Sprockets ???


BStar1992

New Member
Ok so im going to be going to a -2, +3 config on my front and rear sprockets
what kind of loss in top speed can i expect from such big change in gearing , the reason im doing it is to gain torque for better wheelies and faster acceleration any tips/ suggestions
 
Wear a helmet and do it in a parking lot or stunt park.
 
I wouldn't worry about it, if you are trying to do wheelies and have quicker acceleration....You'll still be able to do illegal speeds on the street with it...

condescending_wonka-274x274_q85_upscale.jpg



i got all my wheelie tipz ober der @ gixxer.com they taught me bestest wayz
 
Last edited:
You can definatley expect to lose some top speed. The girl in the linked video will explain it more clearly than I can.

[ame=http://www.youtube.com/watch?v=Qhm7-LEBznk]The real meaning of MPH- The Original - YouTube[/ame]

I've also attached some examples that would go along with the video.
412630_f520.jpg


compared to this wheel diameter.

412628_f520.jpg
 
Based on the numbers reported for our bike, the top speed would go from about 138 to 118 mph.
 
-2/+3 sounds quite excessive. I think I'll run that through my simulation tonight to see just how ridiculous it is. That's about a 22% change in gearing (22% more wheel torque at any given engine speed, but at a 22% lower road speed). You'll probably have no problem doing wheelies around 20-35mph in 1st gear, but you'll have to shift to 2nd around 40mph. From there on out, you won't really have improved acceleration (explanation here), but you'll be up-shifting more often, then cruising at higher RPMs.

I think you'll end up bouncing off the rev limiter in 6th gear right around 107mph. 6th gear will be almost like a stock bike's 4th gear. Go ride around without ever shifting above 4th gear, and that'll give you an idea what it would be like cruising around with -2/+3 sprockets.
 
I haven't actually worked out the results yet. I may have done something backwards with the ratios to come up with the 22% difference. I'll post real results later.
 
I can't explain it, but world champion drag racer Rickey Gadson did a FASTER quarter mile on the ZX-14R with HIGHER than stock gearing. He ran a 9.64 with stock gearing, and a 9.31 with the higher gearing. From March Cycle World.

So if you're looking for faster acceleration, you might want to think twice about the extreme sprocket swap.
 
Ok so im going to be going to a -2, +3 config on my front and rear sprockets
what kind of loss in top speed can i expect from such big change in gearing , the reason im doing it is to gain torque for better wheelies and faster acceleration any tips/ suggestions

Are you planing on using this bike for stunting only? Because with this setup it would be pretty much useless for anything but stunting or maybe the 1/8mile strip.

On the zx14 that could have been from numerous things, I'd be willing to bet that by going up on the gears with it allowed for better launch and one less shift on the 1/4 which will save time, but on 90% of other bikes going down a little not a lot will help it accel a bit faster
 
thats hot....Jsp is hoping for pictures of you two spooning.

He told me not to tell you, but I did anyways.
 
Results are in...

Assuming a 170lb rider, shifting optimally for acceleration, 0.32s per shift...

Test: [stock result] -> [-2/+3 result]

0-60mph (8k rpm launch): 3.75s -> 3.78s
0-100mph (8k rpm launch): 10.89s -> 10.72s
1/4 mile (8k rpm launch): [email protected] -> [email protected]

0-60mph (4k rpm launch): 4.26s -> 3.92s
0-100mph (4k rpm launch): 11.39s -> 10.86s
1/4 mile (4k rpm launch): [email protected] -> [email protected]

(accelerating up to freeway speed from an entrance ramp)
40-80mph: 4.13s -> 4.25s

(passing a slow car on a country road)
45-60mph: 1.23s -> 1.47s

Top speed: 124mph -> 113mph

RPM @ 70mph in 6th gear: 5832 -> 7100

Indicated speed at 70mph: ~74mph -> ~90mph



Conclusion: Yes, -2/+3 sprockets will make you accelerate quicker than stock if starting from 0mph (or other very low speed) and launching at lower RPMs. But it has no advantage over stock when actually trying to launch quickly, or when accelerating from a rolling start at a higher speed.
 



Back
Top