I have been keeping up on most of my new years resolutions except my blog! However, I promise I will update more and with still interesting stuff........and more common interest topics!
till then......have a great ride!
Monday, January 21, 2013
Wednesday, March 14, 2012
Reason To Get A Bike Fit: Full Understanding Of Your Options: Post 2
Seat Tube Length is as good as any place to start. A while back ago, there was a basic formula established to come up with size of bike a person needed. You measure your actual inseam, shoes off, preferably with an inseam device or the lay mans approach with a book shoved up into your crotch against a wall. Centimeters x .657 = center to center (of frame) size, gave you your bike size, i.e; 52cm. This was back when frames were pretty much horizontal and the seat tube-top tube intersections were measured at the center of that junction from the center of the bottom bracket. Now with everything sloping, mix that with companies taking their own approach to measuring seat tube length, top of the top tube at the seat tube joint, and some measuring to top of the seat tube or seat mast (and that extending above the junction 1cm to more than 6cm), it raises all kinds of confusion in interpretation of what some one needs, from one brand to the next and even within the brand. Point: seat tube starting point is only that, you may need to go up or down in size. So, we now look at stand over height. Obviously, once you have shoes on, this will give you a lift, but even though it is necessary to be able to comfortably stand over the top tube, at some location along it's plane, it is still not as important as your upper body's ability to properly spread out, it's height or angle relative to the legs and hip position, and the weight applied onto your hands at the bars.
Stack and Reach, a newer concept in determining or rather measuring the front end height and reach. This is a decent way to look at someone's needs from bike frame to bike frame. You must check, again, on the type of headset the frame uses, as this can take away 2.5cm or add (approximately). Stack is based off measuring the height of the top of the head tube (at the center of it) from the Bottom Bracket. Reach is based off measuring the distance (horizontally) from the center of the BB to the center of the head tube at the top of it. I have to add that the spacers on the steerer tube (the fork's shaft that comes up through the head tube) along with the angle/length of the stem help or subtract from your particular needs. Another way to look at this is in the Head Tube length and the Top Tube length or Effective Top Tube length. Either way, these two measurement are, in my opinion, the most important for proper fitting than just the seat tube. As you will find, from model to model, brand to brand, these numbers will vary a lot. What is right for you is partially determined by a professional fitter, the current bike you are riding (assuming you know what is right and wrong with it), and possibly your test rides on various geometry styles.
Top Tube length and more importantly Effective Top Tube are another key area of concern and evaluation when considering the correct overall size. Since most bikes slope (top tube from head tube down to the seat tube), and at varying angles of slope from brand to brand, model to model, and along the various sizes, Effective is a more accurate number to look at. In fact, many only list Effective vs Actual. For instance, the taller the head tube, and the greater the slope downward, and angles on the Seat and Head Tubes, this number could be shorter or longer than you need. Effective is measured from the top of the Head Tube at the center-horizontal to the ground-back to the center of the Seat Post center. Other factors that can help or detract from these numbers being in the right/wrong direction is Seat Post offset, saddle position (up/down, and fore/aft), then the Stem length and Handlebar dimensions.
Head Tube Angle affects reach, handling (quicker or slower), weight distribution, and even toe overlap with the front wheel. For the most part, this is pretty dialed in now a days from size to size.
Fork Rake also has impact on steering responsiveness. Measured as the amount the fork center line varies from the center of the dropout. This is usually predetermined from the factories, complete bikes, and frame sets. So, changing that is not an option. Most range from 4.3 cm to 4.7 cm (the overall is 4.0-5.2). The lower the number, the quicker the response of steering, essentially. However, many other factors impact this, like; stem length, weight distribution, chain stay length. Another consideration we use in determining fork rake when building a custom frame or a frame up build, is toe overlap and front end stability. For the most part, this is not something you need to consider too much but, wanted to explain it's impact.
Seat Tube Angle is an area that is wide ranging from brand to brand, size to size. This is a particularly interesting area of design for me personally. The basic reason or determination of it is leg length and femur length. Many stats state that the shorter the legs, the shorter the femurs, and you bring the Seat Tube Angle forward (toward the head tube). Male vs Female: Female's usually have longer legs (inseam) than men for any given height. Shorter men and men in general have slightly shorter legs but, it's mostly in the femur. Mix this with the smaller bike frame's make up or geometry dilemma and what you generally find is the smaller bikes have a steeper Seat Tube Angle-i.e; 74-75 degrees. This is one way to also get you closer to the handlebars, assuming you are shorter everywhere else. This is where my personal problem with many stock bikes exists. Bare with me for a second, as my main point is to show how the bell curve and stock geometry bikes do not work for everyone. I am short legged compared to my 5' 8" height, so I get more of my height in my torso length. But, to be specific, my femurs are long, which means in order to get my knees over the pedal spindle or behind, with a 74 degree Seat Tube Angle I have to either use extreme set back seat posts-more than 3 cm, or go custom. Once I get the seat back, then the reach tends to be far too long, add to this that I have been battling an extremely bad back over the last 15 years and I can no longer bend forward as much, so my reach and height need to be even closer. I'm not embarrassed to say that Trek's WSD (Women Specific Design) tends to be more correct for me (stock geometry) than the given 52 cm men's frames. However, I am a lover of Titanium frames and I get to spec my own custom geometry and this has been my preferred approach for my last three road bikes. That all said, I have seen a good trend in bringing that Seat Tube Angle back-slack, and shortening the reach and raising the height. For most, including the WSD, this has been very good.
Chain Stay length is set, mostly, for quicker acceleration (so shorter in length), and for tire size allotment. This length does not vary much on most of the road bikes, sport or race. However, on taller front end bikes (sport rd-Trek H3), touring bikes, and similar, these lengths do get longer. The reason is by extending these out it helps to push weight back into the front end-to stabilize the front end at high speeds. See, when more of your weight bias is on the back wheel you need to balance the weight bias for safe handling. This is something we do with our Steelhead Bicycle frames and I did with my own custom frame.
Now, the last item of note is Bottom Bracket Drop (how much drop from the horizontal line from axle height), some only state Bottom Bracket Height (from ground). The lower this number is on Drop, the higher it is from the ground, thus raising your center of gravity but, allowing for better pedal clearance to the ground, a consideration for criterium type racing or pedaling through corners. The higher the number for Height is also doing the same thing. The greater the Drop, or the lower Height number, sets your body lower, improving stability (common on touring bikes), minimizing in toe overlap for shorter/smaller frames, and helps to increase stand over height, especially beneficial when mixed with tall head tube bike frames. I personally designed a really low Bottom Bracket Height for the above mentioned reasons and I love the feel.
So, there are the basics and for the most part, the most important aspects to understand in bike geometry as it relates to road bicycles. I must point out that we are in an age of a lot of sub-category bikes, special use road bikes, relaxed, racing, commuting, etc. So, most of my points do apply to all of them but things like wheelbase, fork rakes, chain stay lengths, will vary quite a bit.
Some people through the years have come up with really quirky "rule of thumbs", or ways to quickly determine proper fit or if a bike is set right. One of them is when you are sitting on the bike and hands on the bars, and you look down at the front hub, the bars should hide the front hub. This is so far off the beaten path that I actually get angry about it. This is not even pointing out the importance of proper saddle position, proper bar reach and height set first, and leaves no directive of where your hands should be on the bars, not to mention bent elbow (which is correct) or straight. So, needless to say (but, I will), this is just the start of why this sends a really bad concept into some one who does not know any better. Add to this, varying morphological variations, long neck, long arms, bars up high for bad backs, so on and so on. Then, you look at the varying frame types, head tube angle, fork rake, fork offset, wheel size, etc. I posed this question to 7 different bike manufacturer's, to see if they built bikes off this notion, and not a one of them subscribed or gave any truth to this adage. There are many, many more but, I really do not wish to waste my time or yours on giving any of them and credulity. So, let's move on......
Now that Bike manufacturers's are both listening to bike fitters and learning the importance of bike fit and it's impact on geometry, we are all in a good spot with options for comfort, safe handling, and a bike that can do more than one thing well. Sort of like having your cake and eating it too. I am especially happy with the gains made for women! For years, they have been around 50% of the buyers but, heavily ignored in frame geometry, size ranges, saddles, bars, shoes, shifters, and having high end options. We have seen huge gains in options for the ladies. The bike makers are slow to change, slow to respond, but we are in a good place in the cycling industry. Things should only keep getting better, especially because sales growth have not slowed for about the last 11 years. Now, if custom can be had at no extra charge, quickly, and in any material.......then I will be very happy!
In my next post I will talk about the facts, the pros and cons, and opinions on the different frame materials.
Happy Riding!
Tuesday, March 13, 2012
Reasons To Get A Bike Fit: Basic Morphology vs Geometry, Post 1
I wish to explain the very first starting points in understanding why there are so many frame sizes, geometry options, and the most basic understanding of body differences. For the sake of clarity and expediency in this explanation, I will not go into more complex body structure variations, mechanical differences and mal-alignments. This will be addressed, in a later post, as this is much more common and the norm vs the norm being of perfect symmetry and range of motion. The purpose of this post is also to explain why it is almost always best to start with an experienced fitter vs trusting a friend, online fit calculators, or even an inexperienced bike shop salesperson. This is NOT a shot at that person or saying that they don't have your best interest in mind but, rather many just do not possess the detailed and proven knowledge of working with intricate bike fitting techniques and an understanding of bicycle geometry. My hopes are to help clear the air on bicycle manufacturer's geometry differences, why you are not always a certain frame size, and why knowing your own body can overcome someone else's inaccurate recommendation.
A little brief history can start to explain the imposed issues and variations of today. Years and years ago, there was little as 1 size bicycle. Then that became a few sizes, then step thru design in one size, then as many as 9 sizes, and so on. Then about 20 years ago the largest bicycle maker on the planet decided to make three sizes (Small, Medium, Large), mixed with several seat post lengths and set back, as well as several stem options in a dealer kit. They figured this would accommodate most of the people in the bell curve and eliminate making so many sizes, thus reducing costs and improving profit. Sounded like a simple and reasonable idea. However, what most were not aware of is this would really only accommodate an even smaller section of sizes in the bell curve! It took a few years to take hold but, here we are 20 years later and sloping top tubes are the norm. But, this idealistic and selfish approach set the industry back, in terms of proper sizing for the bulk of the adult size ranges, and it's continuance of one key aspect that the industry has greatly neglected for most of it's history-comfort! See, what that bike manufacturer found (and pitched in marketing), was if you sloped the top tube, you would gain stand over height for the shorter inseam person, and one could lengthen or shorten reach by an almost equal proportionality via handlebar stem. This was still mostly targeted at racers or young and flexible riders. They also pitched that this sloping design offered a stiffer frame (smaller triangles) and less weight (less overall tubing). The good news is that a few small frame builders and a few large bike companies saw this as an opportunity. An opportunity to experiment with better stand over clearance for most, and a cool way to raise the front end (head tube), while shortening the reach (top tube). Sure, it made the bikes look a lot different, but this led to bicyclists being more comfortable. This was the start of addressing the needs for the vast majority of riders, recreational not racers. These few pioneers put the insightful/genius into what was a dumb/discriminating new bike geometry.
Now, in 2012, we have most of the major manufacturers making several varying geometry options, as well as more female specific designs than ever before. They are also addressing ergonomics at all the points of contact of the bicycle. This helps, in the vary least, to accommodate not only a wide personal height range but varying flexibilities and personal comfort. See, what is finally being respected here is that if you grab 5 people all 5' 8", they will all require a different set up. Which means different saddle heights, saddle fore/aft positions, different reaches to the handlebars, and different handlebar heights. Going further, those 5 people at 5' 8" might ride everything from a 52cm to a 56cm road bike, and further yet, a tall/relaxed head tube bike frame to a really short/aggressive frame, not to mention an array of ergonomic variations. For instance, Trek makes the same size frame, i.e; 52cm in three geometry options: H1(race performance), H2, H3 (sport performance). Head tube lengths range in 4.5 centimeters, and top tubes range in 6 mm. Specialized makes varying geometries under different model names. For instance the Specialized Roubaix line (endurance road) have taller head tubes vs the Specialized Tarmacs (competitive road). Whatever the brand, understand their descriptions, check out their geometry charts, and try riding both if you can. Head Tubes are also affected by the different headset styles. Integrated, press in, inset, etc. You can either lose 2+cm or gain it, which can cause one frame over the other to fit better. Head Tubes and Top Tubes are more important than seat tube length in my opinion. After performing nearly 9,000 fittings, I have never found a frame not accommodating of a lower handlebar height, even in extreme cases, but have had to do extreme things to make a bike taller in the front to the point of giving up on it. When a frame is near perfection for your needs, the geometry in all the other areas are usually adjusted for optimal and safe weight bias to keep the wheels on the ground and handle safely.
This leads me to underline the point of questioning and being honest with ones self. Asking yourself what type of riding you will be doing. For instance, long rides over 50 miles at a slightly slower pace vs shorter rides under 30 miles at a fast pace. Are you competitive and wish to work at good posture and core strength or is this for fun and excitement along with some good exercise the goal? Add to this, the fact that as we all get older we lose flexibility, lose muscle mass, varying discomforts set in, and generally we ride longer but at a slower pace. These facts and variables are all a part of the vast considerations for proper bike fit set up and impacts the geometry that is beneath you. I have fitted thousands of people that purchased the wrong size bike and I wish to help eliminate that costly mistake. See, not only does this lead to pain and fatigue, but an imbalanced bicycle that can handle in a very unsafe manner. All of these reasons lead to people giving up on cycling as an activity or sport.
Let's point out just a few quick and easy self tests you can perform on yourself, in front of a partner or mirror. Stand with your feet together, legs straight-to just slightly bent, now bend over and reach for the ground. The further you bend over, the strain usually causes more bend in the knee, or the lower spine and hip quits rotating and then the upper or mid spine flexes to get closer to the ground. If you can touch your toes-rate yourself at a 5 (out of10), if you can touch the ground with your finger tips a 6, and so on. The next test is lay on the ground, knees up, feet flat on the ground, arms crossed across the chest, now raise your shoulder blades off the ground and perform a basic sit up. Note if the feet come off the ground, if the hips rotate upwards or down into the ground, and if you shake or are very steady. Now, I have seen people with what appears to be a slight belly but they have a strong core and vice versa with a slim belly with a weak core, but the person with more girth also has to respect this dynamic when your thighs come up to your stomach and you are either in your lowest bar position or even the highest. This test and considerations affect handlebar height (relative to saddle height) and to some degree reach. Being too low not only causes the knees and legs to be pushed outwards, but also causes much discomfort in the back, poor weight distribution, and inefficiency in your pealing mechanics, too name a few problems. Too ignore these factors is a recipe for problems. This is not a pass/fail but, rather acknowledgement of limiters we all have to some degree. One has to respect that your body will change in many ways over a year. What one needs today may vary greatly from a year from now. So, wether you try fitting yourself, or get a bike fitting from a professional, don't go into it thinking I'll set it up one way and just adapt to it. WRONG! Sure, there is always some adaptation, some trade offs, but this sort of thinking only says you are a slave to your bike and it's looks vs the bike will adapt to your bio-mechanical needs for optimal efficiency and comfort. I have played in many many sports, and it amazes me how many people will not use that doctrine in other sports but they will in Cycling. To minimize pain, limit injury, increase efficiency, therefore improving performance, one learns to use the right equipment, run correctly, kick correctly, skate with more finesse according to their body and ability. When it comes to cycling....looks and weight of the bike often precedes correct positioning, comfort, and learning how to pedal with greater efficiency for quicker performance achievements. Most pro's in any sport, get from point A to Z by working with various experts, at some point in their career, to overcome inefficiencies, work smarter, and correct body mechanics. Even if all you aspire to do is ride in the park, there are lessons and tips to respect and utilize to help minimize problems and increase the fun and excitement in the sport of cycling! I should add that Pro's will NOT ride the wrong size bicycle, no exception! Many pro's through the years have even ridden custom bikes built for them but painted and decaled as the sponsored stock bike manufacturer.
So, in summary, seek out shops or fitters with experience and are up to date in training, use accurate fit measuring systems and devices, don't be afraid to ask them detailed questions regarding their fit methods and reasons for doing certain things, you can get a fit from a different store than where you purchase from but again seek out that fitters success, test ride different style geometries and set ups, be honest with yourself and your body needs over the bike's sexiness, and lastly respect what the people who are on the bikes your interested in have to say vs the manufacturer.
In my next post, I will focus on frame materials, more in-depth frame geometry definitions, and custom vs stock.
Happy Riding!
A little brief history can start to explain the imposed issues and variations of today. Years and years ago, there was little as 1 size bicycle. Then that became a few sizes, then step thru design in one size, then as many as 9 sizes, and so on. Then about 20 years ago the largest bicycle maker on the planet decided to make three sizes (Small, Medium, Large), mixed with several seat post lengths and set back, as well as several stem options in a dealer kit. They figured this would accommodate most of the people in the bell curve and eliminate making so many sizes, thus reducing costs and improving profit. Sounded like a simple and reasonable idea. However, what most were not aware of is this would really only accommodate an even smaller section of sizes in the bell curve! It took a few years to take hold but, here we are 20 years later and sloping top tubes are the norm. But, this idealistic and selfish approach set the industry back, in terms of proper sizing for the bulk of the adult size ranges, and it's continuance of one key aspect that the industry has greatly neglected for most of it's history-comfort! See, what that bike manufacturer found (and pitched in marketing), was if you sloped the top tube, you would gain stand over height for the shorter inseam person, and one could lengthen or shorten reach by an almost equal proportionality via handlebar stem. This was still mostly targeted at racers or young and flexible riders. They also pitched that this sloping design offered a stiffer frame (smaller triangles) and less weight (less overall tubing). The good news is that a few small frame builders and a few large bike companies saw this as an opportunity. An opportunity to experiment with better stand over clearance for most, and a cool way to raise the front end (head tube), while shortening the reach (top tube). Sure, it made the bikes look a lot different, but this led to bicyclists being more comfortable. This was the start of addressing the needs for the vast majority of riders, recreational not racers. These few pioneers put the insightful/genius into what was a dumb/discriminating new bike geometry.
Now, in 2012, we have most of the major manufacturers making several varying geometry options, as well as more female specific designs than ever before. They are also addressing ergonomics at all the points of contact of the bicycle. This helps, in the vary least, to accommodate not only a wide personal height range but varying flexibilities and personal comfort. See, what is finally being respected here is that if you grab 5 people all 5' 8", they will all require a different set up. Which means different saddle heights, saddle fore/aft positions, different reaches to the handlebars, and different handlebar heights. Going further, those 5 people at 5' 8" might ride everything from a 52cm to a 56cm road bike, and further yet, a tall/relaxed head tube bike frame to a really short/aggressive frame, not to mention an array of ergonomic variations. For instance, Trek makes the same size frame, i.e; 52cm in three geometry options: H1(race performance), H2, H3 (sport performance). Head tube lengths range in 4.5 centimeters, and top tubes range in 6 mm. Specialized makes varying geometries under different model names. For instance the Specialized Roubaix line (endurance road) have taller head tubes vs the Specialized Tarmacs (competitive road). Whatever the brand, understand their descriptions, check out their geometry charts, and try riding both if you can. Head Tubes are also affected by the different headset styles. Integrated, press in, inset, etc. You can either lose 2+cm or gain it, which can cause one frame over the other to fit better. Head Tubes and Top Tubes are more important than seat tube length in my opinion. After performing nearly 9,000 fittings, I have never found a frame not accommodating of a lower handlebar height, even in extreme cases, but have had to do extreme things to make a bike taller in the front to the point of giving up on it. When a frame is near perfection for your needs, the geometry in all the other areas are usually adjusted for optimal and safe weight bias to keep the wheels on the ground and handle safely.
This leads me to underline the point of questioning and being honest with ones self. Asking yourself what type of riding you will be doing. For instance, long rides over 50 miles at a slightly slower pace vs shorter rides under 30 miles at a fast pace. Are you competitive and wish to work at good posture and core strength or is this for fun and excitement along with some good exercise the goal? Add to this, the fact that as we all get older we lose flexibility, lose muscle mass, varying discomforts set in, and generally we ride longer but at a slower pace. These facts and variables are all a part of the vast considerations for proper bike fit set up and impacts the geometry that is beneath you. I have fitted thousands of people that purchased the wrong size bike and I wish to help eliminate that costly mistake. See, not only does this lead to pain and fatigue, but an imbalanced bicycle that can handle in a very unsafe manner. All of these reasons lead to people giving up on cycling as an activity or sport.
Let's point out just a few quick and easy self tests you can perform on yourself, in front of a partner or mirror. Stand with your feet together, legs straight-to just slightly bent, now bend over and reach for the ground. The further you bend over, the strain usually causes more bend in the knee, or the lower spine and hip quits rotating and then the upper or mid spine flexes to get closer to the ground. If you can touch your toes-rate yourself at a 5 (out of10), if you can touch the ground with your finger tips a 6, and so on. The next test is lay on the ground, knees up, feet flat on the ground, arms crossed across the chest, now raise your shoulder blades off the ground and perform a basic sit up. Note if the feet come off the ground, if the hips rotate upwards or down into the ground, and if you shake or are very steady. Now, I have seen people with what appears to be a slight belly but they have a strong core and vice versa with a slim belly with a weak core, but the person with more girth also has to respect this dynamic when your thighs come up to your stomach and you are either in your lowest bar position or even the highest. This test and considerations affect handlebar height (relative to saddle height) and to some degree reach. Being too low not only causes the knees and legs to be pushed outwards, but also causes much discomfort in the back, poor weight distribution, and inefficiency in your pealing mechanics, too name a few problems. Too ignore these factors is a recipe for problems. This is not a pass/fail but, rather acknowledgement of limiters we all have to some degree. One has to respect that your body will change in many ways over a year. What one needs today may vary greatly from a year from now. So, wether you try fitting yourself, or get a bike fitting from a professional, don't go into it thinking I'll set it up one way and just adapt to it. WRONG! Sure, there is always some adaptation, some trade offs, but this sort of thinking only says you are a slave to your bike and it's looks vs the bike will adapt to your bio-mechanical needs for optimal efficiency and comfort. I have played in many many sports, and it amazes me how many people will not use that doctrine in other sports but they will in Cycling. To minimize pain, limit injury, increase efficiency, therefore improving performance, one learns to use the right equipment, run correctly, kick correctly, skate with more finesse according to their body and ability. When it comes to cycling....looks and weight of the bike often precedes correct positioning, comfort, and learning how to pedal with greater efficiency for quicker performance achievements. Most pro's in any sport, get from point A to Z by working with various experts, at some point in their career, to overcome inefficiencies, work smarter, and correct body mechanics. Even if all you aspire to do is ride in the park, there are lessons and tips to respect and utilize to help minimize problems and increase the fun and excitement in the sport of cycling! I should add that Pro's will NOT ride the wrong size bicycle, no exception! Many pro's through the years have even ridden custom bikes built for them but painted and decaled as the sponsored stock bike manufacturer.
So, in summary, seek out shops or fitters with experience and are up to date in training, use accurate fit measuring systems and devices, don't be afraid to ask them detailed questions regarding their fit methods and reasons for doing certain things, you can get a fit from a different store than where you purchase from but again seek out that fitters success, test ride different style geometries and set ups, be honest with yourself and your body needs over the bike's sexiness, and lastly respect what the people who are on the bikes your interested in have to say vs the manufacturer.
In my next post, I will focus on frame materials, more in-depth frame geometry definitions, and custom vs stock.
Happy Riding!
Thursday, January 1, 2009
2009
Well, Happy New Year and here's to achieving all of your goals for 2009! 2009 will certainly be an interesting year and challenging one.
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