datlas 

I tried the search (thanks ***) but didn't see a thread devoted to fit "rules."

I will post several that I have seen/heard (or even used!) over the years. Some may get you in the ballpark of proper fit, others are probably total BS.

It's up to you to figure out which ones are which...and go ahead and add your own.

1. When you ride in the drops, the front bar should obscure the front hub.
2. If you put your elbow against the front of your saddle, you should be able to just grasp your stem with your hand.
3. The amount of seatpost showing should be the same length of your headtube (remember that one!?!)
4. You should get the size bike that allows you to straddle the top tube with approx 1-2 inches of clearance.
5. Your saddle height should be such that you can just lock your knees if you put your heel on the pedal at farthest extension.
6. Saddle position should be KOPS, i.e. a plumb bob from the tibial tuberosity should intersect the pedal spindle.
7. Saddle height should be 0.883 times your cycling inseam (a/k/a the LeMond method), measured from center of BB to top of saddle.
8. Frame size should be 0.68 x cycling inseam

Any good ones I forgot??

hairnet

I have only been around for a few years, but:

1. I dont base my fit on this, but it just so happens all my bikes line up like that after I feel like the fit is good
2.weird
3.weird
4.pointless
5. ballpark +/- a few mm depending on your pedals/cleats
6. With KOPS I am pretty forward and have too much weight on my hands.
7. if it feels good...
8.Because all frames are made equal, right?

Creakyknees

Yep, rules of thumb become rules of thumb because they are "pretty good" to "good enough" most of the time. In this case, some of those are outdated by modern frame design, but in general they hold mostly true after generations of riders on millions of bikes have averaged out to what we call "fitting rules"

The really funny (sad) thing is, if you dissect the various high-zoot fitting systems in use today... most of them are based on the same set of rules.

A few fitters (very few) actually base their fits on real science. Steve Hogg in Australia comes to mind.

unterhausen

You never hear this one any more:
stem length should be determined by putting your elbow on the saddle and using 1/2/3 fingers in front to the center of the handlebars.

WhyFi

wut.

WhyFi

I've never posted a "wut" before, figured this was a good opportunity.

lazerzxr

What I love about these rules is that no standard bike exists that allows you to follow all of them. So if I have the same amount of seat post showing as the length of my HT (pointless since saddles vary wildly in height from the rails) then I will not have 1 - 2 inches of standover height.

I rate all rules of thumb as pointless becasue no one is average. While they "should work for most people and that is why they are rules of thumb" the fact is they contradict eachother and cant possibly work for most people unless you pick and choose which you use.

Set your bike so it is comfortable to you and then go ride it.

Fits are over rated, at least for me anyway. My proof is my power meter which never lies

jrobe

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

This was worth more than any bike fit I paid for.

pecos

Generally good stuff, but even this guy gets a few things wrong. Saddle tilt being one. On saddle height, his comment on quad burn if set too low is also not quite right. I did feel that when I lowered my saddle by about 1/2 inch, but stuck with it and was able to generate more power. I know b/c I was able to compare my power output averages to before and the gain was significant. At the same time I was able to raise my cadence by 10 rpm (which he also agrees with).

Bike fit is an ongoing quest, no two years go by w/o adjusting something. Your body changes so should your bike settings.

rjones28 

I remember most of those from the first time I paid attention to setting up my bike (back in the 80s).

rollin

https://www.cyclingtipsblog.com/2010/...-bike-fitting/

Been riding for 25+ years and this works perfectly for me.

pecos

You know that's a April Fools joke? right?

rollin

Oh really??

Actually it's based on this sound Di Vinci science:

rollin

Walter

I was never good enough with my math to get the "LeMond" numbers quite right. I did use that as a general guide though and when I set up a new bike I use my previous one as the template so I guess I still do.

The TT clearance is still used widely though it probably doesn't do much at all.

Been around awhile and never heard of the "elbow to stem" rule (#2).

Generally, I conform to #1 and KOPS as well though I don't see either as a rule.

WhyFi

Fixed

mmmdonuts

My #1 rule, to re-quote what Sheldon Brown quoted:

"You never know what is enough
until you know what is too much."

Bob Ross

The only time I ever heard anything remotely like either of those, it was put your elbow on the saddle and use 1/2/3 fingers in front to just touch the center of the steerer...not touching the bars, nor grabbing the stem, but just touching where the stem clamps around the steerer tube.

Considering the source, I immediately presumed it was an old wives tale & ignored it.

UCIMBZ

Don't take it so hard. He/she is new.

UCIMBZ

The biggest obstacle in bike fitting is trying to apply static solutions to a dynamic problem.

rat fink

This bears repeating.

Yo Spiff

Most of them seem in the ball park for me, except for this one. I have shorter legs and more of my height in my upper body. A bike with several inches of standover clearance is so small that I feel cramped on it. I've actually tried it with a road bike I got from a relative once, and there was no stem I could mount that would gain me a comfortable position. The proper size bike usually has the top tube jammed in my crotch.

Juan Foote

Some folks may not consider the value of number 4, and as a fit measurement I am sure it is near to worthless. As a safety measure, it is a good thing to keep in mind.

unterhausen

it is because it ignores the length of your torso and bicep. But it was in common usage in the '70s, that's why I posted it.

halfspeed

9. The Competitive Cyclist fit calculator is a good tool to determine your size/fit.