I am cursed with having a particular affinity for the original (before the deerhead) Deore touring pedals, which means I am also cursed with the original Deore TA-copy touring cranks. Casual measurment of the inner chainring lead me to belive that the BCD is 86mm, the same as older SR triples. Well I finally got an older SR triple with the intent of swapping the inner 32T Deore with the 28T SR.

Is it possible (and probable) that they actually made up yet another chain bolt diameter? 85mm(84mm maybe)??? %$#*% it! Is this correct? I wouldn;t suppose that someone knows of an un-tapped heap of Shimano innerchain rings thatw ere only made for three years.

Do you mean the DynaDrive crankset: https://www.sheldonbrown.com/shimano1982/pages/27.html?

I have one of those and can measure the inner ring, but are you saying the 86mm bcd rings don't fit?

Neal

Yep. Those be the ones. The inner chainring is either an 85 or an 84mm BCD. I measured the chord, bold-bold and came up with about 50.5mm, so assumed it was the same. Looked for a bit and finally found an old SR triple, had to buy the entire thing, BB and all just to get the 28T small ring. But 86's are just a tad too big. It tried all three just to be sure.

That crank is a real mess. The outer ring is odd and hard to find (they only made 48, 49 and 50T...I would really like a 49T), the inner is a standard 130, but the inner is now some other weird dimension. I think it would be easier to machine new spindles for the pedals at this point.

I've got TA rings on mine, since it was only a double, and the one with the larger BCD at that. I'm with you on the pedals all the way.

I can measure the original outer chainring when I get home. I wouldn't be at all surprised if the BCD of the inner ring was a strange diameter, the AX years were the height of "Not Invented Here" disdain at Shimano.

I have toyed with the idea of tossing the Deore chainrings (really the outer one is the one that counts) with TA rings, but not having any handy I was not sure I wanted to fork out the $$ they would demand just to "try" it. Actually I have some on a tandem in the barn now that I think of it...still not all that handy. Anyway, it would solve the impossible-to-find inner ring problem with a difficult-to-find inner ring solution. The only way to make these things a bigger mess is to add something French to the equation.

If you can confirm the TA's will fit, I'll give it a try. Let me know which model. The other solution being considered invoves a Demel tool and the SR chainrings, replacing a tight, not-working fit, for a sloppy one.

I use the TA Pro 5 Vis Cyclotouriste rings, with the TA mounting hardware for outer and inner. The Shimano hardware has a key on it that fits into a slot on the Deore outer ring, so you can't use the original bolts. The rings are available from Harris, Boulder Bicycle, and Velo Orange has a few left.

Every supplier I'm aware of is out of the "double" bolts that attach a single inner chainring to the outer. Boulder and Velo Orange have the triple bolts for two inner chainrings, Harris has the bolts that attach the outer ring to the crank.

The availability of the hardware is spotty to say the least, but VO usually has reproduction bolts.

Great! Thanks!!