Guys,

Maybe somebody set up sprockets with different reduction rate. Any advice ? Is reasonable, what best and so on..

Parus, what do you mean, Im not familar with this "reduction rate" thing... and apologies if I'm being a bit stupid..!!! :)

I think parus means different ratios.

Ive got -1 on the front and +2 on the back with my nc23rrk. it accelerates better but i can get it to the limiter in 6th on a private road.

Ahh... I get it..

I dont ride on the road but my race NC29 runs the following on 3 very different ccts, if this helps at all.
Brands Indy 15/43
Snett 15/41
ManxGP 15/38

I never go smaller on the front as a larger radius (ive been told) provides a more efficent power deliver, (less stress and friction)
Col

Sprocket ratios are easy, but commonly misunderstood.

As a very general rule, a bike will have a standard sprocket ratio of 1:3. 1 tooth on the front, 3 on the rear. It may be 2.8, may be 3.1 but you get the picture, its there abouts.

If you want to know what combination has what theoretical ratio, then divide the number of rear teeth, buy the number of front teeth. The higher the figure obtained the quicker the acceleration, lower the figure then the better the top speed. Again thats a general rule, as engine characteristics also play apart.

15/40 = 2.6 = 1:2.6 ratio
14/45 = 3.2 = 1:3.2 ratio
13/42 = 3.2 = 1:3.2 ratio

So both combinations 14/45 and 13/42 should accelerate noticeably faster than the 15/40 combination. However they may still perform differently but in road riding conditions I dount people could tell a difference, racing you probably could.

Psychosomatic88 wrote: However they may still perform differently but in road riding conditions I dount people could tell a difference, racing you probably could.

yeah got to agree with that......

at the moment my nc30 runs a 14t front sprocket as oppose to the standard 15t and you don't really notice the difference except for top end,the bike is still restricted to 180kph and once over 160kph it struggles to get any more......unless it is a very long straight or great big hill

i think unless you went for a run then changed the sprocket then went for another run then it would be hard to notice the difference!!!!mind you,if i changed the rear sprocket size i might then notice a bigger difference as it is still standard.


william

wullvfr wrote:

Psychosomatic88 wrote: However they may still perform differently but in road riding conditions I dount people could tell a difference, racing you probably could.

yeah got to agree with that......

at the moment my nc30 runs a 14t front sprocket as oppose to the standard 15t and you don't really notice the difference except for top end,the bike is still restricted to 180kph and once over 160kph it struggles to get any more......unless it is a very long straight or great big hill

i think unless you went for a run then changed the sprocket then went for another run then it would be hard to notice the difference!!!!mind you,if i changed the rear sprocket size i might then notice a bigger difference as it is still standard.


william

I dont know the effect with a restricted engine though

That depends on your rear sprocket sizing though aswell, for noticing the difference. What sprockets are you running? standard is 15/38 isnt it on a vfr? or is it 15/40 std?

On my RSV, I went from 17/42 to 16/45. Horrendously quick acceleration, but actually gained top end speed too. The stock gearing does not allow the motor to stretch itself properly. I think I managed 177mph top end on the altered sprocket gearing, standard 169mph top end. However the straight may not have been long enough to get it to top speed

Thanks for so many responses.

I'm thinking to changes following sporckets: Brands Indy 15/43.

Check this file, if show speed calculation for different drive/driven sprockets

http://www.moto.kiev.ua/users/parus/cha ... ew_eng.xls

Psychosomatic88 wrote:or is it 15/40 std?

yeah that is the standard size for the nc30.......

yeah i think that the rear sprocket would have to be changed to notice a difference like you say!!!!!!



william