Alkaline Earth | Taint that hard

October 11, 2007

My brother just got a bike, and I sent him some advice about fit and form. I repost it here for your enjoyment and for Pablo and Javelina to nitpick.

The top mistakes beginning cyclists make:

Ride a bike that doesn't fit, or one that is not adjusted right (esp: set the seat too low).
- 1a. They get a bike seat that is uncomfortable.
Pedal using the arch of their feet (pedal axle should be under the balls of your feet).
Pedal at too slow a cadence

Inside, some advice and links on bike fit.

When your bike is adjusted right:

You should have 2-4" of taint-topbar clearance when standing over the topbar,

your seat should be next to your trochanter (bony protrusion on the side of the hip) when you stand next to the bike,

and your knee should be over the pedal axle when the cranks are at 90degrees. (These are approximations that get your bike to a good average starting point. A good fit system will go quite beyond (and even contradict) this, but without a goniometer, a fit simulator and a year+ of riding so you know what you like, go with the conventional wisdom.)

Your seat nose (the flattish front part of the seat) should be level; err on the side of pointing down. If your taint hurts or falls asleep point it down. If you feel you're sliding forward, point it up (but never past level -- if you are sliding forward with a level seat your reach is wrong). After your first week or so of cycling, if any part of your ass hurts when you're on the bike, it means your seat is mis-adjusted or is the wrong seat for you.

For a road bike, your nose should be about an inch forward of the handlebar axle when on your "hoods" (thumb webs resting on top of the brake lever housing). If your arms hurt (you feel like you're supporting all your weight, and don't want to get into a good forward position) your reach is too long. If you feel like you have little weight on your arms and your ass is bearing all your weight, you're too far back.

See also:

Slowtwitch.com on tri-bike fit and related articles
An illustrated overview of bike fit
Bike fit and what you can adjust

Beginning cyclists want to

adjust their bike seat too low

ride with too much weight on their ass

sit too upright

set their hands on the handlebar's crossbar rather than the hoods

The combined effect is they pedal too slowly and pound their ass; also, they can't easily get their butt off the seat for a pothole or bump. Cycling this way is not only inefficient but uncomfortable.

Don't dive straight in to a wind-tunnel-optimized fit (you'll need time to stretch and build muscles that allow a good position), but recognize these tendencies and try to go against them.

A note about cycling cadence: most beginners are highly skeptical about moving up to an 80-90rpm cadence. The research and conventional wisdom is unequivocal and unanimous:

"In my experience, most athletes should ride at a cadence of 88-95+ rpm".

"The model results clearly show that the optimal cadence (i.e., the cadence that minimized the objective function) was 95-100 rpm".and
"Delta efficiency, (i.e., the ratio of the change in the work accomplished to the change in the energy expended), increases significantly for each increase in cadence so that it is highest at 100 rpm."
(Cycling Science - Summer 1996 - What Determines The Optimal Cadence?)

Very nice, flip . . . I mean admin. I could nitpick lots, but only one mention is truly warranted.

". . . if any part of your ass hurts when you're on the bike, it means your seat is mis-adjusted or is the wrong seat for you."

I think if you make the shift from spending no time on a bike to suddenly putting in some miles - your ass is going to hurt, perfect fitting bike or not, no two ways about it.

Most of all at first - I think the 'fit' or setup should be what ever is going to keep you riding. If the perfect fit - is uncomfortable, change it until you get some hours in the saddle, then play around with fit. these things that you outline are mostly for efficiency and injury - so most leisure riders wont benefit all that much from the ideal set up -- though when they get used to riding and are not afraid to play with the way their bike is set up, they usually asymptote to something close to the ideal fit, assuming their bike allows it (sorry, I'm an html idiot so no line breaks or carriage returns from me!).

(urps. fixed author field to be by me.)

Good points all, thx pablo.

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October 11, 2007