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I currently have an 8spd 12-26t cassette on my old winter/commuting/touring road bike. I'd like to replace it with a new 11-32t cassette (also 8spd). I guess I need a longer chain, but I need a new one anyway. I'm just worried whether the new cassette will work with my current derailleur? Any other potential problems??
Worn chainrings?
...and so slippage with new chain, is that what you're getting at?
Can you look at the code on the mech to see if it is a medium/long cage (which I am sure it is) if its gs model it should be fine? Presuming its shimano ?
mech is a tiagra and the cage is about twice as long as on my other 'sunday best' road bike, so I'm guessing its at least a medium if not a long cage.
I haven't mentioned yet that its a triple up front ( 😳 oh, the shame!) but that shouldn't be an issue should it? Middle chainring looks like it needs replacing, small ring looks as good as new, honest.
length of cage is often independent of cassette capacity.
rear mechs are spec'd by (exclduing pull ratio and speeds):
* What the maximum sprocket size they have handle; and
* How much slack chain they can deal with (capacity in teeth - difference between big ring and little plus difference in teeth between little sprocket and big sprocket added to the chainring difference.) - longer the cage bigger the capacity to deal with more chain slack.
You might find an older 8 speed mech might not be able to deal with the 32, but fit it and see - you will have to play with the 'B' Adjust screw to get the correct clearance from mech top jockey wheel and 32 sprocket..
worth trying before you buy a new mech - nowt to lose by seeing
techdocs for 9 speed tigra says max 27t sprocket size for med and long cage
makes sense as Tiagra is road groupo
cheers rootes, that techdocs is dead handy.
Shame about max 27t though...
Try it and see. The worst that'll happen is the mech sits on the bigger sprockets and it won't change very happily. In which case new mech time!
Might chance the 11-30t then...
Another numpty question: there don't seem to be many 8spd mechs about, I could just use a 9spd and adjust the limits to give me just 8 gears, yes? That's if I end up needing a new mech.
[i]rear cassette question[/i]
I've a genuine Q.
Why do we call it a [b]rear[/b] cassette ?.
Its not as if we have front cassettes, to the best of my knowledge anyway.
❓
I'm running an an 11-28 cassette with a tiagra rear on my road bike with no issues...(actually it's a 12/28 as I did a futz between an 11-28 and a 12-25 cassette and swapped around some of the smaller sprockets)