Can anyone tell me the make/model of an old (must be going back 10 - 15 years?) mountain bike frame that was fully square in cross section? I think it might have been made by Pace? And possibly magnesiumm (might have imagined the last bit). Thanks!

You'll need pics to get any response on an identification thread. (Generally speaking.)

Magnesium??? I dunno about that...

Kirk cast road ATB frames out of magnesium, but they were notoriously fragile and the cross section was I-beam. The timeframe is also slightly older, but not my much.

Using "square tubed mountain bike" with google yielded me a Pace RC300 model in the first few results.

I do know that Pace was one of the few ( if not the only) companies that manufactured their own tubing. Neat stuff, sort of like an external butting/ drillium with countersinking, like what ellsworth does with their rocker arms. Does that make sense.