ccomg I've fit half a dozen women like this over the years, some were custom some were not. Right now I'm dealing with a lady even smaller than what Dan is proposing here.

Creepy, though, I'm 5'5" and my saddle height is 635.....so I'm totally biased here because I know how I ride. Or I am burdened by my own bias, as a fitter, working with ladies of similar stature. But you guys don't have that problem fitting guys similarly proportioned to yourselves??? That's another thread.

Seat angle: better to keep her shallower, someone this small will only weight 45-50kg, so power to weight is commensurate. Let her utilise those hams and glutes to the fullest extent, not compromise power output to accommodate reach.

Let me also point out that, as we are fitting a person who will be racing, under USA Cycling rules, the nose of the saddle must be at least 5cm behind the BB center.

I work with a DFU, so I setup my machine here to mimic Dan's proposed dimensions. My seat angle is actually shallower, and I knew she's be 'off the charts' when I typed numbers into the machine for the X/Y. However, my saddle nose is 70mm behind BB.

When I calculate Stack/Reach she is off the charts, but I expected that once I saw the numbers on the machine.

Per Dan's comment: "...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" Then I have to say yes to comfort and power, but you better know your mechanical limits. I can 'make' you fit just about any bike I have here in the store, trust me. I have certainly 'fixed' customers who were sold bikes under this model, and who's to argue the difference between a 54 with a 110 stem and a 56 with a 90 stem?

Back to Dan's Problem Lady:
Looking at it, I say 'way too much drop', it's measuring at 85mm. She may want the 'racer' look, but that much hip to hand drop is better for the track. She will be better balance if her Y is at 590 or 600.

Overall reach to bar center isn't too crazy, but I'd pay attention to what bar dimension I'm using as well as what shifter brand is preferred. The nose of saddle to shifter 'tip' measurement is 610cm.

---

Anne Barnes
ABBikefit, Ltd
FIST/SICI/FIST DOWN DEEP
X/Y Coordinator
abbikefit@gmail.com

for those who haven't seen it already, i've posted an article on the front page that is the denouement of this problem. i thank everybody who's participated. the last response came after the article was published. too bad, because, good stuff in there.

i'll have another question/problem/conundrum out to you all in a week or so, for those who are interested in taking a stab. and, thanks for participating.

---

Dan Empfield
aka Slowman

Late to this party I know (my wife will point out that this is not uncommon).


Ignoring the elements related to the fit process - running the coordinates you've given through my match system yields 18 different road frames (out of 4500) that will achieve that bar position within a resolution of 3mm in either dimension. Using stems of 60-80mm and spacers of 8-25mm (in 5mm steps after the first 2mm). Brands - Azzurri, Kuota, Pina, Serotta, Specialized.

At the other end of the scale, using stems of 110-130 and spacers as above I have 667 frame options (some of those will be track & CX)

As for the process - since few of my clients are in the mood for custom I always run off to the fit calculator mid session to make sure that we have a position attainable on an available bike - if not we tweak until a position that is both comfortable and attainable is achieved.

the problem we had here is just that the lady preferred to be too far back. so, there are two ways to go about this. one is to say, hmm, i think she's too far back, what can we do during the fit to give her all the riding experience options possible to see if she really wants to sit that far back. the other option is to just leave her where she is and find a way to make a bike fit her.

what i wanted, ideally, was both the question of position broached, that is, is this really where a fitter should have stopped? and i wanted the math broached, that is, wherever she ends up, how do we math our way to a solution?

and i think several fitters did an admirable job at this, and i recapped this with an article on the front page. i'll have another conumdrum in another week.

what's the point of these problems? if you want me to be just transparent and blunt, it's to champion fitters who demonstrate an acumen that shows they should be trusted options for our end users, whether they're FIST-fitters, retul fitters, or any old kind of fitter. i think if you have the knowledge, and the tools, and the instincts and experience, people should know that. customers should know that. secondly, i want other fitters to see what these really good fitters look like, how they solve problems, the techniques, the thought processes, so that they can raise their games.

---

Dan Empfield
aka Slowman

Too far back by what measure? Just because it makes it difficult to fit her to a stock 700C bike?
I fitted a paralympian earlier this week with a saddle height of 622mm and setback of 59mm on a Ruby 143mm saddle. She required that setback to achieve core balance. Part of the issue is compensating for the absence of a lower leg on one side - otherwise she could have been further forward. She was comfortable with a lot more reach than your example which helps.

I've encountered similarly large setback requirements for women who've had C-sections leading to a loss of core strength.
As mentioned - I work to find an appropriate position that leads to getting a bike in budget so I have no contention with the two aspects you outline. And in the instance you propose there are a number of measures that can be employed to modify the position.

But I am not keen on looking at a setback figure and giving an absolute - it is too far forward or back. Based on a quick look at individuals I recall as extrema the setback % of saddle height for my clients ranges from 6-14. I know what you meant with the original question - I'm now just debating the absolute from your last post.

Having pretty much grown up reading your work I had never thought you to be anything other than transparent and blunt... ;)

"Too far back by what measure? Just because it makes it difficult to fit her to a stock 700C bike?"

couple things. first, "she" is sitting back further than is typical, for a man or a woman. as i noted in my article, i was flippant in my estimation of seat angle when i posed the question. really, it's 72° seat angle bike, or 72.5° generously if you consider a seat post with a 2cm offset, that matches a saddle nose plumb line of 60mm on a 63cm saddle height using that saddle. i was careless in my phrasing of the question when i wrote a 73.5° seat angle bike, because i guessed, i didn't calculate, and my guess was wrong by at least a degree. second, the front of the bike is pulled way back, so, yes, she could ride a bike with 650c wheels, but that is not frankly practical these days, because on the front lines in retail stores that market for road bikes is dead, dead, dead.

you mention a ruby. that is one of a very few bikes that work out for people who need short cockpits, but even then, with a very short stem, like 60mm, you're looking at a bike with a reach that's 20mm shorter than anything you can get in a ruby. so, you're still stuck.

but i also disagree with the premise that 60mm setback is automatically out of the question. she is probably too far back. on paper. but it's easy to check. i think the easiest way to discover or uncover this is to simply incline the bike, to somewhere between 7 and 10 percent of slope, and have the rider rider out of the saddle. on the hoods. that's a truth-telling test of balance on a bike. that stretches out cockpits too short. that's why i prefer bikes with incliners for road fits, and i think within 2 years you won't find a good, competitive fit bike for sale that doesn't have a way to incline.

the point of the exercise, again, was to get fitters to talk about how to move a rider forward who's chosen a rearward position because the fit was executed in a nonchalant, complacent fashion; and to work through the math and find complete bike solutions regardless of whether, in the end, the fit finishes with that slack saddle angle or whether the saddle ends up a bit further forward than was stated in the problem's premise.

---

Dan Empfield
aka Slowman

Didn't it take 10 years before there were more than two fit bike options that you liked? We're getting more rapid proliferation now but 2 years seems an awfully short period given the pace of development so far.

I should explain that if I was told that a rider needed to move their bars forward (lets say they need to fit a sponsors bike) I'd first look at moving the bars up and saddle back. Saddle forward would only happen if certain tests were satisfied.


I measure saddles from tip to the 90mm width point (based on sitbone width being ~90 as a minimum for adults so you will likely near that point). A Romin Evo 143 is 162mm, a Ruby 143 is 142mm, Lithia 172, my Cobb HC is 170. So your example could have come in with a 50mm setback on the Lithia (which is rated as a W saddle by SBC so certainly a possibility) and appear to be fine for setback. Or be at 80mm with a Ruby 143 and then there would be much wailing and gnashing of teeth*.


So the question I pose as an addendum to yours is why is it assumed that persuading the rider to move the saddle forward is the key to a resolution here?


And it's not that hard to hit the given coordinates so it would only take minor tweaking to open up the options.


*this may be an exaggeration

"So the question I pose as an addendum to yours is why is it assumed that persuading the rider to move the saddle forward is the key to a resolution here?"

first, it's simple. you incline the bike. the rider rides out of the saddle. if the knees hit the backs of the handlebars, or/if the rider's weight is very obviously in front of the hands, then, that's untenable. i'm not assuming anything. i'm simply asking the rider if that position is comfortable. if not, we have a problem to solve.

second, because of the law of large numbers. if the rider is sitting considerably shallower than is typical, than the mean, i don't care if the rider is 5'4" or 6'4", i'll ask the rider to try a variety of options in as close as possible to real riding situations. not at a very light load, at an unreasonably slow cadence, which is unfortunately the case in too many fits. if the rider chooses to ride in a shallower than typical position then, fine, we fit around that.

---

Dan Empfield
aka Slowman