Saddle fore/aft and crank length...

[Ti Designs]

Question for the forum: how do you set saddle fore/aft position, and how do you select a crank length?

I've been to a number of fitting schools and I've read every book on the subject that I could get my hands on, yet these two subjects are always brushed over with a few words. For example:

Andy Pruitt writes "Saddle position is the key fit variable and the most important measurment to get right". He then spends 4 pages explaining saddle height, and say "The saddle setback should put your knee's center of rotation directly over the pedal axle of the forward crank arm when it's horizontal".

Seems to me that with all the methods of power testing and fine tuning, we should be able to come up with something a little better than that. I have my own ideas based on ratio of muscle groups and long term testing of my riders, I'd like to know what the forum members ideas are...

[stevep]

this sounds wisearss...but its true
but i set it where its always been and i use the length ive always used.
172.5

how does that help anyone else?
doesnt.
read pruitts book.
figure it out yrself.

[davids]

I just left it where you set it... ;)

[Velociotis]

I am toying with my own fit in this way, and I saw this:

From theVelonews Zinn report

Dr. Pruitt lecture at SICI

"We (bike fitters) talk about the ‘center of rotation of the knee' as though there is bolt going through the knee," said Pruitt. "Nothing could be further from the truth. The end of the femur is elliptical, not round, and in fact the end of each condyle on the end of the femur has a different elliptical shape. We're just guessing, guys!"

[Climb01742]

where it feels comfortable. for years, my saddle had been set where my knee was over the spindle. but i kept sliding my butt back on my saddle to get "comfortable". then a fitter listened and slide my saddle back. over time, i listened to where my butt wanted to be, kept messing with my saddle, and finally arrived at a place that now feels very good. when you start out riding, we listen to others, which is both wise and necessary, i think. but then we gotta listen to our bodies. this isn't a great answer i know but it's all i got. i think fitters can set folks up in a good ballpark, but then the rider has to listen to their body.

[Ti Designs]

this sounds wisearss...but its true
but i set it where its always been and i use the length ive always used.
172.5

That's almost exactly what CJ said at Serotta Fit School. The human body is adaptive, so given the hundred or so years you've been in that position I would guess it's working pretty well for you. Just the same, the set it and forget is method sounds somewhat unscientific.


read pruitts book.
figure it out yrself.

I've read just about everything Pruitt has published, no testing methods were disclosed. As for figuring it out myself, I'm working on it. Something Climb said about understanding the function of the glutes and quads got me thinking about rider position a while back, and how so many people complain about their quads burning while climbing. I started setting riders up on trainers and putting a block under the pedal in the horizontal position. I then asked them to push on the pedal and take most of their weight off the handlebars - standard hill climbing position. Most people felt their quads were the major muscle group being used at this point. Now correct me if I'm wrong here, but from 3:00 down there's no more forward component to the pedal stroke, and the quads can only extend the leg from the knee. So with the femur paralell with the ground the use of the quads at that point is pushing almost exactly in the wrong direction.

Changing crank length and saddle to pedal relationships will change the timing and duration of the firing of the glutes and quads. It's a lot like motorheads changing the rise or duration of the cam or the bore or stroke of the piston to alter the torque curve. I can't think of a single motorhead who doesn't know how those numbers change the output of a motor, but I know very few cyclists who have applied the same level of understanding to how they turn the pedals...

[1centaur]

Motors can be tuned to elicit max power through measurable, repeatable, fully-understood units of power. The human body varies from person to person, as does muscle firing time, and in any case is inherently not ideally suited to the perfectly round nature of the crank's arc.

An ideal power position would involve a crank that adjusts its length on every stroke via sensors to the leg that perceive strength and speed several times a second in order to accomodate the effects of terrain and fatigue. Anything else is just adaptation to the imperfect match of human physiology and a "perfect circle" (one reason Simoni wanted that long saddle that became the Arione). Elliptical chainrings are one way to improve, perhaps, or might be seen as just another imperfection to which we adapt.

Moving to what we can do today, I suspect hooking our bodies up to something that indicates muscle firing speed (I've done that once - not fun), then getting that data interpreted by someone of Pruitt's background, might lead to changes in conventional thinking about saddle position as an average of personal tendencies. Not wishing to go through that, we are back to climb's point: those with analytical minds should ride a lot and listen to their bodies when choosing set back, perhaps pushing themselves for max power over max comfort from time to time while looking at a powermeter.

[Too Tall]

I feel yah Ti. That is a clever and intuitive way to work with someone to find what feels right. Neat. I'm sure you know this guide (below). It seems OK and I check against this: 20.8% of inseam, +5mm for long femurs, -5mm for short femurs. also considered is ankling and toes pointing down while pedaling

Leg Length Crank Length
60 to 65cm 150mm
66 to 70cm 155mm
72 to 75cm 160mm
75 to 78cm 162.5mm
79 to 81cm 165mm
82 to 83cm 167.5mm
83 to 86cm 170mm to 172.5mm
87 to 90cm 175mm to 177.5mm
91 to 94cm 180mm
94cm plus 185mm

[Climb01742]

where it gets real complicated though is accurately understanding what our bodies are telling us. to ed's point: when climbing hard, my left quad burns like crazy, much more than my right quad. i "listened" to this and thought my body was telling me that my left quad was weaker than my right. so i worked on strengthening my left quad. but what was really happening was my left quad was having to over-compensate for my left glutes not firing enough. until i discovered that my glutes weren't firing equally, it wasn't accurately getting the message my body was trying to send me. "listening" to our bodies is necessary, but deciphering the message correctly is even more crucial. doing single leg weight training exercises under the trained eye of a good strength dude was how i discovered the true source of my burning left quad. how could most riders decipher their bodies' messages accurately? if someone can build a testing protocol for that, bingo!

[Peter P.]

There are too many variables to find the "perfect" rule, so we have to make up a "general" rule and work around that.

Experience is the best teacher, so observing riders you fit, while using the methods you've read about, will give you the best information and lead you to a fore/aft philosophy you can accept and agree with. The next step is to sell it to your customers.

Even Pruitt's book tends to fall apart on the fore/aft debate because he settles on using the end of the knee cap and the end of the crankarm as reference points because they're easier to discern. For all us technogeeks it doesn't seem accurate enough but you know what?-it probably is. Because in the end that little difference is probably not gonna matter enough.

As far as your theory that not much is happening with the quads after 3:00, I say that's not true. The circle of the pedal stroke is CONSTANTLY changing it's muscle requirements. The quads are still contributing after 3 all the way to BDC; it's just not at peak force.

Something you have to look at with regard to fore/aft is, is the rider tending to scoot forward on the saddle to make up for a seat that's too far rearward?
Or how about vice versa with a too far forward saddle? You really need to consider the input with the customer/rider HEAVILY when setting up their position. Do they spin or mash big gears? Do they ride short distances or long? What are they trying to achieve with a new bike/position? Are they trying to cure a physical problem like back pain?

You really need to re-think how you approach the fit process and think of yourself as a detective or a doctor. In-depth conversation with the customer will usually reveal what's REALLY underlying in their position needs/wants. If you talk to them at length, you will sooner or later separate the wheat from the chaff and get their position where both you and the customer will be happy.

I work in the field service industry and every day I approach a customer and ask what's wrong with the equipment. I invariably get, "It doesn't work!" Well, no feces Sherlock, I figured that's why I'm here in the first place. I know this is gonna happen and I immediately go into my detective/doctor mode asking precise questions which eventually gets the customer to spew out what the real problem is, which makes my repairs quick and accurate.

You have to use the generally accepted fit tools/methods available along with customer interaction to put the customer in a position that will make them want to come back for another frame.

One simple example: when I bought my first mountain bike in 1984, it came with 175mm cranks. I do a lot of riding to and from the trails, and the long cranks drove me nuts when trying to accelerate from stop signs, sprint against my buddies, ride up hills, etcetera. Rather than adhere to the supposed "norm" that ATBs should have longer cranks, I installed 170's and have never looked back. Did it buck the formulas?-yes. Did it feel right and make me happy?-double yes.

LISTEN TO THE CUSTOMER.

[RPS]

Now correct me if I'm wrong here, but from 3:00 down there's no more forward component to the pedal stroke, and the quads can only extend the leg from the knee. So with the femur paralell with the ground the use of the quads at that point is pushing almost exactly in the wrong direction.Isn't that what quads do regardless of the body's position, whether standing, on your back, or standing on your head? I'm not sure why so much emphasis is being put on the affect of gravity as it defines the horizontal other than it holds us down on the bike. When climbing or descending a 10% grade our position changes drastically relative to the horizontal, but we still develop power, don't we? For me position (as long as it is reasonable) is about comfort, not power and which muscles I use.

[Ken Robb]

I know this won't be big news to our bunch of experienced riders but when my saddle is too far back I can apply good low cadence power but I can't spin high rpm. When my saddle is too far forward I can spin high rpm but have relatively low power. I know that technically power=force x rpm so substitute "force" for power in my commentary. I'm not suggesting that riders don't generate lots of power by turning high cadence, rather that there is a sweet spot where I can still generate good force without inhibiting my ability to spin.

I've been experimenting with saddle position on my new/used Kirk and I think I got it right yesterday. Bring on those hills :banana: !

It's easier to do on my Legend because its got a Flight Deck w/cadence which eliminates guesswork about how fast I'm really spinning. Another factor is that is one of my bikes with an Arione saddle. The extra length of it vs. Brooks Pros and B17s lets me cheat. Well maybe a better term would be "adapt". I can slide back when I'm cruising or when I need more force. I can get up on the nose when I want to spin and both extremes are still comfy. This is good because the Legend has 50-34 compact instead of my preferred triples and I sometimes wish I had lower gears. In other words, on this bike I sometimes don't have the option of spinning because I can't turn my lowest gear that fast.

Now the Kirk has a Brooks Pro and Brooks riders know that there is really one sublime spot where your tush is "in the hammock" so-to-speak. I can move around a little but there's no way I want to ride it on the rivet. The compensating factor for me is the gearing: 48-38-28 with 13-29 cassette! I've got a gear for any occassion. 48-13 got me up to 40mph pedalling down a hill. To go faster I would need a steeper hill and then I could tuck in and coast, saving my legs for the inevitable climb beyond so, no, I dont miss a 53-12.

[obtuse]

setback is all about positioning the rider's weight between the wheels. hip flexion and saddle height (and the resulting leg angle) are what determines which muscles are working. it has nothing to do with setback.

obtuse

as for crank arm length no one has any idea. i use 180s.

obtuse

[Grant McLean]

setback is all about positioning the rider's weight between the wheels.
obtuse

whoa, what was that loud sound I just heard?

oh ya:


g

[RPS]

I know this won't be big news to our bunch of experienced riders but when my saddle is too far back I can apply good low cadence power but I can't spin high rpm. When my saddle is too far forward I can spin high rpm but have relatively low power. I know that technically power=force x rpm so substitute "force" for power in my commentary. I'm not suggesting that riders don't generate lots of power by turning high cadence, rather that there is a sweet spot where I can still generate good force without inhibiting my ability to spin.Ken, I find it very helpful to distinguish between power and force. It helps me understand what is being said without having to guess.

In your opinion, how much of the difference you describe above is due to changes in effective saddle height? Have you tested it separately?

[Ken Robb]

the amount of fore/aft movement I'm talking about here isn't enough to have much effect on effective saddle height.

On a slightly different tack: I can't tell a difference of 2.5mm in crank length but I can feel 5mm difference. I have one bike with 170mm cranks and it's easy to spin with maybe a small apparent reduction in power. I had one set of 180mm cranks and I really noticed the extra leverage when powering up hills. Good thing I did, because that was my Legend as delivered with 52-39 and 12-25 gearing and I need lower gears for my local hills.

The down side to this crank was that my knees ached a bit after a strenuous ride. I don't know if that was due to my straining for power or the increased angle of flexion of my knees. If I want to ride and my knees feel a bit tender I take a bike with 170mm cranks and avoid grinding hard gears.

[Ray]

For me position (as long as it is reasonable) is about comfort, not power and which muscles I use.
Along those lines, Peter White's article always made a LOT of sense to me. He more or less punts on crank length but not on fore-aft.

Whole article:

http://www.peterwhitecycles.com/fitting.htm

portion on fore-aft:

================================================== ====

Now we get to what I think is the most important part of fitting a bicycle, the fore-aft position of the saddle. Once you get this right, everything else is easy. This position is determined more by how you intend to use your bike than by anything else. If you look at a typical bike, the saddle is behind the crank center, or bottom bracket. There's a frame tube (the seat tube) running from the cranks to the saddle, and it's at an angle. That angle partly determines the fore-aft position of the saddle relative to the cranks and pedals. That fore-aft position determines how your body is balanced on the bicycle. Your balance determines how comfortable you are, and how efficiently you can pedal the bike.

Stand up straight in front of a mirror and turn to the side. Look at yourself in the mirror. When standing straight your head, hands, seat and feet are all fairly close to being in line with each other. Now bend over at the waist. Notice that not only has your head moved to a position ahead of your feet, but your rear end has moved behind your feet. If this were not the case, you would fall forward. Your seat moves back when you bend at the waist to keep you in balance.

Your torso needs to be leaning forward for two reasons; power output and aerodynamics. With an upright torso, you can't use the gluteus muscles to good effect. Also, you can't effectively pull up on the handlebar from an upright position. An upright torso is also very poor aerodynamically. When cycling on level ground, the majority of your effort goes against wind resistance. The easier it is for your body to move through the air, the less work you'll have to do. With your torso closer to horizontal, you present less frontal surface to the air and don't have to work as hard to maintain a given speed.

Obviously, the most aerodynamically efficient position may not be the most pleasant position to be in for several hours on a cross country tour. So there's a tradeoff. As you move to a more horizontal position, the saddle needs to be positioned further to the rear to maintain your body's balance, just as your rear end moves to the rear as you bend over while standing. It so happens that racers are more inclined to use a horizontal torso position than tourers, and racers are more concerned with having the handlebars further forward to make climbing and sprinting out of the saddle more effective.

If a bicycle had the saddle directly over the cranks, you wouldn't be able to lean your body forward without supporting the weight of your torso with your arms. Because the saddle on a typical bicycle is behind the cranks, your seat is positioned behind your feet and your body can be in balance. Try this test. You'll need a friend to hold the bike up, or set it on a wind trainer. Sit on your bike with your hands on the handlebars and the crank arms horizontal. If you have a drop bar, hold the bar out on the brake hoods. Try taking your hands off the bar without moving your torso. If it's a strain to hold your torso in that same position, that's an indication of the work your arms are doing to hold you up.

For starters, I like to put the saddle in the forward most position that allows the rider to lift his hands off of the handlebar and maintain the torso position without strain. You should not feel like you're about to fall forward when you lift off the handlebar. If it makes no difference to your back muscles whether you have your hands on the bars or not, you know that you aren't using your arms to support your upper body. If you are, your arms and shoulders will surely get tired on a long ride. But this is a starting position. Remember that bicycle fit is a series of compromises.

So what's being compromised? Power. There's a limit to how far you can comfortably reach to the handlebar while seated. If the saddle is well back for balance, the handlebars will need to be back as well. But to get power to the pedals while out of the saddle, it helps to have the handlebars well forward of the cranks. Particularly when climbing out of the saddle, the best position tends to be had with a long forward reach to the bars. You can tell this is so by climbing a hill out of the saddle with your hands as far forward on the brake lever tops as you can hold them, then climbing the same hill with your hands as far to the rear as you can on the bars. Chances are you can climb faster with your hands further forward. So you need to find the best compromise between a comfortable seated position and reach to the handlebar, and a forward handlebar position for those times when you need to stand. Only an inch or two in handlebar placement fore-aft can make a big difference while climbing. That same inch or two in saddle position can mean the difference between a comfortable 50 mile ride and a stiff neck and sore shoulders!

As you move the saddle forward from that balanced position, you'll have more and more weight supported by your arms, but you'll be able to position the handlebars further forward for more power. The track sprinter has the frame built with a rather steep seat tube angle, which positions the saddle further forward from where the tourer would want it. But again, the track sprinter spends very little time in the saddle.

If you can't move your saddle forward enough or backward enough for the fit you want, don't despair. Different saddles position the rails further ahead than others, giving more or less saddle offset. Seatposts are available with the clamps in different positions relative to the centerline of the post.

So, how do YOU want to balance on YOUR bike? Do you want to emphasize speed and acceleration? Do you care mostly about comfort and enjoying the scenery? The answers to these questions determine how you position the saddle, not some computer program or someone's system of charts and graphs. How your best friend fits his bike should have no bearing on what you do even if he has exactly the same body proportions as you. YOU know why you ride a bike. Only YOU know what compromises you are willing to make in order to achieve your purposes on a bicycle.

You may have a bicycle for short fast rides, and another for long tours. Just as the two bikes will have different components so as to be well suited for their purposes, so might the fit be different. The rider hasn't changed. You are still you. But your purpose has changed. The light, fast bike for short rides will likely have a more forward and lower handlebar position than the tourer. And so the saddle may well be further forward too.

[Fat Robert]

somewhere between what obtuse said and what steve hogg on cyclingnews.com says

i use the following jacked-up method for my MP self and my MP teammates:

1) start with a properly-sized bike and (long) proportional stem (i.e., a 130 on a 58 cm bike -- on the long side of proportional)

2) put the stupid saddle at a starting height (30 degree knee bend)

3) put the saddle in the middle of the rails

4) if you start hunching forward when you're going hard, push the stupid saddle back a bit until you're staying on your sit bones. lower it 1mm for every 3mm you go back.

5) if your crotch hurts, put on a 1cm shorter stem and/or raise the stem in 5mm increments until crap doesn't hurt and you're on your sit bones.

I think KOPS is one of the most moronic things north american bike fitters came up with as a "rule." put the saddle in the middle of the rails and move it around until you can cover all the bases comfortably -- from climbing at 75rpm to spinning at 130. when you have a position that lets you do that, leave it and think about girls or something.

[zap]

I think KOPS is one of the most moronic things north american bike fitters came up with as a "rule."

:banana:

Pruitt who?

[RPS]

Along those lines, Peter White's article always made a LOT of sense to me. He more or less punts on crank length but not on fore-aft.

Whole article:

http://www.peterwhitecycles.com/fitting.htm

portion on fore-aft:

================================================== ====
So, how do YOU want to balance on YOUR bike? Do you want to emphasize speed and acceleration? Do you care mostly about comfort and enjoying the scenery? The answers to these questions determine how you position the saddle, not some computer program or someone's system of charts and graphs. How your best friend fits his bike should have no bearing on what you do even if he has exactly the same body proportions as you. YOU know why you ride a bike. Only YOU know what compromises you are willing to make in order to achieve your purposes on a bicycle.

You may have a bicycle for short fast rides, and another for long tours. Just as the two bikes will have different components so as to be well suited for their purposes, so might the fit be different. The rider hasn't changed. You are still you. But your purpose has changed. The light, fast bike for short rides will likely have a more forward and lower handlebar position than the tourer. And so the saddle may well be further forward too.The portion above makes sense to me. One position can not be perfect for all riding needs/styles; and for those of us who are lucky enough to have multiple bikes we should probably consider setting them up differently.

I think KOPS is one of the most moronic things north american bike fitters came up with as a "rule." put the saddle in the middle of the rails and move it around until you can cover all the bases comfortably -- from climbing at 75rpm to spinning at 130. when you have a position that lets you do that, leave it and think about girls or something.A little harsh but your message is clear. I think we tend to take this stuff – like KOPS -- way too seriously. If it were the only way to spin a crank, how would we explain why some guy on a unicycle climbed Mt. Washington at a good clip even though his saddle was directly over the axle (i.e. – BBKT?) with his knees way forward of the pedals, or how a guy on a recumbent can set a speed record with his knees way behind the pedals? It's not as black and white as some would have us think. IMHO everyone should have at least one bike that is comfortable enough to enjoy a long ride without thinking about the bike.

[David Kirk]

I think KOPS is one of the most moronic things north american bike fitters came up with as a "rule." put the saddle in the middle of the rails and move it around until you can cover all the bases comfortably -- from climbing at 75rpm to spinning at 130. when you have a position that lets you do that, leave it and think about girls or something.

Amen Fat man,

I think it's as valid as say the "the bars should block the front hub" or the "inch of clearance between your crotch and the top tube".

Scientific stuff.

Dave

[catulle]

leave it and think about girls or something.

Don't listen to Dr. Doof. He just wants to mix things up. You listen to him and you'll need to switch your position on the saddle again, atmo... :no:

[Simon Q]

where it feels comfortable. for years, my saddle had been set where my knee was over the spindle. but i kept sliding my butt back on my saddle to get "comfortable". then a fitter listened and slide my saddle back. over time, i listened to where my butt wanted to be, kept messing with my saddle, and finally arrived at a place that now feels very good. when you start out riding, we listen to others, which is both wise and necessary, i think. but then we gotta listen to our bodies. this isn't a great answer i know but it's all i got. i think fitters can set folks up in a good ballpark, but then the rider has to listen to their body.

101% what Climb said.

Knee over pedal spindle makes my quads torch before anything else under load. I too worked the saddle back and am now 2 cm behind KOPS and evenly recruit quads, hammies and glutes without any lactic expolsions and am also more powerful as the glutes are more invloved. Many are fine with KOPS, but having now advised some of my riding buddies to try moving back a little it seems many are better behind, if only slightly. I also moved the cleats back so that ball is 10-12 mm in front on the spindle which provides a better pedalling platform for my 49 hoof, another huge improvement for me in balanced recruitment.

I know Pruitt is a superstar and MD but IMHO Steve Hogg that does the Q&A on www.cyclingnews.com is the man. He has put an incredible amount of thought into fitting based on how you function and feel.

[Ti Designs]

You have to use the generally accepted fit tools/methods available along with customer interaction to put the customer in a position that will make them want to come back for another frame.

Oh...

[Trouble]

101% what Climb said.

Knee over pedal spindle makes my quads torch before anything else under load. I too worked the saddle back and am now 2 cm behind KOPS and evenly recruit quads, hammies and glutes without any lactic expolsions and am also more powerful as the glutes are more invloved. Many are fine with KOPS, but having now advised some of my riding buddies to try moving back a little it seems many are better behind, if only slightly. I also moved the cleats back so that ball is 10-12 mm in front on the spindle which provides a better pedalling platform for my 49 hoof, another huge improvement for me in balanced recruitment.

I know Pruitt is a superstar and MD but IMHO Steve Hogg that does the Q&A on www.cyclingnews.com is the man. He has put an incredible amount of thought into fitting based on how you function and feel.

I've perseverated over the saddle fore/aft to point where I've ground my teeth flat while not being able to sleep, not to mention spending hours reading and re-reading articles that support and defeat the KOPS.
Peter Whites article is fun to interpret.

In conclusion to all this, my position is about 1.5-2cm behind (using the front of the knee cap and the end of the crank).
My seat height is set using the extended leg with heels on pedal technique, with a 4-8mm variance allowed.
I also went from a 120cm to a 110cm stem. This is one move/adjustment I haven't tried yet. Something I interpreted from reading Dave Moulton's theory.
The short test ride this morning felt good. Less pressure on the hands...maybe a better balance/compromise...dunno yet.
I'll give this a shot for the next couple of rides, paying attention to proper posture the best I can.
Just to complicate things even more, I'll experiment with raising and lowering the stem/bar height.
For me it's being comfortable on rides in the 50-80 mile range as I get more pleasure and fitness from the longer rides.
I reserve the right to change my mind...

[chrisroph]

my femurs are long, my saddle is far back but sometimes it feels better to move it forward a few mm so I do and them some other times it feels good to slide it back so i do. i think its close to kops but i don't measure that. kops is affected by how high the saddle is at any particular time and it goes up and down a bit depending on where it feels best.

i just moved the saddle forward about 3mm on my cross bike but i haven't ridden it yet.

if my saddle gets too far forward, i start having low back pain and feel too bunched up in the torso. if it gets too far back, i feel like i'm not pedaling efficiently throughout the pedal stroke particularly in the 'power phase".

the saddle on my tt and track bikes are about 1 cm more forward than the road bikes.

nobody can tell you exactly how to sit on a bicycle. you have to figure that our yourself. fitters can suggest a starting point but every fitter has his or her own preferences that may or not jibe with those of your body. its hard for me to be any more analytical than that.

[seanw]

too tall,
are you measuring femur length from the greater trochanter to lateral epicondyle? curious how this is done.

sean

[Too Tall]

too tall,
are you measuring femur length from the greater trochanter to lateral epicondyle? curious how this is done.

sean

Exactly. I located the approx. ctr. of the hip joint (approx. middle of the G.T. head) to medial epicondyle...poTAtoes poTAHtoes. Getting it close will yield the same results. If the calc. falls somewhere in the middle I place more weight on riding style etc.

TiDesigns - bub, have you started using computrainer or other watts measure to test your ideas? That is where I'm at now. By the time snow flies I hope to finish all the work on a custom rig for indoor testing using a fit bike.

[R2D2]

For crank length I've used Peter White's formula (18.5% of the distance from the top of the femur to the floor in bare feet).
For seat height I use the traditional .883 x inseam length.
Fore/aft I use cranks in 3 and 9 position, straight edge from end of crankarm to knee cap.
Sweet and simple.
Anyway I'm comfortable and haven't ended up at a surgeons door.

[Fixed]

bro I set a ballpark figure then go ride take a wrench make little adjustments as needed ..I always seem to go towards the back of the saddle
maybe it's
cos i always wanted to ride like lemond .
cheers