Tried to see what gear ratio my car was today, crawled under and took some "pics"

[Brandon T.]

Re: Tried to see what gear ratio my car was today, crawled under and took some "pics"

I am going with 255/60/15 bfg radials.

wouldn't them being 60 series help me have a little more grunt off the line? looks like that would help my ratio a little correct?

has 215x70's on it right now

[Harmon C.]

Re: Tried to see what gear ratio my car was today, crawled under and took some "pics"

Brandon --- here's from a neat little table in the 1965 Dealer Showroom Brochure. If you've got near stock diameter rear tires, the numbers should be close enough:

Miles per Hour per 1000 engine RPM in 4th gear
---------------------------------------------
3.08 = 26.6
3.36 = 23.1
3.55 = 22.2
3.70 = 21.3
4.11 = 19.2
4.56 = 17.0

So at 3000 rpm in 4th, if you indicate 66.6 mph on the speedo, then you have 3.55 gears (etc...)

Now, put it in 1st gear and take it back up to 3000 rpm. If you have a close ratio, speedo would indicate 66.6 divided by 2.20 = 30.3 mph. If you have a wide ratio, the speedo will read 66.6 divided by 2.54 (or is it 2.52 ?) = 26_1/2 mph.

I tried out the chart today
1st @3000 26MPH
2nd @3000 36MPH
3rd @3000 46MPH
4th @3000 66MPH

Thanks Wayne