What is the point of changing a sprocket?

[simon t]

Can someone please explain to a simpleton why changing a cog reduces top speed? Surely it should let the enging rev a bit more. No way can the Storm reach the redline in top, otherwise it would be a 170 mph bike (which we all know it ain't).

Stock gearing gives 18mph/1000rpm in top, so I reckon it probably runs out of puff at least 500 revs short of the redline. Won't the 7% reduction in gearing simply allow the bike to rev up to the redline, making up for the lower gearing? Or am I being dense

[vtrsteve]

It's a wierd thing really, my last storm would show 165 on the clock on std gearing so allowing for over-reading it' was probably nearer to 150 true speed and wouldn't pull the redline in top.
Fitting the 15t front sprocket and a cycle computer it would top out at 137 and reach the redline so in real terms there wasn't *that* much of a loss.

I'm guessing that there is an aerodynamic limit to serious speeds where big power is needed for small speed increases.

Ultimately the reason to change the gearing is to make the bike more rideable in the real world, no matter what people say nobody rides everywhere at mach3 so why gear it for such?

Steve

[STEVESTORM]

2 X Steve = making sense = AAAARGHH!!

Seriously - the top end on most storms is neither practical or usable - a cheap and simple sprocket change - either semi drastic 15 or 43 or DRASTIC 15 and 45 like mine is a cheap way of using the grunt to enjoy your storm much more.

I'm no expert but the summary is that it takes less effort to turn the rear wheel in high gear ratio ( ie 3:1 like mine) than it does in stock - hence more acceleration low down. This means that the lower gears turn the back wheel more per engine rev and the higher gears less hence less top speed.

If this makes sense then I'm happy - if not then send me a PM and I'll show you!