It's very fun to me trying to define the feeling when we listen to the expression "Só no Girinho", in order to translate it to english.

The "little spin" is more like the actual movement that you perform using a short/light gear (bigger cog/smaller chainring): Your cadence go up and your effort gets a little easier.

So, the expression goes like this:
Come on, buddy..."just a little spin" and you're there!
(Vamos lá, amigo...só no girinho e você chega lá!"

or

Man...look at that slope...let's go "just in a little spin".
(Cara, olha aquela subida...vamos lá, Só no Girinho).

Try to keep in mind that a "little spin" isn't about the slope itself, but the actual movement that you perform, spinning in a light gear to beat the slope...think on it like a mantra: "Go easy spinning light and you'll make it.".

The challenge here is to make this "full of words" expression, into a little one...tricky isn't it? hahahha!

Thanks for all the attention on this matter. Means more than a fun conversation...means learning how to express myself better in a foreing language...