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Posted

good luck with this one!

 

don't think that there is an exact formula that works.

 

i heard / read that the best way to do this is to go for a 30min ride & then start adjusting height until just before you start rocking from side to side.  the best height seems to be about 3mm below this point.

 

below from http://www.coloradocyclist.com/bikefit/

 

"With the right frame size, you?ll be able to set your correct saddle

height, which will be within a centimeter of .883 x inseam length,

measured from the center of the bottom bracket to the low point of the top of

your saddle. This allows full leg extension, with a slight bend in the leg at

the bottom of the pedal stroke.

LeMond recommends that you then shorten this length by 3mm when using

clipless pedals. Also, you might consider a slightly taller saddle height if you

ride with your toes down and your heel raised. Most importantly, make any

changes in saddle height gradually, and give your body time to adapt to the new

position."

 

 

 

Posted

The problem with the .883 x inseam is that it sounds spectacularly accurate until you realise that different crank lengths will through it out.

I think that the other bit of science suggests an angle of 15 degrees at the knee when clipped in and the pedal is at bottom dead centre.

In all seriousness, trial and error is prolly the best to really get this down.  Try raising the saddle in small increments until hips start to rock, then take it back down to the previous setting.

You will prolly find some stuff at www.wrenchscience.com to help, and prolly also at www.sheldonbrown.com

Posted

I'm fimiliar with the.883 equation but because of diff crank lenghts it cant be 100% Thats way I want the centre of axle - saddle height. I had the formula....but ja...

Posted

This can get very technical & in the end of the day you can mess so much with your position that you will never find the correct spot.

 

below some more info i keep around.  most (if not all) of it is from http://www.cyclingnews.com - it covers a lot of stuff!

 

 

Bike fit isssues

 

 

I am 28 years old and am a typical season bike rider and do most of my biking during the wormer months. I cycle about 3 times a week but would like to do more. In the winter I mostly cross country ski. I haven't been cycling that long. About four years ago I started competing in some sprint distance triathlons at a beginner's level. I hade been cycling a little mountain bike the year before that but mostly as rehabilitation because I was diagnosed with patella tendonitis the year before that (about 6 years ago now, before this I never biked).

 

Last year I did not do that much cycling because I was traveling a lot but started up again this year.

 

Symptoms I have had for the past few years.

 

Pain around the Patella in my right knee during and after longer (1:30-2:00 hours and more) bike rides. I get this more or less every time I go over 2:00 hours, it helps a little bit if I stretch a lot before the bike ride and do a good worm up.

 

Pain on the outside of my right knee. Use to get this a lot more before but not so much anymore. I will still get it if I don't do a lot stretching of the IT band right before a bike ride, or if I have not done any stretching for a few days.

 

New Symptoms for this year:

 

Irritating feeling in my left knee, feels like the patella isn't tracking correctly. It is not as bad if I do a lot of aggressive quad stretching right before the bike ride. It is also not as bad with, but still not great, with the new LOOK pedals that I recently put on my road bike where my feet are more angled out on the pedals.

 

I can get bad hip pain, mostly in right hip, after some of my longer bike rides but never during the ride itself. If I get hip pain it usually comes a little wile after I have finished riding and lasts anywhere from a few hours to a few days. I don't always get this, maybe every second or third week depending on how much riding I have done. I have also noticed that if I go to a chiropractor my hip is better for a week or so.

 

Lower back pain during, but mostly after, longer bike rides.

 

Also pretty often both my knees feel a bit sore and get a bit worm in the evenings after a bike ride that I have had previously that day.

 

Eddie Hult, USA

 

Steve Hogg replies:

 

It sounds like you are not sitting squarely on the seat. Can you verify this?

 

I need you to mount your bike on a trainer and pedal under load with your shirt off. You will need an observer to stand on a chair behind you and look down at your low back and pelvis. Which side twists forward if any?

 

On which side do you drop your hip if any?

 

What brand, model and size of shoe do you use?

 

What type of pedal are you using?

 

What seat do you use?

 

How flexible are you?

 

Have you noticed any differences in flexibility between left and right sides?

 

Do any differences in left / right flexibility become more pronounced in your cycling season as distinct from your skiing season?

 

Eddie responded:

 

I jumped on the trainer with my road bike and had my girlfriend observe me for a wile.

 

She looked at me for a few minutes and said that if anything is going on my right hip is dropping. She said if it is dropping it is very little, so little that she is not sure it is actually dropping.

 

She is quite sure however that no side is twisting forward.

 

(I did the same with my MTB and she saw no difference)

 

I have the Specialized S-Works Road shoe size 46 EU, 13 USA. These are my new shoes (about 3-4 weeks old, before I used my MTB shoes which are Specialized mountain bike shoe (don't know what they are called) size 46 and 12 USA (for some reason the USA size differ between the two??))

 

I am now using Look Keo Carbon pedals (use to have the same as on my MTB before I got new shoes, Shimano SPD)

 

My seat is a SelleRoyal Wing (came with the bike, looks like a regular road bike seat).

 

I am pretty flexible, I do a lot of stretching, I can touch my hands on the floor with my legs strait without bigger problems. However my thighs are very heavy to stretch, that is, I have to use a lot of strength to stretch them, it takes a lot of energy. The only thing that may not be as flexible as it should be is my ankles and calf muscles, they are a bit tight.

 

No bigger difference between left and right flexibility, if any my left thigh is bit tighter and perhaps my left glut, but not much if any.

 

I notice no difference at all in my flexibility between my cycling and skiing season or left vs right.

 

Steve Hogg replies:

 

Given everything you have told me, that you are flexible and reasonably square on the bike, there are a number of things that come too mind:

 

1. Have a look at these posts and position your cleats accordingly: www.cyclingnews.com/fitness/?id=2004/letters07-26#cleat and www.cyclingnews.com/fitness/?id=2004/letters10-11#Ball

 

2. Are your cleats at an angle that allows free movement either side of where your foot naturally wants to sit on the pedal?

 

If you have the grey Keo cleats, replace them with the red Keo cleats. The grey ones have very little rotational movement and it can be a chore to get them just right. The red cleats have more than twice as much rotational movement and are cheap insurance. If you are not using the freeplay, it isn't there. If you are using it, then you need it.

 

Once you have done this, go for a ride and put real pressure on the pedals for 10 - 15 strokes on each side. Now coast with right foot forward and attempt to move your heel inwards.

 

Is there available movement?

 

If no, adjust the angle of the cleat by twisting the nose of the cleat outwards and retest.

 

If yes, repeat the process of push hard for 10 - 15 strokes on each side but this time attempt to move your heel outwards when you coast. Is there available movement?

 

If yes and the amount is similar to the amount you have in terms of heel inwards, mission accomplished and repeat the process on the other side.

 

Once you have done both feet, it often pays to recheck the first one.

 

I think this is worth doing, but given that you have problems of two different bikes with differing pedal systems and shoes, this probably isn't your problem.

 

3. The knee is a single plane hinge joint. The plane of movement it is forced to work through can often be dictated by the function of the hips, and lower back at one end of the chain and the function of the foot and ankle at the other end end of the leg.

 

Get hold of some Lemond Wedges and fit 2 for starters to the right shoe and 1 to the left shoe with the thick side of the wedge to the inside of the shoe on both sides. Often this will mean that you have to change the angle of your cleats on the sole of your shoes by following the process outlined in Step 2. You should be able to determine fairly quickly whether the wedges are an improvement or not. If your feet feel more stable on the pedals it is a good sign. If this is what occurs, there should be a positive improvement in the knee wavering. Experiment with the number of wedges until you arrive at the number that feels appropriate.

 

4. Now for the big one; the back pain. At six foot 5, it is possible but not probable that you are riding bikes that fit you. You may have your seat too far forward and possibly too low. This will cause you to load your quads, work your hip flexors hard with back pain the result. If the bars are too low, this will just add to this effect. Alternately, you may have your seat too far back causing you to flex the lower back too much to reach forward to the bars.

 

Raise your seat to the maximum height where you can ride up steep hill at 75 -80 rpm pushing hard at a high heart rate and still feel like you are smooth through the bottom of the pedal stroke. Once you have done this, drop the seat 3mm from whatever height you are at.

 

Once the seat height is set, you want your seat at the minimum distance behind the bottom bracket that allows you support your upper body weight while maintaining a relaxed upper body. Test for this by riding at speed in a big gear at 85 - 95 rpm on the flat. You should be able to remove your hands from the drop bars without uncontrollably collapsing forward. You should be able to teeter for a period without arching your back or swinging your arms back towards the seat to assist you. If you pass this test easily, then move the seat forward until it becomes hard to pass and then move it backwards, say 10mm.

 

If you can't pass this test easily, move your seat back until you can. If this means a change in seat post, let me know and I will advise you what to buy.

 

At higher rpm than stipulated, it will be harder but not impossible to pass this test for most. At lower rpms it will be easier, so try and stick to that. If you have good core strength, you will do it easily. If you have poor core strength, pick the position where you are challenged but not massively. If your self description of flexibiltiy and your girl friends observations of your on bike symmetry are accurate, then you shouldn't have a problem

 

Once you have done all of this; if the seat needed to move back substantially, drop it 1mm for every 3mm that it moved back. If it moved forward substantially, raise it 1mm for every 3mm it moved forward. Then retest both cleat angle as described in Step 2 and seat height as described in Step 4.

 

5. Now you have to position your bars well. The correct position is where you can exercise all your hand placement options; i.e. brake hoods, bar tops, and drops with ease and comfort. It helps if you have an understanding bike shop that will let you trial different stem lengths and angles on a trainer until you are reasonably sure that you have the correct one. Once you think this is the case; confirm or otherwise on some longer, reasonably challenging rides.

 

When you are fairly sure that you have the right stem length and angle, re try the balance test and modify seat position as necessary. This may entail another stem length or angle change.

 

Once you have worked your way through this, let me know what happens. I apologise for the length of reply but you don't seem to have any standout obvious problems in the sense of the information that you have given me.

 

 

Cleat position and seat height

Thank you for all the great advice you provide about cleat position and cyclist posture/biomechanics. I have a question, one that a few others in our Belgium bike club have also wondered about.

I have been riding 15 years, have been told my flexibility is way above average, have never really had on-the-bike problems and thus I have suffered little biomechanical problems on the bike save for shimming my left cleat due to a 6mm left leg being shorter than the right. I ride Sidi shoes (I have narrow feet, size 45) and Look (red cleat) pedals. The ball joint on both shoes/cleats has been about 5mm forward of the axle crank center.

After years of wondering, I recently decided (trying to get to your 10mm suggestion) to just shove the red cleats back as far as they could go on the Sidi shoes, to test your theories. On the first and ensuing ride after doing this, I was in heaven, feeling a more powerful plant on the pedals, feeling even more better in posture (something I couldn't believe), and not noticing any toe pointing in and/or out.

My question is this: when a person begins moving the cleats of any shoe back to lengths you suggest in your articles, what should we be doing with the seat height and seat front/back position? For example, I changed nothing else on the bike when I slid the red cleats all the way back (keeping their same position for everything else). I have noticed over the weeks some soreness in my right (longer leg) frontal knee area (almost like a meniscus soreness), but nothing that my flexibility and comfort while on the bike can't overcome and/or just ignore.

In general, should there be some seat height and/or front-back adjustment when moving cleats to your suggested lengths?

David Whetzel

Mons, Belgium

Steve Hogg replies:

I am assuming from what you have implied that you moved the cleats back 5mm or so further on your shoes. Assuming this is the case, then it is probably likely that you need to drop the seat a couple of mm. I say 'likely' because sometimes a rearward change in cleat position can cause a rider to alter their pedaling technique. This can sometimes mean that seat height may even need to rise.

The balance test

I was reading the fitness letters and reference to getting the saddle position setup dialled using the 'balance test'. Can you point me to an article that explains this test?

Rolf Rae-Hansen

Edinburgh

Steve Hogg replies:

We all want to have an effective position on a bike and there is a lot of often conflicting advice available regarding this. So let's start with basics and define a couple of terms. There are 2 basic philosophical approaches that can be taken to rider positioning; reductionist or holistic. A reductionist approach tends to focus on one aspect of the body. It might be a strict biomechanical approach based on statistical norms or it may be formula driven and based on mathematical formulae. Sometimes a mix of both is used.

I have 2 criticisms of this way of positioning people. The first is that methods based on averages tend to yield average results at best. How does anyone know whether they are Joe or Josephine average? Equally, even if they think they are, how do they know they are average in the various parameters of position that may be considered by any particular reductionist method? 'Average' people are creations of marketing companies, not of real life in most cases. At least, that has been my experience to date. The second criticism that I have is that this way of doing things tends to attract people that learn a 'recipe' or formula and too often this tends to blind them to seeing what is in front of them in any single case. Reductionist methods can be a crutch for those who don't want to think or a hindrance to those that do, but are worried about departing from a formula or recipe based on mathematical/biomechanical/marketing cred at some level.

A holistic approach considers the whole body. An effective position is comprised of often contending requirements. As an example, a rider may want to be aerodynamic but if he pursues that idea too far, breathing ability and power output may be compromised. Or a rider may want terrific leverage on the pedals at low rpm for hills but also be able to spin like really fast when necessary. To pursue either too far will compromise the ability to do the other well. That is what a bike position is; a set of compromises based around the structural and functional realities of the rider and the type of use they wish to put their body and bike to. This makes the task of positioning the rider much more of a task of judgement than of applying norms or formulae and this is something that a lot of people in the positioning biz are uncomfortable with.

So how to go about it and what basis should we operate on?

Let's start with the most basic requirement - neurological fitness. Neurological fitness is the measure of how accurately the signals from the brain and the feedback from the body to the brain travel around the body and is largely determined by how adequate our level of Structural fitness (posture, flexibility and core strength) is. At any moment in time, our level of Structural fitness is a given. No one can change or improve themselves instantly in that regard by waving a magic wand but they can base their position on principles that allow the most efficient use of the motor control parts of their brain no matter what their current Structural fitness level. If they don't, then optimal performance within the constraints of their current structural limitations will always be elusive.

How do we do that?

The way we have evolved neurologically means that our brain gives absolute priority to our postural musculature (allows us to stand erect, hold any given position, plays a very large part in breathing) and lesser priority to our phasic musculature (power producing). If you accept that statement and my understanding is that it is fact, not conjecture; then in the quest for greatest efficiency on a bike, it makes sense to sit on a bike in such a way as to involve the least amount of postural musculature in holding a position on the bike. That way we can devote the greatest effort neurologically and physiologically to propelling the bike rather than in maintaining a position.

Still with me?

If you are, the only way to limit postural muscle involvement on a bike is to have the seat the minimum distance behind the bottom bracket that allows the rider to cantilever their torso out from their pelvis without unnecessary enlistment of torso or shoulder complex musculature to support that upper body weight. Just how far the seat needs to be back is an individual thing that will depend on the core strength, proportions and flexibility of the rider involved.

A simple example: 2 measurably identical riders. Rider 1 has a tight lower back and poor ability to extend (flatten ) the mid thoracic spine. Rider 2 is quite flexible. Rider 1 will need to sit further forward than Rider 2 because his back is convexely curved and so doesn't throw as much of his torso weight forward. Rider 2 may have greater ability to support that extra effective torso length gained by his greater ability to extend his spine but he still has a longer effective torso length. That means that he may need to sit anywhere from slightly further back than Rider1 to way further back depending on a host of other factors.

The short cut to achieving this is what I call the Balance Test. A brief description is as follows. Get on your bike and ride with hands in drops on flat road in a large gear where you are working hard muscularly and are at about 85 - 90 rpm. Take your hands off the bars and hold them beside the bars. Can you do this without arching your back, swinging your arms back or falling uncontrollably forward?

If not, then you may have your seat too far forward. I say 'may' because many peoples level of structural fitness is so poor, and usually accompanied by asymmetries of pelvic function, that they are inherently unstable on a bike seat. That means that they use their shoulder and upper body muscles to brace and stabilise themselves with no matter what. For those people, and there are a lot out there, it becomes a case of best possible compromise. They may not be able to pass the balance test without a lot of structural improvement, but they should feel that the great majority of their weight is borne underneath their sit bones and little borne by their arms.

Cross checks to determine whether you have got it right.

1. Apart from the structurally superior few, you should be able to teeter on the point of balance, not be rock solid.

2. If you are too far back, good leverage and being able to push a big gear will be fine but ability to pedal fast will be compromised.

3. If you are not far back enough, spinning will be fine but big gear ability (relative to strength and ability) will be compromised.

4. A pre condition for all of this is good cleat position as has been mentioned many times in various posts. Cleat position plays a large part in the way the muscles of the leg are enlisted and how stable we are on pedals and seat. See these articles on cleat position and the ball of the foot.

5. Other factors that can derail this are bars that are too far away or too low for a particular riders ability to reach them comfortably under load.

6. Even if all is okay, there will be weight on the bars at low speeds and intensities. The idea is the harder the rider goes, the greater the unweighting of the bars. Remember that it is at high intensities that we need to be really efficient.

In simple terms, the holding of a position should be effortless or nearly so. That way all available effort, neurological, muscular, whatever, can be used to drive that bike down the road. In other words, the position is held passively rather than actively.

What happens if we don't do things this way?

Well for most, they will have too much weight forward for a minority they will be too far back). When there is too much weight borne by the upper body at high intensity (and we have all seen people who look like they are trying to drag their bike down the road with their arms and shoulders when going hard. The back arches and tenses, the shoulders tense and the arms tighten) breathing ability is restricted. There are 20 muscles used in respiration of which 18 have postural implications. That means that they can also be used to bear weight and stabilise the upper body with. If they are bearing weight and stabilising the upper body, then they cannot relax to allow full breathing. It is unlikely that this will matter too much at low speeds and intensities but most races are decided by who can perform the longest at higher intensities. Meaning that if you want the best chance of winning you need to tick the box marked 'Ride at lowest metabolic cost'. The Balance Test, correctly applied is the big picture of being able to do that.

There are plenty of other details but that will get anyone with a modicum of body awareness pretty close to where they need to be in terms of seat position fore and aft. Providing that they have good cleat position and seat height.

 

Cleat position #1

A question for Steve Hogg. When commenting on the lady with the short femur you mentioned the following re cleat position:

5. Make sure that the ball of your foot [centre of the first metatarsal joint] is in front of the pedal axle with the crank arm forward and horizontal. For a rough guide for shoe size metric 36 - 38, 7mm in front; 39 - 41, 8mm in front; 42 - 43, 9mm in front; 44 -45, 10mm in front. It is unlikely that your feet are bigger than that. Don't forget to move the right cleat further back again as outlined in point 3. I know that this is at variance with the commonly given advice but you will find as you try it that it works.

Are you just commenting on her specific case or is this the normal

recommendation for cleat position?

Mike Sinclair

Steve Hogg replies:

The cleat position I recommended for her was not specific to her but rather a general recommendation. It is a normal recommendation for me but somewhat at odds with a lot of what I would describe as ' recieved wisdom' advice re fore and aft cleat position. If I saw that lady in person I may have changed my recommendation a mm or so either way depending on her particular pedalling technique, amount of heel lift in the shoe last she has, her particular foot morphology etc.

In most publications the advice given is to position the cleat fore and aft so that the centre of the first metatarsal joint [ ball of the foot] is over the pedal axle centre with crankarm and shoe forward and horizontal.

The idea, apparently, is to

1. Maximise the lever length of the foot as measured from metatarsal head to centre of ankle; and

2.To engage the 'windlass mechanism', the term used to describe plantarflexion of the ankle [ point foot down] accompanied by dorsiflexion of the toes [flex toes upwards] causing the tightening of the plantar fascia which turns the foot into more or less a rigid beam.

That reasoning makes sense in any quick reading but my experience is that it is way off the mark. Point 1 maximises the effective lever length of the foot but neglects the issue of control. If leverage is everything, then you and I should be able to hit a ball out of the ground with tip of the bat, because that point of contact maximises the lever length of the bat. If you have ever tried it you will know that it is not possible. All that happens is that you jar your wrists and elbows because we cannot fully control the movement. The greatest effective lever length of the bat is approximately 100mm up from the tip, the aptly named 'sweet spot'. And so it is with a foot on a pedal. By reducing lever length slightly we massively increase our ability to control the movement of it. Another factor in my view of this, is that many people are concerned about the amount of leverage they have on the crankarm and rightly so. But to many are hung up with quantifying this at the 3 o'clock position because this is the point of greatest leverage and hence torque development. No matter what parameters of seat and cleat position we set our self on a UCI legal bike this [give or take a fraction] will be where we exert greatest torque. So the question then becomes where can a rider make gains elsewhere in the pedal stroke. The major area in my view, where improvements can be made, is how soon after top dead centre can we get behind and over the pedal axle to propel it forward and down.

At that point, we all relative to individual technique, drop the heel more than elsewhere in the stroke under any reasonable load. If the ball of the foot is over the pedal axle as measured by the usual method, then at that point, the ball of the foot is BEHIND the pedal axle. If the ball of the foot is positioned the way I would do it, then at the same point in the pedal stroke, coming off top dead centre, then the ball of the foot would be OVER the pedal axle. This makes a big difference.

Point 2 is in my view, the misapplication of running / walking foot mechanics to cycling. I am convinced that the windlass mechanism is at work when we are riding OFF the saddle. I am equally convinced that the windlass mechanism is either not engaged or barely engaged when riding ON the seat, which is what we do the great majority of time spent on a bike. The question I would pose, is that if the windlass mechanism is strongly engaged when pedaling on the seat, then why does a rigid soled cycling shoe feel so much better than a more flexible soled cycling shoe. The answer that I would give is that the rigid sole is performing a function that the foot cannot.

I could go into more detail about the way most manufacturers have reduced the amount of heel lift in their shoes over the last 10 years [ this reduces the possibility of windlass mechanism engagement] but this should suffice.

My apologies for the length of this reply, but yours was one of many inquiries that I have received about just this point and I am hoping that this reply will satisfy those others too.

Cleat position #2

[Editor's note: Kim Lopez asked Steve about his reasoning on cleat position and received a reply substantially the same as the one above, then asked the question below.]

I was trying to look for your reply to a similar question (where you listed shoe sizes with appropriate cleat set-back) but I couldn't find it. I hope you don't mind sending it to me (or tell me where I can find it on my own).

Kim Lopez

Phillipines

Steve Hogg replies:

Here is the sizing info you requested for cleat positioning. Shoe size 36 - 38: centre of ball of foot 7mm in front of pedal axle; 39 - 41: 8mm; 42 - 43: 9mm; 44 - 45: 10mm; 46 - 47: 11mm 48 - 50: 12mm. There are a number of qualifiers that I will attach to those recommendations. 1. This info is for road and mtb riders. For general track riding, I would reduce the amount of foot over the pedal by a mm or 2 depending on shoe size and event. For sprinters and kilo riders, I would halve the recommended amount of foot over the pedal. 2. If positioning someone in person, I might vary the above a mm or so either way depending on other factors. 3. For riders with an exceptional heel dropping pedalling style, I would increase the amount of foot over the pedal slightly. The converse is true for the exceptional toe down style pedallers. For both groups I'm talking about technique under moderately severe load, not cruising in a small gear pedalling fast. 4. For riders with a lot of heel lift in their shoe last, I would increase the amount of foot over the pedal slightly. 5. For riders with flexible soled shoe, I would increase the recommendation slightly as with this type of shoe the heel deflects downwards more under load.

 

 

 

 

 

Posted
I'm fimiliar with the.883 equation but because of diff crank lenghts it cant be 100% Thats way I want the centre of axle - saddle height. I had the formula....but ja...

 

What about the amount the padding on the seat sags? The pedal body and cleat thickness also playes a part.
Posted

 

Dr Suess' date=' can we have it in afrikaans asseblief. smiley19.gif [/quote']

 

jammer maat - as jy nie die engels verstaan nie,  gaan jy steeds nie gat of kop daarvan kan uitmaak nie - al is dit in afrikaans!

 

 

 

 

 

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