experiment with sprockets

[quadcrazy]

Hey guys so I'm trying to better understand the relationship between the sprockets. I've heard that putting on a bigger rear sprocket will decrease top speed (which makes sense to me) but will increase acceleration (which I don't fully understand). If this is true I'd definitely be interested in trying it which leads to more questions. How many teeth would I need to add in order to notice a difference in acceleration? And how much would it decrease my top speed? I've topped out my ninja 300 at 110mph (with assistance from the wind) but don't go faster than 80mph often. I'd be willing to give up some top speed for faster acceleration.

Thanks for any help!

[choneofakind]

Go hop on a bicycle, play with the gears, and you'll answer your own questions on how gearing ratios affect the speed of the engine vs the speed of the wheels within 10 minutes (or less) of play time.

Word of wisdom on going with shorter gearing. It's quicker in roll-ons, but going 65+ makes the engine rev really high, and the whole bike feels like it's going "ZIIIIINNNNNNGGGGGGGGGGGGGGGG" as it goes down the highway. It just makes the bike feel very busy.

My 2 cents: If you're trying to get acceleration like a big bike out of a sprocket change, that's not how it's going to work. The bike will roll-on quickly, but will hit the rev limiter quicker as well. If you don't notice the gearing as a problem with your current style of riding, don't change it until you see it as a problem. If you're dead set on making gearing changes, I'd go with taller gearing (15t front) because then your speedo will be much more accurate.

[rojoracing53]

First off I'm highly against this because I believe its just a stupid idea but since you asked ill answer. You have to go at least and I mean at least 6 teeth bigger in the rear, or go 1 smaller in the front and 3 bigger in the rear.

[xSean13]

If you bought a 300 (or 250) looking for awesome speed/acceleration, then you're going to be highly disappointed.

[DaBlue1]

Originally Posted by quadcrazy

.... I'd be willing to give up some top speed for faster acceleration.

Trust what the others have hinted at. There is not a lot of acceleration to be had. Going to smaller front sprockets and larger rears is almost pointless unless you are stunting the bike.

Have a look at the attached Sprocket Combo Speed Chart.

[Motofool]

Originally Posted by quadcrazy

Hey guys so I'm trying to better understand the relationship between the sprockets. I've heard that putting on a bigger rear sprocket will decrease top speed (which makes sense to me) but will increase acceleration (which I don't fully understand)............

DJ,

The sprockets and the chain are nothing but two levers connected by one element (top branch of chain under tension).

They work under the principle of mechanical advantage, which is explained here:

https://en.wikipedia.org/wiki/Mechanical_advantage

What you gain or lose in rotational speed (rpm of each sprocket), you lose or gain in torque (rotational force).

Going to a bigger rear sprocket will slowdown the wheel respect to the engine, but it will have more torque to apply onto the pavement in order to move the bike forward.

Acceleration = Force applied onto the pavement / mass (weight of the bike+you)

Unless you lose weight, mass will remain the same, so acceleration will increase when that rotational force or torque of the rear wheel increases.

In order to reduce engine wear, vibrations and oil consumption, most riders do the opposite, in order to reduce the rpms' of the engine when commuting at sustained speeds of 70~80 mph, which reduces the torque of the wheel and acceleration of the bike.

[quadcrazy]

Don't get me wrong I am extremely happy with my bike. I'm just trying to learn more about it, it's all very interesting. If it was a great boost in acceleration while not giving up much top speed I'd do it but it doesn't seem that way. Thanks for all the replies.

[choneofakind]

eh, you'll not give up much 'top speed', but you also won't gain a ton of acceleration, you'll need to shift more, and you'll be more buzzy at highway speeds. I loved riding with lower gearing in really tight curvy roads, but anything else was less than great.

[warning]

Just ride.