So I am a novice rider and I've seen signatures and threads with this gearing ratio (?)...I was wondering what is the benefit? What are the drawbacks. I'm new enough to where I'm sure I don't know any better. Some input is greatly appreciated.

 

well, its just like the rear end gear ratio on a car, you can favor the ratios more towards acceleration, or top speed, either one adversely affects the other. also, gearing - in the front or + in the rear, you will run @ a higher rpm for any given mph, and your gas mileage will suffer. + in the front or - in the rear will be opposite. as of right now im @ -1+3, speed @ 15krpm in 6th gear is 137 actual, not indicated (168 w/o speedohealer, lol)

 

heres what ive always heard

for every tooth of difference in the back it changes your top speed by like 3mph, so 2 up would drop ya by 6,
for every tooth of dirrerence in the front its 10 mph, so 1 down youd loose approx. 10 more. meaning your bike would top out at roughly 145.....now if you were to go up in the front and down in the back itd be the opposite.

so the only drawback is that its gonna throw your speedo off (who cares) and you lose some top end, but after reading some of your posts i doubt you see 150mph very often.....new sprockets will be like 25 for the front maybe 75 or 80 for the back, and youd hafta get a new chain which im not sure how much that costs...labor at a dealership would be like 50 bucks, which is how much it cost me
so if you got the extra cash, go for it, youll love it, im going 10 up this winter [8D]

 

hey guys correct me if im wrong but doesnt going + in the rear also allow more useable torque . like its easier to bring the bike up if your geard higher in the rear ? i might be stating it wrong but thats what ive always thought

 

yes thats why stunt bikes have 10 teeth added in the back or more

 

The -1,+2 just says that the front sprocket is one smaller than stock, and that the rear sprocket is 2 larger than stock.

The same principle of pulleys apply here. The smaller the front to the rear the more torque you can acheive for the same ammount of work. In terms of pulleys, you can lift more when you use a smaller front to rear ratio - the cost you pay is that you have to pull for longer to get the same distance. In terms of motorcycles - you have to rev higher to acheive the same speed. These bikes will pull to redline so you can't get the revs high enough to get to the same top speed as before... result? you loose top speed.

If you want to ride at lower speeds and/or get bigger torque numbers to the road (for wheelies of fast starts) then going down on the front and up on the rear is the answer.

The cost is that you'll be revving higher... if you tour or commute then changing the sprockets in this way is probably not for you.

In my profile I have several charts showing what the approx speed per gear is with a few different F4 (simular to the F4i) sprocket sets.

I am currently -1,+2 - I do like the extra fun at low speed BUT I find the revs are a bit too high for long highway miles. I sat at 8000-9000rpms for a few hours this summer... with a D&D pipe it's loud and buzzy.

Woot.

 

That is not actually a bad set up. You have to look at what do you do more of. Canyon cutting curvey roads or commuting back and forth to work. You may lose some MPG since you are going to be revving a bit higher. But overall does not sound like a bad gear set up.

Semper Fi
0369

 

Ok i have a question regarding what jzhales said... say i change the gearing on my bike to -1 +2, then i take it out for a cruise and i look at my speedometer and it marks 70mph... am i really going 70mph or does it mark wrong because of the change in gearing?

 

The speedo will be off by the same percentage as the change in sprocket ratio.

to do the math:

Stock front / Stock Rear = A

New front / New rear = B

((B / A) - 1) * 100 = additional speedo error.

Basically when I see 100mph indicated it's much more like 90.