Smaller front sprocket or bigger rear sprocket?

[mass-hole]

I noticed that you can change out the rear sprocket to a 45 tooth and achieve pretty much the same gear ratio as going to a 14t in the front. Is there a preference as to which one to change the size of?

[ttpakasnipe]

A lot of people usually say to go bigger in the back so that the change doesn't lose much area to cover.

They say the chain will stretch faster if you go smaller in the front.

I recently got the 14t in the front with the stock 39, no issues so far.

[mass-hole]

A lot of people usually say to go bigger in the back so that the change doesn't lose much area to cover.

They say the chain will stretch faster if you go smaller in the front.

I recently got the 14t in the front with the stock 39, no issues so far.

Thats kinda what i was thinking, the 14t might put a little more stress on the chain but I wanted some confirmation. Thanks

[Allen]

Its cheaper to go smaller in the front, but that increases the amount of stress per gear tooth. Increasing the rear will give you a little more angle of wrap, and spread the forces over more teeth reducing the stresses.  I would like to go -1 on front, and +1 on back, that way you can try different setups.  But doing just the front will be the cheapest.

[the mole]

+1 on the front. Works for me.

[bill14224]

I noticed that you can change out the rear sprocket to a 45 tooth and achieve pretty much the same gear ratio as going to a 14t in the front. Is there a preference as to which one to change the size of?

Within certain design limits, smaller sprockets are less efficient than bigger ones because they make the chain bend more, causing more wear and power loss, so a larger rear sprocket is a little better than a smaller front sprocket in this case.  45/16 would be theoretically preferable to 39/14, but most people change the front sprocket because it's cheaper.  The 45/16 setup would theoretically last longer than 39/14, but in the real world it may not matter significantly considering the mild power output of this engine.

And I agree with Mole.  +1 in front works for me too.

[mach1]

I ran a 15t front, 14t front and even a 13t front and never had any chain issues. just a bunch of talk.

[burning1]

For mild changes, I'd replace the rear sprocket. For wild changes, I'd replace the front and back. I would never advise going down more than 1 tooth on the front.

If you want taller gearing, I'd do the front first.