So I took Wilma out for a romp to gather data for this thread. Near top speed of 83 at what appeared to be 3700 on the tach. Speedo was reading 2-3 mph high at 45mph compared to a gps unit. Tach appeared close enough when compared to a bench mounted tach/dwell meter. I wouldn't cruise at that speed but it did feel quite comfortable. That wasn't top speed on level ground but Im sure it was close to it. More background info: wilma has a 1970 1600cc motor, later dual port heads with 34pict carb. Mid 70's tranny that someone called a freeway flyer. And last but maybe more important, giant rear tires! I measured a circumference of 2030 millimeters to calibrate the new speedo. I think these tires, combined with the later ( maybe modified ) transaxle help account for lower rpms at speed and the need to downshift to climb hills that don't seem that steep.
So...my question is...would putting on smaller diameter rear tires be much of an advantage? I could regain a little torque for climbing hills, but would the trade-off of less than 36mpg be a good compromise?
What would you do?
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