In article <689%9.325$%[email protected]
>, "JimBob" <[email protected]
> Ok, where can I get different chainrings for my 105 triple (FC-5504)?
In the UK, look at St. John St. Cycles <http://www.sjscycles.com/>
. Go to the store
and select the 130mm pcd (a.k.a. bcd) 5-arm chainrings
from the left. There are 'rings from TA in just about every size you'd want (38 to 57 in 1 tooth
Peter White has them too, go to <http://www.peterwhitecycles.com/chainrings.asp>
and look for the
"Alize" 130mm bcd rings.
You probably know this already, but your inner chainring is 74mm. Still lots of choices there.
> I can find plenty of info from Sheldon Brown re cassettes, but little on chainrings. I aim to
> change chainset to 28-40-52 with Sheldon's 'Century Special' cassette (13-14-15-17-19-21-24-27-30)
> for some nice low gears i.e.
> 25.2" lowest.
Since you want a 4:1 top ratio, and a just-below-1:1 bottom ratio, how about: 24-38-48 chainrings
and a 12-25 cassette? Even a 12-27 is fine there (maybe with a 25t small ring if you so desire).
If you change to a 74/110 setup you can get 24-36-48, but that means new cranks, but some like the
smaller jump from small to middle ring.
> I then need to know all the geeky stuff like rear mech (LX?) capacity, chain length and the like.
Your 105 stuff should shift well enough with the above suggested setup. The front is listed as
tolerating a 22t max difference, but should handle the 24t just fine.
According to Sheldon's handy chart <http://www.sheldonbrown.com/harris/derailers.html#rear>
rear should be able to wrap exactly the 37t capacity of that setup ((48-24)+(25-12)=37 which is what
the capacity refers to). The chain may be a bit sloppy in the 24x12, but you'll probably never use
that combo anyway.
for the geeky stuff on adjusting your
chain-moving thingies (derailleurs, derailers, mechs, what have you).
Drew W. Saunders
dru (at) stanford (dot) eee dee you