The actual width of chainring teeth is unchanged between 5-speed and 10-speed drivetrains - the inner plate width of chains is all 3/16". What differs is the outer width of the chain, and how far apart chainrings are spaced. If you have a narrow chain on a crankset with chainrings spaced too far apart, it may be possible for the chain to get caught between the chainrings. Shimano cautions against this, but more for liability's sake. There is basically zero danger when running a 9- or 10-speed system with the Sugino XD triple cranks. I've done it myself with 9-speed and never had any shifting problems.
As for bottom bracket axle length, you should use a 113mm when pairing with a 135mm-spaced rear hub. I used a 107mm when paired with a 130mm-spaced rear hub. Shimano 107's and 113's are symmetrical, whereas 110 and 115's are asymmetrical - the non-drive-side spindle sticks out further than the drive-side. (If you're using Phil Wood or something, this doesn't apply). But the Sugino crankarms are symmetrical - they stick out the same distance from their mounting point vs. pedals on both drive- and non-drive-sides. So you want a symmetrical BB. Both 113mm and 115mm would get you proper chainline, but with the 115mm the left pedal would be 2mm further from the bike's centerline than the right pedal.
edit: I'm wrong on two counts: the 113mm BB ain't symmetrical (non-drive-side sticks out 2mm further) and the XD cranks are also designed to take an asymmetrical bottom bracket with non-drive-side spindle sticking out a bit further. So my two bits of misinformation cancel out, and the 113mm BB is still good with the Sugino XD crank.
Last edited by TallRider; 04-25-07 at 08:55 PM.