[luminescient]

I already have converted to a 520, and now I am considering changing out my sprockets, going -2 on the front and +1 on the rear, and I am wondering if I should shorten or lengthen my chain at the same time, or if I can make up for any slack by just adjusting the wheel at the swingarm.

Step 1-Twist handle
Step 2-Hold on!

 

[swjohnsey]

The chain will probably be about the right length if it is stock length but why would you want do go down two in front. When the counter sprocket gets smaller you have more wear problems.

 

[Action]

You are better off going up in the rear.
Jack

 

[luminescient]

Going down in the front gives you better torque(?) at low rpm's.

Step 1-Twist handle
Step 2-Hold on!

 

[Rob Lee]

Originally posted by luminescient

Going down in the front gives you better torque(?) at low rpm's.

That is simply not true. The thrust from a final ratio is the same whether you arrived at that ratio from going down in front or up in rear.

A 13t front sprocket may hasten chain wear due to its small radius. On a ZX-6R, the chain will also rub the guard and eventually the swingarm.

You can get nearly the same 13/41 ratio by going 14/44, but you will need a longer chain.

 

[Dave Leonard]

I agree with swjohnsey on this one. Going down two in front and up one on the rear is a huge change. Personally I think you'll be sick of it in an hour or so. The most popular change is down one in front, and even this is pretty significant. I usually recommend going up on the rear only, one or maybe two teeth. This may get you into trouble with the chain's length, but it avoids a potential problem with the chain riding more severely over the front of the swingarm guide. This wastes some power, wears out the guide more quickly, and can make proper chain adjustment more difficult.
Lowering the drive ratio is something else that is often miss-understood. Everyone talks about greater torque and acceleration, but in some ways all you’re doing is covering less ground more quickly. It’s much like peddling your 10-speed in the lowest gears, your peddling like crazy but going no place in a hurry. It certainly does 'feel' much quicker, but you may actually be worse off in all but a few situations.

 

[Rob Lee]

Originally posted by Dave Leonard

I usually recommend going up on the rear only, one or maybe two teeth. This may get you into trouble with the chain's length, but it avoids a potential problem with the chain riding more severely over the front of the swingarm guide.

Just to be clear, you will not need a longer chain if you add only one or two teeth.

 

[Dave Leonard]

I forgot to suggest that you spend a couple hours riding around on your bike and avoid ever shifting into 6th gear. If this drives you crazy, than you might want to reconsider making any change in sprockets. I have made this sort of change several times and I always change back pretty quick and promise to never do it again. It took about three times before I really caught on.
Of course how and where you ride is a big factor. If your trying to extend the life of your front tire than this may be just the ticket, but if you can’t wait to get out of town and cruise at speed, than this is likely to be a mistake.