Triple Chainrings



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Jimbob

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Ok, where can I get different chainrings for my 105 triple (FC-5504)?

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.

I then need to know all the geeky stuff like rear mech (LX?) capacity, chain length and the like.
 
J

Jimbob

Guest
I should also add that front & rear derailleur are 105 as well.
 
P

Paul Kopit

Guest
Decent chainrings, especially large ones aren't cheap. You can get almost what you are looking for
by buying a 28 tooth x 74 bolt pattern ring to replace the 30 you now have. If you must have a 40,
consider a 39t x 130 bolt pattern, where you'll have a much wider choice of rings.

YOu're LX rear derailleur should be fine. Check your chain length to see if you can get the 52/30
without jamming the chain.

You can save the chainring money by asking Sheldon to do a custom
13/32 instead of 13/30. The 5 tooth jump from 27 to 32 works fine mechanically and also doesn't feel
horrible on the legs.

On Sun, 2 Feb 2003 13:36:16 -0000, "JimBob" <[email protected]> wrote:

>Ok, where can I get different chainrings for my 105 triple (FC-5504)?
>
>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.
>
>I then need to know all the geeky stuff like rear mech (LX?) capacity, chain length and the like.
 
B

bobqzzi

Guest
On Sun, 2 Feb 2003 13:36:16 -0000, "JimBob" <[email protected]> wrote:

>Ok, where can I get different chainrings for my 105 triple (FC-5504)?
>
>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.
>
>I then need to know all the geeky stuff like rear mech (LX?) capacity, chain length and the like.
>
>
I'm sure you can find chainrings (in fact i'm sure Sheldon can supply them), but they aren't cheap.
An alternative might be a MTB crankset with a clossr ratio cassette.

Bob
 
D

Drew Saunders

Guest
In article <689%9.325$%[email protected]>, "JimBob" <[email protected]> wrote:

> 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
<http://www.sjscycles.com/store/vIndex.htm> 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
increments).

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> the 105
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.

See <http://www.sheldonbrown.com/derailer-adjustment.html> for the geeky stuff on adjusting your
chain-moving thingies (derailleurs, derailers, mechs, what have you).

Drew

--
Drew W. Saunders

dru (at) stanford (dot) eee dee you
 
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