SPROCKETS

[locOleoN]

Hey guys,

Im not sure how the whole sprocket thing works...
My cb750 had a rear spocket of 48 teeth.
How should I expect it to handle at lower and higher RPMs if I changed it to a 57 or a 58 tooth rear sprocket and leave the front sprocket stock?

 

[Ease]

More teeth in the back = wheelies.
;D ;D ;D

Bike will feel a little jumpier i would say... and you'll need a longer chain... that's a big jump. Plus you might loose your ability to do the ton.
As far as the front sprocket... leave it stock to avoid transmission troubles, or even go up a couple teeth to help match that big sprocket you're planning on putting out back.

Now... If MY bike wasn't a shaft drive, I would probably be testing this theory out.

I do know that stunters use massive sprokets to allow for slow speed wheelies and easy ups.

Quote:
"If you want to ride your bike on the highway and do faster wheelies, add no more than 10 teeth to your rear sprocket, as any higher gearing would greatly reduce your ability to ride faster than 50 mph."

From here: Anatomy of a Stunt Bike

 

[pyro139]

bigger front sprocket the more chain pull per gear rotation,
smaller rear sprocket more tire rotations per chain rotaion,
if you looking fore more kph per gear increase front, or decrease rear(front is prefered but not more than two teeth)
if want more tourqe to rear wheel increase back again not more than 2.


good example my 650 is running stock front/back 16/40 my first gear is 20-30kph
grimz also with a 650 is running 18/40 and he gets 40-50 in first gear.

 

[pyro139]

side note, increase final rpm to wheel(incfease front) will reduce final torque to wheel
increading torque(increase rear) will reduce final rpm.

 

[Shooter]

On my Ducati (S4 Monster 916) I needed to effect a change in the gearing to enable it to be somewhat rideable in the city and to our highway speed limits. The bike was kind of "long legged" and meant constatntly shifting down.

I first tried reducing front sprocket to less teeth. Easy fix and pretty much as racers do cos it does not need a chain change.(Can cause other issues such as chain wear on swingarm).


This sort of worked.

I then asked a dude called "The Gearing Guru" (in the USA) to do me a gearing plan which he did based on a questionnaire he sent me (email) - my weight, my ride, the biker. He provided three comprehensive plans based on sprocket teeth choices and graphed the bike performance for all of them. eg rpm/kph in every gear. (Cost $39 USD)

I chose the one that suited me which was standard front sprocket and a couple of more teeth on the rear. His predictions were perfect and I now have an awesome ride. I met a lot of scepticism from bike mechanics until they did it and saw how it worked. (They were mindset on only front sprocket changes). It did mean a new chain.

A rear sprocket change is a lot finer adjustment offering more precision and choice.

 

[locOleoN]

Thanks gents!!.. I appreciate all the help!!