 13, 2001 8:56 AM
Interesting how the exceptions always seem to be the ones to post. Sure, people are different, but that does not change the argument that too many of those with proportions closer to the mean are on undersized bikes. Get it?