re: Final Drive Gearing

[Jim Huber <jhuber@xxxxxxxxxxx>]

>  From: "Harries, Mort" <mort.harries@xxxxxx>, on 11/08/2000 08:58:
>  Can some of the more knowledgable list members help me out here?  I think
>  the gearing on my '00 ST is too tall, but what do I change?  The front
>  sprocket? the rear sprocket? or both? Can you mix and match the front and
>  rear?  Or are only certain combinations possible (without replacing the
>  chain)?  Are these sprockets all Triumph parts?  
>  
>  Don't know what sprockets are on the bike right now, but indicated speed in
>  2nd gear is approx 60mph = 6000rpm.  

	My understanding is that all 2000 model ST's are 19/43, despite the
owner's manual. You can check it by removing the front drive chain cover.
Either sprocket or both can be changed - it's the overall ratio that matters. I
know the 18 toth front sprocket is a Triumph part 'cause the '99 ST's came with
'em.

Suggestions:

	19/44	=	rpm will run 2.3% higher (why bother?)
	18/43	=	rpm will run 5.5% higher
	18/44	=	rpm will run 8.0% higher
	17/43	=	rpm will run 11.8% higher
	17/44	=	rpm will run 14.4% higher

So if you went with a 17 tooth front and 44 tooth rear, you'd run about 6,860
rpm at 60 in 2nd instead of the 6,000 you're running now.

According to my handy-dandy spreadsheet and assuming a 24.84 inch diameter rear
tire (Dunlop D205), A 2000 ST is running 4,029 rpm at 70 mph in 6th gear, while
a '99 ST runs 4,253. A 17/44 combination would push that up to 4,608 but give a
much more lively acceleration. For comparison, my Suzuki SV650S runs about
5,000 rpm at 70 mph in 6th gear. Mileage may suffer a bit, but probably not too
much. Theoretical top speed comes down from 165 mph to 144 mph, but who cares?

FWIW,

	"Jedi Dawg"  Jim Huber
	'00 blue ST  "Rhiannon"
	'01 red SV650S -unnamed-
	Spring, Texas, USA

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