Ducati.ms - The Ultimate Ducati Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
1,230 Posts
Discussion Starter #1
What kind of improvements in gas mileage would you notice by going from a 15 to a 16 tooth sprocket?

I understand that it will lower my RPMs a bit.

I noticed a difference when I went from 15 to 14, enough to warrent changing back to the 15 to get more mileage out of a tank. It also raised the RPMs 600-800.

I'm just curious more than anything.

Any thoughts?
 

·
Registered
Joined
·
63 Posts
Never heard of going to a 16 and I'm not sure there is enough room (chain could hit the swing arm or engine case) so maybe change the rear sprocket. At 16/40 your chain/wheel ratio is 2.5 (stock, 15/40 is 2.67). IMHO they are geared to high out of the box and if you went w/ 16/40 you would need to be going about 90 mph in sixth just to get into the power band. I'm at 14/39 which is a 2.79 ratio. 15/39 is 2.6, 15/38 is 2.53.
 

·
Registered
Joined
·
1,230 Posts
Discussion Starter #3
keep in mind, I'm not looking for all out performance here. This would be strictly for commuting. When it came time to go out and ride, I would switch back to the stock 15 tooth.
 

·
Registered
Joined
·
1,557 Posts
Re-gearing a 900SS

Keeping the engine in its "sweet spot" is important. If the Ducati 2V isn't running in the 4-6k rev band it is out of its element.
Gearing for fuel economy on a performance motorcycle is working at cross-purposes anyway. You'd get more fuel economy improvement changing to higher-compression pistons than with any gearing change.
 

·
Registered
Joined
·
1,230 Posts
Discussion Starter #5
point taken!

however, to strive for more fiel economy out of a performance machine is nothing out of the ordinary, not by any means....;)
 

·
Chilehead
Joined
·
6,982 Posts
rz33v4 said:
Keeping the engine in its "sweet spot" is important. If the Ducati 2V isn't running in the 4-6k rev band it is out of its element.
I like 5-8 for my SS, and 6-9 for my ST2.

And I noticed no difference in fuel economy with gearing changes.

Anyway, gas is almost free in the US compared to the rest of the world, so don't complain! :eek:

Tom
 

·
Registered
Joined
·
1,230 Posts
Discussion Starter #7
I'll complain all I damn well please, thank you.

There's no reason to just settle on our gas prices, simply because they are cheaper than elsewhere!

;)

also strange that you didn't notice a difference with gearing changes, because I know I did, around town AND on trips.
 

·
Chilehead
Joined
·
6,982 Posts
JDuc said:
strange that you didn't notice a difference with gearing changes, because I know I did, around town AND on trips.
Probably because I'm banging the rev limiter around town AND on trips.

Before I went to a 14T front on the ST2, I never could use 6th gear (and rarely 5th). And with 14/43 on the ST2, and 15/43 on the SS, the ST2 still has a higher top speed as it has 1000 more RPM before hitting the rev limiter then the SS.

Tom
 

·
Registered
Joined
·
1,230 Posts
Discussion Starter #10

·
Registered
Joined
·
235 Posts
Tall gearing is not necessarily the best answer to better fuel mileage. I actually saw my mileage improve when I went from a 15 to 14 tooth front, probably because the gears lined up better for the streets I commute on. For city driving, anyway, I think the lower gearing is better as you don't spend as much time with the throttle wide open, and you need less throttle to get up to speed. I undestand your commuting situation could be completely different, though.
 

·
Registered
Joined
·
1,230 Posts
Discussion Starter #13
whether it's true or not is a different story...lol
 
1 - 13 of 13 Posts
Top