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56t chainring questions; run the combos for me!(12 posts)

56t chainring questions; run the combos for me!JS Haiku Shop
Sep 11, 2003 6:17 AM
i'm not gonna buy the shimano tri rings, as they're too expensive; i'm considering asking santa or the birthday fairy for a stronglight 56t, but am a bit confused by the excelsports.com description on the DA tri rings:

"Order Note: Select your chainring size to match your inner chainring. ie: 54T for 42 inner"

...and the select pulldown says 54-42, 55-42, or 56-44. is this because the gearing would be inappropriate with a 56-39, is that too much of a jump for most people, or is there a technical incompatibility involved?

I "enjoy" the 39/21, but could use a little more than 53/11. yes i am a masher/grinder, more so in the "late season".

TIA!

-J
I've done itDougSloan
Sep 11, 2003 6:23 AM
I've run the 56 Stronglight with a 39 inner. The pins will be further out, or non-existent with the Stronglight, so shifting must be slower and more careful. It works, just not ideally.

You will have to raise your front derailleur, too, and this could cause the chain to drag on the bottom of the cage if you use the 39x11 or 12 combo, which you shouldn't be doing, anyway. Also, in those combos, the chain will rub on the outer chainring, even if not the derailleur cage.

Doug
actually, I still might have itDougSloan
Sep 11, 2003 6:35 AM
Let me check to see if I still have the 56. If I do, I'll give it to you. I'll let you know tomorrow. Only used for some training for and the team 508 on the TT bike (it was a blast zooming down hills on the Cervelo P3 with disc, very low aerobars, and a 56x11 combo - pedalling at 55 mph!).

Doug
awesome, thanks! nmJS Haiku Shop
Sep 11, 2003 6:40 AM
fyi - lots more info on chainringsDougSloan
Sep 11, 2003 7:01 AM
http://www.peterwhitecycles.com/chainrings.asp
got it; e-mail meDougSloan
Sep 12, 2003 6:48 AM
I found the 56 and cleaned it up last night. It is a plain, flat chainring, so shifting will be less than optimal. Send me your address and I'll ship it to you.

E-mail me at dougsloan_public@yahoo.com

Doug
thanks! check your e-mail! nmJS Haiku Shop
Sep 12, 2003 8:27 AM
re: 39/11-12JS Haiku Shop
Sep 11, 2003 6:39 AM
typically i stay off that end of the cluster while in the 39, so it shouldn't be an issue. i figured you'd done this, probably on the p3 for the 508 team ride. not sure i understand your pins comment; please elucidate. thanks.
pinsDougSloan
Sep 11, 2003 6:58 AM
On most chainrings, there are little nubs on the inside of the big chainring (or middle ring of a triple) that help to grab the chain on an upshift. The ideal location of the pins depends on the diameter of the smaller ring. If you have a larger small ring, the pins on the inside of the large ring need to be further out, and vice versa.

Some chainrings have no pins at all; they are just plain, flat aluminum. They will still shift, but probably more slowly and less precisely. I think the Stronglight is plain.

Some rings have "ramps," too, which are cut in areas on the inside of the outer ring that helps to grab and guide the chain. OEM rings are typically "pinned and ramped." Lots of aftermarket rings are plain.

The suggested pairing of rings concerns potentially location of the pins and ramps, or derailleur capacity, both front and back. More of a difference in front will challenge the rear derailleur, too. Despite all the standards quoted, though, often things will work, but maybe just not perfectly.

Doug
got it now, understood. thanks! nmJS Haiku Shop
Sep 11, 2003 7:01 AM
how about this?TNSquared
Sep 11, 2003 7:00 AM
would this work? i'm not a component guy, but a 56t DA for $27 currently.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3625712041&category=36133
??????JBergland
Sep 11, 2003 7:23 AM
I'm not entirely sure, but I thought any DA ring bigger than a 53 had the 'solid' pattern vs. the cut-outs this one has?? Anyone know for sure??

http://bike.shimano.com/product_images/FC/ev_images/FC_7701all_EV.pdf

Item #5.

JB