There have been a quite a number of threads on here discussing 21.1mm stem and possible solutions like machining one down to the correct size.

Alas, a simple solutions has emerged. I wondered why this hasn't come into production earlier.

I came upon this on ebay.
https://cgi.ebay.com/Bicycle-Bike-Ste...item335b8c579f

Unless, you are intent on using a quill stem, this is perhaps the easiest and most practical solution for a 21.1mm. YAY!!!

That stem as been posted in almost every discussion of 21.1 stems. Roger

I've been reading about 21.15 stes on and off for at least a year and never saw this before.

Works for those who don't mind threadless, but it isn't as if nice aluminum .833 quill stems aren't available:



-Kurt

I've never seen it either. Great option to consider.

I found a company online that sells a 21.1 quill to threadless 1 1/8" adapter

The company is called Crank2 and based in Pleasanton CA and the link is here

https://www.crank-2.com/store/product...ess-Stem-Adap/

Pyramid makes a Tourist 21.1mm stem. They are great replacement stems for old Schwinns on which you can't get the stock stem up high enough for upright riding. Its a backsaver and you can find it on Amazon.com.

That stem is fine for a cruiser bike, but for a Schwinn road bike those look tacky and out of place.