shifter query

[roadrash]

can anyone tell me if i understand this correctly
a mate has a rockrider 5.2 it has a 9 speed cassette , if he was to use these 8 speed shifters(just because he prefers the thumb and trigger ) we cant find them in 9 speed.

http://www.winstanleysbikes.co.uk/p...ltus_EF51_EZ_Fire_Plus_STI_8Speed_Shifter_Set

would it simply mean he wouldnt be able to use the smallest sprocket ,is it as simple as that ,

thanks in advance

 

[Milo]

I think so but don't hold me on that.

 

[mattobrien]

I think that you would need to use 9 speed shifters as they will be indexed to shift the chain for a nine speed chain / cassette.

Happy to stand corrected.

 

[sittingbull]

He would have a choice of whether to use all except the smallest or all except the largest sprockets (depending on position of the "stops").

As the gap between sprockets differs on an 8 and 9 speed cassette the indexing will be fractionally out. If the rear derailleur is correctly indexed in the middle of the cassette, the fraction by which it will be out at the extremes should be negligible.

I know someone who did it the other way around and replaced an 8 speed cassette with a 9 speed (he had to replace the wheel and never got around to swapping cassettes), and chose not to use the largest sprocket, it worked fine

So yes it should work OK but is not ideal.

 

[Gary E]

There's only about 1mm difference in the distance between the small cog and the big cog on 8 and 9 speed cassettes (SRAM 8 Speed = 35.4mm, SRAM 9 speed 36.5mm) The problem is that the 8 speed shifters divide that up into increments of 4.8mm but a 9 speed shifter divides it up into increments of 4.34mm. Lay those 8 increments over a 9 speed cassette and the chain just won't ride in the right place, it might sort of work but it would just feel like the bike needed indexing all the time.

Or to put it another way each click on a 8 speed shifter moves the chain 4.8mm to the side but the distance between cogs on a 9 speed cassette is 4.34mm. If you set it up so that gear 1 was correct then gear 2 would be out by 0.46mm (not much) but gear 2 would be out by 0.92mm, gear 3 by 1.38mm etc.

 

[sittingbull]

Your mate could of course replace the cassette and chain too (both 8 speed), I think the derailleurs would be OK but most discussions on this topic are going from 8 to 9 speed so I'm not certain.

 

[Gary E]

These or these might do the trick

Just a word of warning - the RH shifter is the 9 speed (for the rear), The left is for the Fwd chainrings. Make sure you get either a double or triple (number of chain rings on your bike) because they're not interchangeable either :S (although you may be able to use a triple shifter on a double chain ring with 1 extra useless click or a double shifter on a triple chainring but you'd only be able to use 2 of the rings)