Quote:
Originally Posted by Greg
I found out painfully how larger tires can throw off your instrumentation after Melva had larger tires installed on our old Bronco. An Arkansas state trooper was kind enough to write me a note to remind me that the speedometer read wrong after that.
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And now spare a thought for the poor old differential gears.
The scenario,.
We have a flat tire, we have a spare, but it is a different size to the "Big Boots" we show off with. So we stick it on any way and roar off down the road.
With both rear wheels turning at a different speed and the differential gears in the middle hollerin' fer help.
Oh sure, the big time speedway cars have different sized rear tires, and they also have a 7,000 dollar specially built rear axle to do a very specialized job.
Your average GM or Ford product will turn itself to pieces.
The tire diameter, and therefore its circumference is the last part of the mathematical equation that results in the "Final Drive Ratio" between engine crank shaft RPM, and drive wheel RPM for any given road speed and gear combination. Gearbox ratio's, differential gear ratio's and tire circumference, all add up to the Final Drive Ratio.
Yep, we are expected to be a mathematical genius just to be a grease monkey.
Same at sea. The angle of deflection of propeller blades, give a certain number of shaft revolutions per knot or nautical mile.
Same in aeronautics. It's still all school-room maths.
Applied Science. I like it.