Thursday, December 9, 2010

Diamond Frames and Sizing: How Big Is Too Big?

I have come into the possession of a roadbike that was described by the previous owner as a 52cm frame, but in fact measures 54.5cm. On a diamond frame, that can be a significant difference, and I am trying to determine  - without giving in to wishful thinking - whether the bike is too big for me to ride safely. When it comes to step-through bicycles, I prefer to ride the largest frame possible, as long as I am able to hoist myself onto the saddle. My Gazelle is 57cm, my Raleigh DL-1 is 56cm, and my Bella Ciao is 54cm. But with a diamond frame, that approach is not possible, because top tube clearance is an additional factor to consider. That is why my roadbikes have 52cm frames.

To illustrate what a difference just over 2cm can make, here is the new fosterbike (right), face to face with one of my 52cm roadbikes (left). The perspective of the shots exaggerates the larger bike, but look at the space between the lugs on the head tubes to get a more accurate sense of the difference. It is considerable.

The bike is not in rideable condition, so I can't try it out. But standing over the top tube in my bare feet, there is less than 1mm of clearance between my "soft tissue" and that black cable. 

In the shoes I usually wear, the space underneath my forefinger illustrates the clearance I get - less than 1/2". The bike needs a lot of work and some component replacements, before I can actually ride it and determine for sure whether I am okay with so little clearance. And naturally, I am reluctant to do that work if in the end I won't be able to ride it. My main worry, is that when dismounting I might hit my pelvis on the top tube, since our knees tend to bend a little when we jump. But I am not sure whether in actuality that is a valid concern.

How much top tube clearance are you comfortable with? Are there standard guidelines for how much clearance is "safe"?

66 comments:

  1. Have you found an appropriate salve for your Celestial itch? (the B on the fork crown is a giveaway , even if the photo is black and white). I understand the concern about size, but you do clear the top tube. In addition, many people find they mount and dismount a bike without ever having it perfectly vertical. For example, I have about the same amount of clearance as you do on my own beloved Bianchi (very little, I can feel the top tube just beginning to touch my inseam if I am straddling the fame). However, wen I climb aboard, I usually stand to the side, with the bike tilted somewhat towards me, throw my right leg over, put my right foot on the drive side pedal (crank somewhere between 12 oclock and 3 oclock), then press down on that pedal to get underway, simultaneously moving the bike into a vertical position while briefly supporting myself on the right pedal instead of the ground, and bringing my left leg and foot onto the other pedal. At no time during this process am I straddling a perfectly upright frame. Something similar happens in reverse at a stoplight or end of a ride. I pull up to where I am going to stop, support my weight on the right hand/drive side pedal (usually now in the 6 oclock position), pull my left foot off the pedal, and lean to one side to begin supporting my weight with the left leg touching the ground, the bike at an angle, and my right leg remaining on the other pedal. You can then start up again or dismount entirely, but are never really standing over a perfectly vertical frame. Different people may do all this differently. But if this bike is in the same nominal size range you use for other bikes, I think you might want to give it a try. Top tube length is often proportional to seat tube length, so the overall reach may fit you better or worse on a larger or smaller bike. It is also easier to get the handlebars higher relative to the saddle, without running out of stem length, if the frame is close to your stand over height. Good luck and I am looking forward to the color pictures to follow!

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  2. A "too big" frame shouldn't really be a problem, as a cyclist never really needs to put both feet flat on the ground. When stopped at a light or traffic, simply lean to the left and put your foot down (right foot stays on the pedal to avoid contact with the drivetrain). So the bike is leaned over, and the effective height is reduced. No problem-o. The extra reach from a longer top tube would be more of a concern for me.

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  3. David - I didn't want to draw attention to what the bike may or may not be, because I don't want to get attached to her - I mean it - since I may not keep it. There is something mysterious wrong with the entire drivetrain, and we are 90% sure the front wheel is shot altogether, so it would be a huge commitment to bring her - I mean it - back to health. I am reluctant to do that just to sell the bike afterwards, so I want to think carefully about the sizing, or else just let the bike go to begin with.

    You guys are right about leaning the bike over when stopped - I definitely do that as well, propping the top tube up against my left thigh. I guess I just think of myself as an accident prone klutz and imagine jumping off straight forward without thinking when making an emergency stop. The Co-Habitant says he'd ride a bike with that amount of clearance without worrying too much, and that I have too vivid of an imagination about potentially horrible things that could happen. But I still can't help but imagine myself breaking my pelvis!

    As for the top tube length/reach, I am not worried about that. The 6mm stem on my Moser fixed gear has begun to feel much too short, and at this point I have shoved it all the way down to compensate. So I am going to switch it with the longer (12mm) stem on this bike and that should be a good solution.

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  4. Old school says if while standing astride your beast you can lift the front tire one inch off the ground, you are fine. Grant at Riv agrees with the above posters, nobody ever dismounts perfectly bilaterally on top of the top tube. With any space, or even a slight compression fit, you should be fine. The bigger concern with a "too big" frame is ridability, seat height, and reach (which should be commensurately longer.)

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  5. I worked in the Bike department at a major chain store, and generally the guideline we used for diamond frames is an inch of clearance above the top-tube. Since your knees do bend when you jump down, you could potentially knock yourself, especially if you had to jump off the saddle in a hurry for whatever reason.

    I have an old Sears Robuck diamond frame, it fits me like your foster bike fits you, really closely. I tend to have a lot of trouble mounting and dismounting, although that may be because I'm used to a mixte...

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  6. Skald - Okay, glad to know I am not crazy and others have the same concern. The first time I tried a diamond frame bike was in August 2009. First I rode the Co-Habitant's 60cm vintage Raleigh frame in platform shoes, and then I tried a smaller bike in a bike shop. I was equally uncomfortable with them both; it took me quite a while to stop fearing the diamond frame. For what it's worth, the DL-1 with the platform shoes on gave me about as much top-tube clearance as the fosterbike in normal shoes, but I only rode the DL-1 around the block a couple of times, whereas the fosterbike I'd be riding for 20-40 miles, on roads.

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  7. I agree with the first few posters. I don't have a huge amount of clearance on my diamondframe, having insisted on getting one size up from that suggested by the lycra-minded salesman (he was lovely and very helpful about other matters). The top-tube reach is comfy and I feel relaxed on a bike that is built for all day touring, I would have felt the fit less generous on the recommended size. (I have no difficulty with the frame size even when camping with a full set of panniers). If I ever come to a real dead emergency stop my knees may give enough to bump into the top tube, but, if it's that quick a stop that I can't control it, chances are I'll be sailing over the handlebars or unable to get my feet down anyway :)

    I think as long as you can mount and dismount comfortably your main concern is whether it is comfy when you are riding and that your posture is sustainable.

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  8. "A fistful of seatpost" was the motto. I'm afraid the 54 is too tall for you. You'll bang your "soft tissue" sooner or later.
    Now, who said you can't ride a bike too tall ? If you're ok with the length and not intend to ride in town or off road (ie, with frequent dismount) anyway.

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  9. +1 for not worrying about clearance. All but one of my bikes (a MTB) have *zero*, or negative, standover clearance, but I can get the bars where I want them, and they are comfortable to ride. 'fit' when stationary is not important- although it is convenient sometimes to be able to hoist my thigh up on the top-tube and use the bike as a substitute leg at stoplights.

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  10. You have touched upon a danger of buying used, vintage bikes. Finding the right bike can take a considerable amount of effort, so when a great one comes along that isn't sized 'quite right', it is easy to over look the frame sizing issue. I have done this twice (one was too big, the other too small) and regretted it both times. There are well informed folks in the bike community that will argue in favor of a larger frame. Even if it can be ridden, it won't look right if the seat post or stem is adjusted to compensate (the same goes for too high, of course). And when the seat post is too low, a lot of accessories for that area of the bike don't fit. My advice: 'if in doubt about frame size, don't buy it'.

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  11. David, your first poster, describes exactly my Workcycles and, based on a friends Sam Hillborne, the 56 Sam I have on order. I have, and will have, Minimal space between the top tube and "soft tissue" (maybe a couple/few mm). I get on and off just as he describes. I suppose these bikes are technically too large but the Workcycles is the smallest frame they sell on a Secret Service and the 56 Sam Hillborne is the smallest frame size that uses 700 tires. Once up and going the Workcycles feels just right. You will have to make your own decision of course but I am fine with mine.

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  12. A half inch of clearance is less than ideal, and if you're already accustomed to 52cm bikes and feel comfortable on that size, I'm afraid you may end up regretting your purchase. That said, you can certainly make this bike work using the techniques described above; the question is whether you'll be happy with it over the long run.

    Alan

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  13. I have to say, don't get to wrapped up in the "Numbers", specifically the seat tube.
    The position of the seat, pedals and bars and or grips are what is important.
    Many bikes are measured differently. Most lugged bikes [like your Riv] are measured center of crank to top of seat lug [ctt]. Other bikes are measured center of crank to center of top tube/seat tube junction [ctc].
    Many factors can play in the standover height. The bottom bracket drop for one, along with wheel and tire size [drop is the distance of the BB shell below the axle line]. Seat tube angle as well plays a part. The more slack the seat angle, the more top tube clearance you will have.
    Since you have the bike in your possession, you can play with the stem length, height, bars and saddle for and aft to see if you can get the position that you want.

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  14. I have 2 bikes that I ride regularly and the standover height makes not one bit of difference as to the "feel" of the size when I am underway. Here's the deal: I have a Univega Nuovo Sport "beater" and a Miyata 914. They are of the same vintage and made in the same factory. They have seat tubes of identical length. The Miyata has a higher BB, and when I stand over it I have much less clearance (1-2mm) than when I do the same on the Univega, simply because the entire frame is made "higher". However, the Miyata has a shorter top tube, and consequently when I ride it I am in a much more compact position than when I ride the Univega. The Miyata has the smaller frame by actual riding fit than the Univega without question, despite the higher standover height. The height does not make the Miyata feel "larger" by one iota. As long as you are actually able to stand over the bike, the height from the ground to the top tube is a deceptive indicator of fit while riding. I would compare top tube lengths to predict if you will like the fit.

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  15. I had a too big bike for years and I didn't even have the clearance you have. I never had any issue with hitting the tube on dismounting, though if standing over it with flat feet, I was touching it. The bigger issue with that bike was the long reach to the bars and eventually I did sell it and get a bike with a better fit, but I never hit the top tube on a dismount, so you would probably be fine with it. It's going to take a lot more than hitting the top tube to break your pelvis, you are too young for that kind of osteoporosis!

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  16. if you clear the top tube, even by a few millimeters, in shoes, then i would say it's not too big. however, have you measured the top tube to make sure it's not too long for you?

    my 650B conversion project is being done on a 63 cm frame-- 1 cm larger than my jeunet, which gives me about 1/4" of clearance with shoes. however, with the 650B wheels, the top tube will be lowered 1 cm, making the standover height the same as the jeunet's. but unlike the jeunet which has the classic "fistful of seatpost" exposed, the 650B bike will have a more "french" fit, with 1 cm less seatpost exposed.

    i think it's really a personal choice. it seems that most of the men i've spoken with like to ride bikes at the very top of the sizing curve, because it helps them keep stretched out, which provides more long-term comfort. i don't know if this is the consensus among women. i'm trying to convince my wife to take over my 58cm shogun, which is really at the bottom end of the fit curve for me, and would be at the top end of the fit curve for her. she has the same concern as you, and is worried about not having enough standover height. the thing is, her PBH is only 1" less than mine (mine is 34", hers is 33"), and she's straddled the bike and has more clearance than you do on the bianchi-- about 1/2". but it's still a concern for her. i suppose this is because we were raised in the age of the CPSC and the "1 inch rule", and we have to retrain our way of thinking about bike fitting.

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  17. A bike shop sold me a new bike that was too big.
    That was 1972. I still have that bike and have never injured myself with it but I no longer ride it because it is not comfortable at stoplights since even to put a foot down, I have to lean the bike over a bit. Sell the big bike and another will come along.

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  18. Velouria, I wonder if you could find another bike, but in working order, with precisely the same clearance, since this is so much a matter of personal preference.

    For years the ten-speed I rode was too big for me--I had "negative clearance" as referenced above. This was odd in retrospect since I spent hours choosing it in a little shop in Port Jervis, N.Y. I loved that bike but know too well the stop/lean maneuver that took place thousands of times. When I resumed biking a couple years ago, one of the major simple improvements was getting a damn bike that gave me enough clearance.

    But as illustrated above, everyone doesn't feel the same way (even though I have to think that clearance is a bit more crucial for men than women). Just another example of how personalized biking is. And let's face it, if you fell in love with a particular bike then all bets are off. If I came across some amazing bike--I dunno, say the bike Eddy Merckx used in his first, second, third, fourth or fifth Tour de France wins--I'd probably mount it using stilts if I had to.

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  19. On my diamond frame I have about as much clearance as you're describing, and it's mostly fine. I had to think about it at first, but as with so many new things you try in biking, it becomes second nature. That said, on one of my first longer rides with that bike, I did step down and bang my pelvis pretty hard on the top tube. It was painful, but not enough to break my pelvis or anything! (Though I assume you were being hyperbolic about that.) It was sort of like the inevitable slo-mo fallover when you first try clipless pedals: oops, okay, did that, won't do it again. And it looms large in your mind for a bit, but gradually recedes as you get more used to the new thing.

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  20. For a bike that is either to large consider the use of a "lay back" seat post. A solid aluminum rod layback seat post is safest and best.

    A layback will put your feet closer to the ground allowing safe mounting and dismounting.

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  21. My lovely pink-and-purple roadbike, Pizzicatto, is a 62cm diamond frame, and at first I was nervous with how little clearance I had on the bike....but now that I find that frame's geometry as a whole fits me so well, I have adjusted my perception of the clearance and now really love having such a close-fitting bike. It makes me feel super sporty! :)

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  22. Great, so everybody is pretty much split on this 50/50 : )

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  23. I agree with the posters that say clearance is just one measure of fit. I have a diamond frame bike where I have minimal clearance, but everything else (reach, sweep of handlebars, relaxed seat tube) make it work perfectly. I can even stay on the seat and touch the ground with my tip toes at lights. So... consider the whole package. If the bike fits while riding, don't worry about clearance. If it is all about the looks.... well, fashion can beat out function can't it!!
    Walt D: how will a layback seatpost put you closer to the ground? Won't it just be further back?

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  24. Re fit vs clearance: I am not so much worried about the fit or the numbers, particularly the reach. If I keep the bike, I plan to use a seatpost with a bit of set-back as Walt has said, and a short stem. I have tried to simulate the reach that would create, and it seems just fine. The only thing I am worried about is the actual clearance - i.e. top tube and crotch contact. Otherwise I would not care if the bike was labeled 52 or 62cm.

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  25. Before a fist of seat post was standard as big a frame as you could manage to get on was standard. On my Raleigh made sportster I can't get a fist of seatpost, because the stock one isn't anywhere near long enough for that, and it's a "city" bike.

    If you can stand over the bike without actual pain, stop worrying about top tube hight and start worrying about top tube length, which you already seem to be happy with, especially as you intend this for long road rides.

    Conversely your desire for the largest frame size possible in a step through is separating you from riding some nice bikes that simply weren't designed to be fitted that way. At the extreme, what is the "proper" frame size for a Brompton?

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  26. dweendaddy - "how will a layback seatpost put you closer to the ground? Won't it just be further back?"

    Sometimes a picture is worth a thousand words. Sometimes one you draw yourself is worth several thousand.

    Draw a diagram and you'll see how for yourself.

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  27. kfg said...
    "Before a fist of seat post was standard as big a frame as you could manage to get on was standard."


    Is that why we see so many pre-1960s bikes with the saddle shoved all the way down, especially the really early bikes?

    Conversely your desire for the largest frame size possible in a step through is separating you from riding some nice bikes that simply weren't designed to be fitted that way.

    The preference is not ideological, but developed as a result of whatever "experience" I have gained over the past 2 years. For instance, the 57cm Gazelle feels much better to ride than the smaller Gazelles and Batavuses I have tried. The 22" (56cm) DL-1 feels better to ride than the smaller Sports I used to own. And this preference is confined to standard, full-sized step-through bikes - not mixtes and definitely not folding bikes.

    Re the setback seatpost - Walt means that if I plan to remain in the saddle with one foot on the ground when stopped (which I do), having setback will slacken the angle of the seatpost and will therefore make the saddle lower in relation to the ground than if the seatpost were steeper.

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  28. If you are solely concerned with stand over, don't forget about wheel and tire size. If the wheels need total rebuild 700 or 650b might gain some clearance, but also your choice in rubber tires (700x28 will be shorter than 700x40) needs to be considered.

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  29. Anon - The bike is 700C to begin with and I will most likely put 28mm tires on it, so the feel would be similar to what it is now.

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  30. "Is that why we see so many pre-1960s bikes with the saddle shoved all the way down . . .?"

    You got it. In England this lasted right into the sixties, even for TT bikes.

    "Gazelles and Batavuses . . ."

    Are designed to have large frames, just as the diamond frames of the same philosophy were, a philosophy accentuated by the average size of Dutch women and the desire for true "sit up and beg" styles.

    American step throughs were designed like Bromptons, to have as small a frame as possible, only with full size wheels. They are quite properly fitted the same way as an adult small wheel bike is.

    Many modern design European city bikes (Biria, for instance) are now also being designed this way, as it allows a bike to be shared by a family in the manner a car can, only including the children.

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  31. Peppy (the standing over cat)December 9, 2010 at 1:26 PM

    I understand why people worry about stand-over height--the mere thought of your anatomy hitting that top tube is scary. But...

    I've fallen off a bike a bunch of times and many of my friends have done the same, and so did their friends and people that they know and nobody ever, ever fell crotch first onto the top tube.

    So, in my observation, it just does not happen like that. Even if you dismount forward quickly, the bike will be leaned. And if someone, somehow, somewhere manages to prove me wrong and does fall "crotchwise" onto the top tube, meh--an inch or two of difference would not matter--they'll still hit that tube hard with precious anatomy. Fortunately, that's just not something that happens. So, the 1" rule is silly. It should either be a LOT of space or it doesn't matter.

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  32. A layback seat post is kinda the best of both worlds i.e. you can still put your feet down on the ground while your pedal stroke remains at peak length.

    The geometry ,when installed on the bike, makes the layback post a magic "wand" allowing many to safely ride a bike they otherwise could not.

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  33. Walt D - Shhhhhhhh! Electra isn't going to be happy about you blowing their schtick.

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  34. I agree the bike will be fine.

    My soft bits hit the top tube on all of my frames that are actually comfortable to ride. When fitting a bike the only thing I worry about bashing is my pelvic bone. I raise the handlebars until the top tube hits bone, if there's an inch or more under the tire I'm golden, even if it's only 1/2" I'll probably still ride it.

    I subscribe to the whole Grant Peterson fit methodology, most folks ride bikes that are just too small.

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  35. Walt D - Yes, exactly! I was ecstatic when I made the "just push back the saddle" discovery.

    kfg - I think Electra went overboard with the schtik!

    I did not know that, about American step throughs. Could be why I've never been enamoured with the classic Schwinns.

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  36. Let me begin by saying I am 5'8" and pretty typically proportionate. I too have a 57 cm gazelle toer populair, and from the saddle, I have to lean the bike in one direction of the other a few degrees in order to make contact on the ground with one toe.
    I have a 53 cm motobecane mixte which originally felt like the right size, but the more i rode it and on longer rides I began to feel as though it was too small.
    Then i got a 56 cm Sam Hillborne and I was a wee worried it was going to be slightly too large that I fell somewhere between the 52 cm and 56 cm. First ride on that bike and I knew I had made the right decision. I am stretched out exactly like I should be, I can reach the ground with one toe tip from the saddle, at lights, I am leanded to one side flat foot on the ground. I use this bike as my commuter so I am on and off of it a good bit, and I am totally comfortable with the size, and on those long rides I am so glad it is no smaller than it is, and I definitely am glad I have 700C wheels as well.
    I refer to the gazelle as my Cadillac and Sam Hillborne as my BMW.
    Good luck, and I believe once you have it all together you will feel it is just fine if not better than what you had expected.

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  37. There are two ways to tell whether a bike is too big. 1) your pelvic bone has to rock from side to side while you pedal and 2) any irrational or rational basis for personal preference i.e. just don't like it.

    I know you're up above the arctic circle somewhere :-), but down here in SoCal, there is a law on point: California Vehicle Code, Division 11. Rules of the Road, Article 4. Operation of Bicycles, sec. 21201 Equipment Requirements, subsec. (c) No person shall operate upon a highway a bicycle that is of a size that prevents the operator from safely stopping the bicycle, supporting it in an upright position with at least one foot on the ground, and restarting it in a safe manner.

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  38. I like big bikes and I cannot lie. I say try it out.

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  39. Here's another consideration: how badly do you want it? I'm tempted to say smaller is better, because a smaller frame is lighter and gives less wind resistance. I got a Peugeot UO-8 for my birthday in 1973 and I have always regretted getting the frame a size too large - I guess I thought it would shrink in the wash ...

    Affordable Luxury

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  40. "Could be why I've never been enamoured with the classic Schwinns."

    And why you called the Bike Boom era Columbia 3 speed a "children's" bike despite the fact that it was clearly labeled with the sobriquet "Tourist."

    You just haven't groked them yet.

    That's OK, although I'm of the correct age I don't like these bikes through any sense of nostalgia; I began paying my dues as something of a Euro-Snob when my age was still in the single digits and it took me a few decades to not to outright sneer at these bikes ( and I still don't get the whole Stingray thang).

    So now that I've come out the other side of that I have learned to appreciate them for what they are; and what they are turns out to be some damned nice bikes within their proper context. Who knew?

    These are not small bikes. They are actually quite large bikes that happen to have short seat tubes. My biggest bike isn't my 23" Rivendell, it's my 18" Schwinn.

    I've brought up Electra a couple of times in a couple of days. For a couple of reasons they've been on my mind a bit of late. If I start going off on them we'll be here all week, but one of the reasons just happens to be that the first time I saw an Electra "foot forward" bike my reaction was, "But we had that when I was a kid, only we called it a "layback seatpost.""

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  41. down here in SoCal, there is a law on point

    Maybe they're just trying to keep all the Burners from riding their tallbikes around :-)

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  42. "Walt D: how will a layback seatpost put you closer to the ground? Won't it just be further back?"

    yes, it will.....to a point. As I mentioned the geometry comes into play here. Imagine a circle with the center at the bottom bracket. Now extend that circle to the top of the seat post.

    Now you have a circle that when followed around to the rear will get closer and closer to the ground but still the same distance to the BB for pedal stroke. (This assumes that the layback seat post is "L" in shape)

    So you do sit somewhat further back but also much closer to the ground. Electra bikes use this principal on all their "feet on the ground" bikes.

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  43. Walt D said...
    "A layback seat post is kinda the best of both worlds i.e. you can still put your feet down on the ground while your pedal stroke remains at peak length"

    I'm still not seeing how a set back seat post gets you closer to the ground. I do see that using a setback would make it possible to mount the saddle as low as possible in the seat tube, and then move the saddle backwards to try to get as much leg extension as possible, even though there is no "fist full" of seat post showing. However, if a rider can barely straddle the top tube when standing over the bike without any saddle at all, no amount of set back is going to make it possible to stand on the ground once a saddle is put underneath them as well. The only way that could happen is if the setback saddle somehow ended up lower than the top tube itself. If you know of such a thing, please provide an image link so I can see how the geometry works.

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  44. David - It does work, but assumes (1) that the right foot remains on the pedal and only the left touches the ground, (2) that the left foot is on tip-toe and the cyclist is comfortable balancing in this manner, and (3) the bike is leaned over to the left just a tad even as the cyclist remains on the saddle. For example, in this picture it appears as if the saddle is too high for me to remain seated on and touch the ground, yet I can definitely do it using the above method.

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  45. Perfect size for me is a 53cm, but I have an old 56cm Trek I can't let go of. The thing is I will never ride it loaded: bags, panniers, baskets get really awkward when you lean to the side. The one thing I like about it, is that it's right at that size break where there's no toe overlap. So I put fenders on it and it's my rain bike. I put bars with some reach on them (porteurs would be even better) to handle the frame length. It's NOT perfect. I've had guys in my vintage group tell me it's too big. But I like it fine.

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  46. David - I see your problem now; just because you can barely straddle the top tube does not imply that you do not also have a fist full of seat post.

    However, in compliance with your request, here is an extreme example:

    http://tinyurl.com/2a7gpql

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  47. Peppy (the efficiency-minded cat)December 9, 2010 at 7:34 PM

    I don't like being too far behind the bottom bracket because it's not as efficient to pedal, but that's just me.

    All of my bikes have the saddle shoved forward somewhat and show a ton of seat post. There is no other way, I try to get frames as large as I can possibly clear and I raise the seat as high as I can without rocking my hips. So net result is always a ton of seat post showing...

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  48. I think it depends on your comfort level.

    I typically ride 58cm, and with that, my "soft parts" are barely touching the top tube. That said, I also have 56 cm Cannondale and Nishiki bikes (haven't given the 'shiki a ride, but the 'dale is really nice), and a 62 cm Peugeot. The pug is my most comfortable bike, but if I were to straddle it for too long, it'd get kinda painful...

    I'd say you'd be good with the 54cm. I find that there's a bit of fudge factor possible, if you can get the saddle and bars to where you need them. Further, I find that THAT is much easier with a bigger bike, as you need shorter stems and seat posts to make that happen.

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  49. Efficiency, like Performance and Quality, is a word that is essentially meaningless without a context.

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  50. Peppy - What can I say, we have different cycling styles. If my saddle is too far forward, then too much weight falls on my hands and I am soon in agony.

    > http://tinyurl.com/2a7gpql

    Wow...

    Maybe I'll try to draw my own illustration of saddle set-back vs height

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  51. seat tube angle/seat hight

    This should explain it. Alan made a picture that's worth a thousand words.

    http://www.ecovelo.info/2010/11/14/the-problem-with-numbers/

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  52. Ah yes! I was looking for that post but couldn't find it.

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  53. You can make a small bike fit you with a longer stem that will slow steering input, and a longer seat post, set back or not . But you can't make a big bike fit and feel like it should. It will always feel to big.

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  54. Try to fit your Raleigh wheels, they should be 26 x 1" 3/8. They should give you much clearence and a lower bottom bracket. I converted my commuter bicycle from a racey Olmo frame to a semi-roadster.

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  55. I have no problem seeing how a shallower seat TUBE angle will result in a lower standover height for a given seat tube length. However I thought the original claim was that using a layback seat POST, or pushing a saddle back further on its rails, would somehow lower the effective stand over height of a given seat tube length. That still doesn't make sense to me. For a saddle that's level across the top, further back above a given seat tube is still just further back, not further down, right?

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  56. I had a bike that was too tall for me. Before I got around to fixing it up, I had an unexpected stop in traffic. I learned a good lesson about proper fit that day. Though I understand that people ride bikes like this and "have never had a problem" there are also people who ride without helmets without ever having a problem. I know that the consequences of each gamble are certainly different, they are both gambles with your person.

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  57. You know, I'm kinda astonished to see how many people here mention stopping and staying on the saddle with one foot on a pedal. I had no idea that this was a common thing, and is the LAST thing I'd worry about in bike fit. But everybody's different, I guess.

    On ALL my bikes, I'm accustomed to hopping off the saddle as I come to a stop. One foot does stay on a pedal (for me, it's the left pedal), but my right foot goes flat on the ground. I do tend to tilt my bikes a little even when I don't absolutely need to, as with my current bike, but that has more to do with balancing on one leg.

    Having my foot flat lets me give a good push as I start again, and as my left foot pushes the pedal down, I just push myself back up on the seat. No problemo.

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  58. David... The set-back in the seatpost slackens the angle of the seattube compared to what it would be with a straight seatpost. Just picture it and think about it.

    andrealad - My Raleigh has 28" wheels, but even with 26" wheels it is not as simple as just fitting them onto a bike meant for 700C wheels. Plus, the new "fosterbike" is a road bike and I am not looking to convert it to anything else.

    Janice - People might be describing that method of starting/stopping, because they know that it's how I do it. What you describe is considered the more "proper" way to start and stop, but I am unable to do it : (

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  59. Velouria: I was just surprised because it hasn't occurred to me to do that in decades. I tried it today on my road bike (most comfortable bike I've ever ridden), and I simply can't do it YOUR way. :)

    I like a good bit of leg extension when I ride. And as long as your riding is doing what YOU need, you're golden, as far as I'm concerned. :) No criticism expressed or implied, just surprise on my part. But I mostly ride alone, non-socially, so people might be doing it your way right and left, and I'd never see them. :)

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  60. Velouria:
    Please let your loyal readers know if you decide whether to keep this slightly larger frame.
    I support your decision, whatever it may be!

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  61. Some people believe that the top tube doesn't matter as long as you can get onto the seat and ride. I am on the side that the stand over height IS important! I was told by an old timer that half an inch inch was good for a racing/road bike. I was given a road bike that I can just barely straddle, but will see how it goes. While biking we normally stop, lean a bit to one side, but sometimes we do have to stop and stand. If one has to make a sudden stop or avoid an accident it can be pretty painful. I often see people on bikes that are too big for them-probably because they were such pretty bikes. I remember riding adult bikes as a kid and it was scary-especially when I crashed or had to stop suddenly.
    It depends on the overall fit of the bike. But if the lack of standover room is a concern, pass the bike on and wait for the next one. I am kind of clumsy and get spooked easily so I could see myself getting dinged.
    Heather

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  62. Heather - funny, I usually see people riding diamond frames too small for them, with an excessive length of seatpost showing, but rarely ones that are too big. I am curious how the bike you just got will work out for you.

    Janice - Oh I am being quite sincere and not offended when I say that you are doing it correctly and I am not. I have a terrible sense of balance and have a hard time starting and stopping the proper way. I don't go on group rides either, but most cyclists I see at traffic lights - as well as the Co-Habitant - do it your way and not mine.

    MT Cyclist - Thanks. I tried it again today, this time actually getting on the saddle (still can't ride it, but the wheels are stable). To my surprise, I can actually get almost a fistful of seatpost and still have the saddle at a height I am comfortable with. That's encouraging, as I was imagining having to shove the saddle all the way down 1910 style. There is definitely about 1/2" of clearance when I wear shoes, especially considering that the cable is not the top tube. I still have to diagnose the extent of the work this bike needs (esp whether the wheels can be rescued), but I am now leaning towards keeping it. I think I will know for sure after this weekend.

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  63. velouria said: "Heather - funny, I usually see people riding diamond frames too small for them, with an excessive length of seatpost showing, but rarely ones that are too big. I am curious how the bike you just got will work out for you. "

    this is exactly what i observe, as well. my guess is that it's because stems, handlebars and seatposts can be adjusted to accommodate riders who are too big for a frame; the opposite scenario has no solution. i also think that a lot of cyclists see all that exposed seatpost on mountain bikes and think that it's perfectly acceptable to do that on road bikes. and the thing is, it *is* perfectly acceptable. as long as the distance between the three points of contact between the rider and the bike are optimized and comfortable for the rider, from a functional perspective it makes no difference if it's all because of telescoped stems and seatposts or larger main triangles. it becomes more an issue of aesthetics.

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  64. andrealad - My Raleigh has 28" wheels, but even with 26" wheels it is not as simple as just fitting them onto a bike meant for 700C wheels. Plus, the new "fosterbike" is a road bike and I am not looking to convert it to anything else.

    May I suggest going the other way round? What size are the tyres now? If they are 700*28 or 700*25 you would have the chance to get down to 700*23 or also to 700x20 (much more racey...) and gaining a few millimeters...By the way you are a tall girl: the raleigh classic loop frame (and also the italian Bella Ciao) are almost always fitted with 26x1-3/8...many with 24" tyres, go figure!. I'm italian and the classic 26x1-3/8 is the standard tyre for loop frames so my suggestion. ciao ciao !
    Andrea from Italy (there is plenty of Bianchi here...at my LBS there is one just now hanging from the wall and I spotted one in a thrift store for 25 euros...)

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  65. I do see people on bikes that are too small for them too. The vintage fixie craze has people buying anything cute, epic or beyond cool. Like people on fine italian bikes that do not fit. But too large is a bit dangerous. I have a mixte that would be too big for me if it was a diamond frame, but fits wonderfully otherwise. I am short so my diaomond frame bikes are so small! My road bike is in disrepair so I have not test ridden it yet. It should be okay with shoes or I might go for a smaller wheel size if brakes permit.
    Heather

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  66. somervillian said:

    i also think that a lot of cyclists see all that exposed seatpost on mountain bikes and think that it's perfectly acceptable to do that on road bikes. and the thing is, it *is* perfectly acceptable. as long as the distance between the three points of contact between the rider and the bike are optimized and comfortable for the rider, from a functional perspective it makes no difference if it's all because of telescoped stems and seatposts or larger main triangles. it becomes more an issue of aesthetics."

    Not really. The distance between the contact points may remain the same, but those points will be different in relation to where the wheels are, which will affect weight distribution and therefore likely change handling and other sensory perceptions about the ride quality.

    Mark

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