After measuring and studying hundreds if not thousands of customer’s measurements over the years as a custom frame builder. I came to the conclusion that although human bodies are all different; they do follow certain rules of nature.
Choosing frame size on inseam alone does not work across the board because for example it is common for a 6 foot man to have an inseam as short as 30 inches; and you can’t put a 6 foot man on a 51 cm. frame which is what his inseam suggests.
Tall people are not scaled up models of short people. Most of the height difference is in the legs; body length differs by a lesser proportion. If you have long legs then you also have long arms. Short legs; short arms. This makes sense since most animals are four legged; why should we be any different?
Leg length is a combination of the inside leg measurement plus the length of the foot. Length of the foot is important because when pedaling the toe is pointed downward at the bottom of the pedal stroke; so the foot becomes an extension of the leg.
People, who have a short inside leg measurement for their height, generally have longer feet. (Bigger shoe size.) It is as if they were designed as a much taller person, but their heel got turned further up their leg; making a short leg, long foot.
Imagine two people both six feet tall standing side by side; one has a 34 inch inside leg, the other a 32 inch leg measurement. Because they are the same height it follows the one with the shorter leg has a body 2 inches longer; he also has longer feet and shorter arms than the other guy. They can both fit on the same size frame, (59 cm. center to top i.e. 57 center to center.)
They will both have close to the same seat height, because the short leg guy has a longer foot so his seat needs to go higher than his inseam would suggest. They can also use the same top tube length and handlebar stem, because one has short body long arms; the other long body, short arms; making their reach the same. Minor adjustments in seat height and stem length may be called for.
It has occurred to me that with these compact frames on the market now and only available in small, medium, and large; customers are only ball parking frame size anyway. It has long been my opinion that frame size is linked to the overall height of the rider more than any other measurement because of the rules of nature I have just spoken of.
I have formulated this based on my own frame sizing chart. If you are 5’ 3” to 5’ 5” frame size equals Height divide by 3.3. For people 5’ 6” to 5’ 10” frame size = Height divide by 3.2 and if you are 5’ 11” to 6’ 4” frame size = Height divide by 3.1
A example would be someone 6’ 2” = 74” divide this by 3.1 = 23.87 in. (61 cm. measured center to top. i.e. 59cm. center to center. A person 5’ 7” = 67” divide this by 3.2 = 20.93 in. (53cm. center to top. i.e. 51cm. center to center.) The easiest way to convert from inches to centimeters is to get a tape measure with both metric and inches on and simply read across. If you don’t have a tape measure the formula is “inches x 2.54”
Reach which is top tube plus stem length; is frame size center to top plus 10cm. If you want something more accurate go to the chart on my website The chart was derived not by any mathematical formula but by records of custom frames built over many years. Most people find it pretty accurate. What I have put forward here in this Blog is an attempt to come up with a simple formula that comes close to this. If you are an experienced rider don’t change your position based on this alone because this is new thinking. It is intended as a place to start for a newcomer to the sport.
Feedback would be apprecated.
The picture here shows me aged seventeen competing in my native England in the National 12 Hour Time Trial Championship. I remember that I was the first rider off at 5:01 a.m. on a Sunday morning in August 1953 and I rode non-stop until precisely 5:01 p.m. that evening when a time keeper who had followed me for the last few miles told me to stop. The whole course was measured precisely and for the last part of the event riders were directed onto a fifteen mile “finishing circuit” until their time ran out.
The mileage was marked on the finishing circuit at every quarter of a mile. From the point where my time ran out the time keeper went back to the nearest marker and on a fixed wheel bicycle counted pedal revolutions to the point where I had stopped. Using this method each rider had the distance covered measured to the nearest yard. I covered just over 220 miles my best ride for this event and one that I never bettered in later years. The winning ride that day was around 250 miles.
After I set out that morning other riders followed at one minute intervals; 120 in all over a two hour period. It was a perfect day as I remember, overcast but not cold and little or no wind. The course was on the famous Great North Road where time trials had been held since they started in the late 1800s. The Great North Road or “The A1” as it is designated was the main arterial road from London to Scotland at the time. The first freeway or Motorway as they are called in England was not built until 1959.
The course started at Girtford Bridge about 40 miles north of London and went as far north as Grantham in Lincolnshire. The course was laid out like a giant tree with the A1 being the main trunk running south to north and along the way we were diverted off on branches running east and west. Riding along a branch road to a certain point then doing a “U” turn to ride back to the Great North Road. In the picture I had just done one of these "U" turns and was out of the saddle getting back up to speed. The whole event monitored by volunteer marshals and everyone checked to ensure they rode every part of the course.
When I say I rode non-stop I mean non-stop. I was held on the start line by a helper, and as the seconds counted down I strapped my feet into the pedals and they remained there for the entire twelve hours; my feet never touched the ground during that period. I carried food and drink with me, and more was handed up during the event. My favorite food to carry was rice pudding with raisins in it. My mother would bake it in the oven until it was semi solid but still moist and could be cut into rectangular pieces and wrapped in grease proof paper. This was before the time of plastic wrap and aluminum foil.
It was still officially dark when I started and I had to use battery lights. You can just see the tail light mounted above the rear brake. The heavy front lamp was clipped to my handlebars and I had dropped that off en-route by the time this picture was taken. In case you are wondering I did not have to pee the entire twelve hours; I guess perspiration removed any excess liquid from my body.
(Or is it the Physics of Steering?)
Roll a wheel or for that matter any round flat object even something as small as a coin on a flat surface and it will roll in a circle. It will continue rolling in ever decreasing circles until it finally falls and settles in one spot. This is a demonstration of the law of gyroscopics. That a spinning wheel will remain upright as long as it keeps spinning.
Most people know that this is what keeps a bicycle upright while in motion and if you stop you fall over as all cyclists do at least once in their lifetime. Also a spinning wheel (Or rolling coin.) as it looses momentum and starts to fall it will turn in the direction it is falling, which is why it rolls in a circle.
This law of physics gives a bicycle a simple built-in self steering capability. You can demonstrate this to yourself by holding a wheel in both hands by the spindle and spinning it. The first thing you will notice is that the wheel wants to stay upright in the same plane, demonstrating the first law mentioned in the opening paragraph.
If you forcibly move the top of the wheel to the left or right as it is spinning it will also turn in the direction you are leaning it. Just as a rolling coin will turn in the direction it is falling. So as you lean a bicycle into a corner it will steer itself around the corner. Let’s not forget the rear wheel. Although it is in a fixed position within the frame and cannot turn, it is still spinning and leaning therefore assisting in steering the bike around the corner.
This also explains the importance of a frame being straight with both wheels in the exact same plane. If a frame is twisted one wheel is always leaning and therefore always steering the bike in that direction. In normal riding conditions you may not even notice this as you will automatically and subconsciously correct this by steering in the opposite direction. But try riding hands off and the bike will pull to the left or right. Make sure you are on a level surface as a camber in the road will also cause you to move in that direction.
There are some who argue if it is the gyroscopic motion of a spinning wheel that keeps a bicycle upright, how come it is possible to ride at a slow walking pace? The answer is that it is not all gyroscopics, it is balance. The law in balancing anything is that the center of gravity of the object be directly over the point of contact with whatever the object is balancing on. In theory it should be possible to balance a golf ball on a pin head.
Someone walking on a high wire, as they start to fall to the left will shift their body, therefore their center of gravity to the right. Balancing a broom on your hand is a relatively easy trick because you simply move your hand in the direction the broom starts to fall keeping your hand directly under the broom’s center of gravity.
Have you noticed also that it is easier to balance a broom on your hand with the head of the broom up, than it is to balance a lightweight stick on your hand? The center of gravity of the lightweight stick is somewhere in its center, whereas the upturned broom has a center of gravity near the top where the head is.
A bicycle and rider has a high center of gravity; the bike can be twenty pounds or less while the rider is a hundred pounds or more. Center of gravity is somewhere in the middle of the rider, three feet or more from the ground. And just like the high center of gravity of the upturned broom, this works in favor of the bicycle and rider when it comes to balancing.
When riding very slowly, as the bike and rider fall to the left the bike turns to the left. The rider corrects this by steering to the right, then back again as the rider starts to fall in the opposite direction. What the rider is doing is moving the bike from left to right under them just like moving your hand under the upturned broom. And just like the simple broom balancing trick there is no conscious thought process to this, it is automatic.
Sometimes a person will say to me, “I am a perfectionist.” They say it with pride as if perfectionism is a virtue. Perfectionism is a curse that will bring nothing but misery to the perfectionist and those around them. It is a personality trait that goes hand in hand with low self esteem. Why? Because you can never achieve perfection, you are always a loser.
My own perfectionism led to my success as a frame builder but self hatred and anger as a person. My perfectionism was caused by abuse not only from my father but by the British school system; a system that beat down kids, and used sarcasm and ridicule as well as physical abuse. If you have seen the Pink Floyd movie “The Wall” you will know what I mean. That movie touched me deeply and helped me understand later what was going on.
I believe the reason all the great music came out of Britain in the 1960s was because of our childhood during WWII and the school system there. I was just another child of that era whose creativity went in a different direction. But for the fact my anger was directed towards myself I could have just as easily gone a different direction. Had my anger been directed towards others I could have become a violent criminal as many of my generation did. This forms the basis for my novel Prodigal Child It is a work of fiction, a story of what my life might have been had it taken a different turn early on.
As a child I was never given credit for doing well; only punished for doing wrong. As an adult I continued with the self punishment if I screwed up and I would not tolerate anything but perfection from myself. This led to success as an artist, but failure in every other aspect of my life. Many times in my early days as a framebuilder I would take a hammer and destroy a frame because of some minor flaw. Afterwards I would sit and cry like a child, then work all night to replace the frame. This was my punishment for screwing up.
By the late 1980s my second marriage failed and I realized I needed to change. I was not always a pleasant person to be around; the sheet rock on the walls of my frame shop was full of the impressions of tools I had thrown across the room in a temper tantrums. The anger was always directed at myself never others, but those around me had to witness and listen to this. I knew I had to change; for my own sake as well as others around me. I started to look deep within myself to see why I was the way I was.
By the early 1990s the bike business had also changed. Bicycle dealers almost overnight it seemed were switching from road bikes to mountain bikes. By 1993 I knew it was time to leave and there was one incident that I think pushed me over the edge. A customer called me saying his Fuso Lux frame he had bought had a tiny bubble in the Columbus decal. Columbus decals were always a pain because of the material they were made from caused them to bubble when the paint was being baked in the paint oven. This is why you don’t see a Columbus decal on a custom ‘dave moulton’ frame.
I told the customer to send the frame back. When it arrived the “bubble” in the Columbus decal was buried deep within the clear coats and was so tiny you almost needed a magnifying glass to see it. I stood there looking at it, seething with anger. I had finally come to terms with my own perfectionism, but still had to deal with the perfectionism of others. This customer expected me to repaint this frame and there was no guarantee if I did that the Columbus decal would be any different, and maybe it would be even worse.
The frame was in a vise held across the bottom bracket faces. If a fit of rage I grabbed the head tube and folded the frame in two with the head tube ending up next to the rear drop-outs. This time I did not cry; I did not stay up a night building a replacement. Instead I walked into my office and wrote the customer a check for the full retail value of the frame. I attached the check to the frame with scotch tape, threw it in the box and shipped it back. I never heard from him again.
As well as coming to terms with my perfectionism I realized that all creativity comes from the same source. It is not a right brain, left brain thing; it comes from deep within the artist, his soul or very being. The artist is simply a vehicle through which art appears. Because all art comes from the same source; all art is the same and if I had been successful in one art form, I could do so in another.This is why I was able to leave the bike business and take up writing and songwriting. If I screw up in writing unlike frame building it’s easily fixed in a rewrite.
Writing has been great therapy for me; better to get all this shit out than to hold it inside. Which is exactly what I am doing now so thank you for allowing me to indulge myself?
1978 was drawing to a close and I was winding down my framebuilding business in Worcester, England. Finishing up a few remaining orders and preparing to emigrate to the United States in January 1979.
The phone rang one day and a voice on the other end told me the call was from the US. It was someone from the National Enquirer and went on to tell me they were the largest circulation newspaper in America. The part about having the largest circulation was probably correct, but where they were misleading me was in describing the publication as a newspaper. Newspaper implies a paper containing news. But as the National Enquirer does not reach the British supermarkets; in my ignorance I took the man’s word for it.
Why were they calling me? They had somehow found out that I built bicycles and they needed a very special bicycle. There was a family in South Africa, a husband and wife with sextuplets. Actually, these were the Rosenkowitz sextuplets, three boys, and three girls born January 11, 1974. They were the worlds first surviving sextuplets.
Apparently this family had a contract with the National Enquirer which allowed them to exclusively take and publish photos of the kids. They were soon to have their fifth birthday and someone at the National Enquirer thought it would be a neat idea to photograph Mum, Dad and their six offspring on a bicycle made for eight.
What a strange coincidence I thought. Here was I just about to emigrate to the United States where very few people knew who I was, and here was someone from “The largest circulating newspaper” in the US calling me. I had visions of becoming a household name in the US overnight. The next thing I knew I was agreeing to build this strange octi-velocipede (or maybe octdem) at my own expense in exchange for them doing a story about how this special bike was built by a famous builder of racing bicycles.
I drew up sketches of the proposed machine; they sent me measurements of the two adults and their six children and I set to work. The design would be very simple as time was short and as I was paying for it labor and materials had to be minimal. I bought a pair of used moped wheels with balloon tires. They also had drum brakes built into the hubs which made the braking system very simple. All I needed was two brakes levers and cables to connect. The front rider would operate the front brake and the rear rider the rear brake. These would be the two adults; the kids would ride in the middle.
Rectangular 3in. x 2in. box section steel tube would form the lower part of the frame. Eight holes were drilled through sides of the bottom box section and plain bottom bracket shells were welded into place. Eight seat tubes of varying lengths came up at the appropriate angle above each bottom bracket. A fabricated heavy duty front fork and a conventional rear triangle and the frame was complete.
I used inexpensive steel cottered cranks and chainwheels; adult size front and rear and kiddie size with short cranks for the six children. Chain tension was taken care of with little adjustable jockey wheels at the bottom of each chain. This simple design as it turned out made for a very stable and easy to ride machine, because the weight of the steel box section tube together with all these heavy steel cranksets attached was well below the wheel center making for a very low center of gravity.
The National Enquirer commissioned a local photographer to take pictures of myself with the half finished eight seater. The bike was completed in December 1978 and a truck came to pick it up. The National Enquirer arranged and paid for it to be packed and shipped to South Africa. And that was the last I heard from them.
In January 1979 I arrived in New Jersey to begin work with Paris Sport. Sometime in the summer of that year a local bike rider came in with a copy of the National Enquirer. Inside was a photo of the special bike I had built with the family of eight actually riding it. Mother was up front steering and Dad was acting stoker at the rear and the sextuplets, I seem to remember three boys and three girls, pedaling merrily away in the center seats.
In the short caption under the picture there was no mention of the framebuilder, famous or otherwise. The only reason it had caught the attention of the bike rider who brought it in to show me was because I had the foresight to have ‘dave moulton’ painted in three inch letters on the down tube.
All my effort and expense had been in vain. I let the matter drop because I realized that very few serious bike riders read the National Enquirer anyway. But if anyone from the National Enquirer reads this blog; you owe me an article. I have the original drawing and a letter of intent from NE to prove it.
Perhaps they could dig out the original 1979 picture from their archives or even find the bike. The sextuplets will be in their thirties by now so how about a then and now picture. But I am not going to hold my breath and anyway I no longer build bikes. I am a writer now with a published novel, but I doubt many National Enquirer readers are into literature either.