Gearing- 14T and 15T gearings, are they comparable?

[LA]

This is a horse we've beat to death already. For all I've heard about 14t front sprockets causing premature chain wear and rubbing on swing arms, I've never seen it.  I had the opportunity to go back to a 15 tooth when I replaced the chain on my bike about 12,000 or so mi. ago and stayed with a 14t (put it on at 600mi) - 27,000 on the bike now. I happen to like the 3.07 ratio of the 14/43 combo and you would have to have a 15/46 to equal that, and you can't get bigger than a 44t for a single side swing arm bike easily. Fitment of bigger than a 44t rear gets iffy much bigger than that too.
I don't think you mentioned what bike you have. If you have a older bike with the 2.0 primary drive ratio I'd be tempted to use a 15/44. If it's a SSSA bike a quick change unit.  Like Brad Black mentioned, an OEM rear sprocket on a single sided swing arm bike cost more than a quick change sprocket carrier with a rear sprocket included.
Call Chris at Ca-CycleWorks, or any of our sponsors and see what they offer. I've used a couple of 520 DID sets from Chris.

LA

[Norm]

The point where the lines meet is called the "pole of the moments" and it is the top 2 lines that dictate the angle of the lower line. The closeness of the chain to the swingarm only matters if you want to change this angle. The point is not to get a particular gear ratio or to increase chain clearance or chain life, it is to adjust the squat/anti-squat characteristics of the bike during acceleration. This affects how the bike holds a line when accelerating out of a corner.

[NorDog]

The point where the lines meet is called the "pole of the moments" ...

That's what she said.   

[krista]

This is a horse we've beat to death already. For all I've heard about 14t front sprockets causing premature chain wear and rubbing on swing arms, I've never seen it.

+1.

The chains on our Ducatis do not know the difference between 14t and 15t. And this is only because other factors dramatically outweigh the contribution of sprocket size to wear. Whenever industrial chain applications are mentioned in the same conversation with mention of motorcycles, one needs to put more aspects of the design into context... Many industrial chains are expected to go 10,000+ hours of use on a minimum and hundreds of thousands of hours of use would be normal. 12,000 miles at an average of 40 mph is only 300 hours of use. Designers of systems involving chains probably have more than a few parameters to consider beyond tooth size. 300 hours? That's every other month if the chain only works an 8 hour day (5 days a week)! I'd think someone would be fired, shot, or both if they designed an industrial machine that needed a chain replaced every 300 hours.

The only times I have heard of wear on the chain guides is when the rear ride height is increased by non-trivial amounts. And on 2002 and newer models. The older hoop-type rear suspended Monsters don't seem to care as much.

More to the OP's question, I doubt anyone would notice .007 difference in gearing. In my experience, people will wonder if something changed with 1 tooth difference on the rear sprocket. 2 teeth and that's a change. 3 teeth starts wandering into the land of shifting for 7th gear on the freeway. Also, 3 teeth on the rear sprocket is loosely equivalent to 1T in the front and can be simulated on most Ducatis as the difference between 5th and 6th gears. I normally advise customers worrying about the effect a 14T sprocket will have on the freeway to spend time in 5th and 6th and get used to it. Then after the install, they get happier city riding and are prepared for the small change on the freeway.

Chris

[StandTall]

So what exactly happens to the bike when you go down the the 14T? How does it specifically affect the performance and what will I notice?

[jdubbs32584]

So what exactly happens to the bike when you go down the the 14T? How does it specifically affect the performance and what will I notice?

Less bogging/lugging at low RPMs (in my experience, better driveability at very low speeds/in stop and go traffic) and a little loss at the top end.

[the_Journeyman]

The biggest hit I have noticed is fuel mileage when commuting.  Start and stop, never out of 2nd/3rd gear etc.  I get 30-35mpg if I commute for an entire tank.  If I'm out riding, even spirited/hard, even 2-up I get 40-50mpg.  It's a lot more manageable in town though ~

JM

[StandTall]

Less bogging/lugging at low RPMs (in my experience, better driveability at very low speeds/in stop and go traffic) and a little loss at the top end.

I thought about changing over to the 14t next service since I read it was better, but didn't know exactly why. Thanks for the info.

[jdubbs32584]

I thought about changing over to the 14t next service since I read it was better, but didn't know exactly why. Thanks for the info.

Sure thing. It was the first mod on my bike. Easy to do but don't do what my ex did to mine and put it on backwards. It will make the beast with two backs everything up and cost you a couple of sprockets and a chain.