Update: Before you read on I should warn you to take a close look at the date before you take this too seriously.
I’ve already expressed my opinion on how important a proper bike fit is. It’s the best $300 you’ll ever spend to get more comfort and power out of your trusty steed. Or is it?
As it turns out there’s mounting evidence that all these complex hi-tech bike fitting methodologies are completely unnecessary for most of us. A study that just came out of the Biomechanics and Ergonomics Research Laboratory at M.I.T. found another technique of doing a bike fit is 98% as accurate as computer and camera motion analysis fit techniques. Sure, if you want to blow $300 on some quack making your bike fit that’s up to you. However, there’s a proven new method that you can do yourself and it’ll cost you $ZERO.
A bike fit has three basic parameters: correct saddle height, correct saddle-to-stem distance, and correct fore and aft saddle position. Research overseen by Dr. Kristophe de Timze at M.I.T found with 700 test subjects that key upper to lower body proportions are perfectly suited for bike fit approximations. Extremely accurate approximations they found.
Dr. Timze’s findings about some fascinating biomechanical connections and symmetries are difficult to understand so I won’t go into the nitty gritty details. I’ll just cut to the chase and go through what I understand to be the process.
Saddle-to-Stem Distance
Simply start by taking your elbow and lean it against the front of your saddle. Your middle finger should be touching the middle of your steer tube exactly. This measurement will determine the precise position of your saddle relative to the stem.
Saddle Height
Once your seat to stem distance has been established you can now raise your saddle height. Put your armpit on the saddle and make sure your middle finger is exactly touching the top of the bottom bracket. Femur and forearm proportions have been found not to vary between test subjects therefore this is an extremely accurate measurement technique.
Stem Height and Length
Stem height and length has a direct correlation with the fore and aft saddle position. There is a slight amount of room to play with this measurement however because it has a lot to do with your flexibility. However, it’s been found that there’s a fundamental connection between torso rotation and finger size.
For PRO positioning, determine stem length use the 3 finger rule. From the top of the headtube to the top of the steertube there should be 3 fingers of space. No more, no less. For women retaining water at times of the month this measurement may be reduced to two fingers. For old men, commuters, and touring cyclists the 4 finger rule (and in extreme cases the 5 finger rule) is used.
Your stem length isn’t adjustable but this is something that should be checked carefully when buying your bike. Reach your thumb so that it’s at 90 degrees to your index finger. Your middle finger should reach exactly to the end of your stem when your thumb is anchored to the middle of the steertube section.
There you have it. It doesn’t take one of those custom fit studios to do a perfect bike fit. It’s just another upsell for greedy bikeshops to make you believe you need a new bike or new parts to make you fit onto that bike they just sold you. Don’t let them fool you…
{ 45 comments }
I've been Retul-ed and that fit has worked well and is pretty darn close to the body fit here. I'd be interested to see what others also have to say.
I just spent $250 on getting my bike professionally fit and now I'm pissed. I just checked at this method works!
This is one time I disagree with you CT. What about crank length? Seat tube angle? Head tube length?
Ummmmm APRIL FOOLS
When will Scientists learn not to publish reasearch papers between 31st Mar and 2nd April ? On checking my own bike I find I'm not quite PRO on the stem – 3.5 digits .
It may be April fools, but I just checked this against my bike – a perfect fit!!
hi D
Where did you get Retul-ed
I've also been fitted to my bike with the Retul system and found out that these measurements are incredibly close to how I have my bike set up. The only one that was a fair bit off was the 3-finger rule for setting up stem height, but I have long legs and a shorter torso and can get the same position without dropping the stem as much as other riders with more balanced bodies.
I'll definitely use these tips if I have to set up a borrowed bike. It'll take so much of the guesswork out of everything!
Got fooled! Almost started writing an angry message!
However, it’s been found that there’s a fundamental connection between torso rotation and finger size.
For PRO positioning, determine stem length use the 3 finger rule.
It just starts to get ridiculous here hahaha. april fools is a good day.
If this is an April Fools post, I was well and truly snookered – it's still March 31st here in the US of A.
Very clever. Had me fooled up until the connection between torso roation and finger size! I had to Google the existence of 'Dr Timze' just in case it was actually true…
He He He! Funny stuff!
Happy Feaster!
I'm guessing that the 700 subjects were all, or mostly, men and that women would need to tinker with these measurements – if men and women are the same height, the men will generally have longer arms and shorter legs, so any measurement based on arm length won't translate directly for women. The measurements also assume that your frame is a standard size – some bikes now come with different length head tubes, so the three finger rule won't always apply for anyone.
I guess it's quite a good, rough guide and somewhere to start. It's easy, free and you can do it yourself, although the average Joe Bloggs could possibly get a range of different measurements.
There are few issues with it though and obviously bike fit is a bit more complicated than this. For example, stem height in relation to the saddle-stem distance. Some people feel more comfortable a bit higher (more than 3 fingers). Raising this height would effectively shorten the saddle-stem distance, so, if you put the saddle back to accommodate this you are changing the biomechanics of the pedal stroke. Also crank length isn't considered and cleat position is paramount in finding a the best biomechanical position that ensures no discomfort and soft-tissue injuries that can lead to compensatory patterns throughout the body. What about possible leg length discrepancy (functional or structural).
I focus on bike fit a lot in private practice (as an Osteopath) and the only rule of thumb that I adhere to is that everybody is different and can't be placed into a set formula.
Having said all that, CT has only posted an abreviated version of the article and I'm sure many of these issues are mentioned.
CT for Prime Minister!
Haha. So the moral of the story is, you should all come and pay me $250…
To all of you smarty pants who put in a knowing “April Fools comment”, poor form! Why didn't you wait and see how many serious comments were generated before you let the fools in on the gag? Bet you people all start your sprints too early too.
I have seen Dr Kristophe de Timze's bike position and If he has set himself up using these schematics, then there must be some exceptions to the rule. I have never seen someone move around on a bike saddle as much as him. Unless you count Damien Oliver on his way to a group 1 win.
Very funny CT!
Aprils Fools or not, posting about bike fit is sure to open a can of worms …
Now for the real April Fools question: Did BSNYC really reveal his identity? Or is it a pre-April Fools hoax? I'm tipping it's a hoax
http://online.wsj.com/article/SB100014240527023...
funny thing is I was reading it and thinking wow, this is how my dad always told me they used to size up in the 60's, maybe he was right after all. Then i got to the hand over stem bit and thought no, this is getting silly!
very good.
Agree – They just had to post to show how superior they are rather than sit back and watch the posts… Sad really.
Almost got me but I'm going to check my bike tonight when I get home anyway.
Ok, I just spent an hour fitting myself out with this guide. Jumped on the bike and fell straight off! What am I doing wrong? I may need an extra strong panier to lay across so I can pedal with my arms!
This is a very subtle April Fools joke! (I think??) I wouldn't be surprised if a lot of people take it seriously. I just checked out my bike and it lines up almost exactly with these rules. Interesting. Perhaps its not actually a bad way to get an initial fit done….?
It just made me want to go out and buy a FOCUS.
Upon reflection, I was a little too early calling out the April Fools, would have made for much more entertaining reading! My bad.
As for the Snob, its been “word on the street” within the NYC bike racing community for quite sometime that Eben is/was BSNYC, I guess we just had some unofficial code of silence. I used to race for Gotham/Toga, his team, he is a nice guy, very down to earth and obviously has a good sense of humor.
No worries James. If it weren't you it would be someone else soon after. By the looks of it some people don't read comments before posting theirs anyway ;-)
Interesting about BSNYC. Is he really just a mediocre bike racer or is he just being humble?
You made me remember an anatomy tutor years ago who was just like the mythical Dr Timze – but he measured everything in thumb-breadths. 'The oesophagus is ten thumb-breadths long.' Ex-surgeon, brilliant anatomist, no idea if he did bike fitting.
yeah but this bike fit does nothing for cleat set up.. which is a major major element to bike fit!
I used a similar fit method in a recent study of middle-aged 4WD owners and found that none of them actually fit their vehicles or could see past their bull-bars. However the fit method did find that they were perfectly fitted to old Leyland Marinas and mid-eighties Volvos.
Wow, this worked great for me.
I set my seat height using the technique listed here and the height was EXACTLY the same as that dictated by the Lemond Method. And was only a couple centimeters shorter than the height dictated by the Merckx Method, but then again I have short cranks on my bike right now.
It sounds to me like this technique is targeted towards riders who are optimized for racing and long distance (as a opposed to a bar-hopping grocery-getter like myself), but it worked out great for me. I won't have to whip out a tape measure and do calculations when I help someone fit their bike.
Joke or not, this works.
Haters to truly fit your bike you need three things,
1) a live chicken
2) rubber gloves'
3) one of those fainting goats
Once you have those you should be able to figure out the rest.
” Don’t let them fool you…” What a great hint at the end of the post. Very funny you really had me going!
Not sure I should comment on his bike racing ability, but here is his palmares:
https://www.usacycling.org/results/index.php?co...
I didn't see much of him last season, he does the occasional local park race (Central Park & Prospect Park here in NYC) and basically races road so he is ready for Cyclocross.
Denver, CO USA
Thanks for posting this one CT, every day I hop on my trusty commuter I think to myself, man I should really go get a proper bike fitment done. Now I can save my loonies and toonies for the next time a CT kit comes on the market!
Cheers!
Canuckle Head
Better go find that 210mm stem…
Got me so good. I'm a sucker for April Fool's, every time.
As amusing as this is, I still had to check out my set up. Funnily enough its spot on for 3 of the 4 criteria, I guess I must have relatively long arms.
What about TT bikes? Does it work too?
This further supports the notion that getting it close is good enough. I have to admit that for most folks this is apparently true, but the gains that can be realized by getting one's position perfect are substantial. Additionally, riders over 35 are more prone to overuse injury by even slight positional misalignments, and the closer one gets to “perfect”, that potential increases, until the perfect biomechanical position is reached.
I know this must be an April Fools post, but there are many who will take this as gospel to save a buck. “Deals” in cycling rarely are.
I think 33 is the new 35
Funny but corny funny. My sympathies to those who found a correlation with their position Or is that the April Fools spirit very strong in Australia. The most obvious flaw is “stem height should be x number of fingers above head tube. Cervelo R3's and RS's have same geometry but RS has 20mm taller head tube meaning the fingers method raises the bars 20mm higher on the RS than the R3. Has anyone asked what your expert countryman Steve Hogg thinks of this?
Ha – thanks Leigh, theres been alot of trial and error with all my research. The three finger rule is a bit of a newie ;)
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