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Discussion Starter #1
Hi All,

I am interested in finding out what everyones setup of Sprockets front and rear, Tyre Size and RPM that is achieved at a certain speed (KMPH/MPH).

I am trying to get a new set of sprockets to get to 125kmph = 3,000RPM.

i.e. I have the following setup, but, there doesn't seem to be markings on the sprockets for teeth (and no, I haven't counted).

190/50/17 - 5,000RPM = 140kmph (86.992mph)

Can someone please supply me with the sprockets for a cruise style bike for higher speeds (freeway riding), my bike feels like best value is around the 3,000 mark for power to fuel (effort of engine) level, not labouring but not ready to pounce if you get me.

Any assistance would be greatly appreciated, I just don't want to waste money on buying multiple sets of sprockets....

I am thinking that an 18T at the front, then a 44/43T at the rear as a guess.... but im not 100% sure I have the stock ones on already :(

Thanks

Ash

:puzzled:
 

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The centre height of a 190/55 rear tyre over a 200/50 is significant more so with certain manufacturers.
My Pirelli Diablo Rosso Corsa 190/55 was over 35mm taller than my 200/50 Avon Storm. 35 x Pi gives an extra 110mm of roll for each tyre revolution.
This change alone can give 6% or so extra speed for the same revs.
And your handling will be so much sharper.

I have asked before for a "touring sprocket" recommendation, with not much joy! Members on here with sprocket changes tend to do it for performance. ie going down to 17t on the front up on the rear.
I think someone said they had tried dropping a tooth on the rear but went back to standard.
 

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If you load the "speed graphs" they will show you the revs/speed in 6th for standard and custom set-ups,

Even if you went for a 41 tooth rear sprocket you would still be at approx 4,100 rpm at 125KPH

You also have to remember that the speedo is signalled by the gearbox sprocket, therefore if you choose a smaller rear sprocket the speedo will under-read significantly.

i.e with standard gearing 4200 rpm = 118.7 kph

with 41 tooth rear 4200 rpm = 131 kph

but at 4200 rpm the speedo will still read 118 kph and you're actually travelling at 131

You can adjust this so that it's more accurate with a speedo healer or similar.
 

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sweet, thanks mate!
If you want to permanently shorten your chain you can go as low as 41 on the rear but the bike feels really sluggish with that gearing and have run that sort of gearing on my stroker for top speed runs but never on the road.
For road use I use 17 x 47 and find that perfect for "fun" use.
 

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Discussion Starter #11
If you load the "speed graphs" they will show you the revs/speed in 6th for standard and custom set-ups,

Even if you went for a 41 tooth rear sprocket you would still be at approx 4,100 rpm at 125KPH

You also have to remember that the speedo is signalled by the gearbox sprocket, therefore if you choose a smaller rear sprocket the speedo will under-read significantly.

i.e with standard gearing 4200 rpm = 118.7 kph

with 41 tooth rear 4200 rpm = 131 kph

but at 4200 rpm the speedo will still read 118 kph and you're actually travelling at 131

You can adjust this so that it's more accurate with a speedo healer or similar.
wow, ok, didn't know about the front sprocket providing the speed....

hmmm

whats this speedo healer you talk of?

and thanks btw.
 

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Discussion Starter #12
If you want to permanently shorten your chain you can go as low as 41 on the rear but the bike feels really sluggish with that gearing and have run that sort of gearing on my stroker for top speed runs but never on the road.
For road use I use 17 x 47 and find that perfect for "fun" use.
well, i am only about 150lbs (67kgs) so i'll give it a go with a 42 me thinks to start with....
 
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