change sprocket...effect on speedo?

[bigrich]

Hi all, long time since ive been on....too much work i think!

anyways i changed my front sprocket to a 15 and rear to a 43 last year....i thought it the speedo was out, the needle went from 100-150 awfully quick!

after a run out yesterday i now know the speedo is wrong...i had it reading 170mph with a little more left!

so...is there anyway i can tell how far the speedo is out....but also anyway to correct it? answers on a postcard!

[Wicky]

http://www.google.co.uk/#hl=en&newwindo ... 34&bih=995

[agentpineapple]

my sprockets will be 15f 42r, i plan to set my satnav up in my tankbag, so i can figure out the true speed, most importantly, when the satnav shows 30 what will my speedo show, at least it will give me an idea, when i get some more cash together i'll buy a speedo healer to sort it out. i think they cost about £90....

[bigrich]

my mate plans to ride alongside on his fireblade to see what im doing when it says 170....not sure thats such a good idea though !

[agentpineapple]

hahahaha good luck with that, just remember his speedo being standard doesn't garuntee an acurate speed indication, i find a sat nav to be more accurate, you just have to keep your speed constant to give the satnav a chance to update. let me know what you find out

[Image]

Excuse my ignorance but I'm still new to storm specs. Does the 15 43 sprocket tooth ratio increase acceleration or top speed? Also what effect does it have on mpg?

[Snoogle]

Acceleration

Dropping teeth on the front (standard = 16) and raising on the rear (standard = 41) is a sure fire way of lofting the front wheel like a winner!

[Image]

But does that lose top end speed? And what about mpg?

[Snoogle]

It depends what you choose...If you drop at the front and raise at the rear you will lose top speed. If you do a lot of motorway riding and lower the gearing you'll lose mpg because the bike will rev.higher at cruising speeds.

Let's face it, top speed is pretty much irrelevant anyway so depending on what you wanna go for I'd at least drop a tooth on the front and see wot u wanna do from there.

[Image]

mpg isn't irrelevant though

[agentpineapple]

i'm no expert in these things, but i would think changing the sprockets to aid acceleration would not effect mpg that much, although the temptation to accelerate harder/faster more often would have a big effect on mpg, overall the way you use your right hand will be the biggest factor....

[Snoogle]

mpg isn't irrelevant though

Course it is, you've got a 'storm...not the best bike for caring about MPG lol

[Richy]

mpg isn't irrelevant though

must be a miss type of 'Isn't mpg irrelevant though'


Running an old V8 landrover, the storm is the most fuel efficient vehicle I own

[Snoogle]

Running an old V8 landrover, the storm is the most fuel efficient vehicle I own

Top man

[Animal]

To sort your speedo out get one of these http://www.healtech-electronics.com/
You adjust it to what ever sprocket configuration you have, its so accurate you can even adjust it for part worn tyres.