The Vuelta Alloy rings go up to 60T, and there's some RANS and Greenspeed ones that are 62, 65 & 74T. As I recall they used to sell an 80T, not listed now but they might remember who made it. ~
Need to know crank application for diameter and your preferred
format...
A 38 is 2.6% bigger. Oh, the horror.
Long explanation follows:
I've got a set of composite wheels that I'd like to use for all-weather commuter in fairly flat terrain(17 miles each direction). Trouble, and my challenge is that the rear wheel has a S-A 3 spd hub, which is a bit more limited than I like. Through helpful pointers from posters here I found Sheldon Brown's gear calculator and a reasonable starting point(front triple 40-44-48), so now I've spent some time searching for the "ultimate" chainring combo both to widen the range and to add more intermediate steps *w/o repeating* already available gear ratios. One option I've looked at is to make it a quad in front (as found 'here:' (http://abundantadventures.com/quads.html) ) but I thought I could make do w/o their splined carrier and simply bolt it all up. My theory is that I could use two bolt circle diameters, and use chain ring bolts for a double to hang the biggest chainring outboard of the 2nd biggest, then use a smaller bolt circle and chainring bolts from a triple to hang the other two rather more traditionally to the inside. I don't want to use a 36, as the combos I've calculated generate repeat gears, but a 37-40-44-48 would have a slightly more even spacing when combined with a S-A 3 spd than a 38-40-44-48 would.
I've thought of trying to force the S-A hub out of the wheel and stick a Shimano hub compatible with a current body in there, but I'm not certain if that is possible w/o causing irreparable damage to the wheel.
Together with the printers I have available I have to rate the usefulness as "moderate", as the templates that can be printed out are very pale. Still, it shows nicely what can be done with few tools and a bit of dedication.
