Originally Posted by
PimpMan
Checked and rim ERD measures 16"
btw, i am 5'9" ~ 200lb
When I look at your bike, besides a possible problem with the rear shock, I see that the transmission is very short, too short.
The cassette is a normal one without a very small cog and the chainring is very small, something like 44t.
For 16" wheel, a much bigger chainring 60t or a small 10t or 9t cog is needed to obtain the same as with a big wheel road bike.
Typical transmissions are front 52t or 54t and rear smallest cog of 9t. Or 60t - 65t front and 11t rear.
The tires are also important, from your picture, I guess these are old slow tires.
You should check the ETRTO size of your bike (with 16" ERD probably ETRTO305, ETRTO349 or ETRTO355) and buy new tires.