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FIT PROBLEM: Short-statured road rider preferring standard seat angle
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 A thorny, but purely hypothetical, problem for the fitters who frequent this forum:

Woman comes in, wants to be fit for a road race bike, she's 5'5" tall, saddle height of 63cm (BB to saddle top, midway between tip and tail). 165mm cranks.

You give her input on the fit, she's aboard a fit bike that measures X/Y to the handlebar clamp, alternately she's on a fit bike from which you derive an X/Y to that spot via a Serotta X/Y tool or similar.

She prefers a position, if left to her own devices, that yields a bike with a seat angle of 73.5°, nose of her Specialized Romin saddle is 60mm behind the BB, and her handlebar clamp measures 550mm above the BB and 395mm in front of it.

She will face several problems with these results. Name the problems you can think of, and why. Then list any solutions or possible solutions, or clues to solutions, and techniques yielding solutions. Special credit given to those who devise solutions to this problem that include the rider agreeing or choosing the solutions you have in mind of her own accord, rather than our imposing changes in fit metrics on her.

Post your answer below.

Dan Empfield
aka Slowman
Last edited by: Slowman: May 9, 13 18:55
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Pull her forward. The handlebar reach was set too short at 395mm and the saddle setback of -60mm should have never been an option initially. I would lengthen the bar reach a couple cm's and set her saddle setback to -30mm or so and then start over. Coaching will be needed to convince her stabilize the core and spine so she can relax her upper body as more demand is being placed on it now that she is further forward. If a medical problem prevents her from achieving this, I would understand and adjust to her needs and make sure she is biomechanically sound, but that would be rare.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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My impression is you want us to go with her feedback concerning a 73.5 degree seat angle because she is able to discern an increase in efficiency at that saddle position. Custom bike would be the easiest solution but I assume you are looking to fit her on stock models. After quickly skimming through your road bike stack/reach data base, I see several models of bicycles that would do the trick. She needs a bike with a very short reach. I put hbar x/y coordinates in your 'bar to ht calculator' and came up with a frame stack/reach of 493 stack and 350 reach (see below). Then I skimmed your stack/reach road bike data base and noticed the Pinarello Dogma 65.1 in size 42 has a stack of 493 and reach of 351. It also has a seat angle of 73 degrees making the offset of 73.5 (or saddle setback of 60mm) easily in reach. I liked the Dogma because I can use a 60mm +6 stem with no spacers but it looks like there are a few other bikes that would also work.
InputBar-Bore Y550mmBar-Bore X395mmHead Tube Angle73°Stem Length60mmStem Angle6°Stem Clamp Height40mmSpacer Height0mmHeadset Topcap15mm
OutputStack493mmReach350mm
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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With a 100 mm stem that would make her reach 295. Almost no 700c bikes available, and if they are the toe overlap would be horrendous.

My suggestions would be to try steeper seat tube angle or going to a 650c bike that would give her the proper geometry.

I wouldn't recommend a stem shorter than 80mm for a road bike fit.
Last edited by: epgonzalez: May 10, 13 0:04
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [epgonzalez] [ In reply to ]
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With an 80mm stem she would need a bike with a reach of around 330mm. I don't think there is a stock bike with that reach. If we are trying to keep her at a 73.5 seat angle, you would need a shorter stem. I don't believe a 60mm stem is going to have an adverse effect on this small of a bike.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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IMO, I'm surprised she wanted 73.5 over a 71.5 so we're kind of lucky there. Her fitted stack is too high for a racing fit to a racing bike. Is she sure she's gonna race? Why is the stack so high? Saddle discomfort would be the first thought. Lower the nose or choose another saddle to see if you can work the stack down to a reasonable level. Is her belly in the way? Does she lack flexibility? Yoga would be a thought. Still a stem around 35mm is a little short. Is the reach of the handlebar a factor? Shorten the bar reach to get some length back into the stem. In a race she'd need the power position a lot more than the better handling of a 60mm stem. I wouldn't worry about toe overlap unless the course is inside of a single car parking spot doing 4mph.

http://www.mybicyclefit.com
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Geeios] [ In reply to ]
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points of clarification: when i say a road race bike, i'm simply talking about a style of bike. this, instead of a tri bike, for example. so, anything like a tarmac, roubaix, madone, domane, synapse, supersix, R3, S5, a Felt F, AR, or Z series, all of these qualify as "road race bikes" according to the term used here. do not assume she's racing. but do not assume she's not. for the purposes of this exercise, it's immaterial.

also, remember that the X and Y numbers here are NOT stack and reach, they are X and Y to the handlebar bore, where the handlebar passes through the stem. this yields a considerably larger number for both the X and Y axes than would stack and reach.

this is a very hard question. if you nail this, you are ready to tackle the unifying theory in physics ;-)

Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Maybe not so thorny. One piece of info missing from the scenario as stated was the actual cockpit reach. She has selected her seat angle, or more appropriately stated- a setback that gets her hip and femur in a comfortable and powerful relationship to her pedal. Extrapolating her inseam from the selected seat height and her over all height at about 71cm I'm looking for frames in the 47/48cm range that offer a seat angle that allows the 6cm saddle tip setback . I guess the thorny part is in finding a bike that will have enough front center distance without all that pesky toe overlap and also allow us to have a short enough reach to be comfortable. So lets find a bike that offers the right seat tube angle (73-73.5), a short enough top tube to get the reach coordinate (395), a front end that kicks out the head angle some, and a fork with the right offset to maintain a good trail number for good handling. Also, to keep the steering happy, lets use an 8cm stem and a short reach bar. As one poster stated below it looks like the Dogma would do it. Perhaps a Cervelo R series in 48 would do the trick as well. I think I can make a Cannondale Supersix work as well.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [ccbrendan] [ In reply to ]
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we have some real thinking going on. my own view: i would not necessarily assume that this position is optimized. i would not assume that the position is settled, and we just have to find a bike to fit it. a couple of you have zeroed in on the pinarello, because you note its very short reach, and that means you're thinking, you understand important concepts in matching fit coordinates to available bikes. but i'd like to take this a little farther, as todd carver (retul) has done above, and ask whether these are the very best fit coordinates available for this rider (and, if not, methods for deciding whether these fit coordinates are optimized).

Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Well I guess we had to make some assumptions. In reality it would be tough to say whether the fit is optimized or not without actually watching her ride. She selected the set back based on feel but what does her hip angle actually wind up at? If I'm using my guru fit cycle I am also looking at spins can as we go. I would probably save this position as stated and then advance the seat angle forward a bit and allow her to feel both of these positions and look at power output and efficiency. I also do some posture coaching along the way to help the rider understand the positional changes in that context. When we reach that balance between comfort, power, and efficiency I call that the optimized fit, record the measurements and then search for the best frame/control parts for the optimized position.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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She should not have been left to her own devices quite so much. 60mm of setback is too much. That's the 1st thing that jumps out at me. If she went through an intuitive process by which this setback was selected, I think she was focusing (or being directed to focus) on the wrong things. If she did not go through this process, she should.

One problem will be finding an off the shelf bike that will even work. That much setback will dictate a quite short reach to the bars.

Another problem is she might not be able to get the bars that low without going to 650 wheels. That is a good bit of drop for a little lady.

Toe overlap has already been mentioned, could be another issue.

She needs to be re-fit with more guidance. This is not like shopping for a suit. These are bikes. They are made a certain way for a reason, and if you find someone like this who seemingly there are no bikes that will work for her, some fitters first reaction is to go for a custom. I say STOP and figure out why exactly an off the shelf solution would not be available for her. "Where did I lead this rider astray during this bike fit?" would be my first question, not "What can we make work?"

This is one situation where I might drop the old plumb line from the knee and explain while this is not the end all be all of saddle fore and aft, it might not be a bad place to start. Sometimes a visual indicator showing a rider how far they deviate from a norm is a good tool. Even if it is not something I would normally use. I would be explaining all that needs explaining about torque through the knee versus cycling myth and lore while I was measuring it as well.

I would also be sure to have her ride in all positions, particularly down in the drops. Getting her to ride even lower and further away from that set back seat might help my cause. I would be sure to have her ride long enough and hard enough to illicit her best intuitive responses. Sometimes simply repeating the process will yield different, and often more refined results.

I would be surprised if after all this we would still be dealing with 60mm of setback. Which of course would change everything. So I don't know what complete bike solution 'solves' this problem. I think more time on the fit bike is required though.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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This is somewhat of an ethics question, is it not?
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Thanks for bringing this up Dan. This is the exact dilemma we have in the fit industry now with a lot of fitters using fit bikes that are infinitely adjustable without a meaningful approach of what is optimal/obtainable and what is not. At the end of the day I think stock geometries are good and manufacturers are doing a great job of designing bikes that fit the vast majority of riders on the planet. Custom bikes are still a great product and customers will always be lined up to get a bike made just for them, but probably not for geometrical reasons as much. Some of the best custom bikes I see come out of Phil Shamas' studio in Texas and Denver. And looking at how awesome his riders look once he fits them to a bike, I almost guarantee you those customers could ride stock geometry but choose to get custom for the great style and quality they provide.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Dave Luscan] [ In reply to ]
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"This is somewhat of an ethics question, is it not?"

this is not an ethics question. it's really a math question, as was originally stated. it's a math problem more than any other kind of problem. you can't sit aboard and pedal an ethic. a 5'4" lady is looking up at you through l
arge brown hypthetical eyes, right now, in your retail store, hoping for an answer, and you're on the spot.

now, one thing i think worth noting, i got a look at the fit specs of a particular team - a men's pro tour team - that had a notable number of riders of shorter stature. the mean saddle setback was 9 percent of saddle height, that is, if a saddle height was 68cm the saddle nose position v the BB was right on about 61mm, as a mean. and this flowed to those riding saddle heights fairly low. so...

yes, this hypthetical gal's saddle setback is significant, but, by "significant" we're talking about 3mm behind 9 percent of her saddle height (60mm rather than 57mm). you might say that this is not quite fair because, while riders are scalable, saddles are not. saddles are a fixed distance (145mm, 160mm, etc., depending on the saddle) from the center of the saddle's rails forward to the nose. that established, this gal's sitting position is not wholly different than that of a lot of taller riders, that is, if you scale down a taller rider you won't find that this gal's position is wholly out of whack.

what makes this lady's saddle setback problematic is that it pulls back the front of the bike and that creates problems we're familiar with once we try to find complete bike solutions. some (but not all) of these problems are caused by the 700c wheel.

i write the above only because i think we realize that we can't give women everything they want, or think they want, in a bike because of the mechanical problems associated with bike architecture. however, for those who think that a 60mm setback is necessarily bad, and 40mm of setback, 30mm, 20mm is necessarily good, i ask whether the driver in bike fit is to find a comfortable, powerful position; or to find a position underneath which sits a choice of available production bikes; and whether there's anything about how that bike handles that we ought consider?

can we draw the distance between these 3 imperatives down, and provide a selection of options that are comfortable, powerful, that handle well, and that are available? that's the question i'm asking with this hypothetical conundrum. i would prefer not to argue bike theory in this thread. if you'd like to do so, this forum is available precisely for that, i would just ask you to incept a separate thread for that and i'm happy to participate. i'd like to return below to just the question of how to service this hypothetical young lady's needs.


Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [carvertc] [ In reply to ]
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"This is the exact dilemma we have in the fit industry now with a lot of fitters using fit bikes that are infinitely adjustable without a meaningful approach of what is optimal/obtainable and what is not."

i don't mind bikes that adjust (somewhat or slightly) past what is achievable architecturally. i just think fitters need to know when unobtainium is what is occurring during a fit. that's why i say i think this is a math problem. you need to know what handlebar X means in real life. this is going to come about as you fit more and more people, but as HX or reach - however your bike measures - grows and shrinks, the most prudent fitters understand what's going on during the fit.

the guru experience bike can do the math we all do, and it can do that math real time during the fit. one future possible function would be the ability to know, real time, all the time, during a fit, what is actually going on, and how far off you probably are (as in a display on the screen, during the fit, that says, "your HX is woefully short, big buddy, by about 30mm!).


but you don't need this, if you're a good fitter. with an exit, a muve, a purely custom or a guru experience, you should be able to see the numbers and know you're in good shape or that you're in trouble.


Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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I realize it's not actually an ethics question. My point being that this is how it plays out in a lot of bike shops.

I am a little unclear on the hypothetical method used to derive these fit numbers. Was this rider fit properly or not? The process was completed and we trust the output, the process was completed and we don't trust it, or the process wasn't completed?

"You give her input on the fit" means what exactly? "Left to her own devices" means what exactly?

I am not trying to argue bike theory, I am trying to understand the question. This is a great question and general exercise, but it is hard, and I would like more information if that is possible.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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When I suggested the Dogma 42 as a bike that would work with your hbar x/y's, my assumption was you derived this woman's fit numbers from an optimized fit using a protocol similar to the Guru experience. My other assumption was that suggesting a custom bike for those measurements was too easy and you were looking for a stock bike that would work for her. Without seeing her on a bike or fit bike I don't think anyone could say with certainty what the best answer is. If I move a customer through the fit protocol and I notice they are entering the 'land of unobtainium' and I know they are not going to want to pony up for a custom bike, I'll let them know that some compromises will need to be made. This also happens with an existing bike fit. When somebody comes in with a bike he just bought on Ebay or Craigslist, I let them know that our ending optimized fit coordinates may not transfer to their existing bike and a compromise in fit position will have to be made.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Problems that she will face (which can really easily be resolved by a custom geometry are):

1- Too shallow a seat angle for a very small frame size, no one does this in the trade today
2- In conjunction with this seat angle, a very short top tube is required; this too is unavailable in stock geometry in the trade today
3- Front center issue with the front wheel, requiring a slacker head angle which inevitably means you need a fork with greater offset (53mm) to correct the trail.

You can view this person's custom geometry below, drawn here as a Photon SL, lead time 4 weeks from order confirmation:)

We address real life fit problems like this every day.
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Dave Luscan] [ In reply to ]
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"Was this rider fit properly or not?"

this lady's fit is in-process. it's a fit using any of several protocols with which i would not quarrel. we're most of the way through the fit, she feels pretty good now, she would be satisfied if we stopped here. but, is this necessarily where we must stop? can more be done? are there positional changes that might be contemplated? using what techniques? and how do we then decide what bike or bikes match that final position we end up with?


Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Well her first issue is that she rides a Romin saddle. Do girls actually like this saddle? No. Which means she's probably not rotating her pelvis, and it's rather surprising that she can ride with almost 4cm of drop on her handlebars. I'd suggest the Selle Italia Diva. All kidding aside, there are a couple of issues here.


I do not believe a -6 setback with 63 saddle height equate to a 73.5 degree seat tube angle. It's closer to 72. With that said, she can still almost fit on a 44 Cannondale Women's Synapse, a Ridley woman's road XXS or Felt woman's petite. All of those bikes will require a 60mm stem at a -6 degree angle with various heights of head tube top caps. But the biggest need is a ridiculously offset seatpost to get her saddle far enough back, which means she has to ride the entry level bikes which have standard seatpost diameters. I agree with the others that I don't think she prefers this setback. A -4 setback is a much more realistic (yet still rather shallow seat tube angle). All of those bikes have a rather steep angle (75-76) and if you could get her a bit further forward (to an actual measurement of 73.5 degrees) she could fit on the next size up, and those bikes all start to slack out with that angle.


Or, design a custom bike. I've attached her "fit coordinates" and those selected bikes are laid out underneath. For all those naysayers regarding the 60mm stem, personally I rode/race/won on one on a Parlee Z4 small and had no issues with it feeling squirmy. (And unfortunately that bike was stolen.)

Also, unsure of why the women's stack/reach numbers are not listed here: http://www.slowtwitch.com/stackreach/road.php


Rachel Wills
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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Hi Dan,
If the client prefers this position then I'm not going to steer her away from it and I am going to do everything I can to find a bike that fits her. I think a 73.5 degree seat angle sounds about perfect.

I would make sure that she is sitting with good posture and on the correct saddle though. If she is uncomfortable on her saddle she will likely be sitting with a posterior pelvic tilt which will cause her to curve her back and will result in a shorter reach to the bars in order to avoid a reach problem. Assuming she is comfortable on the fitting bike, has good posture and passes my weight distribution tests (not a believer in KOPS) then I am happy and so is she.

The problem lies in the fact that many 700c road bikes are designed around a minimum amount of front center in order to avoid toe overlap. The problem is worsened by the fact that many big manufacturers are forced to use ~73 degree head angles because they are unwilling to go with different fork rakes in the smaller sizes. There are some big manufacturers that deal with this, but not many.

What I would do is to:
Make sure she is using a compact handlebar, if not, I might be able to squeeze an extra 10 or 20mm of handlebar reach out of her without actually changing her position when she is riding the hoods.

I would be comfortable setting this client up with something like a 70mm x -6 degree stem with 25mm of spacers underneath. This nets a stack and reach of 494 and 339 respectively, assuming a standard 73 degree head angle.

This isn't even on the chart of road bike geometries, see attached. So what do I do... I look harder, possibly at a bike with 650 wheels because the front center will be smaller. I also am probably going to be in touch with Guru about drawing up a custom frame for her with something like a 71 degree head angle and a 50 rake fork. This will give her maximum front center and the resulting trail will lead to a nice handling road bike. If the result still winds up in a potential toe overlap situation then I am OK with that but I am just going to have a talk with her about low speed turns.

I would experiment with shortening the cranks beyond 165 to help the toe overlap problem and I would also look at her cleat position to see if any clearance could be gained there.


Jonathan Blyer,
ACME Bicycle Co., Brooklyn, NY
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [willsra] [ In reply to ]
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"Well her first issue is that she rides a Romin saddle. Do girls actually like this saddle? No"

i just plucked the Romin out of thin air. My bad. The ONLY reason I did that is because I did not want anyone to ask whether this was or wasn't an ISM, because saddle nose setbacks vary greatly with this PARTICULAR saddle. Hence my just choosing ANY standard saddle for the purposes of this exercise.


Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [willsra] [ In reply to ]
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"I do not believe a -6 setback with 63 saddle height equate to a 73.5 degree seat tube angle. It's closer to 72."

very shrewd observation, depending on what you mean and where you measure. this is is why i chose my words very carefully, and indicated that this position, "yields a bike with a seat angle of 73.5°." my guess is that the position itself, if measured through the center of the saddle's rails, is probably in the neighborhood of 72.5° or thereabouts, however, almost all bikes now sold are OE spec'd with a setback seat post. hence my using the precise text i did.


Dan Empfield
aka Slowman
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [Slowman] [ In reply to ]
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The three contact points on the bike (saddle, shoe/pedal interface, and handlebar/hood) make a difference when fitting. If one is not quite right, the others will be off too. Finding a saddle that works is a very important part of the fit and can sometimes take a bit of patience. Listening to the rider, but also watching the way they move on the saddle, is imperative in helping find the right match for them.


Rachel
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Re: FIT PROBLEM: Short-statured road rider preferring standard seat angle [willsra] [ In reply to ]
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"The three contact points on the bike (saddle, shoe/pedal interface, and handlebar/hood) make a difference when fitting. If one is not quite right, the others will be off too. Finding a saddle that works is a very important part of the fit and can sometimes take a bit of patience."

you bet. i couldn't agree more. that's why i'm a big fan of paul swift's switchit, for example. just, for the point of this exercise, i'm not focusing much on the saddle being a bad choice. i guess i'm stipulating that the saddle is okay for the purposes of this problem. however, if you said, "look, a proximate cause of her choosing the cockpit she chose is her need to protect her soft tissue from the saddle," i cannot fault the thinking. you get extra credit for that.


Dan Empfield
aka Slowman
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