Crank question...

Festive greetings. I know I have asked this question before but the answers were brilliant if a little technical. I have a 97 Kona explosif. The original Sugino mighty 900 left arm crank is threaded. I have a set of XT M739 cranks which are the same length. The question is can I just use these with the current Sugino rings? Bike in storage hence the question.Cheers.

Probably not.
M739 uses a spider fitting and normally has a special top ring and then has 4 holes for the chainring.

Your sugino will use a compact 5 hole setup.

You may have a 5 hole adaptor on the 739 crank.
If you have that, then yes the ring should swap over.

If you need pictures, just ask.
But pictures of what you have helps the guessing

If the Mighty 900 is 170mm I would be interested in buying. The thread can probably be repaired with a helicoil.

Have an adapter to convert M739's to compact 94/58 bcd if you need one.

The rings might fit if the m737 cranks are the 94bcd 5 arm spider version rather than the version with the spider integrated into the outer ring.