Hey, Deysi, let's take a right.

Okay!

Oh, no, it's a hill.

NATE: This is really steep!

Something I've always wanted to try... ...is to ride up the biggest, gnarliest, steepest hill in town on my bike.

The steepest hill in the city.

Use your gears, Nate!

NATE: I can't change gears, I only have one!

I was just on a single speed.

I surpassed Nate.

NATE: This is so much effort.

DEYSI: He only had one gear.

It's not that much effort for me.

Deysi, with the multiple gears on her bike, changed to the lower gear, which made it easier for her to pedal.

I can go into a really low gear that can help me climb up the hill.

DEYSI: Come on, Nate!

(Nate groans) See you later, Deysi.

Gonna crank... Aw, so Nate, your bike only has one gear.

NATE: Yeah, it goes from a pretty big gear in front to a pretty small gear in back.

So when you go from a big gear to a small gear, it's really hard to pedal, but every time you turn the crank around, the back wheel goes around lots of times.

Okay, I'm just going to turn it once, okay?

And here we go... About three times.

Great for speed, not so good for going up steep hills.

Oh, man.

Now we have my bike up.

NATE: On Deysi's bike, there are three chain rings in the front and seven cogs in the back.

If you have a bike with multiple gears, you can choose a different gear for if you're going up a hill, across flat ground, or going down a hill.

Now, the bigger the cog that the chain is on, the fewer times around the back tire goes every time we turn the pedals.

Now I've got my road bike with multiple gears, like Deysi's.

DEYSI: We're going to test how far Nate's bike goes at different gears.

NATE: On the lowest gear, my bike rolled about eight feet for one revolution of the pedal.

So now I have changed which cog the chain is on on the back wheel.

I went from a really big one down to a much smaller one.

Right there!

On a higher gear, the bike rolled about 14 feet for one revolution.

Yeah!

The gear we used to go not so far would be great for going up a hill, and that was the biggest cog.

Now that I've got my bike with a bunch of gears and you've got your bike with a bunch of gears, let's go try climbing that hill again.

Let's go.

All right, I'm shifting to one.

This is way easier.

NATE: Yeah.

What gear are you in now?

I'm in almost my easiest to pedal combo, which is my smallest in front and just about the biggest cog in back.

DEYSI: Here we go!

NATE: Nice work, Deysi, we made it!

DEYSI: Yes!

My legs are burning.

NATE: Thank goodness we have gears.

I don't think we would have been able to make it up.

DEYSI: I don't think so, either.