cstar 

Hi guys,

I'm hoping someone can shed some light on this one for me.

I have a 1984 Centurion Pro-Tour on which I am using a Sugino AT crankset. The bike came without the original BB unfortunately, so I don''t have that to refer to. The previous owner had been using the AT like a compact double with a cheap Shimano cartridge BB.

Well, I set the AT up as a triple, and everything I've read online told me to find a Sugino MT68 spindle if using the AT as a triple. It took me a long time to find an MT68, but in the meantime I happened to have a non hollow asymmetric JIS spindle that worked very well. I believe it is marked SCMB-3T; I will double check this tomorrow. It is VERY wide, something to the tune of 135mm IIRC (I'll measure it tomorrow)

Anyway, I still lusted for an MT68 because its hollow and very beautifully made. I finally found one, and tried to install it yesterday, and I encountered a lot of problems. I was under the impression that all MT68 spindles have the same dimensions; others have said they measure 37.5mm right, 52mm center, 29.5mm left, and the calipers confirmed mine to be the same.

First problem: My crank almost runs out of taper on the MT 68 (i.e., the fixing bolt almost bottoms out on the spindle) when torqued close to spec
Second problem: It became very clear the granny ring was not going to clear the chainstay even with a 1mm spacer under the drive side cup. I was thinking thinner spacers under the granny ring could help but I don't know how much thinner I could go before interfering with the chain. Also, with 3.5mm spacers under the granny ring, it looks to be perfectly equal distance from the middle ring as the middle ring is from the large ring, which has me thinking 3.5mm spacers are probably the intended thickness and also not the real issue
For reference, the bearing cups and bearings I am using are also Sugino, basically NOS. They are higher end, NJS stamped, and came paired with an MW68 spindle on a Univega Gran Premio I parted out. The non drive cup has small holes drilled in a circular pattern concentric to the spindle hole
Lastly, why are Sugino fixing bolts 15mm lol? I cant find a 15mm socket to fit in the hole in the crank arm so I used other bolts

I put a 2mm spacer (calipers had it more like 1.85mm) under the drive side cup, and once the crank was torqued, the granny ring bolts still would barely not clear the chainstay. Additionally, there really wasn't enough thread on the non drive side cup for the lock ring to grab, in my opinion

Can anyone help me understand why my Sugino AT and Sugino MT68 combo is not right? Are there ISO and JIS versions of the MT68? Which interface does the AT crank use, JIS or ISO? Thanks in advance