7/8" tires are VERY skinny for a '70s bike. Originally, your Sports 10 would have had 27x1-1/4 tires. (or 32mm if you think Metric.) 1-1/8"=28mm, 1"=25mm, 7/8"=23mm.
The Sports 10 was Fuji's entry-level offering, all steel (crank, rims, etc) so it was heavy at 31 pounds.
https://classicfuji.posthaven.com/1976-fuji-catalog
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