I still don't understand what a jis headset is/means. What is the difference with a non jis headset? My stx headset had the same use as a deore dx headset, so i think It Will fit.
A JIS 1" headset is dimensionally different from an ISO 1" headset. ISO is much more common. JIS is the Japanese standard, ISO is international. Early Marins were made in Taiwan presumably to the more local specs and they got JIS headtubes.
A JIS headset has 30.0 mm OD on the cups (ISO has 30.2mm) and 27.0mm on the crown race ID (ISO has 26.4mm). It is apparently possible (although fiendishly difficult in my experience) to force ISO cups into a JIS headtube but there's no way an ISO crown race is going on some JIS forks without them being turned down to suit on a lathe.
If your STX headset is a JIS spec unit I'd be happy to buy it but unless the packaging specifies or the parts have the sizes stamped on them, I would always assume it's an ISO.
It's a road headset but it's a reasonably nice one. The page says Ultegra but the pic seems to say it's Shimano 600. Are these roughly equivalent?
Also, is putting a road headset on an MTB safe? I would imagine it would be fine but maybe shimano anticipated a lighter weight/lower strength requirement to road headsets which makes it a bit iffy, esp for off-road use. Then again, maybe they're the same as the MTB units in all but label.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.