How deep of a reduction is too deep?

[lectraplayer]

This is primarialy for you off-road cyclists, but from a design standpoint, how deep of a reduction is too deep? Right now, I'll say that if you can step down on the pedal and lift the front tire on torque alone while still in contact with the saddle with your hill climbing gear (the deepest reduction), that may be excessive. Where do you decide that the gear is too low?

 

[dabac]

If a gear is so low that: -speed drops to where maintaining balance gets tricky -walking is faster -starting on that gear becomes difficult 'cause I can't get the other foot on the pedal fast enough, before all forward momentum is lost Then it's not that useful any more:

 

[AyeYo]

That's entirely relative to where you're riding. You'd be hard pressed to find a gear that's too low when going up a 25%+ grade on dirt or gravel. Plenty of mountain bikes have gears low enough to lift the front end on flat ground if you take off too hard, but those cease to be too low when you hit a steep hill.

 

[RPatterson]

As a general way of looking at it, we all want our bike to have a lower gear than it does, as soon as we can't make it up a given hill in our lowest gear. What was mentioned elsewhere is also true, that you need forward momentum to assist your ability to balance. There will always be an un-climbable hill, if we care to seek it out, then we are going on a hike. And it is also true that we may experience a shortage of momentum, to the point that we can't get both feet in the pedals from a standing start before stalling between pedal strokes. We then hike some more.We sometimes need advice from our parents -- Mother Nature and Father Time. Or, a set of training wheels, which would allow us to get started with both feet in the pedals halfway up a steep hill. Once thus underway, we could benefit from the added stability they could provide. I know, the notion of training wheels is absurd! I was kidding."dabac" pretty much nails it on the head, and if it seems to be a vague answer to a rather thoughtful question, I'd have to say it is because of all the unknowns involved, due to different styles of riding, levels of fitness, and the trails & pathways we have yet to encounter. As a direct result of all the hill climbing I ever had to do, I have always looked to see if bikes had a really low gear, but I can't say that I've ever looked at any bike's drivetrain, and deemed that it had "too low" of a low gear! It may still be possible to find a cogset with a 38-tooth cog on it. One brand at least, offered some kind of "Wilderness Adventure" gearing setup like that, back in the old days. If you had a 22-tooth small front ring to go with it, you'd be the envy of the bike club!