Sprocket Change vs Fuel Econ

They generally say that you can get a better fuel economy when highway riding if you reduce the final drive ratio (+1 front sprocket).

I’m wondering if the opposite could be the same.
If I increase the final drive ratio (-1 front spocket) for better acceleration in start & stop city traffic could there be better fuel economy?

so your saying a bigger ( +1 ) front sprocket will give better fuel economy…

& you want to know if a smaller (=1) front sprocket will give better fuel economy also ? :doze:

I don’t think you read the post properly.
First of all I said generally.

A bike is doing a steady 80mph at 6500rpm on the stock sprockets
If you were to change that front sprocket +1 you could achieve 80mph at 6000rpm and hopefully increase MPG figures while sacrificing some bottom end power.

The question is if I was to increase the bottom end power for start stop city traffic (by -1) could there possibly be a fuel saving there too? Or will it always just burn more fuel?

The theory is if the bike can get to its peak torque quicker (peak torque being where the bike runs most efficiently) in the start stop traffic will it increase MPG or not?

Please don’t try to answer if you have no understanding of sprockets and gearing ratios.

If you fit higher gearing you will get worse economy although there will be very very little difference with city riding.

Stop start riding will always lower economy no matter what gearing you fit!

to be fair it depends on the sort of miles you do, where your engine makes power, and how you ride. if you do tens of thousands of miles on the motorway, only ever sitting at 80mph, and your bike has a large capacity, hi torque engine that dosnt need lots of revs to make power, then higher gearing can reduce fuel consumption. because for the same speed, you will be using less revs. if you have a mid to small capacity engine that makes power higher in its rev range, then you might not reduce the fuel consumption, because you have to use more throttle to maintain same speed, even though the revs are lower.

lowering your gearing will usually make you use more fuel just because you are now pulling more revs for any given speed. however, your bike will accelerate quicker. then because you bike accelerates quicker, you find that you ride harder, so you use more fuel. now you find your bike wheelies easier, so you save money on front tyres.

i do hope this makes your decision easier for you :smiley:

i went F-1, R+2 on the hornet with no noticable change in fuel consumption


Do it. I get better fuel economy in town with +2 on the back sprocket. As you say I also reckon it must have something to do with getting up to peak torque more quickly. On my bike it also means I have to change up sooner so spend more time in higher gears…hence the improved economy over the commute.

I have also found that reducing the weight of the bike by fitting lighter cans and removing and replacing various bits has noticeably improved performance and fuel economy. Less is more. :Whistling:

revs versus engine speed isn’t what effects fuel economy (not directly anyway) as Matt says it is about throttle position and road speed.

If you lowered your gearing, meaning it took less throttle to achieve the exact same acceleration then I think you would see slightly better mpg yes. Trouble is, it is v likely you will just ride quicker, give it more throttle and go through a set of brake pads a week :laugh: