Ted Ernst said:
There was also the Japanese rim with a plastic block.
That was Ukai, as on the Fuji Finest and Newest, filled with plastic foam. I had a guy cross wheels with me in a race and I had no choice but to steer into him to stay up. The Ukai's did a good job as I rode over his bike! I think any other rim would have folded. But they weighed 400 grams and were always sort of lumpy and hard to true. Replacements were quite expensive also.
Joe Bender-Zanoni
Whitneyville, CT