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Pardon the noob question, but what is the difference/benefit between a road touring triple and a mtb triple? I am looking to put together with either a Rawland Drakkar or Salsa Vaya and plan on a triple setup with wide range cassette. Do mtb cranks not work on road bikes? There seems to be a lot more options going the mtb route.

Barrettscv 

A MTB crankset will work on a bike that normally uses Road Cranksets. However two issues need to be understood. MTB chainrings are offset away from the downtube more than road cranksets. This can cause a chainline that limits the use of 2 or more gear combinations. The second issue is that a MTB front derailleur will not work with Brifters. This can be overcome by using a IRD Alpina front derailleur or by carefully adjusting a road derailleur to work.

Will this bike have a 10, 9, or 8 speed cassette?

JiveTurkey

Assuming the same chainline and chainring sizes, there would be no practical difference.

I see the Sugino XD600 can come with 46/36/26T chainrings. A Shimano MTB/trekking crank will come in 48/36/26T. I'll assume you're going for either of these.

The Sugino can use either a 113mm or 118mm BB spindle for either a 47.5mm (MTB triple spec) or 50mm (oversized MTB triple spec) chainline, respectively. (Maybe the chainline can be reduced with an even shorter BB spindle as long as it doesn't cause interference with the frame??) If you get a newer-style trekking crank with outboard/external BB bearings and integrated BB spindle, then you'll be stuck with whatever chainline it calls for, probably 50mm. Road triples, on the other hand are spec'd for a 45mm chainline.

Either setup above (46/48T outer chainring) is between a MTB (42/44T outer chainring) and road (50/52/53T outer chainring) setup. I believe you could use either a MTB or road front derailleur, depending on the shifters you have.

cs1

Thanks for the chain line information. I did not realize that. I'm a ludite and most of my MTB's are vintage with Deore or XT 48/38/28 cranks. I prefer that gearing on a road bike also.

With that said, I've got more time than brains on my hands. I was looking to put a current Shimano CT double crank on an older 126 or 130mm spaced MTB. Typically vintage bikes use a 122mm square taper crank do you think the current outboard bearing BB's will fit?

cyccommute 

They work just fine. I would suggest using a Shimano Tiagra front derailer if you are using STI over more expensive front derailers. Easier to set up and has a wider range of gears without rubbing. Perfect for the wider chainline of the MTB crank. If you are using barend shifters, go with an MTB front but, again, the less expensive versions work with a wider range of gears on the cassette without rubbing.

If you are going to go with an MTB, go for an external bottom bracket version especially a Shimano. Dead simple to install.

An added benefit of the MTB cranks is a higher Q factor. I find road cranks to be too narrow.