What is the recommended procedure for adjusting the fit of my bike?

Question

I have a road bike which is a reasonable fit, what is the recommended procedure for adjusting the seat position and handlebar height to get the "perfect fit"?

A complete answer should include what order to make adjustments; how to determine height of saddle, fore and aft position of saddle on rails and height of handlebars. Also what testing is required. Is this all done on feel or are there basic measurements and mecahnics that affect the adjustments? Does it help to have a turbo-trainer and large mirror or video camera?

Do the same principles apply for hybrid and/or mountain bikes? What changes to the process are needed for other bike types?

I know that this is a service you can pay for at some pro-cycling shops, but since I have a number of different bikes, I would like to be able to get a good fit for each of them at home for a minimal layout. And also, by understanding the process and doing it myself, getting a better understanding between me and the bike...

Answer 1

There's quite a lot of discussion on the subject of fit, and some folks have considerably different ideas in this regard. I use the old-school methods to get close, then try to "dial in" things according to what my body tells me.

Seat height should be such that you can easily pedal "circles" without rocking or stretching, nor by over-flexing the knee. It's hard to describe...Essentially the leg should not be fully extended at the bottom of the stroke. Just short of being fully extended. The thigh should be more-or-less level at the top of the stroke.

The fore-and-aft measurement is often neglected or even ignored. Again, the classic measurement is that with the pedals level (3 and 9 o'clock) a plumb line dropped from the bony process just below your kneecap should intersect the pedal's shaft. That's assuming you're sitting on the saddle properly, with your "sit bones" on the heavily-padded portion of the saddle. Saddle attitude is one of personal preference; I prefer just a few points nose-down from dead level. "Reach" is somewhat dependent on the type of bike. On roadsters, you want the reach to the hoods such that you can ride with a relaxed upper body at a reasonable angle. Some authorities advise such-and-such a percentage of weight on the hands, and such-and-such on the seat. You don't want to be totally supporting your upper body with your arms. I've seen folks who maintain that these things are "all wrong", and propose all sorts of ideas for getting the perfect position. I know I can ride comfortably and without hurting anything using these methods....

Answer 2

I concur with M. Werner & previously used this answer (someone down voted :-O) for similar question:

IMO single most important factor of cycling joy is FIT!

This is a great tool and worth the effort: http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO

I have used it myself and referred countless folks to it, all with great success! Good luck!

Added for this post: Once you take the measurements and input the data into the fit calculator, you can email yourself the results. Over the years I have been able to move from bike to bike focusing on two measurements which were initially provided by the fit calculator: 1. Saddle Height 2. Cock pit length which is the tip of the saddle to the handlebar.

Also, I have been professionally fitted and came out with identical set up as I did when I did the recommended fit calculator.

Order of adjustments based on the methods described by M. Werner: 1. Set saddle height 2. Set fore-and-aft of saddle (I use a level here and strongly recommend using one)

Once saddle position is set move to handlebars/stem, 3 options here:

1. Use Competitive Cyclist's recommendations
2. Visit LBS and borrow/rent use an adjustable stem to determine correct angle and length based on trial and error.
3. Or lastly, I would refer to personal comfort in terms of how much stress/stretch you desire for your back - the old rule of thumb is while mounted on bike you want the intersection of the handlebar/stem mounting point to obscure the view of your front hub.

Whatever path you decide, my recommendation is to take and record the following measurements, the two main #'s I use as I move from bike to bike: 1. Top of saddle to center of bottom bracket 2. Tip of saddle to handlebar

Hope this helps! Any questions lmk!

Answer 3

I use many of the same techniques that @M.Werner recommends. Get a general fit and then tweak as needed. Generally I will take a guess at where things should be and then climb on. It is usually obvious when I'm way wrong. For a little fine tuning I will balance with a counter top or the like and then pedal backwards for a bit, obviously doesn't work with FG, hopping off and making tweaks. The final tweaks I make come from riding around noting changes to make and then when I take a break or am ready to turn around I make adjustments. I find I get a better idea for how well honed my setup is by actually riding than by measurements.

Answer 4

It depends on what type of riding you're doing. The seat should be slightly lower for less competitive riding style. My bike is currently set for ankling which requires a slightly higher seat set. I've found that the orientation of the settings on the bike depend on style of riding.
Personal preference is to set the seat height by sitting on the bike with leg straight and toe slightly up. Then the handlebar height is set, and finally the orientation of the saddle.
What this does is gives me the most power as I reach the bottom of the stroke.