moet

Something I'm wondering about; considering all the effort that goes into sizing and fitting bikes, there seems to be no adjustment available for the ratio between hip width and pedal width. This surely means that some people are pedalling with their joints at less than optimum angles? The width between pedals seems to be fixed, and I've never seen anything in the way of variable widths offered. Any comments?

late

Yeah,
it's a problem. There is at least one pedal that does adjust Q, the Look CX6 and CX7. I understand there is a Time that has some Q adjustment, but I haven't seen it. It's called Impact. There is a product called Knee Savers; but they shove your pedals way the heck out there. If you can live with old style shifting, Phil Woods does custom lengths on bottom brackets. I have been meaning to call them to ask if they ever plan on doing a Octalink or ISIS BB.
Lastly there are custom cranks but the price is steep. SO there are a few options. Which would not be needed ff the *&***&% pedal makers offered pedal axles in different lengths as an aftermarket item.

feltdude

This is the one of the benefits of float.

formulaben

I always wondered (especially since I don't race, so lean angle isn't usually a concern) if they might size the pedals just as they do the handlebar. I did adjust my Speedplay pedals so that the shoe is at the farthest outward, and it seems fairly comfortable. I'm certain that the farthest inward position would not be...

SDS

Well.....

First, high-quality double and triple cranks used to be narrower. They got wider to allow for indexed chainring shifting and because hardly anybody cares anymore.

Second, humans have been walking for a long time now (4 million years?), and there are a lot of fine-tuning adjustments to make us better at it.

Watch people walk, and you can see that their feet land almost on the same line, either one behind the other or barely offset from the CG plane. If people didn't walk that way, as each foot landed to the left or right of the CG plane, they'd fall to the other side.

So how could it be that feet land almost on the same line when the hips are much wider? That question brings us back to one of those fine-tuning features. At the bottom of your femur the end is not perpendicular to the shaft. Instead there is a bevel so that while the femur slants inward, the tib-fib can go almost straight down to the ground.

So what the heck could this have to do with cycling and best pedal spacing? Remember your quadriceps attach to the patella, which is supposed to follow a groove in the end of the femur, and which transmits the tug from the quadriceps to the tib-fib segment of your leg. And when it does this it pulls the patella to the outside of the patello-femoral groove (?), the more so the smaller the included angle between the outside of the femur and the outside of the tib-fib. The straighter you can keep that angle, the less likely you are to have conflict between the ridge on the bottom of the patella that is supposed to track down the center of the groove, instead of to the outside. And that means you are better off with narrower pedal spacing than wider.

What happens if your pedals are too widely spaced? Well, with the patella rubbing on the outside of the groove, you can get a problem variously known as patello-femoral tracking syndrome, patello-femoral pain syndrome, patello-femoral syndrome, etc., etc.

Women are especially prone to this because they combine wider baby-carrying hips with shorter legs. That means that the angle at the knees tends to be sharper, which places them at extra risk.

Let's suppose we all had bullet-proof, invulnerable Lance Armstrong knees and we didn't have to worry about their various failings. Would most of us be better off with wider or narrower cranks?

Track racers keep their single-chainring drivetrains very narrow indeed. If there were an advantage to wider cranks, perhaps they would use a longer bottom bracket spindle? Could there be another reason why narrower would be better? Why are handlebars the width they are?

Because the pedal center is not on the centerline of the bike, effort applied by the cyclist, push or pull, pushes or pulls the cyclist toward or away. Because arms are weaker than legs, the handlebars must be wider than the pedal spacing to allow the arms sufficient leverage to counter the effort of the legs. The effort of the arms, though, is energy that could be conserved in part if the leverage of the legs was less, something that can be accomplished with narrower pedal spacing.

So for a variety of reasons, most of the time, narrower is better than wider, particularly for persons with short legs or wide hips. It seems like a great idea for pedal spacing to track with some human dimension, but that presupposes that the spacings are not already all too wide.

There are things you can do to narrow your Q (pedal spacing), if it is a problem for you, but that is a somewhat lengthy subject best addressed under another topic.

formulaben

Thank you.

MichaelW

Some makes of crank (such as Specialities-TA) still regard a narrow Q as beneficial. Shimano disregard Q altogether, and space out the rings and cranks to produce better indexed shifting.
The "Superman" track bike used a particularly narrow bottom bracket spindle, and designed the whole rear triangle to avoid catching the riders heels.

late

Hi again,
I know q used to be smaller. I was riding back then. Too narrow a Q bothers my knees. I put on Knee Savers which shove the pedals out about an inch; and that was too wide and THAT bothered my knees. I am not sure exactly what I need for a Q. It's not a lot differentr from what I have now; but I would like to try a couple extra mm; especially on the right, to see if it helps.

wrench

The Q- factor (distance between pedals) needs to be closer on a road and track bike to allow you to pedal with a higher cadence. Clipless pedals with a float of at least 3 degrees allow the joints to align properly. MTB Q-factor is bigger as you are not pedalling so quickly and often need maximum power while in the saddle. Don't worry about it - just ride. Your body will adapt.