What is the Optimal Tightness for Learning to Ride with SPD Pedals? I recently switched the pedals on my road bike over to the SPD clipless system. The pedals I got have an adjustable spring. Tightening the spring increases the force required to twist one's foot out, while loosening it does the opposite.

Initially, I set the tightness as low as it would go. I have ridden the bike every day in the last week without issue, and without even the prophesied falling (though I'm sure my time will come!).

Today, while biking uphill against a strong headwind, my foot detached from the pedal, and I nearly lost control of the bike. It seems to me that this is the result of pedaling vigorously while also swaying a bit to keep my balance. This also seems like exactly the wrong time to have one's feet come loose.

This event makes me think I should tighten up the spring. At the same time, I have had several near falls where I forget to unclip at a light, but was able to quickly unclip after stopping and catch myself.

I have two questions:

1: Is it more dangerous to set the tension too high or too low?

2: What sorts of schedules might be optimal for gradually tightening up the tension while learning to use the clipless pedals?
My preference is to start with the pedals wound right back so your feet fall out if you even think about unclipping. But from my experience of novices most people will fall off at least once due to being clipped in. Regardless of how loose the pedals are.

After a week or so, or when the learner starts complaining that they're unclipping unexpectedly, I crank the tension up to normal levels. I'm not a fan of any kind of gradual change. I do err a little on the loose side while they work out what tension they prefer, but not in a smooth change fashion. It's a step to "firmly fixed" in one hit.

I suspect it's more dangerous to have the tension too tight - at some point anyone will be unable to unclip without damaging themselves - your ankles are not particularly good with twisting forces. 

What I did find when I was learning was that there are time when I twist my feet in the pedals without realising it, so I was unclipping unexpectedly not because of pedalling force per se, but through half unclipping then pedalling. If you're off the saddle and throwing the bike around a bit, you may well have been pulling sideways out of the pedal. Don't do that :)